WO2017122611A1

WO2017122611A1 - Laser device

Info

Publication number: WO2017122611A1
Application number: PCT/JP2017/000414
Authority: WO
Inventors: ▲高▼弘内田; 淳梁瀬; 昌利齋藤; 佑斗室木
Original assignee: 株式会社アマダミヤチ; 株式会社アマダホールディングス
Priority date: 2016-01-14
Filing date: 2017-01-10
Publication date: 2017-07-20
Also published as: JPWO2017122611A1; TW201736887A; JP6522166B2

Abstract

This surface light-emitting laser 10 has: a VCSEL element 26 having a semiconductor substrate 32 as a substrate material; and an output mirror 28 and a band narrowing element 29 that are disposed above the VCSEL element 26 so as to be spaced apart from a light-emitting surface 24 of the VCSEL element 26. During a laser oscillation operation, a part of light SB inductively emitted from an active region 38a of the VCSEL element 26 is taken out as a single laser beam LB to the outside after being subjected to resonance-amplification through repeated reflections between a multilayer reflection mirror 34 inside the VCSEL element 26 and the band narrowing element 29 or the output mirror 28 outside the VCSEL element 26.

Description

Laser equipment

The present invention relates to a laser device using a surface emitting laser as a laser light source, and more particularly to a laser device suitable for use in laser processing.

In recent years, surface emitting lasers (VCSELs) are becoming popular mainly in laser application fields such as optical communication, printers, and displays. A surface emitting laser is a type of semiconductor laser that emits a laser beam perpendicularly to the substrate surface from a semiconductor substrate. Compared with a general (single emitter type) semiconductor laser that emits a laser beam horizontally to the substrate surface. It is attracting attention as a next-generation laser light source that is advantageous for integration, low power consumption, and mass production.

JP 2006-149915 A

A surface emitting laser that is currently popular typically has a light emitting surface of 4.7 mm × 4.7 mm, and the diameter of each beam exit port formed as a two-dimensional array on the light emitting surface is 18 μm, The laser output of a single laser beam emitted from the laser beam is several tens of mW, the laser output of the entire two-dimensional array is about 100 W at the highest, and the beam quality is not good.

Increasing the number of apertures and increasing the number of beam exit apertures is a simple solution to increase the output power of surface-emitting lasers. However, there is a limit to this, and the diameter of the beam exit apertures can be increased. The problem is that the beam quality of a bundle of laser beams obtained in the entire two-dimensional array decreases as the number increases. For this reason, the conventional surface emitting laser cannot be used for laser processing that requires a high-power and high-quality laser beam.

The present invention has been made in view of the problems of the prior art, and provides a laser apparatus that realizes a high-power and high-quality laser beam using a surface emitting laser.

The laser apparatus of the present invention includes a first surface emitting laser that emits a bundle of first laser beams having a wavelength that matches or approximates the first standard wavelength, and a wavelength that matches or approximates the second standard wavelength. A second surface emitting laser that emits a bundle of second laser beams, and the first laser beam from the first surface emitting laser and the second surface emitting laser from the second surface emitting laser. A coupling unit that spatially multiplex-synthesizes the laser beam and emits the combined laser beam, and each of the first and second surface emitting lasers is formed on the semiconductor substrate and the semiconductor substrate And a plurality of light emitting openings provided two-dimensionally and discretely on the active area, each perpendicular to or oblique to the substrate surface of the semiconductor substrate from the light emitting openings. Aligned with a given standard wavelength in the direction Alternatively, a surface emitting laser element that stimulates and emits light having an approximate wavelength, and a light emitting opening of the surface emitting laser element for extracting a single laser beam by resonantly amplifying the light that is stimulated and emitted from each of the light emitting openings And an output mirror disposed at a position facing away from the output mirror.

In the above configuration, the divergence angle of the single laser beam obtained from each light emitting aperture is reduced by the configuration in which the output mirror of the laser resonator is disposed at a position facing the light emitting aperture of the surface emitting laser element. Therefore, even if the diameter of the light emitting aperture is increased and the number is increased, the overlapping or mutual interference of single laser beams within the bundle of laser beams obtained by the entire surface emitting laser element is reduced as much as possible. Both output and beam quality can be achieved. Furthermore, by multiplying and synthesizing each bundle of laser beams obtained from a plurality of surface emitting lasers, multiplication of the laser output, that is, higher output can be realized more efficiently.

