JP2005019881A - Semiconductor laser device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser device which can suppress the quantity of a laser beam emitted from the semiconductor laser device and can drive a VCSEL (vertical cavity surface emitting laser diode) at a high speed. <P>SOLUTION: The semiconductor laser device 20 has a metallic stem 30 for mounting at least one semiconductor laser element (VCSEL) 1 thereon, and a cap 40 mounted on the metallic stem 30 to define an inner space with the metallic stem 30. The cap 40 is formed with a light exit window 44, and the window 44 is provided with a laminate of a light transmitting glass 46 and a neutral density filter 48. For this reason, a part of light from the VCSEL 1 is absorbed by light transmitting windows 44, 46, 48. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor laser device used for optical communication, optical information processing, and the like, and more particularly to a semiconductor laser device mounted with a surface emitting semiconductor laser element.
[0002]
[Prior art]
In recent years, with the increase in capacity and bandwidth of data communication, the development of large-capacity high-speed optical communication networks such as optical wavelength division multiplexing (WDM) is being rapidly deployed. Also, high-speed and parallel processing optical communication technology has permeated in short-distance communications such as Gigabit Ethernet (Ethernet is a registered trademark) and data links. With the role of such optical technology becoming important, semiconductor laser devices are used in many electronic devices such as optical communications, DVDs, CDs, and laser printers.
[0003]
Semiconductor lasers include an edge-emitting laser that emits laser light from the end face of a cleaved semiconductor substrate, and a surface-emitting semiconductor that has a resonator in a direction perpendicular to the semiconductor substrate surface and emits laser light in a direction perpendicular to the substrate. There is a laser (called Vertical Cavity Surface Emitting Laser diode: VCSEL). The VCSEL has an advantage that the laser array is formed on the wafer surface by a semiconductor process, so that it is easy to make the laser array two-dimensional and large-scale element, which is difficult with the edge emitting laser.
[0004]
FIG. 9 is a cross-sectional view showing a schematic configuration of a conventional semiconductor laser device. As shown in the figure, the semiconductor laser device 100 includes a cap (housing) 130 that is attached to a case main body 120 on which the VCSEL 110 is mounted and forms a sealed space inside. A lead pin 122 for supplying current to the VCSEL 110 is connected to the case body 120. In addition, an exit window 132 is formed at a position of the cap 130 facing the VCSEL 110, and laser light from the VCSEL 110 is extracted from the exit window 132 to the outside.
[0005]
With regard to such a semiconductor laser device, the applicant of the present invention drives a plurality of VCSELs with the same signal to simultaneously emit light for the purpose of improving the lifetime of the VCSEL, thereby reducing the injection current density per VCSEL element. The technology is disclosed in Japanese Patent Application No. 2001-348702. The lifetime of the VCSEL is inversely proportional to the increase in the injection current density, and this technology can extend the lifetime of the VCSEL.
[0006]
Patent Document 1 relates to an optical connection element and an optical connection device, and collimates light emitted from the light emitting unit 11 of the surface type monochromatic light source array 10 by a lens array 20 including a plurality of lens units 21. A technique for taking collimated light into an optical fiber 40 through a lens 30 is disclosed.
[0007]
Patent Document 2 relates to a multi-wavelength semiconductor laser array for wavelength multiplexing optical communication, and changes the oscillation wavelength by changing the cross-sectional area of the waveguide portion of the laser integrated on a single substrate. A technique for obtaining a laser light source for oscillating wavelength multiplexing optical communication is disclosed.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-340565 (see FIG. 1)
[Patent Document 2]
JP-A-6-97578
[Problems to be solved by the invention]
However, a semiconductor laser device using a conventional VCSEL as a light source has the following problems. As the data transmission capacity increases, the VCSEL must be driven at a high speed in order to increase the data transmission speed to gigabits, tens or hundreds of gigabits. In order to perform high-speed driving or high-speed modulation of the VCSEL, it is effective to increase the laser pulse from the VCSEL, but this is not preferable in terms of safety standards. For example, an international safety standard (ICE 60825-1) has been established for laser products, and this standard classifies safety levels into classes 1 to 4. In Japan, JIS C068802 (Laser Product Radiation Safety Standard) is established. In safety class 1, no special safety measures are required, and the retina is not damaged even if the light is continuously observed for 100 seconds without blinking. In safety class 2, safety is ensured that the retina is not damaged for a blinking time of 0.25 s. As the safety classes 3A, 3B, and 4 are reached, the risk level becomes higher.
