JP2012033211A - Heat-assisted integrated head and heat-assisted recording apparatus - Google Patents

Abstract

In a thermally-assisted integrated head equipped with a semiconductor laser, stable flying is realized and optical power fluctuation due to wavelength fluctuation is less likely to occur. In addition, the temperature rise of the semiconductor laser is suppressed.
A semiconductor laser is disposed on a side surface or an upper surface of a flying slider. At this time, the direction of the stripe structure 100 in the semiconductor laser is made parallel to the flying surface of the flying slider. A mirror 101 is formed inside the semiconductor laser so that the optical path bends in the in-plane direction of the active layer. Light emitted from the semiconductor laser is guided to the near-field light generating element using the waveguide 3 formed in the slider. When a semiconductor laser is disposed on the side surface of the flying slider, a curved portion or a mirror is formed in the middle of the waveguide 3 so that light incident on the waveguide travels in a direction toward the near-field light generating element.
[Selection] Figure 3

Description

  The present invention relates to a heat-assisted integrated head and a heat-assisted recording apparatus using the same.

In recent years, a heat-assisted recording method has been proposed as a recording method that realizes a recording density of 1 Tb / in ² or more (H. Saga, H. Nemoto, H. Sukeda, and M. Takahashi, Jpn. J. Appl. Phys. 38, Part 1, 1839 (1999)). In the conventional magnetic recording apparatus, when the recording density is 1 Tb / in ² or more, loss of recorded information due to thermal fluctuation becomes a problem. In order to prevent this, it is necessary to increase the coercive force of the magnetic recording medium, but since the magnitude of the magnetic field that can be generated from the recording head is limited, if the coercive force is increased too much, a recording bit is formed on the medium. It becomes impossible to do. In order to solve this, in the heat-assisted recording method, the coercive force is lowered by heating the medium with light at the moment of recording. As a result, recording on a high coercive force medium is possible, and a recording density of 1 Tb / in ² or more can be realized.

  In this heat-assisted recording apparatus, the spot diameter of the irradiated light needs to be the same size (several tens of nm) as the recording bit. This is because information on adjacent tracks is erased if the light spot diameter is larger than that. Near-field light is used to heat such a minute region. Near-field light is a localized electromagnetic field (light having wavenumber having an imaginary component) existing in the vicinity of a minute object having a wavelength equal to or smaller than the light wavelength, and is generated using a minute aperture or a metal scatterer having a diameter equal to or smaller than the light wavelength. For example, Japanese Patent Laid-Open No. 2001-255254 proposes a near-field light generating element using a triangular metal scatterer as a highly efficient near-field light generating element. When light is incident on the metal scatterer, plasmon resonance is excited in the metal scatterer, and strong near-field light is generated at the apex of the triangle. By using this near-field light generating element, light can be collected with high efficiency in a region of several tens of nm or less. Japanese Unexamined Patent Application Publication No. 2004-151046 proposes a structure in which a depression is formed on the surface of the metal scatterer on the slider flying surface side other than the apex where near-field light is generated. With this structure, it is possible to reduce the width of the intensity distribution of near-field light generated at the apex, and to suppress the generation of weak near-field light (background light) generated on the side opposite to the apex.

  For the heat-assisted magnetic recording, it is necessary to heat the medium near the magnetic pole for applying the magnetic field with light. For this purpose, for example, a waveguide is formed on the side of the magnetic pole, and the light generated from the semiconductor laser as the light source is guided to the vicinity of the tip of the magnetic pole. At this time, the semiconductor laser is mounted on the flying slider or guides light from the suspension to the flying slider using a waveguide such as an optical fiber.

  As a method of arranging a semiconductor laser as a light source on a flying slider, for example, a method of arranging an edge-emitting laser so as to stand perpendicular to the upper surface of the flying slider is proposed as in US 2009/0266789 A1. ing. Further, as disclosed in Japanese Patent Application Laid-Open No. 2009-4030, a semiconductor laser is arranged so as to be horizontal with respect to the upper surface of the flying slider, and a mirror is formed on the end surface thereof, so that emitted light is formed in the flying slider. A method of directly coupling to a waveguide is proposed.

  US 2008/0002298 A1 also proposes a method of arranging a semiconductor laser on the side surface of a slider. In this case, a surface emitting laser is used as the semiconductor laser, and the laser is disposed on the side surface on the outflow end side of the flying slider. The slider is provided with a waveguide having a grating coupler formed on its side surface so that light emitted from the semiconductor laser is coupled to the waveguide through the grating coupler.

JP 2001-255254 A JP 2004-151046 A JP 2009-4030 A US 2009/0266789 A1 US 2008/0002298 A1

Jpn. J. Appl. Phys. 38, Part 1, 1839 (1999)

  When the edge-emitting semiconductor laser is disposed on the upper surface of the flying slider, the height of the entire head increases as the semiconductor laser is disposed. When the height is increased in this way, the flying of the slider becomes unstable when an impact is applied to the drive. Also, in order to increase the recording capacity in the drive, it is necessary to place multiple disks and heads. However, if the height of the entire head increases, the distance between the disks must be increased accordingly. Will become thicker. Conversely, in order to keep the thickness of the drive thin, it is necessary to reduce the number of disks, in which case the recording capacity is reduced.

  When a semiconductor laser having a mirror formed on the end face is disposed on the upper surface of the slider, the height of the entire head can be reduced. In this case, however, the semiconductor laser is disposed on the thin submount and the submount is disposed on the upper surface of the slider. However, the distance between the semiconductor laser and the waveguide is increased by the thickness of the submount. Therefore, the efficiency with which light from the semiconductor laser is coupled to the waveguide is reduced. In order to increase efficiency, the thickness of the submount needs to be several tens of microns or less. However, considering the productivity of the submount, it is difficult to produce a large number of submounts with such a thickness. is there. There is also a method of soldering the semiconductor laser with the mirror directly on the slider, but in this case, the semiconductor laser cannot be inspected before mounting on the slider, the slider is distorted by soldering, and the flying height fluctuates. There is a problem. In order to use the near-field light generating element made of the above metal scatterer, it is necessary to make the polarization direction of incident light parallel to the recording track. When a mirror is formed on a semiconductor laser, the polarization direction of incident light becomes a direction perpendicular to the recording track, and there is a problem that it cannot be used for a near-field light generating element made of a metal scatterer. .

  When the semiconductor laser is arranged on the side surface on the outflow end side of the slider, there is no need to arrange the semiconductor laser on the slider, so that there is no problem with the height of the entire head. However, in the conventional example, it is necessary to make light incident from the side surface of the waveguide, and it is necessary to use a grating coupler. Since the grating coupler has a large wavelength dependence, when the wavelength of the semiconductor laser changes due to a change in the environmental temperature, the intensity of light coupled to the waveguide fluctuates. Further, the periphery of the magnetic head needs to be covered with an alumina film, and the outflow end side of the slider is usually covered with an alumina film having a thickness of 30 microns or more. Therefore, the semiconductor laser is placed on a thick alumina film. In this case, the heat generated by the semiconductor laser is difficult to escape, so that the temperature of the semiconductor laser rises significantly and the semiconductor laser is damaged or its life is shortened.

  In the case where the semiconductor laser is mounted on the flying slider, the present invention has a low overall head height, a high coupling efficiency between the semiconductor laser and the waveguide, and is hardly affected by the wavelength variation of the semiconductor laser. There is provided means for arranging the semiconductor laser so that the temperature rise in the laser beam is small.

  In order to achieve the above object, according to the present invention, a semiconductor laser having a mirror formed therein is used as a semiconductor laser, and the lateral surface of the flying slider, which is different from the inflow end and outflow end side surfaces, is different from the side surface. To place. The entrance of the waveguide formed in the flying slider is located on the side surface of the slider on which the semiconductor laser is disposed, and the emitted light from the semiconductor laser is directly coupled to the end face of the waveguide. The waveguide in the slider has a curved portion so that light traveling in the waveguide travels in a direction toward the near-field light generating element.

  If the radius of curvature at the curved portion of the waveguide is too small, light is emitted from the waveguide and a propagation loss occurs. In order to prevent propagation loss, the radius of curvature of the waveguide is preferably 60 μm or more. Further, in order to bend the light traveling direction in the waveguide in the middle, a mirror may be provided in the middle of the waveguide. In this case, the light is totally reflected on the reflecting surface or the light is reflected by forming a metal film on the reflecting surface.

  In order to efficiently couple the light emitted from the semiconductor laser to the waveguide, it is preferable to form a spot size converter at the entrance of the waveguide.

  Mirrors are formed at both ends of a stripe structure in a semiconductor laser (a region formed by channel waveguides formed by etching a ridge for confining light and an active layer, where light amplification is performed). The light reflected by the mirror is incident on the side surface of the semiconductor laser perpendicularly, and the light reflected by the side surface of the semiconductor laser returns to the stripe structure side. The direction of the mirror is such that the reflected light at both ends of the stripe structure travels in opposite directions or in the same direction. When the reflected light travels in opposite directions, the two opposite side surfaces of the semiconductor laser function as a mirror constituting the resonator. When the reflected light travels in the same direction, one opposing side surface of the semiconductor laser functions as a mirror constituting the resonator.

  The mirror for bending the optical path is formed by forming deep grooves by etching at both ends of the stripe structure. At this time, in order to prevent the mirror surface from deteriorating, it is preferable to form a dielectric film on the mirror surface.

The structure of the present invention has the following advantages.
(1) Since the semiconductor laser is formed on the side surface of the flying slider, the height of the entire head does not increase. Accordingly, the slider can be stably floated, and the distance between the disks in the drive can be reduced.
(2) When an object is placed on the side of the slider, the position of the center of gravity may deviate from the center and the flying may become unstable. However, in the structure of the present invention, a mirror is formed in the semiconductor laser and the optical path is folded back. Therefore, the distance from the center of the flying slider to the outer end of the semiconductor laser can be reduced. Therefore, the position of the center of gravity does not greatly deviate from the center and stable levitation can be realized.
(3) When coupling light from the semiconductor laser to the waveguide, there is no need to use a grating coupler. Therefore, the intensity of the light coupled to the waveguide does not fluctuate due to the fluctuation of the wavelength.
(4) Heat generated from the semiconductor laser escapes to the flying slider via the submount. Then, the heat transmitted to the flying slider is released to the recording disk side through an air flow flowing between the flying surface and the recording disk. Therefore, the temperature rise of the semiconductor laser can be suppressed. As a result, the semiconductor laser can be prevented from being damaged or shortened.
(5) Since the direction of the spot size converter can be set to the horizontal direction of the slider, the length of the spot size converter can be increased. As a result, the spot conversion rate can be increased, and the coupling efficiency when the light from the semiconductor laser is coupled to the waveguide can be increased. Therefore, the power of the semiconductor laser can be reduced, and the power consumption and the heat generation amount can be reduced. In addition, since the tolerance for the positional deviation of the semiconductor laser can be increased, the yield during assembly can be increased, and the manufacturing cost can be reduced.

  The mirror for bending the optical path may be formed only on one side of the stripe structure. At this time, as a mirror for constituting the resonator, a deep groove or a grating formed by etching may be used instead of the side surface of the semiconductor laser.

  As means for reflecting light on the emission surface side, a deep groove or a grating produced by etching may be used instead of the side surface of the semiconductor laser.

  The electrodes of the semiconductor laser are formed only in the stripe structure, or in the region including the periphery of the mirror and the region near the emission surface. In order to prevent breakage of the mirror, it may be formed only in a region near the stripe structure and the exit surface.

  The energy band width may be increased to make it difficult for light absorption to occur by diffusing appropriate atoms in the active layer around the mirror or between the mirror and the side surface of the semiconductor laser.

  The stripe structure may be wide in the vicinity of the mirror. At this time, by making the width of the stripe structure in the direction parallel to the reflection surface of the mirror around the mirror larger than the width of the reflection surface of the mirror, the mirror can be etched simultaneously with a mask for etching the stripe structure. become. Therefore, it is possible to suppress the positional deviation between the stripe structure and the mirror.

  The angle of the mirror may be 90 degrees between the incident light and the reflected light, or may be an angle different from that. When the angle between the incident light and the reflected light is greater than 90 degrees, the distance between the stripe structure and the side surface of the semiconductor laser can be increased, so that when the semiconductor laser side surface is cleaved, a part of the stripe structure is missing. Can be prevented. Further, since the width of the semi-moving laser can be increased, the mechanical strength can be increased.

