Distributed multi-single-tube semiconductor laser beam combining device

Abstract

This disclosure provides a distributed multi-single-tube semiconductor laser beam combining device, comprising: a multi-single-tube semiconductor laser spatial beam combining system (A), including multiple semiconductor laser spatial beam combining single modules (1), the multiple semiconductor laser spatial beam combining single modules (1) having superimposed beam spots in the slow axis direction, the semiconductor laser spatial beam combining single module (1) including multiple single-tube semiconductor lasers, the multiple single-tube semiconductor lasers having superimposed beam spots in the fast axis direction; a grating spectral modulation and front cavity co-aperture spectral beam combining system (B), used to lock the beam at different center wavelengths, narrow the spectral width of the laser in the fast axis direction, and perform co-aperture beam combining output; a fast-slow axis conversion system (C), used to perform fast-slow axis conversion and homogenize the fast-slow axis beam quality; and an optical fiber coupling system (D), used to couple the beam into an optical fiber for output.

Description

Technical Field

[0001] This disclosure relates to the field of laser technology, and more particularly to a distributed multi-single-tube semiconductor laser beam combining device. Background Technology

[0002] Semiconductor lasers possess advantages such as wide wavelength coverage, high electro-optical conversion efficiency, small size, good stability, low cost, and long lifespan, making them promising for applications in various fields including military defense, civilian manufacturing, healthcare, and scientific research. However, the low output power and poor beam quality of currently available commercial single-tube semiconductor lasers limit their direct application. Spectral beam combining technology based on diffractive optical elements can amplify the output power of semiconductor lasers while maintaining high beam quality. Theoretically, the beam quality after beam combining is comparable to that of a single emitting unit participating in the beam combining. This technology has attracted widespread attention from research institutions both domestically and internationally in recent years.

[0003] Spectral beam combining technology directly utilizes semiconductor lasers to form a high-efficiency, compact laser system without going through an intermediate pumping conversion process. This results in a high optical-to-optical conversion efficiency for the spectral beam combining system, and the beam quality of the combined laser can be comparable to that of the sub-light-emitting units participating in the beam combining. This overcomes the disadvantage of poor beam quality after spatial beam combining of semiconductor lasers and greatly improves the luminous brightness of semiconductor lasers.

[0004] Currently, semiconductor laser spectral combining systems typically use bars or stacked arrays as the combining objects. However, the Smile effect of bars and stacked arrays significantly impacts beam combining. Furthermore, beam shaping elements (BTS) are required before the grating to reshape the beam, and the small size of bars and stacked arrays leads to significant heat dissipation issues that affect system performance. For stacked arrays, using a BTS for fast-axis spectral combining results in a large difference in beam quality between the fast and slow axes. Without a BTS, using a slow-axis beam for combining suffers from inconsistent slow-axis beam quality due to current variations, and direct use of a slow-axis collimator for stacked arrays yields poor collimation, both of which are detrimental to subsequent fiber coupling. Summary of the Invention

[0005] In view of the above problems, the present invention provides a distributed multi-single-tube semiconductor laser beam combining device to solve the shortcomings of existing spectral beam combining systems.

[0006] One aspect of this disclosure provides a distributed multi-single-tube semiconductor laser beam combining device, comprising: a multi-single-tube semiconductor laser spatial beam combining system, including multiple semiconductor laser spatial beam combining modules, wherein the multiple semiconductor laser spatial beam combining modules have their beams superimposed in the slow axis direction, and each semiconductor laser spatial beam combining module includes multiple single-tube semiconductor lasers, wherein the multiple single-tube semiconductor lasers have their beams superimposed in the fast axis direction; a grating spectral modulation and front cavity common aperture spectral beam combining system, used to modulate the beam output from the multi-single-tube semiconductor laser spatial beam combining system in the fast axis direction with a fixed spectral interval and lock it at different center wavelengths, narrowing the spectral width of each laser beam in the fast axis direction, and performing common aperture beam combining output from beams of locked wavelengths incident on different directions of the grating; a fast-slow axis conversion system, used to perform fast-slow axis conversion on the beam output from the grating spectral modulation and front cavity common aperture spectral beam combining system; and an optical fiber coupling system, used to couple the beam after fast-slow axis conversion by the fast-slow axis conversion system into an optical fiber for output.

