Blue light coherent tuning locking narrow linewidth output system
By using a blue light coherently tuned and locked narrow linewidth output system, and employing adjustable waveplates and polarizing beam splitters to separate the beam, a dual external cavity structure is constructed. This solves the problem of insufficient power and linewidth in semiconductor lasers, achieving high-power and narrow-linewidth laser output to meet the needs of intelligent vehicles and high-speed optical communication.
Patent Information
- Application Number
- CN202511229184.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-29
- Publication Date
- 2025-12-09
AI Technical Summary
Existing semiconductor lasers have insufficient power, narrow linewidth, and wavelength lockability, which cannot meet the high monochromaticity and low phase noise requirements of fields such as intelligent vehicles, high-speed optical communication, and lidar.
A blue light coherent tuning and locking narrow linewidth output system is adopted, including a spatial beam combining module and a dual external cavity tuning and locking module. The beam is separated by an adjustable waveplate and a polarizing beam splitter to construct a dual external cavity structure, which processes P-polarized light and S-polarized light separately to achieve wavelength locking and linewidth compression.
It achieves high power and narrow linewidth output of semiconductor lasers, improves beam space utilization and beam quality, has a compact structure, small spot size and concentrated energy, and meets the requirements of high monochromaticity and low phase noise.
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Figure CN121097499A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of blue semiconductor lasers, and more particularly, to a blue coherent tuning and locking narrow linewidth output system. BACKGROUND
[0002] Semiconductor lasers have been widely used in intelligent vehicles, high-speed optical communication, laser radar, optical sensing, and other fields due to their small size, light weight, high efficiency, long life, and other advantages. In order to meet the requirements of high monochromaticity, low phase noise, and high tunability of laser light sources in these fields, the research on narrow linewidth semiconductor lasers has attracted widespread attention.
[0003] In recent years, the research on narrow linewidth semiconductor lasers has mainly focused on two aspects: intracavity optical feedback technology and external cavity optical feedback technology. Intracavity optical feedback technology achieves linewidth compression by integrating frequency selection structures such as distributed feedback (DFB) gratings or distributed Bragg reflection (DBR) gratings within the laser resonator. For example, in 2016, the University of Kassel in Germany successfully reduced the laser linewidth to 10 kHz using high-quality quantum dot distributed feedback technology. The Chinese Academy of Sciences Institute of Semiconductors achieved a laser linewidth of 35 kHz using a monolithic integrated asymmetric phase shift DFB laser.
[0004] External cavity optical feedback technology couples with mode selection devices outside the laser cavity, reducing the laser linewidth by increasing the effective length and quality factor Q value of the resonator. For example, the FBH Institute in Germany used a DFB laser chip and an integrated confocal Fabry-Perot cavity resonator to form a resonant feedback resonator, achieving a Lorentzian linewidth of 15.7 Hz.
[0005] The National Institute of Metrology in China used a high-precision double-mirror non-confocal cavity Littman structure to successfully reduce the linewidth of an external cavity semiconductor laser to 100 Hz.
[0006] In addition, silicon photonic chip external cavity semiconductor lasers have become a research hotspot. By combining the advantages of silicon photonic chips and semiconductor gain chips, they achieve compact structure, low power consumption, and high stability of narrow linewidth laser output. This type of laser uses micro-ring resonators, ring mirrors, and Mach-Zehnder interferometers to provide optical feedback to narrow the linewidth and achieve a wide tuning range and stable power output.
[0007] The research on narrow linewidth semiconductor lasers continues to make progress, and future development will focus more on improving power and spectral characteristics, solving the key technologies of secondary high-quality epitaxial growth and high-aspect-ratio etching of surface gratings, as well as high-precision grating and other optical feedback element manufacturing technologies. Through breakthroughs in these technologies, narrow linewidth semiconductor lasers are expected to play a key role in more fields.
[0008] Currently, the production of narrow-linewidth laser modules on the market still cannot meet the demand, and it is necessary to further improve the power and spectral characteristics of semiconductor lasers; and to achieve independent research and development of high-power, narrow-linewidth semiconductor lasers. Summary of the Invention
[0009] In view of the shortcomings of related technologies, the purpose of this invention is to provide a blue light coherent tuning locked narrow linewidth output system, which aims to solve the problems of insufficient power, insufficient linewidth, and inability to lock wavelength in semiconductor lasers in the prior art.