  In order to prevent light from spreading between the mirror and the side surface of the semiconductor laser, a waveguide (ridge or channel waveguide) for confining the light in the direction parallel to the active layer is provided from the mirror to the side surface of the semiconductor laser. You may form between. At this time, the waveguide may have the same material or structure as the stripe structure, or may have a different material or structure. The width of the waveguide between the mirror and the semiconductor laser may be such that the mode field diameter is the same as or different from the mode field diameter in the stripe structure. When the mode field diameter in the waveguide between the mirror and the semiconductor laser is made larger than the mode field diameter in the stripe structure, the beam diameter of the emitted light can be increased. The influence of the positional deviation between the waveguides can be reduced.

  The shape of the mirror surface may be a curved surface, for example, a parabolic surface, a spherical surface, an elliptical surface, or the like. By doing in this way, the light reflected by the mirror can be made into convergent light or parallel light. When the reflected light is converged on the side surface of the semiconductor laser, the light reflected on the side surface of the semiconductor laser is efficiently coupled to the stripe structure, so that the light emission efficiency of the semiconductor laser can be increased. Further, when the reflected light is converged at the waveguide entrance in the slider, the efficiency with which the emitted light of the semiconductor laser is coupled to the waveguide can be increased. Further, the reflected light may be substantially parallel. By doing so, fluctuations in the intensity of light emitted from the semiconductor laser and the intensity of light coupled to the waveguide can be reduced due to the difference in distance between the semiconductor laser side surface and the slider side surface. The shape of the mirror is a paraboloid, but may be another shape such as a spherical surface or an elliptical surface. Actually, the light emitted from the stripe structure is different from completely parallel light, and is also different from the light spreading from one point light source. Therefore, when a mirror having a shape such as a paraboloid, a spherical surface, or an ellipsoid is used, the reflected light does not become completely parallel light or light that is completely collected at one point due to aberration. In order to prevent this, the shape of the mirror is preferably an aspheric shape optimized to eliminate aberrations.

  In order to suppress the spread of the emitted light in the direction perpendicular to the direction of film formation of the active layer, a cylindrical lens may be disposed near the side surface of the semiconductor laser. Thereby, the coupling efficiency when light is introduced into the waveguide in the slider can be increased.

  The current to the semiconductor laser is preferably supplied by placing a flexible printed circuit board of the suspension on the upper surface of the semiconductor laser and bringing the wiring formed thereon into contact with the electrode of the semiconductor laser.

  In order to suppress noise caused by light reflected from the slider side and returning to the semiconductor laser, the semiconductor laser is placed so that the direction of the semiconductor laser is oblique to the side of the slider, or the side of the slider is on the air bearing surface. Alternatively, it may be inclined. By doing so, it becomes difficult for reflected light to enter the semiconductor laser, so that noise can be reduced.

  In order to suppress the power fluctuation of the light coupled to the waveguide in the slider, the waveguide in the slider may be branched in the middle, and the power of the light coupled thereto may be monitored by a photodetector. By forming a feedback loop, power fluctuation can be suppressed.

  The semiconductor laser of the present invention may be disposed on the upper surface of the slider (the surface opposite to the air bearing surface). When the semiconductor laser of the present invention is used, the optical path in the semiconductor laser is bent by the mirror, so that the overall height does not increase. In addition, since there is no submount between the emission surface of the semiconductor laser and the slider, the distance between the semiconductor laser and the slider can be reduced. As a result, the efficiency with which the light emitted from the semiconductor laser is coupled to the waveguide can be increased. In addition, light having a polarization direction necessary for a near-field light generating element using a metal scatterer can be generated using a TE mode laser.

  In this specification, a structure in which a semiconductor laser is attached to a flying slider provided with a magnetic pole that generates a recording magnetic field, a near-field light generating element, and a waveguide is referred to as a heat-assisted integrated head.

FIG. 3 is a side sectional view showing an example of the thermally-assisted integrated head of the present invention. 4A and 4B are diagrams showing a heat-assisted integrated head according to the present invention, in which FIG. 4A is a side sectional view seen from the outflow end side, and FIG. FIG. 3 is a cross-sectional view of the heat-assisted integrated head of the present invention as viewed from the top surface of the slider. The figure which shows the main magnetic pole front-end | tip and the part of a near field generation element. It is a figure which shows the main magnetic pole front-end | tip and the part of a near field generation | occurrence | production element, (a) Sectional drawing seen from the side surface side, (b) Sectional drawing seen from the air bearing surface side. The figure which shows the relationship between the transmittance | permeability of the light which propagates the inside of a waveguide, and a curvature radius. The figure which shows the spot size converter of a waveguide. 2A and 2B are diagrams illustrating a structure of a semiconductor laser, in which FIG. The figure which shows the mirror formed in the semiconductor laser. FIGS. 3A and 3B are diagrams showing an electrode structure on a semiconductor laser, in which FIG. 1A shows an example in which an electrode is formed in a portion excluding a mirror and an emission part, FIG. FIG. 4 is a diagram showing an example in which electrodes are formed in a portion excluding a mirror and an emission portion. FIG. 5 is a diagram showing the relationship between a semiconductor laser stripe structure and a mirror; (a) when the stripe structure is separated from the mirror; (b) when the width of the stripe structure is larger than the width of the mirror; FIG. 5 is a diagram showing a case where is arranged to extend to the emission end and surround the mirror. 4A and 4B are diagrams showing directions of a mirror and a ridge, in which FIG. 4A shows an example in which the angle of the mirror is 45 or less, and FIG. FIGS. 5A and 5B are diagrams showing a reflection structure on the opposite side to the emission side, in which FIG. 5A shows an example in which the same surface as the emission side is used as a reflection surface, FIG. 2) An example in which a side surface of a groove formed in a semiconductor laser is used as a reflection surface, and FIG. 3D is a diagram showing an example in which reflection is performed by a grating formed on the surface of an active layer. 4A and 4B are diagrams illustrating an example in which a waveguide is formed between a mirror and an output surface, where FIG. 5A illustrates an example in which the width of the waveguide is constant, and FIG. 5B illustrates an example in which the width of the waveguide is changed. It is a figure which shows the example in which the waveguide of the material different from a stripe structure was formed between the stripe and the output surface, (a) The example using a mirror, (b) The figure which shows the example which bent the waveguide. The figure which shows the example whose reflection surface is a curved surface. 4A and 4B are diagrams illustrating a method for wiring to a semiconductor laser, in which FIG. 4A illustrates an example in which a current is passed through an electrode on a submount, and FIG. 4B illustrates an example in which two electrodes are formed on one surface of the semiconductor laser. The figure which shows the wiring method to the semiconductor laser at the time of using a flat submount. 4A and 4B are diagrams showing the positional relationship between a semiconductor laser and a submount, in which FIG. 5A shows an example in which an active layer is arranged on the submount side, and FIG. 5B shows an example in which the submount is arranged on the side opposite to the air bearing surface. It is a figure which shows the wiring method when a submount is arrange | positioned on the opposite side to an air bearing surface, (a) Whole figure, (b) The figure which shows the structure of a submount. The figure which shows the means to reduce the reflected light in a slider side surface, (a) The example which filled the resin between the semiconductor laser and the waveguide, (b) The example which inclined and arrange | positioned the semiconductor laser, (c) The slider side surface The figure which shows the example which inclined. It is a figure which shows the example which formed the antireflection film on the slider side surface, (a) The example which formed the groove | channel where the side surface was perpendicular | vertical on the wafer, and formed the antireflection film, (b) The side surface became slanting on the wafer The example which formed the groove | channel and formed the antireflection film, (c) The figure which shows the example which mounted the semiconductor laser after a slider cut | disconnecting. The figure which shows the example which bent the direction of the waveguide in a slider using the mirror. It is a figure which shows the example which a waveguide injects diagonally with respect to a near-field light generating element, (a) Whole figure, (b) The example where the whole near-field light generating element was also slanted, (c) Near-field light generation The figure which shows the example in which the front-end | tip part of the element became diagonal. The figure which shows the example which put the weight on the slider side surface on the opposite side to arrange | positioning a semiconductor laser. It is a figure which shows the example which formed the waveguide for optical power monitors, (a) Whole figure, (b) The example of the branch part of a waveguide, (c) The edge part of the termination | terminus part of the waveguide for optical power monitors is slanted (D) The figure which shows the example in which the center axis | shaft of the waveguide for optical power monitors became diagonal with respect to the slider side surface. The figure which shows the arrangement | positioning method of the photodetector for optical power monitors. The figure which shows the example which detects with the optical power monitor waveguide the center axis | shaft of the waveguide for introducing light into a near-field light generating element becomes diagonal with respect to an air bearing surface, and the light reflected by the waveguide terminal end. It is a figure which shows the alignment method, (a) Arrangement example of alignment mark, (b) The figure which shows the holding method of components. FIG. 2 is a diagram showing an example in which a semiconductor laser is arranged on a slider and an electrode is provided on the upper part of a submount, (a) a sectional view seen from the side surface side, (b) a diagram seen from the other side surface side, (c) FIG. 4 is a diagram showing a wiring method in the upper part of the slider. FIG. 3 is a diagram showing an example in which a semiconductor laser is arranged on a slider and an electrode is provided on a side surface of a submount, (a) a sectional view seen from the side surface side, (b) a diagram seen from the other side surface; ) Viewed from the top of the slider. The figure which shows the structural example of a recording / reproducing apparatus. 4A and 4B are diagrams illustrating an example in which a cylindrical lens is disposed in the vicinity of the emission surface of the semiconductor laser, where FIG. 5A illustrates an example in which the lens is disposed on the semiconductor laser, and FIG. The figure which shows the example which set | placed the semiconductor laser out of the slider.

Embodiments of the present invention will be described below with reference to the drawings.
1 to 6 show a configuration example of a heat-assisted integrated head according to the present invention. As shown in FIG. 1, the recording magnetic field is generated by the magnetic head unit 6 including the coil 7, the thick magnetic pole 27 for transmitting the magnetic flux generated by the coil 7, the main magnetic pole 2, and the return pole 8. . The magnetic field generated by the coil 7 is transmitted through the thick magnetic pole 27 and is transmitted to the main magnetic pole 2 disposed in the vicinity of the near-field light generating element 1. At the moment of recording, the magnetic recording medium 14 is heated by the near-field light generated from the near-field light generating element 1, and at the same time, the recording magnetic field generated from the main magnetic pole 2 is applied to the magnetic recording medium 14, thereby recording layer 14 ' A record mark was written on.

FIG. 4 shows an enlarged view of the main magnetic pole 2 and the near-field light generating element 1. FIG. 5A shows the main magnetic pole and the near-field light generating element as viewed from the side, and FIG. 5B shows the view as viewed from the air bearing surface. As the magnetic pole, the main magnetic pole 2 was formed at the tip of the thick magnetic pole 27 for transmitting the magnetic flux generated in the coil 7. The width of the tip of the main pole 2 was narrowed, and the width (W _c , W _d ) in the x and y directions of the tip of the main pole was narrowed so that W _c = 150 nm and W _d = 100 nm. part of the height (throat height) h ₁₀ was 50nm. The width above the thinned portion was gradually increased, and the angle φ of the tapered portion was 45 degrees. The height h ₄ of the main magnetic pole was 900 nm. The distance h ₁₂ between the thick magnetic pole 27 and the slider air bearing surface 17 was 100 nm. The magnetic pole was made of NiFe or CoFe alloy. By using such a structure, the magnetic field generated by the coil can be concentrated in a narrow region, and a strong magnetic field of 10 kOe or more can be generated at the light heating position.

  A reproducing head including a magnetic reproducing element 4 was formed on the side of the write head as shown in FIG. In this embodiment, a Giant Magneto Resistive (GMR) element or a Tunneling Magneto Resistive (TMR) element is used as the magnetic reproducing element 4. A magnetic shield 9 is formed around the magnetic reproducing element 4 to prevent magnetic field leakage.

As the near-field light generating element, as shown in FIG. 5B, the shape seen from the slider air bearing surface 17 has a shape in which the width gradually decreases toward the apex 20 where the near-field light is generated (this embodiment). 4, and as shown in FIG. 4, the metal structure 1 having a shape when viewed from the side of the slider is such that the width W ₃ is wide at the slider upper portion 21 and narrowed at the slider lower portion 22. . A tapered portion 26 was formed between a portion 21 having a wide upper portion and a portion 22 having a narrow lower portion. The length W _a of the bottom triangular portion is 60 nm to ₁₀₀ nm, the apex angle θ ₁ is 60 degrees, the tip width W _b is 10 nm, and the distance s between the apex 20 where the near-field light is generated and the main magnetic pole is 20 ˜30 nm. The height h ₃ of the metal structure 1 was 900 nm, the upper width W ₃ was 3 μm, and the distance h ₇ from the air bearing surface to the expanded portion of the upper portion was 250 nm. The apex angle θ ₂ of the tapered portion 26 was 60 degrees. The material of the metal structure 1 was gold, and the material around the metal structure 1 was alumina (Al ₂ O ₃ ).