[0010]
As shown in FIG. 9, the conventional semiconductor laser device accommodates the VCSEL in a package with an emission window, and prevents the laser light from being emitted in an unnecessary direction. Generally, the exit window 132 is sealed and the laser light is efficiently extracted. In other words, in the conventional semiconductor laser device, when the VCSEL is driven at high speed, there is a problem that laser light exceeding a predetermined safety standard is emitted from the package, and there is a problem that contradicts the high speed driving of the laser element and the safety standard. The semiconductor laser device to solve is not yet available.
[0011]
On the other hand, there is a laser device that increases the reflectivity of the glass of the exit window and detects the light reflected from it by a light receiving element provided on the case body, and monitors the optical output of the VCSEL. The configuration cannot satisfy the safety standards as described above.
[0012]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a semiconductor laser device capable of high speed driving or high speed modulation while satisfying a predetermined safety standard.
A further object of the present invention is to provide a semiconductor laser device that uses a VCSEL and is safe, inexpensive, and capable of high-speed modulation.
[0013]
[Means for Solving the Problems]
A semiconductor laser device according to the present invention includes a case main body on which at least one semiconductor laser element is mounted, and a cap attached to the case main body and forming an internal space with the case main body. The cap has an emission window for emitting light from the semiconductor laser element to the outside. The emission window is provided with a light absorbing member that absorbs part of the light from the laser element. With such a configuration, even if high current driving (modulation) is performed by increasing the injection current value to the semiconductor laser element, a part of the light output from the laser element is absorbed by the light absorbing member. Can be obtained.
[0014]
Preferably, the light absorbing member includes a glass member and at least one neutral density filter disposed to face the glass member. As the glass member, a glass having a high transmittance is used as in the conventional case, and a neutral density filter can be disposed on both surfaces or one of the surfaces of the glass. Preferably, the neutral density filter is an absorption filter that absorbs light from the semiconductor laser element. For example, an ND filter (Neutral Density filter) can be used. The ND filter may be directly coated on the glass member, or may be disposed so as to be bonded to or close to the glass member using a known technical means.
[0015]
More preferably, the light absorbing member may be a light absorbing glass member that absorbs light from the semiconductor laser element at a certain rate. By cutting the amount of laser light with a single light absorbing glass, an inexpensive semiconductor laser device can be provided with a smaller number of parts.
[0016]
The exit window may include a reflecting member that reflects part of the light from the semiconductor laser element. When the reflecting member is used, a relatively large part of the laser beam, for example, about 30% of the laser beam is reflected, and the remaining 70% of the laser beam is emitted from the transmission window. For example, a reflection filter can be used as the reflection member, and a glass member having a high transmittance may be coated with a reflection film, or the reflection filter may be disposed to face the glass member. The reflecting member is placed in a space between the cap and the case main body. Apart from this, the reflective member can also be a glass member filed glass with irregularities formed on the surface. Thereby, a part of light from the laser element is reflected on the surface of the glass member. By performing reflection by the glass member itself, an inexpensive semiconductor laser device can be provided without increasing the number of components.