[0007] Optionally, the semiconductor laser spatial beam combining module further includes: a fast-axis collimating mirror for collimating the plurality of single-tube semiconductor lasers in the fast-axis direction, wherein the plurality of single-tube semiconductor lasers are arranged along the fast-axis direction; a slow-axis collimating mirror for collimating the plurality of single-tube semiconductor lasers in the slow-axis direction; and a fast-axis stepped reflector for spatially arranging the light spots of the plurality of single-tube semiconductor lasers in the fast-axis direction.

[0008] Optionally, the multi-single-tube semiconductor laser spatial beam combining system further includes: a right-angle prism; the multiple semiconductor laser spatial beam combining modules are symmetrically disposed on both sides of the right-angle prism, each directing a beam toward the right-angle prism at an incident angle of 45°; the right-angle prism reflects the beams emitted by the multiple semiconductor laser spatial beam combining modules, so that the beam spots of the multiple semiconductor laser spatial beam combining modules are spatially arranged along the slow axis direction.

[0009] Optionally, the grating spectral modulation and front cavity common aperture spectral beam combining system includes: a half-wave plate for adjusting the polarization state of the beam output from the multi-single-tube semiconductor laser spatial beam combining system, so that the beam matches the single polarization state of the plane diffraction grating; a cylindrical lens for focusing the beam onto the plane diffraction grating in the fast axis direction; a plane diffraction grating for causing the beam to diffract; an output coupling mirror for forming an external cavity with the rear cavity of each of the single-tube semiconductor lasers, thereby locking the single-tube semiconductor lasers at different positions in the fast axis direction to different wavelengths due to the dispersive effect of the plane diffraction grating, wherein, after the action of the output coupling mirror, beams of different wavelengths are incident on the plane diffraction grating at different incident angles and exit at the same diffraction angle, forming a spectral beam combining; and a first reflecting mirror for reflecting the spectral beam combining output; wherein the multi-single-tube semiconductor laser spatial beam combining system and the plane diffraction grating are respectively placed at the front and rear focal points of the cylindrical lens.

[0010] Optionally, the fast and slow axis conversion system includes a second mirror, a third mirror, a fourth mirror, and a fifth mirror, each with a different reflection direction, used to perform multiple fast and slow axis direction conversions on the beam output by the grating spectral modulation and front cavity common aperture spectral combining system.

[0011] Optionally, the fiber optic coupling system includes: a focusing lens, which is a single aspherical lens or a combination of aspherical cylindrical lenses, for focusing the beam output by the fast-slow axis conversion system; and an optical fiber with its port located at the back focal point of the focusing lens.

[0012] Optionally, the fast-axis collimating lens is an aspherical cylindrical lens, and the slow-axis collimating lens is a spherical cylindrical lens. The surfaces of both the fast-axis and slow-axis collimating lenses are coated with a strong light-resistant anti-reflection film. The incident surface of the fast-axis stepped reflector is coated with a strong light-reflectivity dielectric film. The front cavity of the single-tube semiconductor laser is coated with an anti-reflection film, and the rear cavity is coated with a high-reflection film.

[0013] Optionally, the incident surface of the right-angle prism is coated with a dielectric film with high light reflectivity.

[0014] Optionally, the cylindrical lens is an aspherical cylindrical lens with a strong light-resistant anti-reflective coating on its surface; the planar diffraction grating is a transmission grating with a substrate material of fused silica; and the output coupling mirror is a partial reflector with a partial reflectivity coating.

[0015] Optionally, the single-tube semiconductor laser is any one of a semiconductor laser with a wide emission surface structure, a tapered semiconductor laser, a narrow-ridge semiconductor laser, a MOPA semiconductor laser, a photonic crystal semiconductor laser, or a large / large optical cavity semiconductor laser, wherein its rear cavity surface forms an external cavity output laser beam with the planar diffraction grating and the output coupling mirror.

[0016] The above-described at least one technical solution adopted in the embodiments of this disclosure can achieve the following beneficial effects:

[0017] This disclosure uses the results of fast and slow axis collimation and spatial arrangement of multiple single-tube semiconductor lasers as sub-modules of the entire beam combining device. This multi-module distributed spectral beam combining avoids the influence of the smile effect on the overall collimation effect when using bar strips or stacked arrays as light sources. Furthermore, independent single-tube semiconductor lasers are beneficial to solving the heat transfer problem of the entire system, which is beneficial to the heat dissipation of the chip and improves the overall performance of the system.

