WO2008038699A1 - Array type optical component and method for manufacturing the same, and optical system for array type semiconductor laser - Google Patents

Abstract

An array type optical component is constituted by stacking a plurality of triangular prismatic unit transmission optical elements each having a light incident face (3a) receiving the output light from an array type semiconductor laser (1), a light reflecting face (3b) for reflecting the light refracted on the light incident face (3a), and a light exit face (3c) for refracting the light reflected on the light reflecting face (3b) such that the light reflecting faces (3b) are substantially parallel. Assuming the arranging direction of light emitting points of the array type semiconductor laser (1) is X direction, traveling direction of the output light is Z direction, and the direction perpendicular to the X direction and the Z direction is Y direction, the light reflecting face (3b) of each unit transmission optical element is arranged to be in parallel with the Z direction and to intersect the X-Z plane at substantially 45°. An array type optical component and an optical system for an array type semiconductor laser in which the output light from an array type semiconductor laser can be converted to an isotropic condensing light beam are thereby obtained through a relatively simple arrangement.

Description

 Specification

 Array-type optical component, manufacturing method thereof, and optical system for array-type semiconductor laser

 Technical field

 The present invention relates to an array type optical component for coupling output light from an array type semiconductor laser to an optical element such as an optical fiber, an optical system for an array type semiconductor laser using the same, and an array type The present invention relates to a method for manufacturing an optical component.

 Background art

 [0002] The application of array type semiconductor lasers is expanding as a laser light source that is small and can provide high output. The array type semiconductor laser has a plurality of light emission points of several tens to several tens, and is configured to output light from each light emission point. By converging a plurality of output lights having these array-like light emission points, they can be used as a high-power laser light source. For example, by coupling the output light of an array type semiconductor laser to an optical fiber, it is possible to make various applications with a higher degree of freedom.

 In general, the output beam of each light emitting point of an array type semiconductor laser has a high light collecting property in a direction perpendicular to the light emitting point arrangement direction, but is concentrated in a direction parallel to the light emitting point arrangement direction. It has characteristics such as low light intensity. Therefore, since many beams are aligned in the direction of low condensing property, the condensing property in the direction parallel to the arrangement direction of the light emitting points becomes extremely low as an entire array type semiconductor laser, and it is coupled with an optical fiber having a circular cross section. It is difficult.

[0004] As a coupling optical system of an array type semiconductor laser, for example, FIG. 8 of Non-Patent Document 1 below describes a step mirror. This is the same as that disclosed in Patent Document 1 below. The step mirror is made by stacking two mirrors with a structure cut out in the shape of a washboard, and twisting the inclined step surface by 90 ° to face each other. The stepped surfaces facing each other are reflecting surfaces, and each outgoing beam from each light emitting point of the array type semiconductor laser is rotated 90 ° by a total of two reflections by the first and second step mirrors. As a result, the beams at the respective emission points are rearranged so that a large number of beams are aligned along the direction of high light collection, and the output light of the array type semiconductor laser is connected to a circular optical fiber. It is converted into an isotropic condensing beam suitable for the case.

 However, such a combination of step mirrors has a complicated shape and is difficult to manufacture, and there is a problem that the coupling optical system becomes expensive.

 [0006] In practice, apart from the step mirror, a collimating lens is used to collect the force by aligning the divergence angles of different beams in parallel in a direction parallel to the direction perpendicular to the light emitting point arrangement direction. For parallel directions, it is necessary to collimate the beam from each emission point before the beam between each emission point is mixed by the divergence angle. Conventional step mirror In the one-sided formula, the beam between the light emitting points is mixed after the step mirror, which has a long propagation distance for beam rearrangement. You need to purchase an array. As a result, there is a problem that the entire optical system becomes more expensive.

 [0007] FIG. 6 of Non-Patent Document 1 also reports a configuration using a prism array. FIG. 7 of Non-Patent Document 1 schematically shows how a beam incident from an array type semiconductor laser is converted by a reflection in a prism and emitted. By the total internal reflection of the prism inner surface, it is possible to rotate the beam emitted from each light emitting point of the array type semiconductor laser by 90 ° and replace the parallel component with the vertical component. Similarly, the output light of the array type semiconductor laser can be converted into an isotropic condensing beam suitable for coupling to a circular optical fiber.