[0017]
Preferably, a plurality of semiconductor laser elements may be arranged on the case body and driven so that the plurality of semiconductor laser elements emit light simultaneously. Since the output is increased by simultaneously driving a plurality of semiconductor laser elements, it is necessary to increase the ratio of light absorption by the light absorbing member. In addition, a plurality of semiconductor laser elements may have a plurality of oscillation wavelengths, which can be used as an optical wavelength multiplexing light source.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration example of a VCSEL mounted on the semiconductor laser device according to the present embodiment. In the figure, a VCSEL 1 includes an n-type buffer layer 3, an n-type lower DBR (Distributed Bragg Reflector) 4, an undoped lower spacer layer 5 and an undoped lower layer 5 on an n-type GaAs substrate 2. An active region 8 including a quantum well active layer 6 and an undoped upper spacer layer 7, a p-type upper DBR 9, and a p-type contact layer 10 are sequentially stacked. Mesa 11 is formed by anisotropic etching of these semiconductor layers, and a part of the side wall and upper surface of mesa 11 is covered with interlayer insulating film 12. An opening is formed in the interlayer insulating film 12 on the contact layer 10, and the p-side electrode 13 is ohmically connected to the contact layer 10 through the opening. In the center of the p-side electrode 13, a laser emission port 14 for emitting laser light is formed. The p-side electrode 13 extends to an electrode pad (not shown) formed on the mesa bottom. A p-type AlAs layer 15 is inserted in the lowermost layer of the upper DBR 9, and the AlAs layer 15 has a circular opening 15 b surrounded by an oxidized region 15 a partially oxidized from the side surface of the mesa 11. To confine light and confine current. An n-side electrode 16 is formed on the back surface of the GaAs substrate 2.
[0019]
The lower DBR 4 is a multilayer stack of an n-type Al _0.9 Ga _0.1 As layer and an n-type Al _0.3 Ga _0.7 As layer, and the thickness of each layer is λ / 4n _r (however, , Λ is the oscillation wavelength, and n _r is the refractive index of the medium), which are alternately stacked in a 40.5 period. The carrier concentration after doping silicon, which is an n-type impurity, is 3 × 10 ¹⁸ cm ⁻³ .
[0020]
The lower spacer material layer 5 in the active region 8 is an undoped Al _0.6 Ga _0.4 As layer, and the quantum well active layer 6 is an undoped Al _{0. 11} Ga _{0. 89} As quantum well layer and undoped Al _{0. 3} Ga _{0. 7} Including an As barrier layer. The upper spacer layer 7 is an undoped Al _0.6 Ga _0.4 As layer.
[0021]
The upper DBR 9 is a stacked body of a p-type Al _0.9 Ga _0.1 As layer and a p-type Al _0.3 Ga _0.7 As layer, and the thickness of each layer is λ / 4n _r (where λ Is the oscillation wavelength, and _nr is the refractive index of the medium), which are alternately stacked for 30 periods. The carrier concentration after doping with carbon, which is a p-type impurity, is 3 × 10 ¹⁸ cm ⁻³ . The p-type contact layer 10 is a GaAs layer, and has a film thickness of 20 nm and a carbon concentration of 1 × 10 ²⁰ cm ⁻³ . The p-side electrode 13 is a laminated film of Ti / Au.
[0022]
Next, FIG. 2 shows a configuration of a semiconductor laser device in which the VCSEL of FIG. 1 is mounted. 2A is a plan view when the cap of the semiconductor laser device is removed, and FIG. 2B is a cross-sectional view taken along line XX with the cap attached. The semiconductor laser device 20 includes a metal stem (or case body) 30 and a metal cap 40 attached to the metal stem 30. The metal stem 30 has a disk shape, and a flange 32 having a step from the surface is formed on the outer periphery. The metal stem 30 is formed with a through hole 36 for connecting a lead pin to be described later.
[0023]
The cap 40 has a cylindrical shape with one surface open, and an end portion 42 is formed to protrude perpendicularly outward from the circumferential surface. The end portion 42 is welded to the flange portion 32 of the metal stem 30 by welding or the like. The bottom of the cap 40 is substantially parallel to the surface of the metal stem 30, and a circular emission window 44 is formed at the center thereof. A circular transmission glass 46 is attached to the back surface of the cap 40 according to the shape of the back surface. The transmissive glass 46 is fixed by, for example, fusing the outer periphery thereof to the inner surface of the cap 40. Preferably, the transmissive glass 46 is made of a material having a high transmittance. Further, a neutral density filter 48 is provided on the back surface of the transmissive glass 46 as a light absorbing member. As the neutral density filter 48, for example, an ND filter can be used. The neutral density filter 48 may be bonded to the rear surface of the transmissive glass 46 or may have an end fixed to the inner surface of the cap 40. Further, in the example of FIG. 2B, the neutral density filter 46 having the same size as the transparent glass 46 is joined to the transparent glass 46, but the neutral density filter 48 is at least large enough to cover the emission window 44. Good.