[0018] This disclosure eliminates the need for a BTS to perform fast-slow axis conversion on the light source. Instead, it sequentially collimates and arranges individual semiconductor lasers into sub-modules for beam combining. This ensures that the collimation effect of each individual semiconductor laser is consistent, optimal, and stable. This multi-module spectral beam combining avoids the adjustment errors of the BTS in spectral beam combining, which would affect the overall beam. By moving the fast-slow axis conversion system after spectral beam combining, the beam quality of the fast-slow axis spectral beam after multi-slow axis fast-axis beam combining can be homogenized, which is beneficial for subsequent fiber coupling and avoids the impact of poor fast-slow axis conversion on spectral beam combining. Attached Figure Description

[0019] To gain a more complete understanding of this disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 The illustration shows a schematic diagram of a distributed multi-single-tube semiconductor laser beam combining device provided in an embodiment of the present disclosure in the slow axis direction;

[0021] Figure 2 The illustration shows a schematic diagram of a distributed multi-single-tube semiconductor laser beam combining device provided in an embodiment of the present disclosure in the fast axis direction;

[0022] Figure 3 This schematic diagram illustrates a light spot of a light source after collimation and alignment according to an embodiment of the present disclosure.

[0023] Figure label:

[0024] A-Multi-single-tube semiconductor laser spatial beam combining system; B-Grating spectral modulation and front cavity common aperture spectral beam combining system; C-Fast-slow axis conversion system; D-Fiber coupling system; 1-Semiconductor laser spatial beam combining single module; 2-Right-angle prism; 3-Half-wave plate; 4-Cylindrical lens; 5-Plane diffraction grating; 6-Output coupling mirror; 7-First reflecting mirror; 8-Second reflecting mirror; 9-Third reflecting mirror; 10-Fourth reflecting mirror; 11-Fifth reflecting mirror; 12-Focusing mirror; 13-Fiber optic cable. Detailed Implementation

[0025] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0027] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0028] like Figure 1 and Figure 2 As shown in the figure, a distributed multi-single-tube semiconductor laser beam combining device provided in this embodiment includes: a multi-single-tube semiconductor laser spatial beam combining system A, a grating spectral modulation and front cavity common aperture spectral beam combining system B, a fast and slow axis conversion system C, and an optical fiber coupling system D arranged sequentially. The beam output from the multi-single-tube semiconductor laser spatial beam combining system A is sequentially passed through the grating spectral modulation and front cavity common aperture spectral beam combining system B, the fast and slow axis conversion system C, and the optical fiber coupling system D to complete the optical fiber output.

[0029] The multi-single-tube semiconductor laser spatial beam combining system A includes multiple semiconductor laser spatial beam combining single modules 1. The multiple semiconductor laser spatial beam combining single modules 1 have their light spots superimposed in the slow axis direction. The semiconductor laser spatial beam combining single module 1 includes multiple single-tube semiconductor lasers. The multiple single-tube semiconductor lasers have their light spots superimposed in the fast axis direction.

[0030] In this embodiment, the semiconductor laser spatial beam combining module 1 further includes: multiple single-tube semiconductor lasers, a fast-axis collimating mirror (FAC), a slow-axis collimating mirror (SAC), and a fast-axis stepped-back mirror. The multiple single-tube semiconductor lasers are sequentially collimated by the fast-axis collimating mirror and the slow-axis collimating mirror, spatially arranged along the fast axis by the fast-axis stepped-back mirror, and spatially arranged along the slow axis by a right-angle prism 2. The final laser beam is output from one side of the front cavity of the multi-single-tube semiconductor laser spatial beam combining system A to the grating spectral modulation and front cavity common-aperture spectral beam combining system B.

[0031] Preferably, the fast-axis collimating lens is an aspherical cylindrical lens, and the slow-axis collimating lens is a spherical cylindrical lens, both of which are coated with a strong light-resistant anti-reflection film. The incident surfaces of the fast-axis stepped reflector and the right-angle prism 2 are coated with a dielectric film with high light reflectivity.