[0010] To achieve the above objectives, the present invention provides a blue light coherent tuning-locked narrow linewidth output system, comprising: a spatial beam combining module and a dual external cavity tuning-locking module; The spatial beam combining module is used to output a blue light beam; The dual external cavity tuning and locking module includes an adjustable waveplate, a polarizing beam splitter, a first external cavity, and a second external cavity. The adjustable waveplate is used to change the polarization state of the blue light beam to obtain a mixed polarized beam with an adjustable ratio of P-polarized light to S-polarized light. The polarizing beam splitter is used to separate P-polarized light and S-polarized light in the mixed polarized beam. The P-polarized light enters the second outer cavity, and the S-polarized light enters the first outer cavity. The first external cavity is used to process the S-polarized light and return it to the spatial beam combining module along the original optical path, so that the spatial beam combining module locks the wavelength of the blue light beam and compresses the linewidth of the blue light beam. The second external cavity is used to output a portion of the P-polarized light, and after processing, return the other portion to the spatial beam combining module along the original optical path; The receiver receives the P-polarized light fed back when the beam returns along the original path in the second external cavity, and transmits it to the host computer to obtain the spectral parameters of the feedback beam.
[0011] Optionally, the first external cavity sequentially includes a polarizing beam splitter, a transmission grating, and a first reflecting mirror; the second external cavity sequentially includes a polarizing beam splitter, a beam splitter, a half-wave plate, a second reflecting mirror, a transmission grating, and a third reflecting mirror; wherein the polarizing beam splitter and the transmission grating are shared by the first and second external cavities. The polarizing beam splitter is used to transmit P-polarized light in the mixed polarization beam and reflect S-polarized light in the mixed polarization beam. The transmission grating is used to concentrate 95% of the energy in the incident S-polarized light into the +1 order transmitted light output. The first reflector is used to reflect the +1 order transmitted light generated in the first external cavity back to the spatial beam combining module along the original optical path, so that the spatial beam combining module locks the wavelength of the blue light beam and compresses the linewidth of the blue light beam. The beam splitter is used to split the P-polarized light output from the polarizing beam splitter according to a preset ratio, with one part being output and the other part being incident on the half-wave plate. The half-wave plate is used to convert the incident beam from P-polarized light to S-polarized light, which is then reflected by the second mirror to the transmission grating. The third reflector is used to reflect the +1 order transmitted light generated in the second outer cavity and return it to the space beam combining module along the original optical path.
[0012] Optionally, the adjustable waveplate includes a waveplate and an adjustment frame; The waveplate is used to change the polarization state of the blue light beam to obtain a mixed polarized beam of P-polarized light and S-polarized light. The adjustment frame is connected to the host computer and is used to adjust the angle of the waveplate to change the ratio of P-polarized light to S-polarized light in the mixed polarized beam.
[0013] Optionally, a half-wave filter may also be included; The half-wave filter is used to convert the blue light beam output by the spatial beam combiner module into 100% S-polarized light.
[0014] Optionally, the spatial beam combining module includes a heat sink base, a blue light array composed of blue light single tubes, a fast-axis collimating mirror array, a slow-axis collimating mirror array, a reflector array 5 composed of plane reflectors, and a water cooler. The heat sink base is used to fix the blue light array; the blue light single tube is used to generate a blue light beam; the fast-axis collimating lens array and the slow-axis collimating lens array are used to collimate the fast axis and slow axis of the blue light beam, respectively. The mirror array is used to encrypt and output the aligned blue light beam; The water chiller is connected to the heat sink base and is used to water cool the heat sink base.
[0015] Optionally, the dual external cavity tuning and locking module includes an adjustment base; The adjustment base is connected to the transmission grating and is used to adjust the angle of the transmission grating.
[0016] Optionally, the dual external cavity tuning and locking module includes a first electronic control module and a second electronic control module; The first electronic control module is connected to the first planar reflector and is used to adjust the angle of the first planar reflector; The second electronic control module is connected to the second planar reflector and is used to adjust the angle of the second planar reflector.