[0024]
The exit window 44 of the cap 40 is sealed by the laminated body of the transmission glass 46 and the neutral density filter 48, and a sealed internal space is formed between the cap 40 and the metal stem 30. The interior space is preferably filled with an inert gas containing nitrogen gas. Thus, in the emission window 44, the laminated body of the transmissive glass 46 and the neutral density filter 48 functions as a light absorbing member that absorbs part of the laser light from the VCSEL 1, and one light amount emitted from the emission window 44 to the outside. Cut the part.
[0025]
The metal stem 30 is formed with a through hole 36 for attaching a plurality of lead pins 34a, 34b. The through hole 36 is coated with an insulator film 38, and when the lead pin 34 is inserted into the through hole 36, the lead pins 34 a and 34 b and the metal stem 30 are electrically insulated by the insulator film 38. One end of each of the lead pins 34 a and 34 b is exposed to the surface of the metal stem 30 through the through hole 36. The exposed lead pins 34 a and 34 b are located on a line passing through the center of the metal stem 30.
[0026]
The mounter 50 is positioned and fixed substantially at the center of the metal stem 30. At this time, the mounter 50 is in a position facing the exit window 44. The mounter 50 has a rectangular shape, and a metal such as Au is plated or deposited on the surface thereof, and the n-side electrode 16 on the back surface of the VCSEL 1 is connected to this portion. Preferably, the VCSEL 1 is positioned substantially at the center of the mounter 50. The mounter 50 is preferably made of a material having a thermal expansion coefficient close to that of the substrate of the VCSEL 1. For example, when the substrate is GaAs, ceramic such as AlO or AIN can be used. The electrode pad 17 extending from the p-side electrode 13 of the VCSEL 1 is connected to the lead pin 34 a by a bonding wire 52. Further, the surface of the mounter 50 is connected to the lead pin 34b by the bonding wire 54, whereby the n-side electrode 16 of the VCSEL 1 is electrically connected to the lead pin 34b.
[0027]
The lead pin 34a is connected to a current drive source for driving the VCSEL 1, and the lead pin 34b is connected to the ground potential. When a current of a predetermined magnitude is injected into the VCSEL 1 through the lead pins 34a and 34b, the VCSEL 1 emits a laser beam from the central mesa 11 in a direction perpendicular to the substrate. Part of the laser light is absorbed by the neutral density filter 48, and the remaining light is output from the exit window 44 through the transmission glass 46. In the present embodiment, since the neutral density filter 48 is provided on the back surface of the transmissive glass 46, the light from the VCSEL 1 is absorbed by the neutral density filter 48 even when the VCSEL is driven or modulated at high speed. The light emitted from 44 is substantially reduced. As a result, it is possible to provide a semiconductor laser device that satisfies safety standards while driving the VCSEL at high speed.
[0028]
Next, a semiconductor laser device according to the second embodiment is shown in FIG. In the first embodiment, the neutral density filter 48 is disposed on the back side of the transmission glass 46. However, in the semiconductor laser device 20a according to the second exemplary embodiment, the neutral density filter 48a is disposed on the surface side of the transmission glass 46. It is arranged in. For example, the neutral density filter 48 a may be inserted into the emission window 44 so as to coincide with the shape of the emission window 44 and closely joined to the surface of the transmission glass 46. In addition, the neutral density filter 48 a may be disposed on the surface of the cap 40 using an attachment member or the like so as to cover the emission window 44. In this case, the neutral density filter 48a is preferably detachable from the cap 40 according to the operating state of the semiconductor laser device. When the semiconductor laser device is not driven at high speed, the neutral density filter 48a is removed from the cap 40. To leave.
[0029]
Next, a semiconductor laser device according to a third embodiment is shown in FIG. A semiconductor laser device 20b according to the third embodiment is a combination of the first embodiment and the second embodiment. That is, the neutral density filters 48 and 48a are attached to both sides of the transmissive glass 46, respectively. When the VCSEL is driven at a higher speed, the injection current value increases proportionally and the light output also increases. Therefore, the two neutral density filters 48 and 48a may preferably absorb light.
