A filter device for line width compression of multi-layer blue light semiconductor laser array

Abstract

The present invention discloses a filter device for line width compression of a multilayer blue light semiconductor laser array. The filter device comprises: a fast and slow axis collimation system placed along the optical path, an optical path space beam combining system, a beam filtering and modulation system, and a line width compression system; the fast and slow axis collimation system comprises a combination of multiple blue light single tube arrays and a fast and slow axis collimation lens group; the optical path space beam combining system comprises: a reflector group and a triangular prism; the beam filtering and modulation system comprises: an optical path adjustment lens group, a fast axis compression lens, a slow axis compression lens, and an adjustable beam filtering and modulation device; the line width compression system performs data analysis on the modulated light beam, and adjusts the optical path adjustment lens group and the adjustable beam filtering and modulation device. The effect of compressing the line width of the laser beam is improved, the compression efficiency is improved, and the compression difficulty is reduced. According to the feedback data, the angle and position of the beam adjustment lens are accurately adjusted by a servo motor to achieve the best line width compression effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of blue light semiconductor lasers, and more specifically, relates to a filter device for compressing the line width of a multi-layer blue light semiconductor laser array. Background Art

[0002] Blue light semiconductor lasers are a new generation of visible light sources in the world, with important application prospects. They are mainly used in laser processing (such as copper, gold, etc.), laser pumping, underwater detection, laser medical treatment and other fields. However, due to the relatively flat gain curve of the working material of the blue light semiconductor laser, the line width of its output spectrum is large, which is difficult to meet the requirements of narrow line width output in applications. It is necessary to construct a grating external cavity structure to compress the line width of the laser. A feasible solution is to use a distributed feedback (DFB) laser or a distributed Bragg reflector (DBR) laser. However, these two lasers have high process requirements and production costs. The method of adding a grating to the periphery of the blue light semiconductor laser and forming a grating external cavity is simple to operate and low in production cost, and is an effective alternative. The grating external cavity system overcomes the shortcomings of semiconductor lasers with wide line width and poor wavelength tunability.

[0003] With the commercialization of GaN-based blue semiconductor lasers, research on grating external cavity systems based on blue semiconductor lasers has become popular. In 2014, N. Ruhnke et al. from the Ferdinand Braun Institute in Germany proposed a Littrow-type grating external cavity structure based on GaN-based blue semiconductor lasers, and obtained an output power of 400mW, an output linewidth of 20pm, and an edge-mode suppression ratio of more than 40dB. In 2016, the MJChi team of the Technical University of Denmark built a Littrow-type grating external cavity laser based on a 455nm blue light single tube. They used ruled gratings and holographic diffraction gratings as external cavity feedback elements, respectively, and measured the line width, output power and tunable range of the two grating external cavity lasers under different injection currents. The measurement results show that when a holographic diffraction grating is used, the wavelength tunable range is small and the output power is high. When a ruled grating is used, the wavelength tunable range is large, but the output power is low. In 2017, Li Bin's team at Huazhong University of Science and Technology built a 410nm Littrow-type grating external cavity laser. At the maximum injection current of 500mA, the spectral linewidth is compressed to 50pm, the output power is 500mW (external cavity efficiency exceeds 85%), the tunable range is about 5nm and the edge mode suppression ratio exceeds 20dB. In 2021, Parashu R. Nyaupane and others from the University of Central Florida in the United States proposed a grating external cavity laser based on a blue light dual-tube beam combining structure. Unlike traditional blue light single-tube grating external cavity semiconductor lasers, this system uses a dual-tube beam combining system. The two blue light single tubes are combined through a polarization beam splitter (BS) and form a grating external cavity with the same grating, which effectively improves the output power of the grating external cavity laser.

[0004] There are still many problems with linewidth compression of multi-tube beam combining. Due to the limitation of beam quality, simply stacking a number of single light-emitting tubes often leads to less than ideal linewidth compression effect due to insufficient beam parallelism and different collimation effects. Summary of the invention

[0005] In view of the defects of the related art, the purpose of the present invention is to provide a filter device for line width compression of a multi-layer blue light semiconductor laser array, aiming to solve the problem that the line width compression effect of a semiconductor laser array with a power of hundreds of watts cannot be achieved.

