Dual-wavelength narrow-linewidth laser output device and method

Abstract

The invention relates to the technical field of laser, in particular to a dual-wavelength narrow-linewidth laser output device and method.The dual-wavelength narrow-linewidth laser output device comprises a semiconductor laser unit emitting linearly polarized light beams, and a light beam conversion lens is used for achieving conversion of semiconductor laser fast-axis light beams and semiconductor laser slow-axis light beams; the light beam conversion lens is used for collimating and compressing a semiconductor laser fast axis divergence angle, and the slow axis collimating lens is used for collimating and compressing a semiconductor laser slow axis divergence angle; the linearly polarized light beam is divided into a first light beam and a second light beam through the rectangular prism; the first light beam sequentially passes through a first volume Bragg grating, a first reflector, a half-wave plate and a polarization beam combiner; the second light beam sequentially passes through a second volume Bragg grating, a second reflector and a polarization beam combiner; the dual-wavelength narrow-linewidth semiconductor laser can solve the problems of precise regulation and control and power amplification of the central wavelength of the dual-wavelength narrow-linewidth semiconductor laser, has power expansibility, and realizes improvement of laser power by stacking a plurality of laser units in the vertical direction.

Description

Technical Field

[0001] The present invention belongs to the field of laser technology, and particularly relates to a dual-wavelength narrow linewidth laser output device and method. Background Art

[0002] With the continuous expansion of the application fields of semiconductor lasers, whether as a pump source or a direct application light source, high-power semiconductor lasers with narrow linewidth characteristics have become a highly regarded research field. In recent years, narrow linewidth semiconductor lasers with single-wavelength output have been unable to meet the specific requirements of certain professional fields. Therefore, researchers are working on developing semiconductor lasers with high power, narrow linewidth, and dual-wavelength output characteristics. This type of semiconductor laser has broad application prospects in fields such as pumping gas lasers, Raman spectroscopy, terahertz radiation generation, and terahertz imaging.

[0003] Currently, there are mainly two relatively mature methods, namely the intracavity regulation method and the extracavity regulation method.

[0004] The intracavity regulation method refers to installing a grating in the active region of a semiconductor laser chip to control the spectral characteristics of the output laser. The advantages of this method are small size integration, stable structure, and high reliability. The disadvantages are large temperature drift and difficulty in ensuring the consistency of the central wavelength during high-power operation, resulting in an increase in the overall linewidth. Therefore, it is limited in applications with watt-level or even higher power requirements. The extracavity regulation method refers to adding dispersion components outside the semiconductor laser cavity, such as surface gratings, volume Bragg gratings (VBGs), etc. In currently reported cases, a combination of surface gratings and volume Bragg gratings (VBGs) is mainly used to achieve dual-wavelength narrow linewidth laser output. However, the surface grating structure has extremely high requirements for the directional accuracy of the laser system, which easily leads to the misalignment of the extracavity feedback structure. The surface grating structure is only applicable to watt-level low-power semiconductor lasers. When the incident power is relatively high, the diffraction grating is extremely prone to thermal deformation, further affecting the extracavity feedback efficiency and the spectral locking effect. In addition, the surface grating structure is more suitable for wide-range tuning of the central wavelength in the nanometer range. When some application fields require high-precision small-range tuning of the central wavelength of the laser with a narrow linewidth to the sub-nanometer range, this method has certain limitations and is difficult to meet the corresponding requirements.

[0005] The disadvantages of the prior art are mainly reflected in two aspects: on the one hand, it is the problem of regulating the central wavelength of a dual-wavelength laser after the linewidth is narrowed. In the current solution, a combination of a surface grating and a volume Bragg grating (VBG) is mainly used, which can achieve dual-wavelength narrow-linewidth laser output. However, the interval between the two output central wavelengths is generally large, and once these two central wavelengths are locked, it is difficult to achieve fine tuning in a small range, and the regulation accuracy of the central wavelength is low, making it difficult to achieve narrow-range dual-wavelength laser output with an interval in the sub-nanometer range. On the other hand, there are limitations in the power amplification of the laser. It is difficult to ensure the spectral narrowing effect of the dual-wavelength laser when high-power output is achieved. Summary of the Invention

[0006] In view of this, the present invention aims to provide a dual-wavelength narrow-linewidth laser output device with a novel structure and a dual-wavelength narrow-linewidth laser output method implemented by this device. By adopting the external cavity feedback technology of a dual-volume Bragg grating (VBG), combining semiconductor laser beam splitting technology, polarization beam combining technology, and VBG precise temperature control technology, the problems of precise regulation of the central wavelength of a dual-wavelength narrow-linewidth semiconductor laser and laser power amplification are solved.