In a preferred aspect of the present invention, the first surface-emitting laser has a first band narrowing element that narrows the wavelength of a single laser beam near the first standard wavelength, and the second surface. The light emitting laser has a second band narrowing element that narrows the wavelength of a single laser beam near the second standard wavelength. Thus, in each surface emitting laser, the spatial coupling can be performed stably and with high accuracy by locking the wavelength of the single laser beam near the standard wavelength and narrowing the band. More specifically, the coupling unit may include a wavelength coupling element that multiplex-synthesizes the first laser beam and the second laser beam by wavelength coupling. According to such a wavelength coupling method, by multiplying the laser oscillation wavelength (standard wavelength) for each surface emitting laser, the laser output can be easily multiplied or increased in output. As another aspect, the first and second laser beams can be multiplexed and synthesized by polarization coupling using a polarization coupling element.

In another preferred embodiment, the narrowband element also serves as an output mirror. In this case, the band narrowing element not only narrows the wavelength band but also functions as a main external resonator, and emits a single laser beam having a small divergence angle and a stable wavelength locked to the outside.

In another preferred embodiment, any of the thin films provided on the active region in each of the light emitting openings has a property of being transmissive or non-reflective with respect to stimulated emission light. According to this configuration, the stimulated emission light on the active region is reflected by the external output mirror separated by a considerable distance, so that the stimulated emission light obliquely deviated from the vertical direction (that is, having a large spread angle). Can be effectively removed from the single laser beam.

In another preferred embodiment, the coupling unit includes a wavelength coupling element that multiplex-synthesizes the first and second laser beams having the first and second standard wavelengths offset from each other by wavelength coupling. . Alternatively, the coupling unit includes a polarization coupling element that multiplex-synthesizes the first and second laser beams having the same first and second standard wavelengths by polarization coupling. A configuration in which a wavelength coupling element and a polarization coupling element are used in combination is also possible. With this configuration, it is possible to arbitrarily increase the number of surface emitting lasers used for increasing the output of the synthetic laser beam, and to realize a significant improvement in the laser output of the surface emitting laser.

According to the laser apparatus of the present invention, a high-power and high-quality laser beam can be realized using a surface emitting laser by the above-described configuration and operation.

It is a figure which shows the whole structure of the laser processing apparatus in one Embodiment of this invention. It is a perspective view which shows the external appearance structure of the principal part of the surface emitting laser with which the said laser processing apparatus is provided. It is a top view which shows typically the two-dimensional array of the light emission surface in the said surface emitting laser. It is sectional drawing which shows the structure of the said surface emitting laser. It is a figure which shows the wavelength-reflectance characteristic of the dichroic mirror used as a wavelength coupling element in the said laser processing apparatus. It is a figure which shows the whole structure of the laser processing apparatus in another embodiment. It is a figure which shows the structure of the principal part of the laser processing apparatus in another embodiment. It is sectional drawing which shows the modification of a structure of the said surface emitting laser. It is sectional drawing which shows the structure of the surface emitting laser in another embodiment.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[Configuration of the entire device]
In FIG. 1, the structure of the laser processing apparatus in one Embodiment of this invention is shown. This laser processing apparatus is a laser apparatus applicable to various types of laser processing such as laser welding, laser marking, laser cutting, and laser drilling, and a plurality (two in this example) of surface emitting lasers (VCSEL) 10A, 10B, The coupling unit 14, the fiber transmission system 15, the laser emission unit 16, the stage 18, the control unit 20, and the like are included.

Control unit 20 controls each unit and the entire operation of the laser processing apparatus. In particular, for each of the

surface emitting lasers

10A and 10B, the control unit 20 can arbitrarily control the laser oscillation operation (continuous oscillation, pulse oscillation, etc.) through the individual

laser power sources

22A and 22B. Further, when a scanning mechanism such as a galvano scanner is mounted on the laser emission unit 16 or when a feed mechanism such as an XY table is mounted on the stage 18, the control unit 20 is synchronized with the laser oscillation operation, Alternatively, the operations of the motion mechanisms (scanning operation, workpiece feeding operation) are controlled for the alignment of the processing points. The control unit 20 is also connected with an input / output device (not shown) for man-machine interface.

[Schematic structure and operation of surface emitting laser]
FIG. 2 schematically shows the appearance of the main part of the surface emitting laser 10A (10B) and the state of the laser emission state. The surface emitting laser 10A (10B) includes, for example, a plate-like surface emitting laser element (hereinafter referred to as “VCSEL element”) 26 having a rectangular light emitting surface 24, and a light emitting surface 24 above the VCSEL element 26. A plate-like or block-like output mirror 28 arranged in parallel at an appropriate distance, and a plate-like or block-like narrow-band narrowing element 29 arranged in parallel above the output mirror 28 (FIG. 1, FIG. 4).