 [0008] In the method using a prism array, the shape of each prism element is an oblique prism shape, and the five surfaces are the optical surfaces including the input / output surface and the three reflecting surfaces. There is a problem that the coupling optical system becomes expensive because it needs to be finished.

 [0009] Also, even in a system using a prism array, it is necessary to insert a microlens array having a relatively long propagation distance required for beam rearrangement, and there is a problem that the entire optical system becomes more expensive.

 [0010] Patent Document 1: JP 10-510933 Gazette

 Non-Patent Document 1: Tetsu Yamaguchi, “Transmission Technology of Semiconductor Laser Light” Laser Research, Vol. 27, No. 3 (March 1999), Plate ~ 166 pages

Non-Patent Document 2: OPTICS LETTERS, Vol. 20, No. 8, April 15, 1995 Disclosure of the invention

 Problems to be solved by the invention

[0011] As described above, the conventional array-type semiconductor laser coupling optical system rearranges the beams at the respective emission points of the array-type semiconductor laser to convert them into beams suitable for coupling to a circular optical fiber. There is a problem that an expensive part that is difficult to manufacture is required as an optical part for the purpose.

 [0012] Further, since a relatively long propagation distance is required for beam rearrangement, it is necessary to use a microlens array together, and there is a problem that the entire optical system becomes more complicated and expensive.

Yes

 An object of the present invention is to provide an array type optical component and an optical system for an array type semiconductor laser that can convert the output light of the array type semiconductor laser into an isotropic light beam with a relatively simple configuration. Is to provide.

[0014] Another object of the present invention is to provide a method for manufacturing an array-type optical component capable of producing such an array-type optical component at low cost and in large quantities.

 Means for solving the problem

[0015] An array type optical component according to the present invention includes a light incident surface, a light reflecting surface that reflects light refracted by the light incident surface, and a light emitting surface that refracts light reflected by the light reflecting surface. A plurality of triangular prism-shaped unit transmission optical elements are stacked so that the light reflecting surfaces are substantially parallel to each other.

 An optical system for an array type semiconductor laser according to the present invention is an optical system for condensing output light from an array type semiconductor laser having a plurality of emission points,

 Triangular prism-shaped unit transmitted light having a light incident surface on which output light is incident, a light reflecting surface that reflects light refracted by the light incident surface, and a light emitting surface that refracts light reflected by the light reflecting surface It is equipped with an array type optical component constructed by stacking multiple elements so that the light reflecting surfaces are substantially parallel to each other.

The arrangement direction of the emission points of the array type semiconductor laser is the X direction, the traveling direction of the output light is the Z direction, and the X direction and the direction perpendicular to the Z direction are the Y direction. Parallel to the direction and intersect the X-Z plane at approximately 45 °. The array type optical component is arranged.

In the present invention, a first condenser lens provided between the array type semiconductor laser and the array type optical component for condensing output light from the array type semiconductor laser in the Y direction, and an array type A second condensing lens for condensing the light that has passed through the optical component in the Y direction, and a third condensing lens for condensing the light that has passed through the second condensing lens in the X and Y directions. It is preferable to further comprise.

[0018] In the present invention, it is preferable to further include an optical fiber for transmitting light that has passed through the third condenser lens.

[0019] Further, in the method of manufacturing an array type optical component according to the present invention, the bottom surfaces are substantially parallel to each other.

A material having a cross-sectional shape in which a plurality of triangles are stacked is produced by stretching along a vertical direction of the cross-section.

 The invention's effect

 [0020] According to the present invention, it is possible to convert the output light of an array type semiconductor laser into an isotropic condensing beam by using an optical component in which relatively simple triangular prism-shaped elements are stacked. become. As a result, it is possible to realize a low-cost array-type semiconductor laser optical system suitable for mass production as a coupling optical system to a circular optical fiber, compared to the conventionally known step mirror and prism array methods. Can do.