[0007] To achieve the above object, the technical solution of the present invention is realized as follows: A dual-wavelength narrow-linewidth laser output device, the dual-wavelength narrow-linewidth laser output device includes a semiconductor laser unit, a beam conversion lens, a slow-axis collimating mirror, a right-angle prism, a first volume Bragg grating, a first reflector, a half-wave plate, a polarization beam combining mirror, a second volume Bragg grating, and a second reflector; The semiconductor laser unit emits a linearly polarized light beam, the linearly polarized light beam includes a semiconductor laser fast-axis beam and a semiconductor laser slow-axis beam, the semiconductor laser fast-axis beam has a semiconductor laser fast-axis divergence angle, and the semiconductor laser slow-axis beam has a semiconductor laser slow-axis divergence angle; The beam conversion lens is used to realize the conversion between the semiconductor laser fast-axis beam and the semiconductor laser slow-axis beam; the beam conversion lens is used to compress the semiconductor laser fast-axis divergence angle, and the slow-axis collimating mirror is used to compress the semiconductor laser slow-axis divergence angle; The linearly polarized light beam is divided into a first beam and a second beam by the right-angle prism; the first beam sequentially passes through the first volume Bragg grating, the first reflector, the half-wave plate, and the polarization beam combining mirror; the second beam sequentially passes through the second volume Bragg grating, the second reflector, and the polarization beam combining mirror; The first volume Bragg grating is used to narrow the spectral linewidth of the first light beam; the first mirror is used to change the propagation direction of the first light beam; the half-wave plate is used to change the polarization direction of the second light beam to achieve the interchange between the P polarization state and the S polarization state; the second volume Bragg grating is used to narrow the spectral linewidth of the second light beam; the second mirror is used to change the propagation direction of the second light beam; the polarization beam combiner is used to achieve the polarization beam combination of the first light beam and the second light beam.

[0008] Further, the semiconductor laser unit is in a bar structure, and the output power of the bar structure is 60 W; the laser center wavelength of the semiconductor laser unit during free running is 780 nm ± 3 nm, and the spectral linewidth is 5 nm.

[0009] Further, the linearly polarized light beam includes P-polarized light and S-polarized light, and the degree of polarization of the P-polarized light is ≥ 95%.

[0010] Further, the fast-axis divergence angle of the semiconductor laser is 60°; the slow-axis divergence angle of the semiconductor laser is 10°.

[0011] Further, the parameters of the first volume Bragg grating are the same as those of the second volume Bragg grating.

[0012] Further, the diffraction center wavelength of the first volume Bragg grating is 780 nm ± 0.1 nm, the diffraction efficiency of the volume Bragg grating is 15% ± 5%; the thickness of the volume Bragg grating is 3 mm.

[0013] Further, the diffraction center wavelength of the second volume Bragg grating is 781 nm ± 0.1 nm, the diffraction efficiency of the volume Bragg grating is 15% ± 5%; the thickness of the volume Bragg grating is 3 mm.

[0014] Further, the spectral linewidth of the first light beam narrowed by the first volume Bragg grating is on the order of 0.2 nm; the spectral linewidth of the second light beam narrowed by the second volume Bragg grating is on the order of 0.2 nm.

[0015] Further, the center wavelength of the half-wave plate is 780 nm ± 5 nm; the center wavelength of the polarization beam combiner is 780 nm ± 10 nm.

[0016] The present invention also provides a method for outputting dual-wavelength narrow-linewidth laser, and the method for outputting dual-wavelength narrow-linewidth laser is realized by the dual-wavelength narrow-linewidth laser output device of the present invention.