  In order to guide the light generated by the light source to the near-field light generating element, the waveguide 3 (the core portion is shown in the figure) was used. As shown in FIG. 5A, the waveguide core 3 is disposed beside the metal structure 1. The distance between the waveguide core 3 and the metal structure 1 (dx in FIG. 5) was 20 nm. At the interface between the core 3 and the clad 15 of the waveguide, evanescent light generated so as to ooze out into the clad 15 exists. When the evanescent light strikes the side surface 29 of the upper portion 21 of the metal structure 1, surface plasmons, which are charge density waves, are generated at the interface 29 between the metal structure 1 and the clad 15. When this wave travels downward (toward the tip 20 of the metal structure 1) and reaches the portion 22 where the width of the bottom of the metal structure 1 is reduced, the width of the bottom of the metal structure 1 is reduced. Localized plasmons are generated in the portion 22. In the portion 22 where the width of the bottom portion of the metal structure 1 is narrowed, the charges oscillating inside the metal are concentrated on the sharply pointed tip portion 20, and a localized electromagnetic field, that is, near-field light is generated in the vicinity thereof. To do. In particular, when the magnetic recording medium 14 is present in the vicinity of the near-field light element 1, it interacts with the image charge in the medium, so that the charge in the metal is further attracted to the medium side, and is strongly close to the vertex 20 near the medium. Field light is generated.

  In the above structure, the width of the upper portion 21 of the metal structure 1 when viewed from the side of the slider is increased and the tapered portion 26 is provided. By doing so, the surface generated in the upper portion 21 of the metal structure 1 Plasmons gather at the portion 22 where the width of the bottom of the metal structure is narrowed. As a result, the electromagnetic field strength is increased at the bottom of the metal structure, and the generation efficiency of near-field light generated at the apex 20 can be increased.

In the above structure, the portion of the metal structure 1 other than the vertex 20 on the medium side surface (25 in FIG. 4) is such that the distance between the surface of the scatterer and the medium surface is the distance between the vertex 20 of the scatterer and the medium surface. To be bigger. When light is incident on the scatterer, weak near-field light (background light) is generated not only at the vertex 20 but also at the side opposite to the vertex. When this background light hits the medium, the medium is heated also at portions other than the apex portion 20, and the recorded information may be erased. As described above, when the bottom surface 25 of the metal structure 1 is cut so that the distance between the bottom surface 25 of the metal structure 1 and the medium surface is increased, weak near-field light generated on the side opposite to the vertex 20 is generated on the medium surface. And the influence of the near-field light on the medium can be reduced. In this embodiment, the recess h ₂ amount of the bottom surface 25 is 10 nm.

  In the above structure, in order to excite surface plasmon at the interface between the metal structure 1 and the clad 15, it is necessary to irradiate the side surface of the metal structure 1 with light having an electric field component perpendicular to the interface. In general, in order to excite surface plasmons on the surface of a metal film, it is necessary to make light having an electric field component perpendicular to the film surface incident on the film. For this purpose, the polarization direction of the light introduced into the waveguide core 3 needs to be perpendicular to the interface between the metal structure 1 and the clad 15 (in the direction of the arrow 23 in FIG. 5A).

  As a light source for light heating, a semiconductor laser 30 having a wavelength of 780 to 980 nm is used. As shown in FIGS. 2 and 3, it is not the inflow end side but the outflow end side of the four side surfaces of the flying slider 5. But it was placed beside the side. The height of the flying slider was 230 μm, and the width in the direction parallel to the surface of the recording disk was 850 μm in the direction parallel to the recording track and 700 μm in the direction perpendicular to the recording track.

  As a semiconductor laser, the direction of the stripe structure of the semiconductor laser (a region formed by channel waveguides formed by etching a ridge for confining light or an active layer, where light amplification is performed) is directed to the side surface 63 of the slider. In contrast, a mirror structure in which mirrors 101 are formed at both ends of the stripe structure is used. The angle θ of the mirror 101 is 45 °, and the light transmitted through the stripe structure is bent by the mirror 101 in a horizontal direction (in-plane direction of the active layer 31) with respect to the active layer 31 deposition surface in the semiconductor laser. The semiconductor laser was advanced in a direction perpendicular to the side surface of the semiconductor laser (surface located on both sides of the stripe structure). The direction of the mirror 101 is such that the reflected light at both ends travels in opposite directions. Part of the light reflected by the mirror is reflected on the side surface and returns to the stripe structure side. At this time, the two opposite side surfaces function as a mirror that forms an optical resonator. By injecting current into the active layer from the electrode 45 on the upper surface of the semiconductor laser, laser oscillation occurs and laser light is emitted from the side surface. By forming a reflectance adjustment film (dielectric multilayer film or single layer film) 109 on the side surface of the semiconductor laser, the reflectance on the side surface on which the laser beam is emitted is low, and the reflectance is reflected on the opposite side surface. The rate was made higher.

  The semiconductor laser 30 was disposed on the submount 32, and the submount 32 was bonded to the side surface 63 of the slider using a conductive adhesive 37. Although heat is generated from the semiconductor laser 30, if the heat does not escape, the temperature of the semiconductor laser rises, leading to damage to the semiconductor laser or a decrease in life. When the side surfaces of the submount 32 and the slider 5 are joined using the conductive adhesive 37, the heat generated by the semiconductor laser is transmitted to the submount and then to the slider 5. The heat transmitted to the flying slider 5 is released to the recording disk side through an air flow flowing between the flying surface and the recording disk. As a result, temperature rise in the semiconductor laser can be suppressed.

  The entrance of the waveguide formed in the flying slider 5 is positioned on the side surface of the slider on which the semiconductor laser is disposed so that the light emitted from the semiconductor laser 30 is directly coupled to the waveguide formed in the flying slider 5. I made it. In order to increase the coupling efficiency when light emitted from the semiconductor laser is coupled to the waveguide, the distance between the semiconductor laser and the side surface of the slider is preferably as short as possible. In this embodiment, the distance is set to 0 to 10 μm. The ideal is 0, but a width of 0 to 10 μm occurs due to the alignment error.

  The waveguide 3 in the slider is provided with a curved portion so that light travels in a direction substantially parallel to the air bearing surface of the slider in the vicinity of the light incident portion 16, and in the vicinity of the near-field light generating element 1, The light travels in a direction perpendicular to the flying surface of the slider. In this way, light emitted from the semiconductor laser 30 in the horizontal direction hits the near-field light element 1 from above (the direction opposite to the air bearing surface 17). Note that when the waveguide 3 is processed, the substrate surface becomes a plane parallel to the yz plane. Therefore, the waveguide having the curved portion as described above can be easily manufactured by lithography.

The material of the core 3 of the waveguide is Ta ₂ O _5, and the material of the clad portion 15 is Al ₂ O ₃ . When the wavelength is 830 nm, the core width W _{1 in the} direction perpendicular to the recording track direction is 500 nm, the core width W _{2 in the} direction parallel to the recording track direction is 300 nm, and the wavelength is 980 nm. The core width W _{1 in the} direction perpendicular to the direction of the recording track was 650 nm, and the core width W _{2 in the} direction parallel to the direction of the recording track was 300 nm. The core width may be other values, for example, W ₁ = 500 nm and W ₂ = 200 nm when 830 nm. The material of the waveguide 3 is not limited as long as the refractive index of the core is larger than the refractive index of the clad. For example, the clad material is Al ₂ O ₃ and the core material is TiO ₂ , SiN, or SiO _x N _y. Good. The clad material may be SiO ₂ and the core material may be Ta ₂ O ₅ , TiO ₂ , SiO _x N _y , or Ge-doped SiO ₂ .

If the radius of curvature R of the curved portion of the waveguide 3 is too small, light is emitted from the waveguide and a propagation loss occurs. FIG. 6 shows the relationship between the radius of curvature R and the transmittance of the waveguide when the core width is 500 nm × 300 nm. As shown in this figure, when the radius is 60 μm or more, no propagation loss occurs, but when the radius is less than that, a propagation loss occurs, and the light intensity reaching the near-field light generating element 1 decreases. In this example, the radius of curvature was set to 100 μm or 150 μm so as not to cause propagation loss. Waveguide near the near-field light generating element 1 as a straight line, the length L ₁₀ of the straight portion was set to 30 [mu] m. The length L ₁₀ of the straight portion, if not hit the coil or magnetic pole and waveguide of the magnetic head, may be other values.

In order to efficiently couple the light emitted from the semiconductor laser to the waveguide 3, a spot size converter 19 as shown in FIG. 7 is formed at the entrance of the waveguide 3. The width W ₂₀ on the entrance side of the waveguide 3 is made smaller than W ₁ , and has a refractive index intermediate between the refractive index of the core and the refractive index of the cladding 15 around the core of the waveguide 3 made of Ta ₂ O _5. A layer 18 made of material was formed. When such a structure is used, the mode field diameter at the incident portion of the waveguide can be increased. As a result, the coupling efficiency between the light emitted from the semiconductor laser and the waveguide can be increased. In this embodiment, the material of the layer 18 and addition of SiN on Al ₂ O _3, amount of SiN, rather than the refractive index of the refractive index of Al ₂ O ₃ but the addition of SiN on Al ₂ O ₃ It adjusted so that it might become 0.05 larger. The width W ₂₀ on the incident side of the waveguide core was 80 nm. The width W _{21 of the} layer 18 was 10 μm, the width W ₂₂ was 5 μm, and the length W ₂₃ was 250 μm.

In the structure of the present invention, the direction of the spot size converter (direction in which light travels) is the horizontal direction (y direction) of the slider. Therefore, it is possible to increase the spot diameter conversion rate (the ratio of the mode field diameter at the entrance of the spot size converter to the mode field diameter at the exit) of the spot size converter. That is, generally, as the length W ₂₃ of the spot size converter 19 is large, it is possible to increase the conversion ratio of the spot diameter. When the semiconductor laser is installed on the slider, the direction of the spot size converter is perpendicular to the air bearing surface 17 (z direction). In this case, the length W ₂₃ of the spot size converter can not be greater than the height of the slider (z-direction width).

  On the other hand, if the structure of the present invention is used, the direction of the spot size converter is in the horizontal direction of the slider (y direction), so that the spot size converter is more perpendicular to the air bearing surface 17 than the spot size converter. The length of the spot size converter can be increased. This is because the horizontal width (y-direction width) of the slider is more than twice as large as the thickness (z-direction width). Therefore, the spot diameter conversion rate can be increased. If the spot diameter conversion rate can be increased in this way, the mode field diameter at the waveguide entrance 16 can be increased, so that the coupling efficiency between the semiconductor laser and the waveguide can be increased. In addition, since the amount of decrease in coupling efficiency when the position of the semiconductor laser is shifted is reduced, the allowable range for the position shift amount of the semiconductor laser can be increased.

  In this example, a TE mode laser was used as the semiconductor laser, and the polarization direction 64 of the emitted light 110 of the semiconductor laser was made parallel to the flying surface of the slider as shown in FIG. When this light propagates through the waveguide 3 having a curved portion, the propagation direction changes, so that the polarization direction is perpendicular to the side surface 29 of the metal structure 1 in the vicinity of the near-field light generating element 1. That is, the polarization direction of incident light coincides with the polarization direction necessary for generating surface plasmons in the metal structure 1.

The structure of the present invention has the following advantages.
(1) Since the semiconductor laser is formed on the side surface of the flying slider, the height of the entire head does not increase. Therefore, the flying does not become unstable, and it is not necessary to increase the distance between the disks in the drive, and the thickness of the entire apparatus can be kept thin as in the conventional case.
(2) Although a laser with an output of 30 to 60 mW needs to be used as the heat-assisted recording laser, when a conventional edge emitting laser is used, in order to realize such an output, a laser of 300 to 600 μm or more is used. A resonator length is required. When such a semiconductor laser is formed on the side surface of the flying slider (a surface different from the outflow end), the direction of the resonator is perpendicular to the direction of the recording track. The distance to the outer end of the recording medium (the distance in the direction perpendicular to the direction of the recording track) increases, and the position of the center of gravity deviates greatly from the center of the flying slider. As a result, levitation becomes unstable. On the other hand, in the structure of the present invention, since the optical path is bent inside the semiconductor laser, the longitudinal direction of the semiconductor laser is parallel to the direction of the recording track. Therefore, the width of the semiconductor laser in the direction perpendicular to the direction of the recording track is small, and the position of the center of gravity does not deviate greatly from the center. Therefore, stable levitation becomes possible.
(3) When coupling light from the semiconductor laser to the waveguide, there is no need to use a grating coupler. Therefore, the intensity of the light coupled to the waveguide does not fluctuate due to the fluctuation of the wavelength.
(4) The heat generated from the semiconductor laser escapes to the floating slider and the flexure portion of the suspension through the submount. Then, the heat transmitted to the flying slider is released to the recording disk side through an air flow flowing between the flying surface and the recording disk. Therefore, the temperature rise of the semiconductor laser can be suppressed. As a result, the semiconductor laser can be prevented from being damaged or shortened.
(5) Since the direction of the spot size converter can be set to the horizontal direction of the slider, the length of the spot size converter can be increased. As a result, the spot conversion rate can be increased, and the coupling efficiency when the light from the semiconductor laser is coupled to the waveguide can be increased. Therefore, the power of the semiconductor laser can be reduced, and the power consumption and the heat generation amount can be reduced. In addition, since the tolerance for the positional deviation of the semiconductor laser can be increased, the yield during assembly can be increased, and the manufacturing cost can be reduced.