[0032] In this embodiment, the multi-single-tube semiconductor laser spatial beam combining system A also includes a right-angle prism 2. Multiple semiconductor laser spatial beam combining modules 1 are symmetrically arranged on both sides of the right-angle prism 2, each directing its beam towards the right-angle prism 2 at a 45° incident angle; the right-angle prism 2 reflects the beams emitted from the multiple semiconductor laser spatial beam combining modules 1, causing the beam spots of the multiple semiconductor laser spatial beam combining modules 1 to be spatially arranged along the slow axis direction.

[0033] The grating spectral modulation and front cavity common aperture spectral beam combining system B is used to control the beam output from the multi-single-tube semiconductor laser spatial beam combining system A at a fixed spectral interval in the fast axis direction and lock it at different center wavelengths. It narrows the spectral width of each laser beam in the fast axis direction and performs common aperture beam combining output of the beams of locked wavelengths incident on different directions of the grating.

[0034] In this embodiment, the grating spectral modulation and front cavity common aperture spectral beam combining system B includes a half-wave plate 3, a cylindrical lens 4, a plane diffraction grating 5, an output coupling mirror 6, and a first reflecting mirror 7 arranged sequentially along the beam output direction. The system comprises: a half-wave plate 3 for adjusting the polarization state of the beam output from the multi-single-tube semiconductor laser spatial beam combining system A, matching the single polarization state of the plane diffraction grating 5; a cylindrical lens 4 for focusing the beam onto the plane diffraction grating 5 along the fast axis; the plane diffraction grating 5 for causing diffraction of the beam; an output coupling mirror 6 for forming an external cavity with the rear cavity of each single-tube semiconductor laser, which, combined with the dispersive effect of the plane diffraction grating 5, locks the single-tube semiconductor lasers at different positions along the fast axis to different wavelengths. After the action of the output coupling mirror 6, beams of different wavelengths are incident on the plane diffraction grating 5 at different incident angles and exit at the same diffraction angle, forming a spectral beam combining system; a first reflecting mirror 7 for reflecting the spectral beam combining system; and the multi-single-tube semiconductor laser spatial beam combining system A and the plane diffraction grating 5, respectively, are placed at the front and rear focal points of the cylindrical lens 4. Beams of different wavelengths are incident on the planar diffraction grating 5 at different incident angles and then exit at the same diffraction angle. The resulting spectral beam is output to the fast-slow axis conversion system C after passing through the first reflecting mirror 7.

[0035] Preferably, the cylindrical lens 4 is an aspherical cylindrical lens with a strong light anti-reflection coating on its surface.

[0036] Preferably, the planar diffraction grating 5 is a transmission grating, the substrate material is fused silica, and the parameters such as the center wavelength and grating period are designed to match the center wavelength, the spacing of the light-emitting units, and the focal length of the cylindrical lens 4 of the output spatial beam of the multi-single-tube semiconductor laser spatial beam combining system A; the multi-single-tube semiconductor laser spatial beam combining system A and the grating 5 are respectively placed on the front and rear focal points of the cylindrical lens 4.

[0037] Preferably, the output coupling mirror 6 is a partial reflector coated with a partial reflectivity film.

[0038] The single-tube semiconductor laser can be any one of the following: a semiconductor laser with a wide emission surface structure, a tapered semiconductor laser, a narrow ridge semiconductor laser, a MOPA semiconductor laser, a photonic crystal semiconductor laser, or a super-large / large optical cavity semiconductor laser. Its rear cavity surface can form an external cavity output laser beam with the planar diffraction grating 5 and the output coupling mirror 6.

[0039] The front cavity of the single-tube semiconductor laser is coated with an anti-reflection film, and the rear cavity is coated with a high-reflection film. The semiconductor laser spatial beam combining module 1 has N single-tube semiconductor lasers arranged in the fast axis direction. The number N is designed to match the gain bandwidth range of the single-tube semiconductor laser chip, the focal length of the cylindrical lens 4, and the spacing of the single-tube semiconductor lasers in the fast axis direction.

[0040] The fast-slow axis conversion system C is a mirror group composed of a second mirror 8, a third mirror 9, a fourth mirror 10, and a fifth mirror 11 arranged in different directions. All mirrors are high-intensity, high-reflectivity mirrors coated with a dielectric film. The mirror group is used to receive the beam after spectral beam combining and to convert its fast-slow axis direction to homogenize the beam quality. The converted beam is then output to the fiber optic coupling system D.