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects: The present invention provides a dual-wavelength narrow linewidth laser output device with a novel structure and a dual-wavelength narrow linewidth laser output method implemented by this device. By adopting the external cavity feedback technology of a dual-body Bragg grating (VBG), combining semiconductor laser beam splitting technology, polarization beam combining technology, and precise temperature control technology of VBG, the problems of precise regulation of the central wavelength and laser power amplification of a dual-wavelength narrow linewidth semiconductor laser are solved.

[0018] The dual-wavelength narrow linewidth laser output device with a novel structure provided by the present invention divides a single beam of semiconductor laser into two beams by using beam splitting technology, combines the external cavity feedback technology of a volume Bragg grating (VBG) and precise temperature control technology. A single VBG performs feedback and tuning on a single beam of laser, and there is no thermal crosstalk between them, realizing the narrowing of the spectral linewidth. At the same time, based on the temperature drift characteristic of VBG, by adjusting the temperature of VBG, even after the central wavelength is locked, the central wavelength can be changed within a certain range, and high-precision tuning of the central wavelength at the sub-nanometer level can be achieved. The split lasers are combined with semiconductor laser polarization beam combining technology to realize the re-coincidence of the beams, achieving the output of dual-wavelength laser of a single laser beam. The dual-wavelength narrow linewidth laser output method provided by the present invention based on this device has good power scalability. Since the unit VBG corresponds to a single laser beam, multiple laser units can be placed vertically, without interference between them. When realizing the output of dual-wavelength narrow linewidth laser, the laser power can be further increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 It is a schematic diagram of the optical path structure of the dual-wavelength narrow linewidth laser output device described in the embodiment of the present invention.