As shown in FIG. 3, the light emitting surface 24 of the VCSEL element 26 is provided with a number of light emitting ports 30 arranged in a two-dimensional direction discretely or in an array. The diameter φ of each light emitting port 30 is much larger than a normal one, and is selected from 100 to 1000 μm, for example. In FIG. 3, the number of the light emitting openings 30 is shown as 16 (4 × 4) for simplification, but is actually several hundred or more or 1000 or more.

Of the light SB stimulated and emitted from each light emitting port 30 of the light emitting surface 24, it is reflected between the reflecting mirror 34 (FIG. 4) built in the VCSEL element 26 and the external output mirror 28 or the band narrowing element 29. Is amplified by resonance amplification and is taken out of the output mirror 28 as a single laser beam LB. Then, all the single laser beams LB taken out simultaneously from the output mirror 28 are combined to form a bundle of laser beams SLB _A (SLB _B ).

In this embodiment, each single laser beam LB obtained outside the output mirror 28 has a very small divergence angle, the diameter φ of the light emitting aperture 30 is selected to be a considerably large size (100 to 1000 μm), and the density Is increased, the overlap or mutual interference of the single laser beams LB in the bundle of laser beams SLB _A (SLB _B ) is reduced as much as possible to improve the beam quality.

[Detailed configuration and operation of surface emitting laser]
FIG. 4 shows an internal configuration (cross-sectional configuration) of the surface emitting laser 10A (10B). The VCSEL element 26 includes, for example, a GaAs-based semiconductor substrate 32 as a base material, and a multilayer reflector such as a DBR (Distributed Bragg Reflector) 34, a single layer or a multilayer lower semiconductor layer 36 is formed on the semiconductor substrate 32 by a normal semiconductor process. The active layer 38, the single-layer or multilayer upper semiconductor layer 40 and the upper electrode 42 are sequentially stacked, and the lower electrode 44 is formed on the back surface of the semiconductor substrate 32. Usually, the lower electrode 44 is coupled to a cooling heat sink (not shown) through an insulator (not shown).

The lower semiconductor layer 36 and the upper semiconductor layer 40 include a carrier injection layer. Further, the upper semiconductor layer 40 also includes an antireflection film. In this embodiment, the thin films constituting the lower semiconductor layer 36 and the upper semiconductor layer 40 are both non-reflective or transmissive with respect to light having an oscillation wavelength. The upper electrode 42 is formed with an opening 42 a that forms the light emitting port 30. A portion of the active layer 38 located immediately below the light emitting opening 30 forms an active region 38a.

When the surface emitting laser 10A (10B) performs laser oscillation, a driving voltage E is applied between the upper electrode 42 and the lower electrode 44 from the laser power source 22A (22B). As a result, carriers are injected into the active layer 38 via the lower semiconductor layer 36 and the upper semiconductor layer 40, and light SB that matches or approximates a predetermined standard wavelength λ _S is stimulated and emitted from the active region 38 a to the outside of the light emitting opening 30. Is done.

Here, in order to construct an optical resonator for the standard wavelength λ _S and its neighboring wavelengths, the multilayer reflecting mirror 34 inside the VCSEL element 26 has a reflectance of approximately 100%, and an external output mirror For example, 28 has a reflectance of 1 to 90%, preferably 2 to 30%. Of the light SB stimulated and emitted from the active region 38a, the light SB that has been repeatedly reflected and amplified between the multilayer reflecting mirror 34 and the output mirror 28 or the band narrowing element 29 is resonantly amplified as a single laser beam LB. Is taken out.

In this case, as shown in FIG. 4, the light emitted from the light emitting port 30 of the VCSEL element 26 at an angle perpendicular to or close to the substrate surface of the VCSEL element 26 is the opposite surface of the output mirror 28 (shown by the solid line SB). The light is reflected substantially vertically at the lower surface and returns to the light emitting opening 30. However, the light emitted from the light emitting opening 30 by more than a certain angle is reflected obliquely by the facing surface (lower surface) of the output mirror 28 and does not return into the light emitting opening 30 as indicated by a one-dot chain line SB ′. . As a result, the light SB propagating perpendicularly or at an angle close to the substrate surface of the VCSEL element 26 is repeatedly reflected and amplified between the multilayer reflecting mirror 34 and the output mirror 28 or the narrowband element 29. The single laser beam LB having a small divergence angle is taken out of the output mirror 28.