[0041] The fiber optic coupling system D is used to couple the light beam, after being converted to a faster or slower axis by the fast / slow axis conversion system C, into an optical fiber for output. The fiber optic coupling system D includes a focusing lens 12 and an optical fiber 13. The surface of the focusing lens 12 is coated with a strong light-resistant anti-reflection film. The front end of the optical fiber 13 is placed at the rear focal point of the focusing lens 12. The light beam, after being converted to a faster or slower axis, is focused by the focusing lens 12 onto the front end of the optical fiber 13, achieving fiber coupling, and the light beam is output from the rear end of the optical fiber.

[0042] The focusing lens 12 in the fiber optic coupling system D can be a single aspherical lens or a combination of a group of aspherical cylindrical lenses, and its parameters are designed to match the output beam and fiber parameters of the fast and slow axis conversion system C.

[0043] The distributed multi-single-tube semiconductor laser beam combining device disclosed in this embodiment uses multiple semiconductor laser spatial beam combining modules as beam combining sub-units. Compared with bars or stacked arrays, this method offers better heat dissipation performance, significantly reducing the impact of heat dissipation on the overall system stability. Secondly, using multiple semiconductor laser spatial beam combining modules as beam combining sub-units eliminates the need for further collimation of the output beam compared to bars or stacked arrays. Furthermore, each single-tube semiconductor laser within the module is collimated separately, resulting in better and more stable performance and avoiding SMI (Self-Mixing). The impact of the Ley effect on the system; in addition, compared with slow-axis spectral combining of stacked arrays, the single module of spatial combining of multiple semiconductor lasers can use a larger focal length of the slow-axis collimating lens, resulting in better collimation of the slow axis, smaller unit linewidth and narrower spectrum after spectral combining, and reduced influence of current on the output spectrum; compared with fast-axis spectral combining of stacked arrays, there is no need for beam shaping by BTS before spectral combining, moving the function of BTS before the fiber coupling system, avoiding the influence of BTS error on the spectral combining result, and homogenizing the beam quality of the fast and slow axes after spectral combining, which is more conducive to fiber coupling.

[0044] Figure 3 The illustration shows a schematic diagram of a light spot after collimation and alignment of a light source according to an embodiment of this disclosure. Figure 3 As shown, the emitted light spot is uniformly arranged and has a good collimation effect after being collimated by the multi-single-tube semiconductor laser spatial beam combining system A.

[0045] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0046] Although this disclosure has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made to this disclosure without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Therefore, the scope of this disclosure should not be limited to the above embodiments, but should be defined not only by the appended claims, but also by their equivalents.

Claims

1. A distributed multi-single-tube semiconductor laser beam combining device, characterized by, Comprise: Multi-single-tube semiconductor laser spatial beam combining system (A), comprising a plurality of semiconductor laser spatial beam combining single modules (1), the plurality of semiconductor laser spatial beam combining single modules (1) are superimposed in the slow axis direction, the semiconductor laser spatial beam combining single module (1) comprises a plurality of single-tube semiconductor lasers, and the plurality of single-tube semiconductor lasers are superimposed in the fast axis direction; Grating spectrum regulation and pre-cavity common-aperture spectral beam combining system (B) is used for regulating and locking the light beams output by the multi-single-tube semiconductor laser spatial beam combining system (A) on different center wavelengths in the fast axis direction, narrowing the spectral width of each laser in the fast axis direction, and combining the light beams of the locked wavelengths incident to different directions of the grating in the common-aperture; Fast-slow axis conversion system (C) is used for converting the light beams output by the grating spectrum regulation and pre-cavity common-aperture spectral beam combining system (B) in the fast-slow axis direction; Fiber coupling system (D) is used for coupling the light beams converted by the fast-slow axis conversion system (C) into the optical fiber and outputting.

2. The apparatus of claim 1, wherein, The semiconductor laser spatial beam combining single module (1) further comprises: A fast-axis collimating mirror is used for collimating the plurality of single-tube semiconductor lasers in the fast axis direction, and the plurality of single-tube semiconductor lasers are arranged along the fast axis direction; A slow-axis collimating mirror is used for collimating the plurality of single-tube semiconductor lasers in the slow axis direction; A fast-axis stepped mirror is used for spatially arranging the light spots of the plurality of single-tube semiconductor lasers in the fast axis direction.