[0020] Description of the reference numerals in the drawings: 1. Semiconductor laser unit; 2. Beam conversion lens; 3. Slow axis collimating mirror; 4. Right-angle prism; 5. First volume Bragg grating; 6. First reflector; 7. Half-wave plate; 8. Polarization beam combining mirror; 9. Second reflector; 10. Volume Bragg grating. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further describes the present invention in detail with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0022] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0023] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0025] A dual-wavelength narrow linewidth laser output device is provided in the specific embodiment of the present invention. The dual-wavelength narrow linewidth laser output device includes a semiconductor laser unit, a beam conversion lens, a slow axis collimating mirror, a right-angle prism, a first volume Bragg grating, a first mirror, a half-wave plate, a polarization beam combiner, a second volume Bragg grating, and a second mirror; in the specific embodiment, the provided dual-wavelength narrow linewidth laser output device has no limitation on the wavelength, and theoretically can be any wavelength, such as 450nm, 808nm, 976nm, etc., and the corresponding lenses and VBGs can be corresponding to the corresponding wavelength bands; as an example, the central wavelength of the half-wave plate is 780nm ± 5nm; the central wavelength of the polarization beam combiner is 780nm ± 10nm; The semiconductor laser unit emits a linearly polarized light beam, the linearly polarized light beam includes a semiconductor laser fast axis beam and a semiconductor laser slow axis beam, the semiconductor laser fast axis beam has a semiconductor laser fast axis divergence angle, and the semiconductor laser slow axis beam has a semiconductor laser slow axis divergence angle; The beam conversion lens is used to achieve the conversion between the fast-axis beam and the slow-axis beam of the semiconductor laser; the beam conversion lens is used to collimate and compress the divergence angle of the fast axis of the semiconductor laser, and the slow-axis collimating mirror is used to collimate and compress the divergence angle of the slow axis of the semiconductor laser; specifically, the beam conversion lens and the slow-axis collimating mirror mentioned here are both for the initial beam, that is, the initial angle before conversion. The divergence angle of the fast axis of the semiconductor laser is 60°; the divergence angle of the slow axis of the semiconductor laser is 10°; after conversion, the new divergence angles of the fast-axis and slow-axis lasers can be collimated to the order of 10 mrad after being collimated by the beam conversion lens and the slow-axis collimating mirror; the beam conversion lens has two functions, one is to collimate the divergence angle of the fast axis, and the other is to achieve the conversion between the fast-axis and slow-axis beams; the freely operating laser passes through the beam conversion lens. First, the divergence angle of the fast axis is collimated, and after collimation, the beam rotates 90 degrees to achieve the conversion between the fast-axis and slow-axis beams; after passing through the beam conversion lens, only the divergence angle of the fast axis is collimated and the beam direction is changed, while the divergence angle of the slow-axis laser is still not collimated. Therefore, a slow-axis collimating mirror is further introduced to collimate the divergence angle of the slow-axis laser. The linearly polarized light beam is divided into a first beam and a second beam by the right-angle prism; the linearly polarized light beam includes P-polarized light and S-polarized light, and the polarization degree of the P-polarized light ≥ 95%; for example, the polarization degree of the P-polarized light is 95%, and the polarization degree of the S-polarized light is 5%; the first beam sequentially passes through the first volume Bragg grating, the first mirror, the half-wave plate, and the polarization beam combiner; the second beam sequentially passes through the second volume Bragg grating, the second mirror, and the polarization beam combiner. The first volume Bragg grating is used to narrow the spectral linewidth of the first light beam; the first mirror is used to change the propagation direction of the first light beam; the half-wave plate is used to change the polarization direction of the second light beam to achieve the interchange between the P polarization state and the S polarization state; the second volume Bragg grating is used to narrow the spectral linewidth of the second light beam; the second mirror is used to change the propagation direction of the second light beam; the polarization beam combiner is used to achieve the polarization beam combination of the first light beam and the second light beam; specifically, the parameters of the first volume Bragg grating and the parameters of the second volume Bragg grating may be different. For example, the diffraction center wavelength of the first volume Bragg grating is 780 nm ± 0.1 nm, the diffraction efficiency of the volume Bragg grating is 15% ± 5%; the thickness of the volume Bragg grating is 3 mm; the diffraction center wavelength of the second volume Bragg grating is 781 nm ± 0.1 nm, the diffraction efficiency of the volume Bragg grating is 15% ± 5%; the thickness of the volume Bragg grating is 3 mm; in a preferred embodiment, the parameters of the first volume Bragg grating and the parameters of the second volume Bragg grating may be the same. For example, the diffraction center wavelengths of the first volume Bragg grating and the second Bragg grating are both 780 nm ± 0.1 nm; by using such a volume Bragg grating, it is possible to better avoid the problem that due to the too high diffraction efficiency of the volume Bragg grating, the laser power returning to the inner cavity of the chip is higher, which is likely to burn the front cavity surface of the chip and cause optical catastrophic damage (COD); the spectral linewidth of the free-running semiconductor laser before narrowing is usually 3 nm to 5 nm, and the spectral linewidth of the first light beam narrowed by the first volume Bragg grating is on the order of 0.2 nm; the spectral linewidth of the second light beam narrowed by the second volume Bragg grating is on the order of 0.2 nm.

[0026] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0027] As Figure 1As shown in the figure, it is a schematic optical path structure diagram of a device for realizing dual-wavelength narrow linewidth laser output of a semiconductor laser provided by an embodiment of the present invention. It can be seen from the figure that the dual-wavelength narrow linewidth laser output device provided by this embodiment includes a semiconductor laser unit 1, a beam conversion lens 2, a slow axis collimating mirror 3, a right-angle prism 4, a first volume Bragg grating 5, a first mirror 6, a half-wave plate 7, a polarization beam combiner 8, a second volume Bragg grating 10, and a second mirror 9; specifically, the semiconductor laser unit 1 can be a single-tube structure or a bar structure. Among them, the single-tube structure in the art refers to a single laser with a single light-emitting point, and the bar structure in the art refers to a single laser with multiple light-emitting points along the horizontal direction; preferably, the semiconductor laser unit 1 is a bar structure, and the output power of the bar structure is 60W; the laser center wavelength of the semiconductor laser unit 1 during free running is 780nm ± 3nm, and the spectral linewidth is 5nm; the linearly polarized light beam includes P-polarized light and S-polarized light, the polarization degree of the P-polarized light is 95%, and the polarization degree of the S-polarized light is 5%.