As described above, in this embodiment, the light SB stimulated and emitted on the active region 38a of the VCSEL element 26 is reflected by the external output mirror 28 with a considerable distance, so that it is obliquely shifted from the vertical direction. It is possible to effectively remove the stimulated emission light SB ′ (that is, having a large divergence angle) from the single laser beam, thereby effectively reducing the divergence angle of the single laser beam LB obtained outside the output mirror 28. can do.

Furthermore, in this embodiment, a collimator is suitably provided as means for further reducing the divergence angle of the single laser beam LB. For this purpose, for example, as shown in FIG. 4, a spherical convex portion 28a is formed on the upper surface of the portion of the output mirror 28 facing the light emitting port 30, so that the output mirror 28 functions as a collimator lens. Good. Alternatively, although not shown, a configuration in which an independent collimator lens is disposed outside the output mirror 28, for example, between the output mirror 28 and the band narrowing element 29 or outside the band narrowing element 29 is also possible.

The band-narrowing element 29 is made of, for example, VBG (Volume Bragg Grating) or VHG (Volume Holographic Grating), functions as an external resonator, and is a single laser beam LB or one laser beam emitted from the surface emitting laser 10A (10B). The wavelength width of the bundle laser beam SLB _A (SLB _B ) is narrowed to a sufficiently narrow band λ _SA ± Δλ _A (λ _SB ± Δλ _B ), and the variation of the center wavelength is suppressed, and the standard wavelength λ _SA (λ _SB ) Lock nearby. Here, the standard wavelength λ _SA of the laser oscillation in one surface emitting laser 10 and the standard wavelength λ _SB of the laser oscillation in the other surface emitting laser 10B are constant so as not to overlap each other. Offset λ _K is provided (FIG. 5). As an example, λ _SA = 950 nm, λ _SB = 960 nm, Δλ _A , Δλ _B = 0.1 to 3 nm, and λ _K = 10 nm.

According to this embodiment, the light emitting aperture 30 of the VCSEL element 26 has a large aperture (100 to 1000 μm), and the wavelength of the laser oscillation is stably locked in a narrow band. It is possible to realize the beam LB. Therefore, by providing 1000 or more light emitting ports 30 with such a large aperture, for example, at 100 mW per chip on one chip of the VCSEL element 26, a laser output of 100 W or more and a bundle of high beam quality can be obtained. A laser beam SLB _A (SLB _B ) can be obtained.

[Operation of the entire device]
In this embodiment, as described above, the pair of

surface emitting lasers

10A and 10B including the VCSEL element 26, the output mirror 28, and the band narrowing element 29 have a large beam diameter and a narrow divergence angle. _A bundle of laser beams SLB _A and SLB _{B which} are composed of a number of high-power single laser beams LB and whose wavelengths do not overlap each other are output.

In FIG. 1, a bundle of laser beams SLB _A output from one surface emitting laser 10A and a bundle of laser beams SLB _B output from the other surface emitting laser 10B are orthogonal to each other on the same plane. Then, the light enters the coupling unit 14. The coupling unit 14 is composed of a dichroic mirror 50 having reflectivity characteristics as shown by a curve M in FIG. 5 and transmits one laser beam SLB _A while folding the other laser beam SLB _B at a right angle. Reflected in the traveling direction of the beam SLB _A. Here, since the wavelengths of the laser beams SLB _A and SLB _B do not overlap, they are spatially multiplexed and synthesized by wavelength coupling. In particular, in both

surface emitting lasers

10A and 10B, the narrowband element 29 narrows the wavelength of both laser beams SLB _A and SLB _B by locking them in the vicinity of the standard wavelengths λ _SA and λ _SB. The mirror 50 can perform stable and highly accurate wavelength coupling.

_A combined laser beam SLB _AB obtained by wavelength coupling of both laser beams SLB _A and SLB _{B by} the dichroic mirror 50 is emitted through a fiber transmission system 15 having an incident unit (condensing lens) 52 and an optical fiber 54. The workpiece W on the stage 18 is focused and irradiated by a condenser lens (not shown) in the laser emitting unit 16.

This laser processing apparatus collects and irradiates a workpiece W with a high-power and high-beam quality synthetic laser beam SLB _AB, thereby performing various laser processing such as laser welding, laser marking, laser cutting, and laser drilling. Can be done well by specification.