[0006] To achieve the above-mentioned object, in a first aspect, the present invention provides a filter device for line width compression of a multilayer blue light semiconductor laser array, comprising: a fast and slow axis collimation system placed along an optical path, an optical path spatial beam combining system, a beam filtering and modulation system, and a line width compression system;

[0007] The fast-slow axis collimation system comprises a combination of a plurality of blue light single tube arrays and a fast-slow axis collimation lens group, wherein the blue light single tube array is used to excite blue light laser beams of equal spacing and power, and the fast-slow axis collimation lens group is used to reduce the divergence angle of the blue light laser beam;

[0008] The optical path space beam combining system comprises: a reflector group and a triangular prism, wherein the reflector group and the triangular prism are combined to reflect the blue laser beam array output after passing through the fast and slow axis collimator group, so that the blue laser beams in each array are closely arranged with equal spacing in the horizontal direction and are consistent in the vertical direction; the light spots between arrays are consistent in size in the horizontal direction and have equal height differences in the vertical direction;

[0009] The optical beam filtering and modulation system comprises: an optical path adjustment mirror group, a fast axis compression mirror, a slow axis compression mirror and an adjustable optical beam filtering and modulation device; the optical path adjustment mirror group is composed of N pairs of parabolic reflectors, and is used to adjust the optical path, spacing and light spot between each light beam; the fast axis compression mirror and the slow axis compression mirror respectively perform fast and slow axis compression on the reflected blue light laser array, and converge the light beams to the adjustable optical beam filtering and modulation device, so as to modulate each light beam separately and filter out stray light;

[0010] The line width compression system performs data analysis on the modulated light beam, and adjusts the optical path adjustment mirror group and the adjustable light beam filtering and modulation device according to the analysis result.

[0011] Optionally, the blue light single tube array includes N TO-packaged blue light single tubes, and each of the blue light single tubes is correspondingly provided with a fast-slow axis collimating lens group.

[0012] Optionally, the reflector group includes N identical rectangular reflectors, the rectangular reflectors are arranged in a zigzag pattern and are arranged one-to-one with the blue light single tubes; the rectangular reflectors are at an angle of 45 degrees to the blue light laser beam;

[0013] The triangular prism is arranged in parallel with the reflector group and is used to deflect the passing blue laser beam by 90 degrees.

[0014] Optionally, the optical path adjustment mirror group includes: a first optical path adjustment mirror, a second optical path adjustment mirror and an adaptive adjustment base, the first optical path adjustment mirror and the second optical path adjustment mirror are arranged opposite to each other to form N pairs of parabolic reflectors; the adaptive adjustment base is arranged at the bottom of the first or second optical path adjustment mirror, and is controlled by a servo motor to adjust the relative position and angle of the two optical path adjustment mirrors so that the optical path of each blue light laser beam is equal and the optical paths are parallel.

[0015] Optionally, the fast-axis compression mirror and the slow-axis compression mirror have different focal lengths, and the two compression mirrors are arranged front and back along the optical path. The focal length is selected according to the total width of the light beam so that the light spot after passing through the fast-axis compression mirror and the slow-axis compression mirror just passes through the adjustable beam filtering and modulation device.

[0016] Optionally, the adjustable beam filtering and modulation device is connected to a computer, and each input beam is phase modulated by the computer to filter out side lobes, and the output beam signal is fed back to the computer for adaptive adjustment.

[0017] Optionally, the number of the blue light single tube arrays is the same as the number of the optical path adjustment lens groups.

[0018] Optionally, the linewidth compression system includes: a grating, a spectroscope, a power meter, a CCD camera and a spectrometer; the grating is used to compress the linewidth of the modulated light beam, and the output light beam is divided into a first light beam and a second light beam through the spectroscope, the first light beam is received by the power meter, the second light beam is captured by the CCD camera, and the waveform of the light is transferred to the spectrometer for observation, the linewidth and waveform are analyzed, and the data of the light beam is transferred to a computer for data analysis, and the computer adjusts the optical path adjustment mirror group and the adjustable beam filtering and modulation device according to the analysis results.

[0019] Optionally, it also includes a water cooling system; the water cooling system includes a brass pipe seat, a water cooling pipe and an external water cooling machine;

[0020] Each of the brass tube holders is of an integrated type and wraps around one of the blue light single tube arrays;

[0021] The water cooling pipe is connected to a plurality of the brass tube holders and the external water cooling machine, and is used for dissipating heat from the filter device.

[0022] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0023] 1. The technical solution of the present invention uses a servo motor to adaptively adjust the base to adjust the relative position and angle of the two beam adjustment mirrors, change the optical path of each light spot, and fine-tune the output angle to achieve precise adjustment; a power detection system and a spectrometer are installed at the light output end, and the output spectrum is monitored in real time so that the motor automatically finds the optimal position for line width compression without manual adjustment. By adding a filter modulation device in front of the grating, the side lobes of the beam are filtered out and the interference of line width compression is reduced, and each beam can also be phase modulated to further ensure the consistency of the optical path difference and phase of the output beam.

[0024] 2. The blue light output by the technical solution of the present invention has a high beam quality and good compression efficiency. Since the multiple blue light single tube arrays of the present invention remain consistent in the horizontal direction and have equidistant heights in the vertical direction, the light beams of the blue light single tube array are arranged into parallel light beams with a rectangular distribution, and the light path is compressed as much as possible, so that the arrangement of each light beam is closer, the volume is smaller, and the light beam is convenient for focusing, so that the optical path difference between the single tubes is extremely small, and the overall beam quality is higher. Moreover, since the overall structure of the present invention passes through fewer mirrors, and most of them are coated with anti-reflection films or anti-reflection films corresponding to 450nm, the loss of laser power is also small, thereby achieving a higher compression efficiency.