[0028] Specifically, the semiconductor laser unit 1 emits a linearly polarized light beam, which includes a semiconductor laser fast-axis beam and a semiconductor laser slow-axis beam. The semiconductor laser fast-axis beam has a semiconductor laser fast-axis divergence angle, and the semiconductor laser slow-axis beam has a semiconductor laser slow-axis divergence angle. The initial semiconductor laser fast-axis divergence angle is 60°; the initial semiconductor laser slow-axis divergence angle is 10°; the beam conversion lens 2 is used to realize the conversion between the semiconductor laser fast-axis beam and the semiconductor laser slow-axis beam; the beam conversion lens 2 is used to collimate and compress the semiconductor laser fast-axis divergence angle, and the slow axis collimating mirror 3 is used to collimate and compress the semiconductor laser slow-axis divergence angle; after the fast-axis direction and the slow-axis direction are converted by the beam conversion lens 2, the slow-axis direction is no longer affected by the longest focal length limit of the slow axis collimating mirror SAC, and the focal length of the slow axis SAC can be designed according to the beam shaping requirements, without the need to use a plano-convex lens array anymore. Only a single plano-convex cylindrical lens can realize slow-axis collimation, greatly reducing the collimation difficulty, and a smaller laser divergence angle can be obtained. Combining with VBG for external cavity feedback is beneficial to obtaining a better linewidth narrowing effect.

[0029] Specifically, the linearly polarized light beam is divided into a first beam and a second beam by the right-angle prism 4, so that the two beams can be regulated separately without interference with each other, thereby realizing the output of dual-wavelength laser with a single laser; among them, the first beam sequentially passes through the first volume Bragg grating 5, the first mirror 6, the half-wave plate 7 and the polarization beam combiner 8; the second beam sequentially passes through the second volume Bragg grating 10, the second mirror 9 and the polarization beam combiner 8; the first volume Bragg grating 5 is used to narrow the spectral linewidth of the first beam; the first mirror 6 is used to change the propagation direction of the first beam; the half-wave plate 7 is used to change the polarization direction of the second beam to realize the conversion between the P polarization state and the S polarization state, so that the first beam plays a total reflection role after entering the polarization beam combiner 8; the second volume Bragg grating 10 is used to narrow the spectral linewidth of the second beam; the second mirror 9 is used to change the propagation direction of the second beam; the first beam and the second beam are both incident on the polarization beam combiner 8, and the polarization beam combiner 8 is used to realize the polarization beam combination of the first beam and the second beam.

[0030] Specifically, the divergence angle of the quasi-straightened fast axis of the laser is usually 30° to 60°, and the divergence angle of the slow axis of the laser is usually 8° to 12°. For example, the initial laser divergence angle in the fast axis direction is about 60 degrees, and in the slow axis direction is about 10 degrees. The linearly polarized light beam emitted by the semiconductor laser unit 1 compresses the divergence angle of the fast axis of the semiconductor laser through the beam conversion lens 2. At the same time, the light intensity distribution and the divergence angle distribution of the fast axis and the slow axis of the semiconductor laser beam are both flipped by 90 degrees, so that the fast and slow axes are converted. Then, the divergence angle of the slow axis of the semiconductor laser is compressed through the slow axis collimator 3, and the divergence angles of the two axes of the laser can be compressed to the order of 10 mrad. Due to the angular selectivity of the volume Bragg grating, a smaller laser divergence angle is beneficial to achieving a better spectral locking effect.

[0031] The collimated and compressed linearly polarized light beam is divided into two beams by a right-angle prism 4. Among them, the first beam is incident on a first volume Bragg grating 5 with a diffraction center wavelength of 780 nm ± 0.1 nm, a diffraction efficiency of 15% ± 5%, and a thickness of 3 mm, realizing the linewidth narrowing and spectral locking of the free-running laser. Before narrowing, the spectral linewidth of the free-running semiconductor laser is usually 3 nm to 5 nm. After narrowing, the spectral linewidth of the first beam can reach the order of 0.2 nm, and the center wavelength is locked near 780 nm. In addition, the second beam is incident on the second volume Bragg grating 10. When the parameters of the second volume Bragg grating 10 are the same as those of the first volume Bragg grating 5, the center wavelength spacing of the final dual-wavelength laser is relatively smaller and is locked near 780 nm; when the parameters of the second volume Bragg grating 10 are different from those of the first volume Bragg grating 5, such as a diffraction center wavelength of 781 nm ± 0.1 nm and a diffraction efficiency of 15% ± 5%, the center wavelengths of the two laser beams are locked near 780 nm and 781 nm respectively, and the center wavelength spacing of the dual-wavelength laser is relatively larger. The Bragg grating VBG with different diffraction center wavelengths can be selected according to different application scenarios.