Here, the detailed structure of the semiconductor laser with a mirror used in the structure of the present invention will be described.
The thickness L ₂ of the semiconductor laser was 50 μm, the length L ₁ in the long side direction was 550 μm, and the length L ₃ in the short side direction was 80 to 100 μm. The length L ₁ in the long side direction depends on the required light amount, and may be shortened when recording is possible with low power, for example, 300 μm. The length L ₃ in the short side direction depends on the distance L ₂₀ from the end of the stripe structure to the side surface 65 of the semiconductor laser. When the distance L ₂₀ is too large, while proceeds from the mirror to the side, the beam will spread. As a result, when the light reflected by the side surface 65 of the semiconductor laser returns to the stripe structure portion, the ratio of the return light coupled to the stripe structure becomes small. Therefore, the light emission efficiency is lowered. In order to prevent this, the distance L ₂₀ is preferably small. However, since the side surface of the semiconductor laser (the emission surface and the opposite surface) is formed by cleavage, chipping is present at the edge of the cleavage surface. Therefore, if the distance L ₂₀ is too small, cleavage may cause a part of the stripe structure to be damaged and hinder laser oscillation. In the present embodiment, in consideration of this, the target value of the distance L ₂₀ is set to 40 to 50 μm. Due to the variation due to cleavage, the actual value was larger or smaller than this value.

FIG. 8A shows a cross-sectional structure of the semiconductor laser 30. A GaAs substrate was used as the substrate 105, and an AlGaAs lower clad layer 103 and an Al _x Ga _1-x As active layer 31 were formed thereon. The mixed crystal ratio x was adjusted according to the wavelength used. On the active layer, an AlGaAs upper cladding layer 102, an insulating layer 104, and an electrode layer 45 were formed. A ridge 100 is formed in the upper clad layer 102 so that light is confined in a direction horizontal to the film (in the portion where the ridge is formed, the equivalent refractive index of the active layer is larger than that of the periphery, so that the light is Trapped). The width W _{30 of the} ridge 100 was 1.5 to 2.5 μm. The Al _x Ga _1-x As active layer can generate light having a wavelength of 0.7 to 0.9 μm. However, by using another material for the active layer, light having other wavelengths can be generated. May be generated. For example, In _x Ga _x As (or wavelength 900 nm) or may be a material such as _{In 1-x Ga x As y} P 1-y ( wavelength 1.3~1.6μm).

  As the stripe structure of the semiconductor laser, another structure may be used. For example, as shown in FIG. 8B, a buried structure may be used. In this case, after forming the lower clad layer 103, the active layer 31, and the upper clad layer 102, the portions other than the central portion were etched to form the clad layer 106 in the periphery. After the insulating layer 104 was formed on the upper surface other than the portion where the active layer 31 remained, the electrode layer 45 was formed thereon. In this structure, since the refractive index of the active layer in the part that has not been etched becomes higher than the surroundings, it functions as a channel-type waveguide, and light is confined in the active layer.

FIG. 9 shows the structure of the mirror 101 formed at both ends of the semiconductor laser 30. In this example, the ridge type structure of FIG. 8A is used as the structure of the semiconductor laser. Deep grooves 107 were formed at both ends of the ridge 100 of the semiconductor laser by dry etching. The depth D ₁₀ of the deep groove and the width W ₃₄ in the direction perpendicular to the ridge were made sufficiently larger than the beam diameter of the light transmitted through the active layer. In this embodiment, the depth D ₁₀ is 6 to 8 μm, and the width W ₃₄ is ₁₀ to 15 μm. The side surface of the groove is inclined at the end surface of the ridge 100 so that the side surface 118 functions as a mirror. The side surface (mirror surface) 118 of the deep groove was covered with a dielectric film 108 having a refractive index such as SiO ₂ smaller than the refractive index of the active layer in order to prevent deterioration of the end surface. The thickness of the dielectric film was 0.3-2 μm. By forming such a structure, the light transmitted through the active layer is totally reflected on the side surface of the deep groove and reflected in the lateral direction. The angle of the mirror (θ in FIG. 3) was 45 degrees. As the material of the dielectric film 108 formed on the surface of the mirror surface 118, SiO ₂ is used, but other materials may be used, for example, SiN, Al ₂ O ₃ , TiO ₂ or the like. The shape of the deep groove 107 is arbitrary as long as the side surface 118 is formed, and may be a triangle as shown in FIG. 10 or a rectangle as shown in FIG.

A dielectric film 109 for adjusting the reflectivity was formed on the side surface (emission surface) of the semiconductor laser on the laser beam emission side and the side surface on the opposite side. The dielectric film was made of a transparent material such as SiO ₂ , SiN, Al ₂ O ₃ , or TiO _2, and the optimum reflectance was obtained by adjusting the thickness. The dielectric film may be a multilayer film made of different materials. In this embodiment, the reflectance of the exit surface is 30%, and the reflectance on the opposite surface is 95%. These reflectance values may be other values as long as the amount of reflected light on the side surface is sufficient to satisfy the oscillation conditions of the semiconductor laser. For example, the reflectance on the emission side is set to 20%. May be.

  In the above embodiment, the semiconductor laser electrode 45 (p-electrode) was formed on the ridge 100 other than the periphery of the mirror 101 as shown in FIG. Since light absorption in the active layer increases in a region where no current is injected, it is preferable to increase the area covered by the electrode as much as possible. The electrode is formed so as to include the mirror 101 as shown in FIG. May be. However, when the mirror 101 is processed, impurities may be mixed in or the lattice defects may occur on the mirror surface 118. As a result, there are impurity ranks and lattice defect ranks in the energy rank, and carrier recombination occurs through those ranks. And the mirror surface may be damaged by the heat generated by the recombination. In order to prevent this, as shown in FIG. 10C, portions other than the mirror may be covered with electrodes.

  On the side surface 65 from which the laser light is emitted and the mirror surface 118, there is a possibility that light absorption may occur due to impurity contamination, lattice defects, or oxides generated during cleavage or etching. As a result, heat is generated and the side surface may be destroyed. In order to prevent this light absorption, by diffusing atoms such as zinc in the active layer in the vicinity of the semiconductor laser side surface 65 and the mirror surface 118, the energy bandwidth is made larger than the energy bandwidth in the active layer. The light absorption may be made difficult to occur. In addition, in order to prevent light absorption in a portion where there is no electrode (a portion where there is no current injection) in FIG. 10A, light absorption occurs in the entire region 115 between the mirror surface and the side surface of the semiconductor laser. It may be difficult.

In the above embodiment, the ridge 100 and the mirror 101 are in contact with each other. However, the ridge 100 and the mirror 101 may be separated as shown in FIG. As shown in FIG. 11B, the ridge 100 and the mirror 101 are in contact with each other, and the width W _{32 in the} direction parallel to the mirror surface 118 of the ridge 100 is greater than or equal to the width W ₃₁ of the mirror surface 118 in the vicinity of the mirror. It may be made to become. By doing so, the mirror can be formed so that there is no positional deviation between the ridge 100 and the mirror surface 118. That is, first, a first mask layer (resist layer or hard mask layer) is formed to cover the ridge 100 and the portion 119 where the width of the ridge end portion is wide, and the periphery thereof is etched. Next, a second mask layer that covers the outside of the deep groove 107 is formed. At this time, as shown by a dotted line, the size of the portion covered with the second mask is made larger than the deep groove 107 forming the mirror so that the portion of the side surface 118 of the mirror is not covered with the second mask. To. At this time, if the width W _{32 of the} ridge 100 is equal to or greater than the width of the mirror surface 118 (width in the direction perpendicular to the light incident direction) W ₃₁ , the periphery of the portion that becomes the mirror surface 118 is the first mask. Since it is covered with the layer, it is not etched, and the shape of the mirror surface 118 is finally determined by the shape of the first mask layer. Accordingly, the ridge 100 and the mirror surface 118 are not misaligned. In this embodiment, the width W ₃₁ of the mirror surface 118 is 10 μm, the width W ₃₂ in the direction parallel to the mirror surface of the portion 119 where the width of the ridge end portion is wide is 12 μm, and the width W in the direction perpendicular to the mirror surface. ₃₃ was set to 2 μm.

  As shown in FIG. 11C, the portion 119 where the width of the ridge end portion is wide may be formed so as to reach the side surface 65 of the semiconductor laser. Further, a portion 119 having a wide ridge end portion may be formed so as to surround the mirror 101. In the above embodiment, the ridge type structure is used as the stripe structure of the semiconductor laser. However, the buried type as shown in FIG. 8B is the same as the case of FIGS. 11B and 11C. In addition, the active layer portion may be widened in the vicinity of the mirror 101.

In the above embodiment, the angle θ of the mirror 101 is 45 degrees, but it may be 45 degrees or more or 45 degrees or less. For example, in the embodiment of FIG. 12A, the mirror angle θ is set to 55 degrees. The distance L ₂₀ from the end of the stripe structure (ridge or buried waveguide) 100 to the side surface of the semiconductor laser is preferably small in consideration of the light emission efficiency of the semiconductor laser. However, since the side surface of the semiconductor laser manufactured in cleaving, when the angle is 45 degrees, the distance L ₂₀ is too small, the chipping caused by cleavage, likely that some may be damaged stripe structure is there. When the angle is 45 degrees, the width L _{3 of the} semiconductor laser becomes very small if the distance L ₂₀ from the end of the stripe structure 100 to the side surface of the semiconductor laser is small. For example, if the distance L ₂₀ from the end of the stripe structure to the side surface of the semiconductor laser is ₂₀ μm at both ends of the stripe structure, the width L _{3 of the} semiconductor laser is 40 μm. When the width is reduced in this manner, the mechanical strength is weakened, and the laser may break during the processing of the semiconductor laser or the operation of attaching the semiconductor laser to the slider. Further, heat generated in the active layer is likely to be trapped in the semiconductor laser, and the laser may be damaged by heat generation.

On the other hand, as shown in FIG. 12A, when the angle θ of the mirrors at both ends of the stripe structure is larger than 45 degrees, the stripe structure 100 can be tilted. The distance between the side surfaces can be increased, and the width L _{3 of the} semiconductor laser can be increased. Therefore, problems such as chipping during dicing, mechanical strength, and heat generation can be avoided. For example, in this embodiment, the distance L ₂₁ between the two mirrors is 500 μm, and the distance (L ₂₀ , L ₂₁ ) from the stripe structure end to the side surface of the semiconductor laser is 20 μm at both ends. Therefore, L ₃ was 128 μm.

In order to prevent the width L ₃ of the semiconductor laser from becoming too small as described above, the mirror angle is set to 45 degrees as shown in FIG. 12B, and the stripe structure 100 is gradually bent halfway. Also good. In this embodiment, the distance L ₂₂ between the two mirrors is 500 μm, the distances (L ₂₀ , L ₂₁ ) from the ridge end to the side of the semiconductor laser are both 20 μm, and the stripe structure is gradually bent. , L ₃ was 90 μm.

  In the above embodiment, the traveling directions of the light reflected by the mirror 101 are different from each other on the laser light emitting side and the opposite side, but may be advanced in the same direction as shown in FIG. . That is, the two reflecting surfaces forming the resonator may be the same surface. The reflectivity of the end face on the emission side of the semiconductor laser is preferably smaller than the reflectivity of the end face on the opposite side, but in order to realize this, a film of the dielectric film 109 for adjusting the reflectivity It is necessary to make the thickness and composition different from each other on the laser beam emission side and the opposite side. Therefore, in this embodiment, the dielectric film 109 is formed separately on the emission side and the opposite side so that the reflectance differs between the emission side and the opposite side. For example, the reflectance on the emission side is 30% and the reflectance on the opposite side is 95%.