 Brief Description of Drawings

 FIG. 1 is a perspective view showing a first embodiment of the present invention.

 [Fig. 2] An explanatory diagram showing the function of the array-type optical component. Fig. 2 (a) shows the XY plane perpendicular to the light traveling direction, and Fig. 2 (b) shows a cross-sectional view of the unit transmission optical element. Show.

 FIG. 3 is a schematic view of the array type optical component shown in FIG. 1 as viewed from the position of a collimating lens.

 FIG. 4 is a cross-sectional view of array type optical components in which triangular prism-shaped unit optical elements are stacked, cut along a plane perpendicular to the axis of the triangular prism.

 FIG. 5 shows the positional relationship of each part in the optical system for an array type semiconductor laser.

 Explanation of symbols

 [0022] 1 array type semiconductor laser, 2 collimating lens, 3 array type optical component,

3a Light entrance surface, 3b Light reflection surface, 3c Light exit surface, 4 Collimating lens, 5 condenser lens, 6 optical fiber.

 BEST MODE FOR CARRYING OUT THE INVENTION

 [0023] Embodiment 1.

 FIG. 1 is a perspective view showing a first embodiment of the present invention. The optical system for the array type semiconductor laser has a function of coupling the output light from the array type semiconductor laser 1 to the optical fiber 6, and along the light traveling direction, the collimating lens 2, the array type optical component 3, and the collimating lens. It consists of a lens 4 and a condenser lens 5.

 The array type semiconductor laser 1 has a plurality of light emission points of several tens to several tens, and light is output from each light emission point. Here, for easy understanding, the arrangement direction of the emission points of the array type semiconductor laser 1 is set as the X direction, the traveling direction of the output light is set as the Z direction, and the X direction and the direction perpendicular to the Z direction are set as the Y direction.

 [0025] The collimating lens 2 has a function of condensing the output light from the array type semiconductor laser 1 in the Y direction, and is constituted by, for example, a cylindrical lens having a generatrix parallel to the X direction.

 [0026] The collimating lens 4 has a function of condensing light that has passed through the array-type optical component 3 in the Y direction, and is formed of, for example, a cylindrical lens having a generatrix parallel to the X direction.

 The condensing lens 5 has a function of condensing light that has passed through the collimating lens 4 in the X direction and the Y direction, and is composed of, for example, a rotationally symmetric lens.

 The array-type optical component 3 includes a light incident surface 3a, a light reflecting surface 3b that reflects light refracted by the light incident surface 3a, and a light emitting surface 3c that refracts light reflected by the light reflecting surface 3b. A plurality of triangular prism-shaped unit transmission optical elements are stacked so that the light reflecting surfaces 3b are substantially parallel to each other. The array type optical component 3 is collimated with the collimating lens 2 so that it is parallel to the light reflecting surface 3b of each unit transmission optical element and intersects the X-Z plane at approximately 45 °. Located between the lenses 4.

FIG. 2 is an explanatory view showing the function of the array type optical component 3. FIG. 2 (a) shows an XY plane perpendicular to the light traveling direction, and FIG. 2 (b) is a unit transmission optical element. FIG. As shown in Fig. 2 (a), when a horizontal slit-shaped light beam (a-b) travels in the Z direction and enters the light incident surface 3a, it is refracted by the light incident surface 3a, and light Proceed toward the reflective surface 3b. Subsequently, the light beam is reflected by the light reflecting surface 3b, travels toward the light emitting surface 3c, and refracts at the light emitting surface 3c. It is converted into a straight slit-shaped light beam (A—B).

[0030] Therefore, when a light beam that is elongated in the X direction is incident on the light incident surface 3a along the Z direction, one unit transmission optical element rotates the light beam by 90 ° around the Z axis, It can be seen that it functions as a 90 ° rotating prism that emits a light beam that is elongated in the Y direction along the Z direction.