[0032] After external cavity feedback spectral locking and linewidth narrowing, the two laser beams of the first beam and the second beam respectively change the transmission direction of the laser through the first mirror 6 and the second mirror 9. Among them, the first beam changes the polarization direction of the beam through a half-wave plate 7, and the conversion between the P polarization state and the S polarization state can be realized. After the first beam passes through the polarization beam combiner 8, since the polarization beam combiner 8 can transmit the P polarization state beam and reflect the S polarization state beam at the same time, the first beam is output after being reflected by 90 degrees; while the second beam still maintains the P polarization state and can directly pass through the polarization beam combiner 8. Finally, the two laser beams coincide again, realizing the output of single-laser dual-wavelength narrow-linewidth laser; specifically, the first beam initially includes 95% P polarization + 5% S polarization. After passing through the half-wave plate 7, it can be regarded as 95% S polarization + 5% P polarization. At this time, when this beam passes through the polarization beam combiner 8 again, the 95% S polarization light is totally reflected, and the 5% P polarization light is totally transmitted (lost); the second beam includes 95% P polarization + 5% S polarization initially. After being reflected, it directly passes through the polarization beam combiner 8. The 95% P polarization light is transmitted, and the 5% S polarization light is totally reflected (lost). Finally, the 95% S polarization light and the 95% P polarization light are combined together.

[0033] There will be a certain power loss when the light beam passes through various lenses during the transmission process. For the initial laser power of about 60W, finally about 50W can be output. Since the VBG has the characteristic of temperature drift, with the change of temperature, the diffraction center wavelength will also change. Therefore, the center wavelength of the laser will also change accordingly after the spectrum is locked. Based on this, by controlling the temperature of the VBG, precise tuning of the center wavelength of the laser in the sub-nanometer level can be achieved. For example, after the spectrum is locked, the center wavelengths of the two laser beams are both 780.00nm. The temperature drift coefficient of the VBG is about 0.008nm / °C, and the initial temperature of the VBG is the ambient temperature of 25°C. The temperature of one of the VBGs is controlled at 40°C, and the corresponding laser center wavelength is adjusted to 780.12nm; the temperature of the other VBG is controlled at 60°C, and the corresponding laser center wavelength is adjusted to 780.28nm. Therefore, the device and method provided by the present invention can precisely control the two wavelengths of the laser respectively, and realize the laser output with different center wavelengths according to different application scenarios.

[0034] The specific embodiment of the present invention also provides a method for outputting dual-wavelength narrow linewidth laser, which is realized by the dual-wavelength narrow linewidth laser output device provided by the present invention.

[0035] The above embodiments introduce the situation of a single laser. In order to obtain a higher-power laser output, multiple unit lasers can be stacked vertically and packaged into a stack array structure. Correspondingly, each unit laser in each path corresponds to a beam transformation lens (BTS), a slow-axis collimating mirror (SAC), and a volume Bragg grating VBG. Among them, the right-angle prism, the mirror, the half-wave plate, and the polarization beam combiner can be made into large sizes according to the spot size, and there is no need to correspond one by one and they can be shared. Therefore, this structure has good power scalability. In addition, when the number of split light beams in the structure is more than 2, not only can dual-wavelength laser output be realized, but also multi-wavelength laser output can be realized by controlling the temperature of the VBG. Therefore, the structure of the dual-wavelength narrow linewidth laser output device provided by the present invention also has good center wavelength scalability.

[0036] It should be understood that various forms of the processes shown above can be used, reordering, adding or deleting steps. For example, the steps recorded in the disclosure of the present invention can be executed in parallel, sequentially, or in different orders, as long as the desired results of the technical solutions disclosed in the present invention can be achieved, and no limitations are made herein.