[Other Embodiments or Modifications]
According to the technical idea of the present invention, various other embodiments are possible as extensions or modifications of the above-described embodiments.

The embodiment shown in FIG. 6 shows a configuration example in which a polarization coupling element 56 is used instead of the wavelength coupling element 50 as the coupling unit 14.

In this case, a bundle of laser beams SLB _A having a standard wavelength λ _SA is output as P-polarized light from one surface emitting laser 10A, and a bundle of laser beams SLB _B having a standard wavelength λ _B is output from the other surface emitting laser 10B. Is output as S-polarized light. Here, the standard wavelength λ _SA and the standard wavelength λ _SB are selected to be the same value. Although not shown, a half-wave plate may be used to create P-polarized light or S-polarized light. The polarization coupling element 56 is composed of, for example, a polarization beam splitter, spatially multiplex-combines laser beams SLB _A and SLB _B incident perpendicularly to each other by polarization coupling, and travel of the laser beam SLB _A traveling straight ahead. A synthetic laser beam SLB _AB having a standard wavelength λ _SA (λ _SB ) in the direction is emitted.

The embodiment shown in FIG. 7 uses a combination of the wavelength coupling element 50 and the polarization coupling element 56 in the coupling unit 14 and greatly increases the number of surface emitting lasers (VCSEL) 10 used for increasing the output of the combined laser beam ( In the illustrated example, the number is increased to 6).

In this case, the six surface emitting lasers (VCSEL) 10A to 10F are divided into three pairs (10A / 10B), (10C / 10D), and (10E / 10F). In the first pair (10A / 10B), a bundle of laser beams SLB _A having a standard wavelength λ _SA is output from one surface emitting laser 10A as P-polarized light, and a standard wavelength λ _SB is output from the other surface emitting laser 10B. A bundle of laser beams SLB _B having (λ _SB = λ _SA ) is output as S-polarized light. The two laser beams SLB _A and SLB _B are incident on the first polarization coupling element 56 (1) orthogonally to each other, where they are polarization-coupled, and the combined laser beam SLB having the standard wavelength λ _SB (λ _SB ). _AB is obtained.

Similarly, in the second pair (10C / 10D), a bundle of laser beams SLB _C having a standard wavelength λ _SC (where λ _SC = λ _SA + λ _K1 ) is P-polarized light than the surface emitting laser 10C. A bundle of laser beams SLB _D having a standard wavelength λ _SD (where λ _SD = λ _SC ) is output as S-polarized light from the other surface emitting laser 10D. Then, both laser beams SLB _C and SLB _D are orthogonally incident on the second polarization coupling element 56 (2), where they are polarization-coupled, and the combined laser beam SLB having the standard wavelength λ _SC (λ _SD ). _CD is obtained. In the third pair (10E / 10F), a bundle of laser beams SLB _E having a standard wavelength λ _SE (where λ _SE = λ _SC + λ _K2 ) is output as P-polarized light from one surface emitting laser 10E. Then, a bundle of laser beams SLB _F having a standard wavelength λ _SF (where λ _SF = λ _SE ) is output as S-polarized light from the other surface emitting laser 10F. Then, both laser beams SLB _E and SLB _F are orthogonally incident on the third polarization coupling element 56 (3), where they are polarization-coupled, and the combined laser beam SLB having the standard wavelength λ _SE (λ _SF ). _EF is obtained.

The combined laser beam SLB _AB having the standard wavelength λ _SA (λ _SB ) emitted from the first polarization coupling element 56 (1) and the standard wavelength λ emitted from the second polarization coupling element 56 (2). _The synthesized laser beam SLB _CD having _SC (λ _SD ) is incident on the first wavelength coupling element 50 (1) orthogonally to each other, where it is wavelength-coupled and two kinds of standard wavelengths λ _SA (λ _SB ), Λ _SC (λ _SD ), a combined laser beam SLB _ABCD is obtained.

This synthetic laser beam SLB _ABCD is incident on the second wavelength coupling element 50 (2) and has a standard wavelength λ _SE (λ _SF ) from a third pair (10E / 10F) orthogonal thereto. Wavelength coupled with the beam SLB _EF . In this way, the three standard wavelengths λ _SA (λ _SB ) and λ _SC (λ _SD ) are obtained by adding all the laser outputs of the six surface emitting lasers 10A to 10F from the second wavelength coupling element 50 (2). , Λ _SE (λ _SF ) and a high-power synthetic laser beam SLB _ABCDEF are emitted toward a _subsequent laser optical system (not shown).