[0030]
Next, a semiconductor laser device according to the fourth embodiment is shown in FIG. The semiconductor laser device 20c according to the fourth embodiment is different from the above embodiment in that the transmittance of the transmissive glass 46a is reduced. Thereby, the transmission glass 46a can absorb the laser beam from the VCSEL at a predetermined ratio. When the transmission glass 46 is used alone, the number of steps for attaching the neutral density filter can be reduced, and the number of components can be reduced and an inexpensive semiconductor laser device can be provided.
[0031]
Next, a semiconductor laser device according to a fifth embodiment is shown in FIG. In the semiconductor laser device 20d according to the fourth embodiment, a reflecting member 60 is attached to the back side of the transmissive glass 46 instead of using a neutral density filter. When the reflecting member is used, a relatively large part of the laser beam, for example, about 30% of the laser beam is reflected, and the remaining 70% of the laser beam is emitted from the transmission window. Further, the reflection member 60 may be inclined so that the reflected light from the reflection member 60 does not directly hit the VCSEL. For the reflection member 60, for example, a reflection filter may be attached on the transmission glass 46, or a reflection film may be coated on the transmission glass 46 by vapor deposition or the like.
[0032]
Further, as shown in FIG. 6B, instead of using the reflecting member 60, it is possible to use a single piece of ground glass 60a. Since unevenness is formed on the surface of the ground glass 60 a, a part of the laser light is reflected by the uneven surface, so that the remaining laser light is emitted from the emission window 44. By reflecting the surface of the glass having unevenness (for example, ground glass) itself, the number of components can be reduced and an inexpensive laser device can be provided.
[0033]
The light absorbing member and the reflecting member described in the first to fifth embodiments may be used alone, or these may be combined. For example, the reflecting member 60 may be attached to the rear surface side of the transmissive glass 46 and the neutral density filter 48 a may be attached to the front surface side of the transmissive glass 46. In addition, the transmission glass 46a with reduced transmittance used in the fourth embodiment may be combined with the neutral density filter 48 and the reflection member 60.
[0034]
Next, a semiconductor laser device according to a sixth embodiment is shown in FIG. A semiconductor laser device 20e according to the sixth embodiment has four VCSELs 1a, 1b, 1c, and 1d mounted on a mounter 50. The p-side electrode of each VCSEL is connected to the lead pins 34a, 34b, 34c, and 34d by bonding wires 52, 54, 56, and 58, and the n-side electrode is electrically connected to the metal stem 30 through the mounter 50. Connect to the installation potential. The four VCSELs can be applied to an optical wavelength multiplexing light source by making the oscillation wavelengths different from each other, driving them with the same signal, and simultaneously emitting light. For example, the VCSELs 1a, 1b, 1c, and 1d are mounted on the mounter 50 as elements (chips) having wavelengths of 780, 800, 820, and 840 nm. As described in the first to fifth embodiments, by providing the light reducing filter 48 or the reflecting member 60 in the exit window 44 of the cap 40, a part of the light from the VCSEL is absorbed, and the cap 40 Substantially cuts the light output from.
[0035]
Next, an example in which the semiconductor laser device according to this embodiment is applied to an optical transmission system is shown in FIG. FIG. 8A shows a configuration of an optical module 70 in which a semiconductor laser device mounting a single VCSEL shown in the first to fifth embodiments and an optical member are combined. FIG. 6 shows a configuration of an optical module 80 in which a semiconductor laser device on which four VCSELs described in the sixth embodiment are mounted and an optical member are combined.
The optical module 70 includes a collimating lens 72 that collimates the light emitted from the emission window 44 of the semiconductor laser device 20, a condensing lens 74 that condenses the collimated light, and an optical fiber 76 that receives the light from the condensing lens 74. It consists of. Similarly, the optical module 80 includes four collimator lenses 82, a condenser lens 84, and an optical fiber 86 arranged at positions corresponding to the emission points (mesas) of the respective VCSELs. Laser beams of different wavelengths from the VCSEL are combined by a collimator lens 82 and a condensing lens 84, taken into an optical fiber 84, and transmitted as wavelength multiplexed light.