  As shown in FIG. 13B, the reflecting surface opposite to the side on which light is emitted may be a side surface 113 orthogonal to the side on which light is emitted. In this way, since the number of mirrors 101 can be reduced to one, loss due to light scattering generated on the mirror surface 118 can be reduced.

In the above embodiment, the side surface of the semiconductor laser is used as the resonator mirror, but a deep groove may be formed on the substrate by etching, and the side surface of the groove may be used as the resonator mirror. In the embodiment of FIG. 13C, the deep groove 116 is formed at the end of the stripe structure opposite to the emission side. By making the direction of the perpendicular line on the side surface of the groove the direction of light in the stripe structure, the light emitted from the stripe structure travels in the opposite direction, and the side surface of the deep groove 116 and the semiconductor laser on the emission side A resonator is configured by the side surface. The side surface (reflection surface) of the deep groove 116 was covered with a dielectric film such as SiO ₂ or Al ₂ O ₃ in order to protect the surface and adjust the reflectance.

  In the embodiment of FIG. 13B, the light is reflected using the side surface 113 that is orthogonal to the side surface on which light is emitted. However, when the side surface on the emission side is formed by cleavage, the side surface that is orthogonal to the side surface is formed. It is difficult to cleave 113, and the surface may be rough. On the other hand, as shown in FIG. 13C, when the light is reflected by the deep groove, the reflection surface can be flattened, so that the light loss can be reduced. In addition, you may use the reflective surface produced by such an etching at the output surface side. When the side surface of the semiconductor laser is used as the output side mirror, the side surface is formed by cleavage, but the distance between the mirror 101 and the side surface 65 of the semiconductor laser varies due to the displacement of the cleavage position. Although the light spot spreads while propagating from the mirror to the side surface of the semiconductor laser, when the distance between the mirror 101 and the side surface 65 of the semiconductor laser fluctuates, when the light reflected by the side surface returns to the stripe structure 100, the light coupled to the stripe structure Will change. As a result, the laser beam generation efficiency varies. When the output side mirror is manufactured by etching, the position of the mirror is accurately determined, and thus such fluctuations in generation efficiency are reduced.

  As shown in FIG. 13D, light may be reflected by forming a grating 117 on the surface of the active layer instead of using the side surface or deep groove of the semiconductor laser. Light can be reflected by optimizing the period of the grating.

In the above embodiment, a waveguide (ridge or channel waveguide) for confining light in the direction parallel to the active layer (the x direction in FIG. 3) is not formed between the mirror 101 and the side surface 65 of the semiconductor laser. However, as shown in FIG. 14A, a waveguide 114 such as a ridge waveguide or a channel waveguide may be formed between the mirror 101 and the side surface 65 of the semiconductor laser. Without such a confinement structure between the mirror and the side surface of the semiconductor laser, a light spot spreads while propagating from the mirror to the side surface of the semiconductor laser. In this case, when the light reflected by the side surface 65 of the semiconductor laser returns to the stripe structure 100 of the main body, the mode field diameter of the stripe structure 100 of the main body is different from the spot diameter of the reflected light, so that coupling loss occurs. As a result, the light emission efficiency of the semiconductor laser decreases. Further, although the side surface of the semiconductor laser is formed by cleavage, the deviation of the cleavage position causes variation in the spot diameter of the emitted light. On the other hand, by forming a waveguide between the mirror and the semiconductor laser, the spread of the light spot in this region can be suppressed. As a result, it is possible to suppress the generation of coupling loss when the reflected light is coupled to the stripe structure, and it is also possible to suppress the variation in the spot diameter of the emitted light due to the shift of the cleavage position. In this embodiment, a waveguide 114 having the same material and film structure as the stripe structure 100 of the main body is formed between the mirror and the side surface of the semiconductor laser, the ridge width W ₃₀ of the stripe structure 100 of the main body is 2 μm, The width W ₃₁ of the ridge of the waveguide 114 between the side surfaces of the semiconductor laser was set to 2 μm. The width W ₃₀ of the stripe structure 100 of the main body and the width W _{31 of the} waveguide 114 between the mirror and the side surface of the semiconductor laser may be different. For example, W ₃₀ = 2μm, as in such W ₃₁ = 2.5 [mu] m, it may be a W ₃₀ <W _31. By doing so, the mode field diameter in the waveguide 114 can be made larger than the mode field diameter in the stripe structure 100. As a result, since the beam diameter of the emitted light is increased, the influence of the positional deviation between the semiconductor laser and the waveguide in the slider can be reduced.

The width W _{31 of the} waveguide 114 between the mirror and the side surface of the semiconductor laser may be gradually changed. For example, in the embodiment of FIG. 14B, the width W ₃₁ is gradually increased from 2 μm to 2.5 μm as it proceeds in the direction of the exit surface (the distance between the mirror and the side surface of the semiconductor laser near the exit surface). The width W ₃₁ is made constant so that the spot diameter does not vary due to variation in L ₂₀ ). When the width W _{31 of the} waveguide 114 between the mirror and the side surface of the semiconductor laser is made larger than the width W ₃₀ of the stripe structure 100 of the main body without providing the taper portion in this way, the semiconductor laser side surface 65 When the reflected light returns to the stripe structure 100 of the main body, a coupling loss occurs because the mode field diameter of the stripe structure 100 of the main body and the spot diameter of the reflected light are different. On the other hand, by providing the tapered portion, the spot diameter of the reflected light gradually decreases as it proceeds in the direction opposite to the exit surface, and becomes close to the mode field diameter of the stripe structure 100 of the main body. Therefore, coupling loss can be suppressed.

In the above embodiment, the waveguide having the same material and film configuration as the main body stripe structure 100 is formed between the mirror and the side surface of the semiconductor laser. It may be formed. For example, in the embodiment of FIG. 15A, a material obtained by adding SiN to Al ₂ O ₃ between the mirror 101 and the semiconductor laser side surface 65 in the same manner as the waveguide on the entrance side of the spot size converter shown in FIG. A core 111 having a rectangular cross-sectional shape was formed, and an Al ₂ O ₃ clad 112 was formed around the core 111. Amount of SiN, the refractive index of the added material of SiN was controlled to 0.05 greater than the refractive index of the Al ₂ O ₃ to Al ₂ O _3. The width W _{21 in} the x direction of the waveguide core was 10 μm, and the width W ₂₂ in the z direction (thickness direction) was 5 μm. Other materials may be used for the core and cladding. For example, a semiconductor material having a wide band gap by changing the atomic composition ratio of the material constituting the active layer may be used as the material of the waveguide core 111. Good. For example, in this embodiment, the material of the core is Al _x Ga _1-x As, and the ratio x is adjusted so that the laser beam is not absorbed. The material of the clad 112 was the same material (AlGaAs) as the clad layer of the stripe structure 100.

When the difference between the refractive index of the waveguide core 111 formed near the exit surface and the refractive index of the clad 112 is large, as shown in FIG. You may change the direction of travel. For example, in this embodiment, the material of the core 111 is Al _x Ga _1-x As with the ratio x adjusted so that the laser beam is not absorbed, and the material of the clad 112 is SiO ₂ . The distance L ₂₀ between the stripe structure 100 and the side surface 65 of the semiconductor laser was 70 μm.

  In the embodiment using the mirror, the reflection surface 118 of the mirror 101 may be a curved surface as shown in FIG. For example, in this embodiment, the curved surface is a paraboloid. That is, when the angle between the traveling direction of the light incident on the mirror surface 118 and the traveling direction of the reflected light is θ ′, the center of the incident light passes through the intersection of the central axis of the incident light and the central axis of the reflected light. When the straight line whose angle to the axis is θ ′ / 2 is the Y ′ axis and the straight line perpendicular to it is the X ′ axis, the coordinates of the curve on the X ′ and Y ′ coordinates satisfy the following equation: .

Y '= X' ² / 4a (1)
Here, a is a constant. By doing so, the reflected light does not spread but becomes convergent light or parallel light.

  The mirror having the above-described structure functions to suppress the spread of the beam in the direction (x direction) parallel to the film formation surface of the active layer. Regarding the direction (z direction) perpendicular to the film formation surface, a laminated structure of lower clad / active layer / upper clad exists between the mirror 101 and the semiconductor laser side surface 65, so that light is confined in the active layer. The beam diameter is not widened.

In the mirror having the parabolic shape as described above, the distance f from the center of the mirror 101 (the point where the central axis of the stripe structure 100 and the mirror surface 118 intersect) to the point where the beam diameter becomes the smallest is from the center of the mirror to the semiconductor. When the constant a is adjusted to be equal to the distance to the side surface of the laser, the beam diameter of the light reflected from the semiconductor laser side surface and returned to the end of the stripe structure 100 is the beam diameter when emitted from the stripe structure 100. Will be the same size. As a result, the returned light is easily coupled to the stripe structure 100 (coupling loss is reduced), and the laser emission efficiency can be increased. In this example, the mirror angle (θ = θ ′ / 2) was 45 degrees, the distance L ₂₀ between the semiconductor laser side surface and the mirror center was 30 μm, and the value of a was 30 μm.

The value of a of the curved mirror may be such that the reflected light converges at the waveguide entrance portion of the slider side surface 63. As described above, when the light is converged at the waveguide entrance, the ratio (coupling efficiency) at which the incident light is coupled to the waveguide can be increased. For example, in this embodiment, the mirror angle (θ = θ ′ / 2) is 45 degrees, the distance between the semiconductor laser side surface 65 and the slider side surface 63 is 10 μm, the distance L ₂₀ between the semiconductor laser side surface and the mirror center is 30 μm, The value of a was 40 μm.

The value of a of the curved mirror may be such that the laser light becomes substantially parallel light on the slider side surface 63 (or the semiconductor laser side surface 65). By doing so, fluctuations in the intensity of light emitted from the semiconductor laser and the intensity of light coupled to the waveguide can be reduced due to the difference in distance between the semiconductor laser side surface and the slider side surface. In this embodiment, when the distance between the semiconductor laser side surface 65 and the slider side surface 63 is 10 μm, and the distance L ₂₀ between the semiconductor laser side surface and the mirror center is 30 μm, the value of a is 50 to 60 μm.

When the shape of the curved mirror is a paraboloid, the direction of the axis of the paraboloid may be another direction. For example, as shown in FIG. 16, when the direction of the central axis of the stripe structure 100 is Y ″ and the direction perpendicular to it is X ″,
Y ″ = (X ″ −α) ² / 4a + β (2)
When the direction perpendicular to the side surface 65 of the semiconductor laser is Y ′ ″ and the direction perpendicular to the direction is X ′ ″,
Y ′ ″ = (X ′ ″ − α) ² / 4a + β (3)
You may make it become. Here, α and β are constants and are adjusted so that the reflected light is perpendicularly incident on the side surface 65 of the semiconductor laser and the reflected light becomes parallel light or light that converges at a desired position. . In this embodiment, the shape of the mirror is the shape of the formula (2), and the mirror angle θ is 45 degrees, α = 2a, and β = −a. At this time, the light converges at a position approximately f = 2a away. The value of a was 15 μm so that the light converged at the waveguide entrance on the side surface of the slider.

In the embodiment using the curved mirror, the angle θ of the mirror is 45 degrees. However, similarly to the case of FIG. 12A, θ may be a value different from 45 degrees, such as 55 degrees. Further, in order to prevent the positional deviation between the mirror surface 118 and the stripe structure 100, the width W ₃₂ of the stripe structure is the width of the mirror at the end of the stripe structure 100 as in the case of FIGS. 11B and 11C. It is preferable to be larger than W ₃₁ (width in the x ′ direction).

  In the above embodiment, the shape of the mirror is a paraboloid, but may be another shape such as an arc or an ellipse. In practice, the light emitted from the stripe structure is different from completely parallel light, and is also different from the light spreading from one point light source. Therefore, when a mirror having a shape such as a paraboloid, a spherical surface, or an ellipsoid is used, the reflected light does not become completely parallel light or light that is completely collected at one point due to aberration. In order to prevent this, the shape of the mirror is preferably an aspheric shape optimized to eliminate aberrations. The shape can be optimized by a simulator.