The embodiment shown in FIG. 8 is characterized in that, in the surface emitting laser (VCSEL) 10, the output mirror 28 is individually arranged at a position corresponding to each light emitting port 30 of the VCSEL element 26. Also in this case, in order to make the divergence angle of the single laser beam LB as small as possible, each output mirror 28 may have a function of a collimator lens, or an independent collimator in the subsequent stage of each output mirror 28. A lens (not shown) may be arranged.

The embodiment shown in FIG. 9 is characterized in that, in the surface emitting laser (VCSEL) 10, the narrowing element 29 is also used as the output mirror 28. That is, the band narrowing element 29 functions not only as a wavelength band narrowing but also as an external resonator, and can be used as an output mirror. In this case as well, a collimating lens (not shown) can be disposed downstream of the band-narrowing element 29 in order to reduce the divergence angle of the single laser beam LB as much as possible.

Note that, as described above, the above-described embodiment preferably employs a configuration in which an antireflection film is provided on the upper semiconductor layer 40 and each layer of the upper semiconductor layer 40 is made non-reflective or transmissive. However, a reflective film can be provided in the upper semiconductor layer 40 as a modification or a configuration example.

Further, the laser apparatus of the present invention has a particularly great advantage when applied to the laser processing apparatus as in the above embodiment, but can also be applied to other applications such as a laser medical apparatus.

10, 10A-10F Surface emitting laser (VCSEL)
14 Coupling unit 15 Fiber traditional system 16 Laser emitting unit 20 Control unit 26 Surface emitting laser element (VCSEL element)
28 Output Mirror 29 Narrow Bandwidth Element (VBG / VHG)
DESCRIPTION OF SYMBOLS 30 Light emission port 32 Semiconductor substrate 38a Active region 42a Opening part 50, 50 (1), 50 (2) Wavelength coupling element 56, 56 (1), 56 (2), 56 (3) Polarization coupling element

Claims

A first surface emitting laser that emits a bundle of first laser beams having a wavelength that matches or approximates a first standard wavelength;
A second surface emitting laser that emits a bundle of second laser beams having a wavelength that matches or approximates a second standard wavelength;
A coupling unit that emits a combined laser beam by spatially multiplexing and combining the first laser beam from the first surface emitting laser and the second laser beam from the second surface emitting laser. And
Each of the first and second surface emitting lasers includes:
A semiconductor substrate; an active region formed on the semiconductor substrate; and a plurality of light emitting apertures provided two-dimensionally and discretely on the active region. A surface emitting laser element that stimulates and emits light having a wavelength that matches or approximates a predetermined standard wavelength in a direction perpendicular or oblique to the substrate surface of
An output mirror disposed at a position spaced apart from the light emitting port of the surface emitting laser element and opposed thereto to resonately amplify light emitted from each of the light emitting ports and extract a single laser beam. , Laser equipment.
The first surface-emitting laser has a first narrowband element that narrows the wavelength of the single laser beam in the vicinity of the first standard wavelength;
The second surface-emitting laser has a second band-narrowing element that narrows the wavelength of the single laser beam near the second standard wavelength.
The laser device according to claim 1.
3. The laser apparatus according to claim 2, wherein the first and second band narrowing elements are provided independently of the output mirror.
3. The laser device according to claim 2, wherein the first and second narrowband elements also serve as the output mirror.
2. The laser according to claim 1, wherein in each of the light emitting apertures, any thin film provided on the active region has a property of being transmissive or non-reflective with respect to the stimulated emission light. apparatus.
The laser device according to claim 1, wherein the output mirror has a lens function for collimating the single laser beam.
The laser device according to claim 1, further comprising an optical lens for collimating the single laser beam independently of the output mirror.
The laser device according to claim 1, wherein the coupling unit includes a wavelength coupling element that multiplex-synthesizes the first laser beam and the second laser beam by wavelength coupling.
The laser device according to claim 1, wherein the coupling unit includes a polarization coupling element that multiplex-synthesizes the first laser beam and the second laser beam by polarization coupling.
A fiber transmission system for transmitting the synthetic laser beam emitted from the coupling unit through an optical fiber;
The laser apparatus according to claim 1, further comprising: a laser emitting unit that collects and irradiates the synthetic laser beam extracted from the other end of the optical fiber toward the object to be processed.