 [0031] Referring back to FIG. 1, the beam emitted from each light emitting point of the array type semiconductor laser 1 has a low light collecting property in the X direction, which is the arrangement direction of the light emitting points, and is condensed in the Y direction. Because of its high performance, it is focused only in the Y direction by the collimating lens 2 and converted into a beam that is substantially parallel to the Y direction. In the X direction, the radiation angle of the array-type semiconductor laser 1 is maintained as it is, so that the array-type optical component 3 is positioned so that the 90 ° rotation is completed before the beams from adjacent emission points mix with each other. Is done.

 [0032] When each beam force S that has passed through the collimating lens 2 is incident on each light incident surface 3a of the array type optical component 3, it is rotated by 90 ° around the Z axis as described above, and is emitted from the light emitting surface 3c. To do. This exchanges the X- and Y-direction divergence angles of each beam. Furthermore, when each beam emitted from the light exit surface 3c passes through the collimating lens 4, it is condensed only in the Y direction and converted into a beam substantially parallel to the Y direction. In the X direction, the divergence angle controlled by the collimating lens 2 is maintained as it is.

 FIG. 3 is a schematic overview of the array-type optical component 3 shown in FIG. 1 viewed from the position of the collimating lens 4. However, the upper and lower sides of the collimating lens 2 and the array type optical component 3 are omitted. As shown in Fig. 3, the array pitch of the array type optical component 3 in the X direction (interval in the X direction of the light reflecting surface 3b) is the array pitch of the array type semiconductor laser 1 (interval of each light emitting point 1a). Dp Is equal to, and the light beam from each light emitting point of the array type semiconductor laser 1 is rotated by 90 ° around the Z axis to form an array light beam aligned in the X direction.

[0034] The beam emitted from each light emitting point in this manner is converted into an isotropic condensing beam by passing through the collimating lens 2, the array-type optical component 3 and the collimating lens 4, and is orthogonal to two directions. The divergence angle for is controlled. Furthermore, by adjusting the magnification of the collimating lenses 2 and 4, a circular beam with the same X-direction divergence angle and Y-direction divergence angle can be obtained. wear.

 The beam that has passed through the collimating lens 4 is condensed in the X and Y directions by the condensing lens 5, adjusted to a divergence angle and a beam diameter that match the numerical aperture of the optical fiber 6, and then the optical fiber 6. Is incident on.

 FIG. 4 is a cross-sectional view of the array-type optical component 3 in which triangular prism-shaped unit optical elements are stacked, cut along a plane perpendicular to the axis of the triangular prism. The number of unit optical elements is equal to the number of light emitting points of the array type semiconductor laser, but only a part thereof is shown here. In Fig. 4, the array pitch in this direction is hp and the width of the light reflecting surface is wt. Figure 5 shows the positional relationship of each part.

 Here, an actual numerical example is shown. For example, an array with an array pitch dp of 0.5 mm, the length of each light emitting point in the X direction 150 μm, the Y direction length 1 μm, the X direction divergence angle 10 °, and the Y direction divergence angle 50 ° Type semiconductor laser 1, a semi-cylindrical collimating lens 2 with a focal length of 0.5 mm is placed at a position of L 1 = 0.5 mm from the emitting surface of the array type semiconductor laser 1, and the collimating lens 2 forces , Et al. An array type optical component 3 in which triangular prisms having an array pitch in the X direction of 0.5 mm, that is, hp = 0.353 mm, wt = lmm, are stacked at the position of L2 = 0. 1 mm. A semi-cylindrical collimating lens 4 with a focal length of 57 mm is arranged at a position L3 = 55 mm from this array type optical component 3. By arranging in this way, the collimating lens 4 is placed at the position of L4 = lmm from the collimating lens 4 and the condensing lens 5 with the aperture of 15mm and the focal length of 25mm is 50 μm in the X direction and 66 μm in the Y direction. It can be seen that the laser beam from the array-type semiconductor 1 can be efficiently incident on the fiber 6 having a fiber diameter of 100 μm.

 As described above, the array-type optical component 3 is configured by stacking triangular prism-shaped transmission optical elements having a simple shape in multiple stages, so that the coupling optical system can be configured at low cost.