  The mirror having the curved surface functions to suppress the spread of the beam in the direction (x direction) parallel to the film formation surface of the active layer. Regarding the direction (z direction) perpendicular to the film formation surface, a laminated structure of lower clad / active layer / upper clad exists between the mirror 101 and the semiconductor laser side surface 65, so that light is confined in the active layer. The beam diameter is not widened. However, the spot diameter in the z direction of the light emitted from the semiconductor laser increases as the distance from the emission surface of the semiconductor laser increases. Therefore, if the distance between the side surface 65 of the semiconductor laser and the slider side surface 63 varies, the light spot diameter varies at the entrance to the waveguide in the slider, and the coupling efficiency varies. In order to prevent this, a cylindrical lens 124 may be disposed on the side surface 65 of the semiconductor laser as shown in FIG. In this way, since the spread of the emitted light in the z direction can be suppressed, the influence of variations in the distance between the side surface of the semiconductor laser and the side surface of the slider can be suppressed. In addition, when the light incident on the waveguide is parallel light or light that converges at the waveguide entrance, the coupling efficiency to the waveguide is increased. Therefore, by arranging the cylindrical lens as described above, the efficiency with which light is coupled to the waveguide can be increased. In addition, when a lens is arranged on the exit surface side, it is necessary to align the lens. However, in the case of a cylindrical lens, since alignment in only one direction is sufficient, it is easier to align than using a normal spherical lens. Become. If the purpose is to increase the coupling efficiency, the cylindrical lens 124 may be disposed on the slider side surface 63 as shown in FIG.

The wiring method to the semiconductor laser of the present invention will be described below.
As shown in FIG. 2B, the two electrodes 45 of the semiconductor laser were formed on the surface on the submount 32 side and the surface on the opposite side. The thickness L ₇ of the submount 32 is 150 μm, and the thickness L ₉ is 100 μm at the portion where the semiconductor laser is mounted. The width L ₅ was 120 μm and the length L ₆ was 750 μm. The material of the submount was Si, SiC, or AlN. On the surface of the submount 32 on the side in contact with the semiconductor laser 30, a semiconductor laser electrode 33 was formed on the entire surface. The electrode 33 on the submount has a multilayer structure of Ti / Pt / Au (gold is the surface). The electrode 33 on the submount and the electrode 45 of the semiconductor laser 30 were joined by solder 36.

  As shown in FIGS. 2B and 17A, the wiring 13 (material: copper or a laminated structure of copper and gold) on the flexible printed circuit board extends on the semiconductor laser 30 and the submount 32. The electrode 45 on the semiconductor laser and the electrode 33 on the submount were connected to the wiring 13 by solder or a conductive adhesive 46. In the embodiment of FIG. 17A, the size of the part (electrode pad) 121 in contact with the semiconductor laser at the tip of the wiring 13 or the electrode on the submount (electrode pad) 121 is set to about 100 μm × 100 μm. Here, the contact surface property between the electrode 45 of the semiconductor laser and the wiring 13 may be further increased. By doing so, the heat generated from the semiconductor laser escapes to the wiring 13, so that the temperature rise in the semiconductor laser can be reduced. When the wiring 13 is attached, there is a possibility that the two electrodes of the semiconductor laser may be short-circuited due to the conductive adhesive protruding and coming into contact with the opposite electrode. In order to prevent this, the gap between the side surface of the semiconductor laser and the electrode 33 may be filled with an insulating material 71 such as a photocurable resin.

The surface of the wiring 13 was covered with polyimide (73 in FIG. 2B) in order to prevent electric leakage and corrosion except for the portion that contacts the electrode 33 on the submount and the electrode 45 of the semiconductor laser. At this time, the end of the portion 72 where the wiring 13 is exposed was positioned inside the end of the electrode 33 on the submount or the electrode 45 of the semiconductor laser. In such a case, the side wall of polyimide at the boundary between the portion 72 where the wiring 13 is exposed and the portion where the wiring 13 is not exposed prevents the solder or the conductive adhesive 46 from protruding outside the electrode 33 or the electrode 45 of the semiconductor laser. To work. In this example, the thickness T ₁ of the polyimide on the surface was 5 μm, and the periphery of the adhesion region was surrounded by a polyimide wall having a height of 5 μm to prevent the solder or the conductive adhesive 46 from protruding from the electrode.

  In the embodiment in which the semiconductor laser is arranged on the upper part of the submount, the wiring 13 may be brought into contact with the flexure 10 of the suspension with the electrode 33 on the submount or the electrode 45 on the semiconductor laser as the ground. Since the flexure 10 is made of metal (usually stainless steel), the heat transferred to the wiring 13 can be released to the flexure by bringing the wiring 13 into contact with the flexure. Therefore, the temperature rise in the semiconductor laser can be reduced. For example, in this embodiment, the wiring connected to the electrode 45 of the semiconductor laser 30 is brought into contact with the flexure. Here, the surface of the flexure on the side in contact with the wiring 13 may be covered with a metal material having a high thermal conductivity such as copper or gold. By doing so, the heat transmitted to the flexure can easily escape and the temperature rise in the semiconductor laser can be further reduced.

In the above embodiment, the thickness of the submount 32 is reduced at the portion on which the semiconductor laser 30 is placed, but the submount 32 may be flattened as shown in FIG. In this case, the wiring 13 was brought close to the electrode 33 on the submount by bending a part of the thin stainless steel plate 122 with the flexible printed board 35 to the submount side. The wiring 13 and the electrode 33 on the submount were joined using a conductive adhesive or solder 46. The thickness L ₇ of the submount 32 is 100 μm, and the widths L ₅ and L ₆ are the same as those in the embodiment of FIG.

  In the above embodiment, the two electrodes (p-electrode and n-electrode) of the semiconductor laser are formed on two opposing surfaces of the semiconductor laser surface. However, the two electrodes may be formed on one surface. . For example, in the embodiment of FIG. 17B, two electrodes are formed on the surface of the semiconductor laser on the suspension side. In this case, the wiring 13 is directly joined to the electrode 45 on the semiconductor laser without passing through the electrode 33 on the submount.

  In the above embodiment, the active layer 31 of the semiconductor laser 30 is disposed on the opposite side of the submount 32, but may be disposed on the submount side as shown in FIG. Thus, when arranged on the submount side, the heat generated in the active layer 31 can easily escape to the submount side, and the temperature rise of the semiconductor laser can be reduced.

  In the above embodiment, the submount 32 is arranged on the air bearing surface side of the slider 5, but the submount 32 may be arranged on the opposite side of the air bearing surface 17 as shown in FIG. Good. FIG. 20 shows a method for forming electrodes at this time. As shown in FIG. 20B, the electrode pattern is formed on the submount so that the two electrodes 33 are exposed on the side surface 66 of the submount 32 and are connected to the two electrodes 45 of the semiconductor laser 30. Formed. One of the electrodes on the submount is in contact with the semiconductor laser electrode 45 at the portion where the thickness of the submount is reduced, and the other electrode is on the side surface 67 of the step portion on the other electrode of the semiconductor laser. 45. The electrode 45 of the semiconductor laser and the electrode 33 on the submount were joined with solder or a conductive adhesive 46. As shown in FIG. 20A, the submount 32 and the semiconductor laser 30 are arranged on the side surface of the slider 5, and the electrode 33 formed on the side surface of the submount 32 is connected to the wiring 13 on the suspension to the recording / reproducing head. In the same manner as the electrode 34, the solder 36 was used for bonding. In the embodiment of FIG. 19B, the submount 32 is arranged on the side surface of the slider 5, but a part of the submount 32 is arranged so as to enter the upper part of the slider 5 (between the suspension and the slider). May be.

  Hereinafter, a method for coupling the semiconductor laser and the waveguide in the slider and the structure of the waveguide in the slider will be described.

  When the light from the semiconductor laser is incident on the side surface of the slider, if the incident light is incident on the slider side surface perpendicularly, the light reflected by the slider side surface may return to the semiconductor laser, and return light noise may occur. In order to reduce the amount of return light generated on the side surface of the slider, a light-transmitting resin 70 having a refractive index greater than 1 is formed between the semiconductor laser 30 and the slider 5 as shown in FIG. May be. By forming the resin 70 having a refractive index larger than 1 as described above, the refractive index difference on the slider side surface is reduced, and the reflectance on the slider side surface can be reduced. Further, by covering the emitting end face of the semiconductor laser in this way, it is possible to prevent the end face from being deteriorated. That is, it is possible to prevent the end face from being deteriorated or contaminated due to the end face coming into contact with air. In the present embodiment, a photo-curing resin is used as the resin 70, and the refractive index thereof is made equal to the refractive index of the spot diameter converting core 18 constituting the spot size converter 19. When the amount of reflected light generated at the interface between the cladding 15 and air is larger than the amount of reflected light generated at the interface between the spot diameter converting core 18 and air, the refractive index of the resin 70 is equal to the refractive index of the cladding 15. You may make it equal.

In order to reduce the amount of reflected light on the side surface of the slider, as shown in FIG. 21B, the direction of the semiconductor laser 30 is arranged obliquely, and the emitted light from the semiconductor laser 30 is incident on the side surface of the slider obliquely. You may make it do. By doing so, reflected light returning to the semiconductor laser 30 can be reduced, and return light noise can be reduced. At this time, in order for the light from the semiconductor laser 30 to be efficiently coupled to the waveguide, the direction of the waveguide core in the vicinity of the waveguide entrance 16 is preferably inclined with respect to the side surface of the slider. In order to make the return light sufficiently small, the angle θ ₅ formed by the direction of the emitted light of the semiconductor laser 30 and the normal of the side surface of the slider is smaller than ½ of the beam divergence angle (full width at half maximum) of the emitted light of the semiconductor laser. It is preferable to increase the value. In this example, the beam divergence angle of the emitted light from the semiconductor laser was 12 degrees, so the angle θ ₅ formed by the direction of the emitted light from the semiconductor laser and the perpendicular to the side surface of the slider was set to 7 °. The angle θ ₁₀ formed between the direction of the waveguide core 3 at the waveguide entrance and the normal of the slider side surface is preferably set to satisfy sin θ ₅ = n · sin θ ₁₀ in consideration of light refraction on the slider side surface. Here, n is the refractive index of the spot diameter converting core 18 constituting the spot converter 19. When the amount of reflected light generated at the interface between the cladding 15 and air is larger than the amount of reflected light generated at the interface between the spot diameter converting core 18 and air, n is the refractive index of the cladding 15. In this embodiment, the angle θ ₁₀ is 4 °. Note that the angle θ ₅ formed by the direction of the emitted light of the semiconductor laser 30 and the normal of the side surface of the slider is larger than ½ of the beam divergence angle (full width at half maximum) of the emitted light of the semiconductor laser as described above. However, if the effect can be obtained, it may be equal to or less than ½ of the beam divergence angle (full angle at half maximum). For example, the angle θ ₅ may be 4 degrees.

In order to reduce the influence of the reflected light generated on the side surface of the slider, the side surface of the slider 5 may be inclined with respect to the flying surface 17 as shown in FIG. As described above, when the side surface of the slider is inclined, the light reflected on the side surface of the slider does not return into the active layer 31 of the semiconductor laser 30, and the generation of noise due to the return light can be suppressed. The tilt angle θ ₅ of the slider side surface, that is, the angle formed by the traveling direction of the emitted light of the semiconductor laser 30 and the normal line of the slider side surface is larger than ½ of the beam divergence angle (full width at half maximum) of the emitted light of the semiconductor laser 30. It is preferable to do so. In this embodiment, since the beam divergence angle of the emitted light from the semiconductor laser was 12 degrees, the tilt angle θ _{5 on the} side surface of the slider was set to 7 °. The side surface of the submount was also slanted according to the inclination of the slider side surface. The angle θ ₁₀ formed by the direction of the waveguide core 3 at the waveguide entrance and the normal of the side surface of the slider is set to satisfy approximately sin θ ₅ = n · sin θ ₁₀ as in the case of FIG. The angle θ ₅ formed by the direction of the emitted light of the semiconductor laser 30 and the normal of the side surface of the slider may be equal to or less than ½ of the beam divergence angle (full width at half maximum) if an effect is obtained. The angle θ ₅ may be 4 degrees.

In order to reduce the influence of the reflected light generated on the side surface of the slider, an antireflection film composed of a dielectric multilayer film may be formed on the side surface of the slider. However, in order to form the antireflection film on the side surface of the slider, it is necessary to cut out the slider by dicing and then form the antireflection film on each side surface, which increases manufacturing costs. Therefore, as shown in FIG. 22A, in the wafer state, a groove 62 is formed at a position cut out on the slider, and an antireflection film 61 is formed inside the groove 62. At this time, the width W ₄₀ of the groove is made larger than the thickness W ₄₁ of the dicing blade in order to prevent the dicing blade from hitting the antireflection film portion and damaging the film when the slider is cut out by dicing. Is preferred. In this embodiment, the groove is formed by a dicing apparatus or etching, and the antireflection film is formed by using a film forming apparatus such as CVD (Chemical Vapor Deposition) or sputtering. The thickness of the blade was 70 μm, and the width W ₄₀ of the groove was 90 μm.