[0017] Optionally, the output system may further include a focusing lens and an optical fiber; The focusing lens is used to focus the P-polarized light output from the beam splitter onto the optical fiber.
[0018] Optionally, the beam splitter is an 8:2 beam splitter.
[0019] Compared with the prior art, the above-described technical solutions conceived in this invention can achieve the following beneficial effects: 1. This invention provides a blue light coherently tuned, narrow-linewidth output system. The blue light beam output from the spatial beam combiner module consists of two coherent beams. An adjustable waveplate is used to adjust the ratio of P-polarized light to S-polarized light in the resulting mixed polarization beam. A dual-cavity structure is constructed to process the P-polarized and S-polarized light in the mixed polarized beam separately, allowing them to return to the spatial beam combiner module along their original optical paths. This achieves wavelength locking of the blue light beam and compresses its linewidth. This solves the technical problem of further improving the power and spectral characteristics of semiconductor lasers, enabling high-power and narrow-linewidth output of semiconductor lasers while simultaneously locking the output wavelength.
[0020] 2. The present invention provides a blue light coherent tuning locked narrow linewidth output system. The spatial beam combining module uses blue light semiconductor laser spatial beam combining to improve the spatial utilization of the beam, resulting in higher beam quality and laser power, and a compact structure. The adjustable waveplate consists of a waveplate and an adjustment frame. The angle of the waveplate is adjusted by a rotating disk on the adjustment frame to ensure that specific polarized beams can enter their respective external cavity structures to obtain narrow linewidth output. The use of fiber optic output makes it convenient to use, with a smaller spot size, concentrated energy, and greatly improved practicality. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of a blue light coherent tuning locked narrow linewidth output system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the blue light array collimation principle according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the blue light array polarization beam combining principle according to an embodiment of the present invention; Figure 4 This describes the relationship between the beam-splitting capability and polarization state of the transmission grating in this embodiment of the invention. Figure 5 This is a schematic diagram of the dual external cavity locking narrow linewidth output principle of an embodiment of the present invention; Figure 6 This is a schematic diagram of the adjustment principle of the circular adjustment frame according to an embodiment of the present invention; Figure 7 This is a blue light array output optical path diagram according to an embodiment of the present invention.
[0022] In the above figures, the reference numerals are the same, and the reference numerals are: 1. Heat sink base; 2. Blue light single tube; 3. Fast axis collimating lens array; 4. Slow axis collimating lens array; 5. Mirror array; 6. Half-wave filter; 7. Wave plate; 8. Adjustment frame; 9. Polarizing beam splitter; 10. Transmission grating; 11. Adjustment base; 12. First mirror; 13. First electronic control module; 14. Second mirror; 15. Half-wave plate; 16. Beam splitter; 17. Receiver; 18. Host computer; 19. Focusing lens; 20. Optical fiber; 21. Water chiller; 22. Third mirror; 23. Second electronic control module. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0024] The following description, in conjunction with a preferred embodiment, illustrates the content involved in the above embodiments.
[0025] like Figure 1 As shown, an embodiment of the present invention provides a blue light coherent tuning-locked narrow linewidth output system, comprising: a spatial beam combining module and a dual external cavity tuning-locking module; The spatial beam combining module is used to output a blue light beam; The dual external cavity tuning and locking module includes an adjustable waveplate, a polarizing beam splitter 9, a first external cavity, and a second external cavity. The adjustable waveplate is used to change the polarization state of the blue light beam to obtain a mixed polarized beam with an adjustable ratio of P-polarized light to S-polarized light. The polarizing beam splitter 9 is used to separate the P-polarized light and the S-polarized light in the mixed polarized beam. The P-polarized light enters the second outer cavity, and the S-polarized light enters the first outer cavity. The first external cavity is used to process the S-polarized light and return it to the spatial beam combining module along the original optical path, so that the spatial beam combining module locks the wavelength of the blue light beam and compresses the linewidth of the blue light beam. The second external cavity is used to output a portion of the P-polarized light, and after processing, return the other portion to the spatial beam combining module along the original optical path; The receiver 17 receives the P-polarized light fed back when the beam returns along the original path in the second external cavity, and transmits it to the host computer 18 to obtain the spectral parameters of the feedback beam.