3. The apparatus of claim 1, wherein, The multi-single-tube semiconductor laser spatial beam combining system (A) further comprises: A right-angle prism (2); The plurality of semiconductor laser spatial beam combining single modules (1) are symmetrically arranged on both sides of the right-angle prism (2), and each semiconductor laser spatial beam combining single module (1) is arranged to be incident to the right-angle prism (2) at an angle of 45°; The right-angle prism (2) reflects the light beams emitted by the plurality of semiconductor laser spatial beam combining single modules (1), so that the light spots of the light beams of the plurality of semiconductor laser spatial beam combining single modules (1) are spatially arranged along the slow axis direction.

4. The apparatus of claim 1, wherein, The grating spectrum regulation and pre-cavity common-aperture spectral beam combining system (B) comprises: A half-wave plate (3) is used for adjusting the polarization state of the light beams output by the multi-single-tube semiconductor laser spatial beam combining system (A), so that the light beams match a single polarization state of a plane diffraction grating (5); A cylindrical lens (4) is used for focusing the light beams to the plane diffraction grating (5) in the fast axis direction; The plane diffraction grating (5) is used for diffracting the light beams; An output coupling mirror (6) is used for forming an external cavity with the rear cavity of each single-tube semiconductor laser, and combining the dispersion effect of the plane diffraction grating (5) to lock the single-tube semiconductor lasers at different wavelengths at different positions in the fast axis direction, wherein the light beams of different wavelengths are incident to the plane diffraction grating (5) at different angles of incidence after the action of the output coupling mirror (6), and are output at a same diffraction angle, to form a spectral beam combining; A first mirror (7) is used for reflecting and outputting the spectral beam combining. The multi-single-tube semiconductor laser space beam combining system (A) and the planar diffraction grating (5) are respectively arranged on the front and rear focal points of the cylindrical lens (4).

5. The apparatus of claim 1, wherein, The fast-slow axis conversion system (C) comprises a second mirror (8), a third mirror (9), a fourth mirror (10) and a fifth mirror (11), each mirror has different reflection directions, and is used for regulating the grating spectrum and converting the light beam output by the front cavity common-aperture spectrum beam combining system (B) in the fast-slow axis direction for multiple times.

6. The apparatus of claim 1, wherein, The fiber coupling system (D) comprises: a focusing mirror (12), which is a single aspheric lens or a combination of a group of aspheric cylindrical lenses, and is used for focusing the light beam output by the fast-slow axis conversion system (C); a fiber (13), the port of which is arranged at the rear focal point of the focusing mirror (12).

7. The apparatus of claim 2, wherein, The fast-axis collimating mirror is an aspheric cylindrical lens, the slow-axis collimating mirror is a spherical cylindrical lens, the surfaces of the fast-axis collimating mirror and the slow-axis collimating mirror are coated with strong light-resistant anti-reflection film, and the incident surface of the fast-axis stepped mirror is coated with strong light-resistant dielectric film with high reflectivity. The front cavities of the single-tube semiconductor lasers are coated with anti-reflection film, and the rear cavities are coated with high-reflection film.

8. The apparatus of claim 3, wherein, The incident surfaces of the right-angle prisms (2) are coated with strong light-resistant dielectric film with high reflectivity.

9. The apparatus of claim 4, wherein, The cylindrical lens (4) is an aspheric cylindrical lens, and the surface thereof is coated with strong light-resistant anti-reflection film; the planar diffraction grating (5) is a transmission grating, and the base material thereof is fused quartz; and the output coupling mirror (6) is a partial mirror coated with a partial reflectivity film.

10. The apparatus of claim 4, wherein, The single-tube semiconductor laser is any one of a semiconductor laser adopting a wide emitting surface structure, a tapered semiconductor laser, a narrow-ridge semiconductor laser, a MOPA semiconductor laser, a photonic crystal semiconductor laser and an ultra-large / large optical cavity semiconductor laser, and the rear cavity thereof forms an external cavity output laser beam together with the planar diffraction grating (5) and the output coupling mirror (6).

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