 The array type optical component 3 according to the present invention requires a short propagation distance for 90 ° rotation of the beam. Therefore, the array type optical component 3 rotates 90 ° before the beam from the adjacent light emitting point of the array type semiconductor laser 1 is mixed. Can be completed. For this reason, the divergence angle in the X direction of the beam from each light emitting point can be controlled using a simple-shaped collimator lens 4, eliminating the need for a conventional microlens array and an inexpensive coupling optical system. Can be configured.

[0040] The unit transmission optical elements constituting the array-type optical component 3 have at least the light incident surface 3a. And the force S described for the case of a substantially triangular cross-sectional shape including the light reflecting surface 3b and the light emitting surface 3c, it goes without saying that the polygonal shape obtained by cutting off the non-passing part of the beam has the same function. Absent.

 [0041] Further, by making the array pitch in the X direction of the array type optical component twice the array pitch dp of the array type semiconductor laser, the light beam from the two light emitting points of the array type semiconductor laser is converted into the array type optical component. With one unit transmission optical element, it can be rotated 90 ° around the Z axis, and as a whole, it can be an array light beam arranged in two rows in the X direction. In this way, a plurality of light beams from each light emitting point of the array type semiconductor laser as shown in FIG. 3 are not incident on each unit transmission optical element of the array type optical component. The light beam from the light emitting point may be incident on one unit transmission optical element.

 [0042] As a method of manufacturing the array-type optical component 3, manufacturing by cutting and polishing is easy, or manufacturing of a mold for molding is easy.

 [0043] Since the array-type optical component 3 is a triangular prism having three optical surfaces, it is manufactured inexpensively by manufacturing a long triangular prism, and dividing and stacking appropriately like a so-called Kintaro. The power S to do.

 [0044] Also, the array-type optical component 3 is a similar material (preform) having a cross-sectional shape in which a plurality of triangles are stacked so that the bottom surfaces are substantially parallel to each other, as in the optical fiber drawing method. Can also be produced by stretching along the vertical direction of the cross-section, which makes it possible to produce a large amount at low cost.

 Industrial applicability

[0045] According to the present invention, it is possible to realize a low-cost array type semiconductor laser optical system suitable for mass production as compared with a conventional optical system.

Claims

The scope of the claims  [1] A triangular prism-shaped unit transmission optical element having a light incident surface, a light reflecting surface that reflects light refracted by the light incident surface, and a light emitting surface that refracts light reflected by the light reflecting surface, An array type optical component, wherein a plurality of light reflecting surfaces are stacked so as to be substantially parallel to each other.  [2] An optical system for condensing output light from an array type semiconductor laser having a plurality of emission points,  Triangular prism-shaped unit transmitted light having a light incident surface on which output light is incident, a light reflecting surface that reflects light refracted by the light incident surface, and a light emitting surface that refracts light reflected by the light reflecting surface It is equipped with an array type optical component constructed by stacking multiple elements so that the light reflecting surfaces are substantially parallel to each other.  The arrangement direction of the emission points of the array type semiconductor laser is the X direction, the traveling direction of the output light is the z direction, and the direction perpendicular to the X direction and the Z direction is the Y direction. The array-type semiconductor laser optics, wherein the array-type optical components are arranged so as to be parallel to the direction and intersect the X-Z plane at about 45 ° [3] a first condensing lens provided between the array type semiconductor laser and the array type optical component for condensing the output light from the array type semiconductor laser in the Y direction;  A second condenser lens for condensing the light that has passed through the array-type optical component in the Y direction, and a third condenser lens for condensing the light that has passed through the second condenser lens in the X and Y directions. 3. The optical system for an array type semiconductor laser according to claim 2, further comprising: 4. The optical system for an array type semiconductor laser according to claim 3, further comprising an optical fiber for transmitting light that has passed through the third condenser lens. [5] A method of manufacturing an array-type optical component, characterized by producing a material having a cross-sectional shape in which a plurality of triangles are stacked so that the bottom surfaces are substantially parallel to each other along a vertical direction of the cross-section .