[0026] The polarizing beam splitter 9 is typically composed of two right-angled prisms cemented together, with a polarizing dielectric film coated on the hypotenuse of one of the prisms. This dielectric film possesses special optical properties, enabling it to control the transmission and reflection of light based on its polarization state. When light is incident on the polarizing beam splitter, it is split into P-polarized and S-polarized light. P-polarized light passes almost completely through the polarizing beam splitter, while S-polarized light is reflected. This separation is achieved by utilizing the properties of light incident at Brewster's angle; that is, the transmittance of P-polarized light is close to 100%, while the transmittance of S-polarized light is much less than 1. Based on this principle, the composite polarized light is split into S-polarized and P-polarized light.
[0027] The polarization beam splitter 9 allows S-polarized light and P-polarized light to be transmitted in two external cavities. The first and second external cavities process the S-polarized light and P-polarized light respectively, so that they return along the original optical path. The feedback light is incident on the blue light single tube of the spatial beam combining module. After the blue light single tube receives energy of a specific wavelength, the threshold of that wavelength in the active region of the blue light single tube decreases, and it occupies the gain competition advantage, thereby causing the blue light single tube to achieve a narrow linewidth output of a specific wavelength.
[0028] In the second external cavity, when the light beam returns along the original path, part of the feedback P-polarized light is absorbed by the receiver 17, which is used to detect the linewidth and wavelength of the optical path and transmit the data to the host computer 18.
[0029] Furthermore, the adjustable waveplate includes a waveplate 7 and an adjustment frame 8; The waveplate 7 is used to change the polarization state of the blue light beam to obtain a mixed polarized beam of P-polarized light and S-polarized light. The adjustment frame 8 is connected to the host computer 18 and is used to adjust the angle of the waveplate 7 to change the ratio of P-polarized light to S-polarized light in the mixed polarized beam.
[0030] In this embodiment, the adjusting frame 8 is a circular adjusting frame, which matches the shape of the waveplate 7, and the waveplate 7 is embedded in the circular adjusting frame. The adjusting principle diagram of the circular adjusting frame is shown below. Figure 6 As shown, the host computer 18 obtains information such as the wavelength and linewidth of the polarized beam in the optical path from the P-polarized feedback light absorbed by the receiver 17. The host computer 18 controls the rotation angle of the circular adjustment frame 8 to control the ratio of P-polarized light and S-polarized light in the optical path, so as to regulate the wavelength and linewidth of the beam in the optical path.
[0031] In this embodiment, a dual-cavity structure is used to process the P-polarized and S-polarized light generated after adjusting the blue light beam output from the light source, and then return them to the blue light single tube of the light source. This locks the wavelength and compresses the linewidth of the beam, achieving narrow linewidth output at a specific wavelength. Compared to the single-cavity structure in the prior art, the dual-cavity structure in this solution can fully utilize the energy of the light beam output from the light source, improving the output power and narrow linewidth output capability of the semiconductor laser.
[0032] Optionally, the first external cavity sequentially includes a polarizing beam splitter 9, a transmission grating 10, and a first reflecting mirror 12; the second external cavity sequentially includes a polarizing beam splitter 9, a beam splitter 16, a half-wave plate 15, a second reflecting mirror 14, a transmission grating 10, and a third reflecting mirror 22; wherein the polarizing beam splitter 9 and the transmission grating 10 are shared by the first and second external cavities. The polarizing beam splitter 9 is used to transmit P-polarized light in the mixed polarization beam and reflect S-polarized light in the mixed polarization beam. The transmission grating 10 is used to concentrate 95% of the energy in the incident S-polarized light into +1 order transmitted light output. The first reflector 12 is used to reflect the +1 order transmitted light generated in the first external cavity and return it to the spatial beam combining module along the original optical path, so that the spatial beam combining module locks the wavelength of the blue light beam and compresses the linewidth of the blue light beam. The beam splitter 16 is used to split the P-polarized light output by the polarizing beam splitter 9 according to a preset ratio, with one part being output and the other part being incident on the half-wave plate 15. The half-wave plate 15 is used to convert the incident beam from P-polarized light to S-polarized light, and reflect it to the transmission grating 10 through the second mirror 14. The third reflector 22 is used to reflect the +1st order transmitted light generated in the second outer cavity and return it to the space beam combining module along the original optical path.