In the above embodiment, the side surface of the groove is perpendicular to the wafer surface. However, when the antireflection film is formed, the film is easily attached to the side surface of the groove as shown in FIG. In addition, the side surface of the groove may be inclined. For example, in this embodiment, the angle θ ₁₂ on the side surface of the groove is set to 5 °. The depth D _{40 of the} groove may be any depth as long as the entrance 16 of the waveguide in the slider is covered with the antireflection film, and may be 10 μm, for example. However, if there is a difference between the thickness W ₄₁ of the dicing blade and the width W ₄₀ of the groove, a large step is generated on the side surface of the slider after cutting out by dicing. In this case, the distance between the semiconductor laser 30 and the entrance 16 of the waveguide increases, and the light coupling efficiency decreases. In order to prevent this, the depth D _{40 of the} groove is made larger than the thickness L ₂ of the semiconductor laser so that the emission surface of the semiconductor laser enters the inside of the slider as shown in FIG. It is good to. In this example, the thickness L ₂ of the semiconductor laser was 50 μm, and the groove depth D ₄₀ was 70 μm.

In the above embodiment, the direction of the waveguide 3 is changed by providing a curved portion in the middle of the waveguide 3, but the direction of the waveguide 3 is changed by forming a mirror 38 in the middle as shown in FIG. You may change it. The mirror this time, using a material obtained by forming a film of low refractive index dielectric reflective portion side than the cladding 15, the incident angle theta ₄ of the incident light to the reflecting surface of the mirror 38, becomes greater than or equal to a total reflection angle Like that. In this embodiment, the mirror is made of a material such as SiO ₂ or MgF ₂ , and the incident angle θ ₄ is 60 °. The waveguide was slightly bent between the spot size converter 19 and the mirror 38 so that the incident angle θ ₄ was 60 °. In the above embodiment, a dielectric is used as the material of the mirror 38, but a metal such as gold, aluminum, silver, or copper may be used.

In the above embodiment, the direction of the central axis of the waveguide 3 (direction of the light traveling direction) is perpendicular to the slider flying surface in the vicinity of the near-field light element 1 at the end of the waveguide. As shown in FIG. 24A, the direction of the central axis of the waveguide 3 may be inclined with respect to the slider air bearing surface 17. That is, the angle formed by the central axis of the waveguide and the normal line of the slider air bearing surface 17 may be larger than zero. By doing so, the light propagating through the waveguide 3 is incident on the slider air bearing surface 17 at an angle, so that the light reflected by the slider air bearing surface 17 does not return to the incident side of the waveguide 3. . Therefore, the return light noise of the semiconductor laser 30 can be reduced. In addition, since the radius of curvature of the curved portion of the waveguide core 3 can be increased by making such an inclination, it occurs at the curved portion that occurs when the refractive index difference between the waveguide core 3 and the cladding 15 is small. Light propagation loss can be reduced. In the present embodiment, the waveguide direction θ ₃ in the vicinity of the near-field light generating element 1 is set to 60 to 80 °.

  As described above, when the traveling direction of light in the waveguide in the vicinity of the near-field light generating element is oblique with respect to the slider air bearing surface, the near-field light generating element 1 is shown in FIG. As shown in c), the shape may be asymmetrical. In these embodiments, the metal structure 1 is inclined to the incident side of the waveguide. When the traveling direction of light in the waveguide is inclined with respect to the slider air bearing surface 17, the surface plasmon excited in the metal structure 1 also propagates in the same direction as the traveling direction of light in the waveguide. By tilting the metal structure 1 as in these embodiments, surface plasmons traveling in an oblique direction are likely to gather at the tip portion 20 and the near-field light intensity can be increased.

  In the above embodiment, when the semiconductor laser 30 and the submount 32 are disposed on one side of the slider side surface, the weight on one side becomes heavy and the flying of the slider becomes unstable, as shown in FIG. In order to balance, a weight 76 may be disposed on the side opposite to the slider side. The weight and position of the weight 76 were adjusted so that the entire center of gravity was located at the center.

  The intensity of the output light of the semiconductor laser 30 varies as the environmental temperature changes. If the drive is used for a long period of time, the output intensity gradually decreases due to deterioration of the semiconductor laser 30. Further, the position of the semiconductor laser 30 with respect to the waveguide 3 may also change due to a change in environmental temperature or long-term use. Due to these factors, the intensity of light coupled into the waveguide 3 may vary. When the light intensity changes, the rising temperature of the magnetic recording medium changes, so that stable recording becomes difficult. In order to solve the above problems, a second waveguide for monitoring the power of light in the waveguide 3 may be formed in the slider 5 as shown in FIG.

In the embodiment of FIG. 26, as shown in FIG. 26A, in an area where evanescent light around the waveguide core 3, that is, light generated so as to ooze out into the cladding at the interface between the core and the cladding, is generated. A power monitoring waveguide 43 is disposed. When the waveguide 43 is arranged in this way, a part of the evanescent light component in the light transmitted through the waveguide 3 is coupled to the waveguide 43. The light transmitted to the power monitoring waveguide 43 was detected by the photodetector 40 arranged on the opposite side of the semiconductor laser 30. Based on the intensity of light detected by the photodetector 40, a feedback circuit is formed so that the current flowing to the semiconductor laser 30 is increased when the light amount is small, and the current flowing to the semiconductor laser 30 is decreased when the light amount is large. . The intensity of light coupled to the power monitoring waveguide 43 is shown in FIG. 26. The distance D between the main waveguide 3 and the power monitoring waveguide 43 and the length of the overlapping portion of each waveguide (coupling) length) depends on the L _11. In the present embodiment, the distance D and the coupling length L ₁₁ are optimized so that the intensity of light coupled to the waveguide 43 is 1 to 10% of the intensity of the main waveguide 3. For example, the width of the waveguide 43 is 500 nm × 200 nm, the distance D between the two waveguides is 700 nm, and the coupling length L ₁₁ is 25 μm.

In order to prevent the reflected light from returning to the direction of the semiconductor laser 30 at the end portion of the waveguide 43, the end surface of the waveguide 43 is inclined with respect to the slider side surface 77 as shown in FIG. Alternatively, as shown in FIG. 26 (d), the direction of the waveguide 43 is bent halfway so that light is incident on the slider side surface 77 obliquely. As shown in FIG. 26C, when the direction of the end face is inclined, the angle θ _{10 of the} terminal portion is set to 5 to 15 °. As shown in FIG. 26 (d), when the waveguide 43 is disposed obliquely with respect to the slider side surface 77, the angle θ ₁₁ formed by the center line of the waveguide 43 and the slider side surface 77 is 75 to 85 °. I made it. The photodetector 40 may be anything as long as it converts light into an electrical signal, but in the present embodiment, a photodiode is used. The size of the light receiving surface was made sufficiently larger than the light spot at the waveguide exit so that the position adjustment of the photodiode was easy. In this embodiment, the size of the light receiving surface 42 is set to 50 μm in the z direction and 70 μm in the x direction. The photodiode was fixed on the flexible printed circuit board 35 on the slider side or suspension. As shown in FIG. 27, the photodiode electrode 41 is formed on the surface opposite to the light receiving surface, and is connected to the photodiode wiring 44 formed on the flexible printed board 35 on the suspension. The electrode 41 of the photodiode and the wiring 44 were connected by solder or conductive adhesive 46.

  In the above embodiment, the power monitoring waveguide is formed so as to branch from the middle of the waveguide 3 for introducing light into the near-field light element 1, but as shown in FIG. On the other hand, a waveguide 3 for introducing light into the near-field light element 1 is disposed so that light is incident obliquely, and the light reflected by the slider air bearing surface 17 is detected by the power monitor waveguide 43 with the photodetector 40. You may lead to. By doing in this way, since it is not necessary to branch in the middle of the waveguide 3 for introducing light into the near-field light element 1, the amount of light introduced into the near-field light element 1 can be increased, Light utilization efficiency can be increased.

  FIG. 29 shows an embodiment of an apparatus (alignment apparatus) for attaching the mount 32 on which the semiconductor laser 30 is mounted to the side surface of the slider 5. FIG. 29A is a diagram showing an example of arrangement of alignment marks, and FIG. 29B is a diagram showing a component holding method.

The submount 32 and the slider 5 were fixed on the vacuum suction stage 49, respectively. In order to know the laser light emission position and the waveguide entrance position, alignment marks were formed near the surface of the semiconductor laser 30 and the top surface of the slider. As the alignment mark 56 of the semiconductor laser, a square alignment mark having a width of 30 μm × 30 μm was used, and two alignment marks were formed in the vicinity of the emission position so that the distance L ₂₃ was 100 μm. The emission position of the laser beam was set to be on the center line of the two alignment marks. The alignment mark 56 was formed at the same time when the ridge 100 and the mirror 101 of the semiconductor laser were formed by etching. The alignment mark 57 of the slider 5 is a rectangular metal pattern formed near the upper surface of the slider. When viewed from the upper surface of the slider, the width in the x direction is 5 μm, the width in the y direction is 30 μm, and is perpendicular to the upper surface of the slider. The width D ₄ in the proper direction (z direction) was set to 10 μm. Two marks were formed such that the distance L ₂₄ between the alignment mark and the waveguide center was 5 μm, and the distance L ₂₅ between them was 100 μm. The distance D ₃ from the slider upper surface to the alignment mark was about 5 μm, and the distance from the alignment mark to the center of the waveguide was 5 μm.

The alignment was performed according to the following procedure.
(1) The alignment mark 57 is observed from the upper surface of the slider 5 with a CCD camera, and the direction of the waveguide 3 and the position in the x direction are obtained. That is, since the positional relationship between the waveguide 3 and the alignment mark 57 is known, the position of the waveguide 3 is obtained from the position of the alignment mark 57.
(2) From the alignment mark 56 on the semiconductor laser 30, the direction in which the laser beam travels and the position in the x direction are obtained.
(3) By irradiating the upper surface of the semiconductor laser 30 and the upper surface of the alignment mark 57 on the slider 5 with the laser beams 58 and 59 from the laser length meter, the respective positions in the z direction are obtained. From the result, the position in the z direction of the laser light emitted from the semiconductor laser 30 and the position in the z direction of the waveguide 3 in the slider 5 are obtained.
(4) The distance between the semiconductor laser 30 and the slider 5 is obtained by observing the edge 65 on the side surface on the emission side of the semiconductor laser 30 and the edge on the side surface of the slider 5 with a CCD camera.
(5) From the position information, the position of the vacuum suction stage 49 on which the semiconductor laser is mounted or the vacuum suction stage 49 on which the slider is mounted is adjusted so that the laser beam enters the center of the waveguide entrance.
(6) The adhesive 37 applied in advance is cured by light irradiation or heating.

  Note that the shape and dimensions of the alignment mark are merely examples, and other shapes and dimensions may be used.

  In the above alignment method, the alignment is performed based on the alignment mark. However, the position may be finely adjusted while monitoring the power of the light coupled to the waveguide 3 in the slider. That is, during the alignment, a current is supplied to the semiconductor laser, and the vacuum suction stage 49 is moved in a state where light is emitted. At this time, the intensity of light emitted from the exit of the waveguide 3 (exit with a near-field light element) or the exit of the waveguide 43 for power monitoring is measured using a photodetector such as a photodiode or a photomultiplier tube. To detect. The adhesive 37 is cured after adjusting the position so that the light intensity becomes maximum. By performing alignment in this way, alignment accuracy can be further increased. In the alignment performed while monitoring the light intensity, it is possible to shorten the time required for alignment by first performing alignment using the alignment mark and finally performing alignment while monitoring the intensity. I can do it.

  In the above embodiment, the semiconductor laser is arranged on the side surface of the slider. However, as shown in FIG. 30, the semiconductor laser may be arranged on the slider. FIG. 30A is a cross-sectional view as seen from the side, FIG. 30B is a view as seen from the other side, and FIG. 30C is a diagram showing a wiring method in the upper part of the slider.