[0037] The above specific implementation manners do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A dual-wavelength narrow-linewidth laser output device, characterized in that: The dual-wavelength narrow-linewidth laser output device comprises a semiconductor laser unit, a beam conversion lens, a slow-axis collimator, a right-angle prism, a first volume Bragg grating, a first reflector, a half-wave plate, a polarization beam combiner, a second volume Bragg grating and a second reflector; The semiconductor laser unit emits a linearly polarized light beam, the linearly polarized light beam includes a semiconductor laser fast axis beam and a semiconductor laser slow axis beam, the semiconductor laser fast axis beam has a semiconductor laser fast axis divergence angle, and the semiconductor laser slow axis beam has a semiconductor laser slow axis divergence angle; The beam conversion lens is used to realize the conversion of the semiconductor laser fast axis beam and the semiconductor laser slow axis beam; the beam conversion lens is used to collimate and compress the fast axis divergence angle of the semiconductor laser, and the slow axis collimator is used to collimate and compress the slow axis divergence angle of the semiconductor laser; The linear polarized light beam is divided into a first light beam and a second light beam through the right-angle prism; the first light beam passes through the first volume Bragg grating, the first reflector, the half-wave plate and the polarization beam combiner in sequence; the second light beam passes through the second volume Bragg grating, the second reflector and the polarization beam combiner in sequence; The first volume Bragg grating is used to narrow the spectral linewidth of the first light beam; the first reflector is used to change the propagation direction of the first light beam; the half-wave plate is used to change the polarization direction of the second light beam to achieve the interchange of the P polarization state and the S polarization state; the second volume Bragg grating is used to narrow the spectral linewidth of the second light beam; the second reflector is used to change the propagation direction of the second light beam; the polarization beam combiner is used to achieve polarization beam combining of the first light beam and the second light beam.

2. The dual-wavelength narrow-linewidth laser output device according to claim 1, characterized in that: The semiconductor laser unit is a bar structure, and the output power of the bar structure is 60W; the laser center wavelength of the semiconductor laser unit when it is in free operation is 780nm±3nm, and the spectral line width is 5nm.

3. The dual-wavelength narrow-linewidth laser output device according to claim 1, characterized in that: The linearly polarized light beam includes P polarized light and S polarized light, and the polarization degree of the P polarized light is ≥95%.

4. The dual-wavelength narrow-linewidth laser output device according to claim 1, characterized in that: The fast axis divergence angle of the semiconductor laser is 60°; the slow axis divergence angle of the semiconductor laser is 10°.

5. The dual-wavelength narrow-linewidth laser output device according to claim 1, characterized in that: Parameters of the first volume Bragg grating are the same as parameters of the second volume Bragg grating.

6. The dual-wavelength narrow-linewidth laser output device according to claim 1, characterized in that: The diffraction center wavelength of the first volume Bragg grating is 780nm±0.1nm, the diffraction efficiency of the volume Bragg grating is 15%±5%; and the thickness of the volume Bragg grating is 3mm.

7. The dual-wavelength narrow-linewidth laser output device according to claim 1, characterized in that: The diffraction center wavelength of the second volume Bragg grating is 781nm±0.1nm, the diffraction efficiency of the volume Bragg grating is 15%±5%; and the thickness of the volume Bragg grating is 3mm.

8. The dual-wavelength narrow-linewidth laser output device according to claim 1, characterized in that: The spectral line width of the first light beam narrowed by the first volume Bragg grating is on the order of 0.2 nm; the spectral line width of the second light beam narrowed by the second volume Bragg grating is on the order of 0.2 nm.

9. The dual-wavelength narrow-linewidth laser output device according to claim 1, characterized in that: The central wavelength of the half-wave plate is 780nm±5nm; the central wavelength of the polarization beam combiner is 780nm±10nm.

10. A dual-wavelength narrow-linewidth laser output method, characterized in that: The dual-wavelength narrow-linewidth laser output method is implemented by the dual-wavelength narrow-linewidth laser output device described in any one of claims 1 to 9.

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