[0033] The schematic diagram showing the relationship between the beam splitting capability of the transmission grating and the polarization state is shown below. Figure 4 As shown in the figure, the energy proportions of diffracted light under different polarization conditions can be obtained. When the incident beam is 100% P light, the 0th order reflected light accounts for 2% of the total energy, the +1st order reflected light accounts for 0% of the total energy, the 0th order transmitted light accounts for 90% of the total energy, the +1st order transmitted light accounts for 4% of the total energy, and the remaining energy is absorbed by the grating. When the incident beam is 100% S light, the 0th order reflected light accounts for 1% of the total energy, the +1st order reflected light accounts for 2% of the total energy, the 0th order transmitted light accounts for 0% of the total energy, the +1st order transmitted light accounts for 95% of the total energy, and the remaining energy is absorbed by the grating. From the polarization perspective, when the incident angle is α, the 0th order light has no dispersion; the diffraction angles of the +1st order transmitted light at different wavelengths are α, β, γ, and d, respectively.
[0034] In this embodiment, as Figure 5 As shown, the beam output by the spatial beam combining module passes through a waveplate 7 whose rotation angle is controlled by a circular adjustment frame 8, thereby changing the polarization state of the beam and thus changing the ratio of P-polarized light to S-polarized light in the mixed polarized light. The polarization beam splitter 9 separates the P-polarized light and S-polarized light in the mixed polarized beam. In this process, S-polarized light is incident on the transmission grating 10 in the first external cavity. The 0th-order reflected light accounts for 1%, and the +1st-order reflected light accounts for 2%. Most of the energy is carried by the 1st-order transmitted light, and 95% of the energy is concentrated in the +1st-order transmitted light output. It is incident on the first plane mirror 12, so that the 1st-order transmitted light can return along the original optical path, forming the external cavity feedback of S-polarized light. P-polarized light is incident on the beam splitter 16 in the second external cavity. The transmitted P-polarized light is output, and the reflected P-polarized light is incident on the half-wave plate 15 and adjusted to S-polarized light. This beam is incident on the second plane mirror 14, and the beam transmission angle is changed by 90°. It is incident on the transmission grating 10 at a specific angle, and the 1st-order transmitted light transmitted at another specific angle carries 95% of the energy. It is incident on the third plane mirror 22 and returns along the original optical path again, forming the external cavity feedback of P-polarized light.
[0035] In this embodiment, the beam splitter 16 is an 8:2 beam splitter. An 8:2 beam splitter typically uses a special coating that can interfere with light waves traveling along different paths. By precisely designing the coating's thickness and refractive index, some light waves can interfere with each other as they pass through the beam splitter, thus achieving light separation. Based on the principle of the 8:2 beam splitter, 80% of the energy of P-polarized light is transmitted through, while the P-polarized light carrying 20% of its energy is incident on the half-wave plate 15.
[0036] Based on the above embodiments, such as Figure 1 As shown, optionally, a half-wave filter 6 is also included; The half-wave filter 6 is used to convert the blue light beam output by the spatial beam combiner module into 100% S-polarized light.
[0037] In this embodiment, a half-wave filter 6 is used to convert the blue light beam into 100% S-polarized light, so that the ratio of P-polarized light to S-polarized light in the composite polarized light can be accurately changed by passing through the wave plate 7.
[0038] like Figure 2 and Figure 3 As shown, optionally, the spatial beam combining module includes a heat sink base 1, a blue light array composed of blue light single tubes 2, a fast-axis collimating mirror array 3, a slow-axis collimating mirror array 4, a reflector array 5 composed of plane reflectors, and a water cooler 21. The heat sink base 1 is used to fix the blue light array; the blue light single tube 2 is used to generate a blue light beam; the fast axis collimating lens array 3 and the slow axis collimating lens array 4 are used to collimate the fast axis and slow axis of the blue light beam respectively. The mirror array 5 is used to encrypt the aligned blue light beam and output it. The water chiller 21 is connected to the heat sink base 1 and is used to water cool the heat sink base 1.