In this case, the entrance of the waveguide 3 in the slider is positioned above the slider so that the light emitted from the semiconductor laser 30 is directly coupled to the waveguide in the slider. The distance between the semiconductor laser 30 and the slider was 0 to 10 μm. The semiconductor laser 30 was disposed on the side surface of the submount 32 disposed on the slider. The size of the sub-mount is slightly protruding size from one size slider 5 fits on the upper surface of the slider 5, the thickness L ₃₀ of the submount was 100-150 .mu.m. Since the submount 32 and the semiconductor laser 30 cover only one side of the upper surface of the slider, a space is opened between the slider 5 suspension 10 on the opposite side. To fill the space, the thickness on one side of the suspension upper surface is arranged equal spacer 132 to the thickness L ₃₀ of the sub-mount. A metal electrode 33 for supplying a current to the semiconductor laser was formed on the upper surface and the side surface of the submount 32, and the semiconductor laser 30 was fixed on the side electrode 33 with solder. Metal electrodes 60 were also formed on the upper and side surfaces of the spacer 132, and the electrode on the side surface of the spacer and the other electrode of the semiconductor laser were joined with the conductive adhesive 37. On the electrode 33 on the submount and on the electrode 60 on the spacer, the wiring 13 connected to the driver of the semiconductor laser on the flexible printed circuit board is arranged, and the two electrodes and the wiring 13 are connected with a conductive adhesive or solder. And joined. The electrode 34 for the magnetic head formed on the slider is separated from the suspension 10, but as shown in FIG. 30A, the flexible printed board 35 on the suspension is bent and lowered to the air bearing surface side. The magnetic head wiring 78 was connected to the magnetic head electrode 34. The wiring 78 and the electrode 34 were joined using the solder 36.

  As described above, when the semiconductor laser in which the mirror of the present invention is formed is arranged on the slider, the optical path in the semiconductor laser is bent by the mirror, so that the overall height does not increase. In addition, since there is no submount between the emission surface of the semiconductor laser and the slider, the distance between the semiconductor laser and the slider can be reduced. As a result, the efficiency with which the light emitted from the semiconductor laser is coupled to the waveguide can be increased. Further, in order to use the near-field light generating element shown in FIG. 4, it is necessary to make the polarization direction of the incident light parallel to the recording track. Incident light having such a polarization direction can be generated using a TE mode laser.

  The semiconductor laser electrode 33 formed on the submount 32 and the semiconductor laser electrode 60 formed on the spacer 132 are exposed to the side surface and flexible as shown in FIGS. The wiring 13 on the printed board 35 and the side surface may be joined by solder 36. In this case, as shown in FIGS. 31A and 31B, the magnetic head electrode 79 is formed on the side surfaces of the submount 32 and the spacer 132, and the wiring 78 and the solder 36 on the flexible printed circuit board are formed. It was joined by. This electrode 79 and the electrode 34 on the slider were further joined by solder 36.

In the above embodiment, the width L _{32 of the} submount 32 is substantially half the width of the slider, but it may be larger than that. For example, in this embodiment, the distance L ₃₁ from the side surface of the slider to the near-field light generating element 1 is set to be larger than half the slider width, or the position of the near-field light generating element 1 is near the center of the slider. In this state, the waveguide L in the slider is bent so that the entrance of the waveguide in the slider is closer to the side surface, so that the width L _{32 of the} submount ₃₂ is widened. By increasing the width L _{32 of the} submount 32 in this way, the contact area between the submount and the slider increases, so that heat generated in the semiconductor laser can easily escape to the slider side, and temperature rise in the semiconductor laser can be reduced. I can do it.

  FIG. 32 shows an overall view of a recording apparatus using the heat-assisted integrated head of the present invention. The flying slider 5 was fixed to the suspension 56 and positioned at a desired track position on the magnetic disk 14 by an actuator comprising a voice coil motor 51. A flying pad was formed on the head surface, and the magnetic disk 14 was floated with a flying height of 5 nm or less. The magnetic disk 14 was fixed and rotated on a spindle 53 that was rotationally driven by a motor. The semiconductor laser and the submount 55 were arranged on the side surface of the slider 5. The semiconductor laser and the submount 55 were arranged on the outer peripheral side of the disk so as not to hit the axis of the spindle 53. The driving current of the semiconductor laser was supplied through the flexible printed board 50, and the driving IC was disposed on the circuit board 52. The recording signal was generated by the signal processing LSI 54, and the recording signal and the power supply for the semiconductor laser were supplied to the semiconductor laser driver through the flexible printed board 50. At the moment of recording, a recording magnetic field was generated by a coil provided in the flying slider 5 and simultaneously a semiconductor laser was emitted to form a recording mark on the recording layer of the magnetic recording medium 14. Data recorded on the magnetic recording medium 14 was reproduced by a magnetic reproducing element (GMR or TMR element) formed in the flying slider 5. The signal processing of the reproduction signal was performed by the signal processing circuit 54.

  In the above embodiment, the semiconductor laser in which the mirror of the present invention is formed is arranged on the slider, but it may be arranged outside the slider 5 as shown in FIG. In this embodiment, a semiconductor laser having a curved mirror formed as shown in FIG. 16 is used and is arranged near the end of the tail portion of the suspension. The light emitted from the semiconductor laser 30 was coupled to an optical fiber or polymer waveguide 125 to guide the light toward the slider 5. The entrance of the waveguide in the slider is positioned on the upper surface of the slider, and the light transmitted through the optical fiber or polymer waveguide 125 is reflected by the mirror 126 and coupled to the waveguide 3 in the slider. As described above, when the light of the semiconductor laser is introduced into the optical fiber or the polymer waveguide, it is preferable that the emitted light from the semiconductor laser becomes convergent light in order to increase the light coupling efficiency. The light may be converged by a lens or the like, but the cost of the lens is increased. On the other hand, if the semiconductor laser using the curved mirror of the present invention is used, only the direction parallel to the stacking direction of the active layer is used, but the emitted light can be made into convergent light, so that a lens is not used. When the light of the semiconductor laser is introduced into the optical fiber or polymer waveguide 125, the light coupling efficiency can be increased.

  The semiconductor laser of the present invention may be used for a recording apparatus other than the heat-assisted recording, for example, a recording apparatus using a phase change medium. In this embodiment, as shown in FIG. 28, the recording head in which the photodiode 40 is arranged is used as the recording head, and the photodiode 40 is used for reproducing the recording data. That is, the light from the semiconductor laser 30 was condensed by the near-field light generating element 1, and the phase change medium was locally heated by the light to write the recording data. During reproduction, near-field light was generated in a state where the intensity of light generated from the semiconductor laser 30 was weakened. When the near-field light and the phase change medium interact to generate scattered light, the scattered light intensity changes depending on the state of the recording bit. The scattered data was guided to the photodiode 40 through the waveguide 43, and the recorded data was reproduced by detecting the intensity change.

  The semiconductor laser of the present invention may be used for apparatuses other than the recording apparatus, for example, optical communication or optical wiring. In optical communication and optical wiring, as in the case of FIG. 34, it is necessary to introduce light from a semiconductor laser into an optical fiber or polymer waveguide. At this time, a semiconductor laser in which a mirror having a curved surface is formed. By using, the coupling efficiency between the semiconductor laser and the optical fiber or polymer waveguide can be increased without using a lens.

1 Near-field light generating element (metal structure)
2 Main pole 3 Waveguide core 4 Reproducing element 5 Slider 6 Magnetic head 7 Coil 8 Return pole 9 Shield 10 Flexure 11 Load beam 12 Dimple 13 Wiring 14 Magnetic recording medium 14 ′ Recording layer 15 Waveguide clad 16 Waveguide inlet 17 Slider floating Surface 18 Spot diameter conversion core 19 Spot size converter 20 Peak portion 21 where near-field light is generated 21 Upper portion of metal structure 22 Lower portion of metal structure 25 Recessed portion of scatterer surface 26 Tapered portion of metal structure 27 Generated in coil The magnetic pole 28 for transmitting the magnetic flux 28 The main magnetic pole upper portion 29 The side surface 30 of the metal structure on the waveguide side Semiconductor laser 31 Active layer 32 Submount 33 Laser electrode 34 Magnetic head electrode 35 Flexible printed circuit board 36 Solder 37 Conductive adhesive 38 Mirror 40 Photodetector 41 Photodetector electrode 42 Surface 43 Waveguide for power monitor 44 Photodiode wiring 45 Electrode on semiconductor laser 46 Conductive adhesive or solder 49 Vacuum suction stage 50 Flexible printed circuit board for driver 51 Voice coil motor 52 Circuit board for driver 53 Spindle 54 Signal processing LSI
55 Semiconductor Laser and Submount 56 Alignment Mark 57 on Semiconductor Laser Alignment Mark 58 on Slider Laser for Alignment Irradiated on Semiconductor Laser Surface 59 Alignment Laser Irradiated on Alignment Mark 60 Semiconductor Laser Electrode 61 on Spacer Antireflection film 62 Groove 63 Slider side surface 64 Polarization direction 65 Semiconductor laser side surface 66 Submount side surface 67 Submount side surface 70 Side-transmitting resin 71 Insulating material 72 Wiring exposed portion 73 Polyimide 76 Weight 77 Slider side surface 78 Magnetic head wiring 79 Magnetic head electrode 100 Stripe structure (ridge)
DESCRIPTION OF SYMBOLS 101 Mirror 102 Upper clad layer 103 Lower clad layer 104 Insulating layer 105 Substrate 106 Cladding layer 107 Deep groove 108 Dielectric film 109 formed on the mirror surface surface Dielectric film 110 for adjusting reflectivity Emitted light 111 Waveguide made of different materials (core)
112 Waveguide (cladding) of another material
113 Side surface orthogonal to side surface on emission side 114 Waveguide 115 formed between the mirror and the side surface of the semiconductor laser Doped region 116 Deep groove 117 Grating 118 Mirror surface 119 Portion 120 in which the width of the ridge end portion is increased Portion covered with mask 121 Electrode pad 122 Stainless steel thin plate 124 Cylindrical lens 125 Optical fiber or polymer waveguide 126 Reflection mirror 132 Spacer

Claims (16)

A semiconductor laser having an optical amplification region including an active layer and a resonator constituted by two reflecting surfaces;
A magnetic pole that generates a recording magnetic field, a near-field light generating element, and a slider provided with a waveguide that guides light emitted from the semiconductor laser to the near-field light generating element,
The semiconductor laser has an optical path bent in the in-plane direction of the active layer inside the resonator,
A heat-assisted integrated head, wherein emitted light emitted from a side surface of the semiconductor laser is coupled to the waveguide provided in the slider.   2. The heat-assisted integrated head according to claim 1, wherein a mirror for bending an optical path is formed inside the resonator of the semiconductor laser.   3. The heat-assisted integrated head according to claim 2, wherein the mirror is formed on both ends or one side of the optical amplification region.   2. The heat-assisted integrated head according to claim 1, wherein the two reflecting surfaces constituting the resonator are respectively provided on two opposite side surfaces of the semiconductor laser.   2. The heat-assisted integrated head according to claim 1, wherein two reflecting surfaces constituting the resonator are provided on one side surface of the semiconductor laser.   2. The heat-assisted integrated head according to claim 1, wherein a structure for confining light is formed in the optical amplification region of the semiconductor laser, and the width of the structure for confining the light is widened around a bent portion of the optical path. A heat-assisted integrated head characterized by that.   3. The heat-assisted integrated head according to claim 2, wherein the mirror is a curved mirror.   8. The heat-assisted integrated head according to claim 7, wherein the reflecting surface of the mirror is a paraboloid, a spherical surface, or an elliptical surface.   8. The heat-assisted integrated head according to claim 7, wherein light emitted from the semiconductor laser is parallel light.   8. The heat-assisted integrated head according to claim 7, wherein light emitted from the semiconductor laser is converged at an entrance of the waveguide.   8. The heat-assisted integrated head according to claim 7, wherein the light reflected by the mirror is converged on a side surface on the emission side of the semiconductor laser.   3. The heat-assisted integrated head according to claim 2, wherein a waveguide is formed between the mirror and a side surface of the semiconductor laser.   3. The heat-assisted integrated head according to claim 2, wherein an energy bandwidth of a region where light propagates between the mirror and a side surface of the semiconductor laser is larger than an energy bandwidth in the optical amplification region. Thermally assisted integrated head.   2. The heat-assisted integrated head according to claim 1, wherein the semiconductor laser is formed on a side surface of the slider, and the direction of the waveguide is changed in the slider.   2. The heat-assisted integrated head according to claim 1, wherein the semiconductor laser is formed on a surface opposite to the air bearing surface of the slider. A magnetic recording medium;
A medium driving unit for driving the magnetic recording medium;
A recording head for irradiating the magnetic recording medium with a recording magnetic field and a near-field light to write a recording mark;
In a thermally assisted recording apparatus having a recording head drive unit for aligning the recording head with a desired position on the magnetic recording medium,
The recording head includes a semiconductor laser having a resonator composed of an optical amplification region including an active layer and two reflecting surfaces, a magnetic pole that generates a recording magnetic field, a near-field light generating element, and light emitted from the semiconductor laser. A slider provided with a waveguide that leads to the near-field light generating element, and the semiconductor laser has an optical path bent in the in-plane direction of the active layer inside the resonator. A thermally assisted recording apparatus, wherein emitted light emitted from a side surface is coupled to the waveguide provided on the slider.

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