[0036]
The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Deformation / change is possible. For example, the shape and material of the metal stem (case body) and cap according to the present embodiment are examples, and the shape and material are not limited to such shape and material. Further, the laser element is not necessarily limited to the VCSEL, and an edge-emitting laser element may be used.
[0037]
【The invention's effect】
According to the present invention, a light absorbing member (or a reflecting member) that absorbs part of the light from the semiconductor laser element is provided in the exit window of the cap that is attached to the case body on which the semiconductor laser element is mounted. Even if the injection current value to the semiconductor laser element is increased and this is driven (modulated) at high speed, a part of the light is absorbed by the light absorbing member, so the light output emitted to the outside is substantially reduced. can do. Therefore, it is possible to provide a semiconductor laser device that satisfies a predetermined safety standard while performing high-speed driving, and can contribute to high-speed optical communication using the semiconductor laser device.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration example of a VCSEL mounted on a semiconductor laser device.
2 shows the semiconductor laser device according to the first embodiment, FIG. 2 (a) is a plan view of the metal stem with the cap removed, and FIG. 2 (b) is a state with the cap attached. FIG. 3 is a sectional view taken along line XX in FIG.
FIG. 3 is a cross-sectional view of a semiconductor laser device according to a second embodiment.
FIG. 4 is a cross-sectional view of a semiconductor laser device according to a third embodiment.
FIG. 5 is a cross-sectional view of a semiconductor laser device according to a fourth embodiment.
FIG. 6 is a sectional view of a semiconductor laser device according to a fifth embodiment.
FIG. 7 is a plan view of a metal stem according to a sixth embodiment.
FIG. 8 is a diagram in which a semiconductor laser device is applied to an optical module. FIG. 8A shows an example of a semiconductor laser device mounting a single VCSEL, and FIG. 8B shows a plurality of VCSELs. An example of a semiconductor laser device that implements the above will be shown.
FIG. 9 is a cross-sectional view showing an example of the configuration of a conventional semiconductor laser device.
[Explanation of symbols]
1 VCSEL
11 Mesa 20, 20a, 20b, 20c, 20d, 20e Semiconductor laser device 30 Metal stem 34a, 34b, 34c, 34d Lead pin 40 Cap 44 Emission window 46, 46a Transmission glass 48, 48a Dimming filter 50 Mounter 52, 54, 56 58 Bonding wire 60 Reflective member 60a Ground glass 70, 80 Optical module

Claims (13)

A case body on which at least one semiconductor laser element is mounted;
A cap attached to the case body and including an exit window for emitting light from the semiconductor laser element to the outside;
A semiconductor laser device, wherein the exit window is provided with a light absorbing member that absorbs part of the light from the semiconductor laser element. The semiconductor laser device according to claim 1, wherein the light absorbing member includes a glass member and at least one neutral density filter disposed to face the glass member. 3. The semiconductor laser device according to claim 2, wherein the neutral density filter is provided on both surfaces of the glass member or one of the surfaces. 4. The semiconductor laser device according to claim 2, wherein the neutral density filter is an absorption filter that uniformly absorbs light from the semiconductor laser element. The semiconductor laser device according to claim 1, wherein the light absorbing member includes a glass member capable of absorbing light at a predetermined ratio. The semiconductor laser device according to claim 5, wherein the light absorbing member is formed of a single glass member. A case body on which at least one semiconductor laser element is mounted;
A cap attached to the case body and including an exit window for emitting light from the semiconductor laser element to the outside;
A semiconductor laser device, wherein the exit window is provided with a reflecting member that reflects part of light from the semiconductor laser element. The semiconductor laser device according to claim 7, wherein the reflecting member is disposed to face the glass member. The semiconductor laser device according to claim 7, wherein the reflection member includes a glass member having irregularities formed on a surface thereof. The semiconductor laser device according to claim 9, wherein the glass member is made of a single ground glass. 11. The semiconductor laser device according to claim 1, wherein a plurality of the semiconductor laser elements are arranged on the case body, and the plurality of semiconductor laser elements are driven to emit light simultaneously. The semiconductor laser device according to claim 11, wherein the plurality of semiconductor laser elements have a plurality of oscillation wavelengths. The semiconductor laser device according to claim 1, wherein the semiconductor laser element is a surface emitting semiconductor laser.

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