[0039] In this embodiment, the blue light array collimation principle diagram is as follows: Figure 2 As shown, the blue light array 1, composed of blue light tubes 2, is collimated by a fast-axis collimating mirror array 3 composed of cylindrical mirrors and a slow-axis collimating mirror array 4 composed of cylindrical mirrors. The collimated beams of each tube are closely arranged, with smaller gaps between the beams. The gap width is consistent with the beam width. Furthermore, the mirror array 5 deflects the light path direction by 90° to achieve spatial beam combining, and the output blue light beam consists of two coherent beams.
[0040] The schematic diagram of the blue light array spatial beam combining principle is as follows: Figure 3 As shown, the blue light beam output by the blue light array is incident on the half-wave plate 6. The half-wave plate 6 adjusts the polarization state of the beam from P polarization to S polarization. The blue light array is fixed by the heat sink base 1, which is cooled by the water chiller 21.
[0041] like Figure 1 As shown, optionally, the dual external cavity tuning and locking module includes an adjustment base 11; The adjusting base 11 is connected to the transmission grating 10 and is used to adjust the angle of the transmission grating 10.
[0042] In both the first and second external cavities, S-polarized light is incident on the transmission grating 10. The angle of the transmission grating 10 is controlled by the adjusting base 11 to ensure that a beam of specific wavelength and specific polarization is incident at the correct angle, thereby ensuring that the wavelength of the locked blue light beam is the target wavelength. In this embodiment, the S-polarized light is incident on the transmission grating 10 at a 45-degree angle. At this angle, the proportion of S-polarized light in the first-order transmission light is the highest, the 0th-order reflected light accounts for 1%, and the +1st-order reflected light accounts for 2%, with 95% of the energy concentrated in the +1st-order transmission light.
[0043] like Figure 1 As shown, optionally, the dual external cavity tuning and locking module includes a first electronic control module 13 and a second electronic control module 23; The first electronic control module 13 is connected to the first planar reflector 12 and is used to adjust the angle of the first planar reflector 12; The second electronic control module 23 is connected to the second planar reflector 22 and is used to adjust the angle of the second planar reflector 22.
[0044] The electronic control module controls the angle of the corresponding reflector to ensure that the incident S-polarized light is incident on the corresponding reflector, so that it is incident on the transmission grating along the original light path, and thus it can return along the original light path to form the corresponding external cavity feedback.
[0045] Optionally, the output system further includes a focusing lens 19 and an optical fiber 20; The focusing lens 19 is used to focus the P-polarized light output from the beam splitter 16 onto the optical fiber 20.
[0046] The output light uses fiber optic cable, which is convenient to use, has a smaller spot size, more concentrated energy, and greatly improves its practicality.
[0047] In this embodiment of the invention, the blue light beam output by the spatial beam combining module consists of two coherent beams. An adjustable waveplate is used to adjust the ratio of P-polarized light to S-polarized light in the resulting mixed polarization beam. A dual-cavity structure is constructed to process the P-polarized and S-polarized light in the mixed polarized beam separately, allowing them to return to the spatial beam combining module along their original optical paths. This achieves wavelength locking of the blue light beam and compresses its linewidth. This solves the technical problem of further improving the power and spectral characteristics of semiconductor lasers, enabling high-power and narrow-linewidth output of semiconductor lasers. Furthermore, it enables high-quality secondary epitaxial growth technology and high aspect ratio etching technology for surface gratings; and overcomes key technologies in the manufacturing of high-precision gratings and other optical feedback components.
[0048] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A blue light coherently tuned locked narrow linewidth output system, characterized in that, include: Space beam combining module and dual external cavity tuning and locking module; The spatial beam combining module is used to output a blue light beam; The dual external cavity tuning and locking module includes an adjustable waveplate, a polarizing beam splitter (9), a first external cavity, and a second external cavity; The adjustable waveplate is used to change the polarization state of the blue light beam to obtain a mixed polarized beam with an adjustable ratio of P-polarized light to S-polarized light. The polarizing beam splitter (9) is used to separate the P-polarized light and the S-polarized light in the mixed polarized beam. The P-polarized light enters the second outer cavity, and the S-polarized light enters the first outer cavity. The first external cavity is used to process the S-polarized light and return it to the spatial beam combining module along the original optical path, so that the spatial beam combining module locks the wavelength of the blue light beam and compresses the linewidth of the blue light beam. The second external cavity is used to output a portion of the P-polarized light, and after processing, return the other portion to the spatial beam combining module along the original optical path; The receiver (17) receives the P-polarized light fed back when the beam returns along the original path in the second external cavity and transmits it to the host computer (18) to obtain the spectral parameters of the feedback beam.
2. The output system as described in claim 1, characterized in that, The first external cavity includes, in sequence, a polarizing beam splitter (9), a transmission grating (10), and a first reflecting mirror (12); the second external cavity includes, in sequence, a polarizing beam splitter (9), a beam splitter (16), a half-wave plate (15), a second reflecting mirror (14), a transmission grating (10), and a third reflecting mirror (22); wherein, the polarizing beam splitter (9) and the transmission grating (10) are shared by the first and second external cavities; The polarizing beam splitter (9) is used to transmit P-polarized light in the mixed polarized beam and reflect S-polarized light in the mixed polarized beam. The transmission grating (10) is used to concentrate 95% of the energy in the incident S-polarized light into the +1 order transmitted light output; The first reflector (12) is used to reflect the +1 order transmitted light generated in the first external cavity and return it to the spatial beam combining module along the original optical path, so that the spatial beam combining module locks the wavelength of the blue light beam and compresses the linewidth of the blue light beam. The beam splitter (16) is used to split the P-polarized light output by the polarizing beam splitter (9) according to a preset ratio, with one part output and the other part incident on the half-wave plate (15). The half-wave plate (15) is used to convert the incident beam from P-polarized light to S-polarized light, and reflect it to the transmission grating (10) through the second mirror (14). The third reflector (22) is used to reflect the +1 order transmitted light generated in the second outer cavity and return it to the space beam combining module along the original optical path.
3. The output system as described in claim 1, characterized in that, The adjustable waveplate includes a waveplate (7) and an adjustment frame (8); The waveplate (7) is used to change the polarization state of the blue light beam to obtain a mixed polarized beam of P-polarized light and S-polarized light. The adjustment frame (8) is connected to the host computer (18) and is used to adjust the angle of the waveplate (7) to change the ratio of P-polarized light to S-polarized light in the mixed polarized beam.
4. The output system as described in claim 1, characterized in that, It also includes a half-wave filter (6); The half-wave filter (6) is used to convert the blue light beam output by the spatial beam combining module into 100% S-polarized light.
5. The output system as described in claim 1, characterized in that, The spatial beam combining module includes a heat sink base (1), a blue light array composed of blue light single tubes (2), a fast axis collimating mirror array (3), a slow axis collimating mirror array (4), a reflector array composed of plane reflectors (5), and a water chiller (21). The heat sink base (1) is used to fix the blue light array; the blue light single tube (2) is used to generate a blue light beam; the fast axis collimating lens array (3) and the slow axis collimating lens array (4) are used to collimate the fast axis and slow axis of the blue light beam respectively. The mirror array (5) is used to encrypt the aligned blue light beam and output it; The water chiller (21) is connected to the heat sink base (1) and is used to water cool the heat sink base (1).
6. The output system as described in claim 2, characterized in that, The dual external cavity tuning and locking module includes an adjustment base (11). The adjustment base (11) is connected to the transmission grating (10) and is used to adjust the angle of the transmission grating (10).
7. The output system as described in claim 2, characterized in that, The dual external cavity tuning and locking module includes a first electronic control module (13) and a second electronic control module (23). The first electronic control module (13) is connected to the first planar reflector (12) and is used to adjust the angle of the first planar reflector (12); The second electronic control module (23) is connected to the second plane mirror (22) and is used to adjust the angle of the second plane mirror (22).
8. The output system as described in claim 2, characterized in that, The output system also includes a focusing lens (19) and an optical fiber (20). The focusing lens (19) is used to focus the P-polarized light output from the beam splitter (16) onto the optical fiber (20).
9. The output system as described in claim 2, characterized in that, The beam splitter (16) is an 8:2 beam splitter.