[0025] 3. The technical solution of the present invention is designed with a water cooling system for each system, and the temperature of a single tube is stably guaranteed. The power will not drop due to a rise in the temperature of the single tube due to long-term continuous operation. The line width compression device also has a water cooling system, which can remove the heat near the filter and beam modulation device in time to prevent the device from burning due to heat accumulation. It has strong stability and can adapt to long-term work.

[0026] 4. The technical solution of the present invention has a smaller overall volume. As for a single array, the base of the present invention adopts an integrated design, so that the arrangement between single tubes is extremely tight with almost no gaps, and between arrays, the light spot width is already smaller than the fast axis in the slow axis direction. The superposition method is adopted to utilize the extra space, and the light spot size is further compressed by the reflector group, and a cylindrical mirror with a relatively small focal length is selected as the compression mirror.

[0027] 5. The technical solution of the present invention has good prospects in applications such as fiber coupling, spectral beam combining and polarization beam combining. In the present invention, the arrays are exactly the same, and the arrays can also be used as units to design the structure in other designs such as polarization beam combining. The arrays are highly interchangeable, and if damaged, only the corresponding array needs to be replaced. In addition, the present invention has low adjustment difficulty and low reproduction difficulty, and has great advantages in subsequent productization and industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The overall structure and optical path schematic diagram of a multi-layer blue light semiconductor laser array line width compression filter device provided by an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of the structure of a blue light single tube array provided by an embodiment of the present invention passing through a fast and slow axis collimator lens group;

[0030] Figure 3 A schematic diagram of the structure of a reflector assembly provided in an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of an optical path adjustment lens assembly provided in an embodiment of the present invention;

[0032] Figure 5 A schematic diagram of a fast-axis compression mirror and a slow-axis compression mirror provided in an embodiment of the present invention;

[0033] Figure 6 A schematic diagram of the structure of a beam filtering and modulating device and a grating provided in an embodiment of the present invention;

[0034] Figure 7 A schematic diagram of light beam reception and feedback adjustment of a linewidth compression system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] The contents involved in the above embodiment are described below in conjunction with a preferred embodiment.

[0037] In the prior art, the relationship between the output line width Δv and the output power P of a semiconductor laser can be expressed as:

[0038]

[0039] α m =(1 / L)ln(1 / R)

[0040]

[0041] Among them, α m Represents output loss; v g represents the group velocity; g represents the gain; n sp represents the spontaneous radiation factor; L represents the length of the resonant cavity; ΔE F represents the difference in the quasi-Fermi level of the active material; α represents the line width enhancement factor, which is mainly related to the band structure of the semiconductor material; h is Planck's constant, v is the optical frequency, k is the Boltzmann constant, t is the temperature, and r is the radius of the slant-oscillation cavity. It can be seen that the shorter the cavity length L, the smaller the output loss α m The larger the value, the wider the output line width. The line width of a semiconductor laser is generally 2-3nm. By introducing a grating external cavity, the output line width of a semiconductor laser can be greatly narrowed.

[0042] For grating external cavity semiconductor lasers, the introduction of grating external cavity can narrow the line width of the laser mainly in two aspects: first, the laser line width is inversely proportional to the square of the lifetime of photons in the resonant cavity, that is, the laser line width is inversely proportional to the square of the cavity length. For grating external cavity semiconductor lasers, the external cavity length is much larger than the intrinsic cavity length of the gain device, so the introduction of the external cavity can greatly compress the laser line width of the output laser; second, the dispersion effect of the grating allows the output light in an extremely narrow band to be fed back to the gain device to participate in mode competition, effectively reducing the loss of specific wavelengths in the gain device cavity, thereby suppressing the lasing of other modes in the cavity, making the output line width narrower.

[0043] like Figure 1 As shown, a filter device for line width compression of a multilayer blue light semiconductor laser array comprises: a fast and slow axis collimation system placed along an optical path, an optical path spatial beam combining system, a beam filtering and modulation system, and a line width compression system;

[0044] The fast-slow axis collimation system comprises a combination of a plurality of blue light single tube arrays 2 and a fast-slow axis collimation lens group 3, wherein the blue light single tube array 2 is used to excite blue light laser beams of equal spacing and power, and the fast-slow axis collimation lens group 3 is used to reduce the divergence angle of the blue light laser beam;

[0045] The optical path space beam combining system comprises: a reflector group 4 and a triangular prism 5, wherein the reflector group 4 and the triangular prism 5 are combined to reflect the blue laser beam array output after passing through the fast-slow axis collimator group 3, so that the blue laser beams in each array are closely arranged with equal spacing in the horizontal direction and are consistent in the vertical direction; the light spots between arrays are consistent in size in the horizontal direction and have equal height differences in the vertical direction;

[0046] The optical beam filtering and modulation system comprises: an optical path adjustment mirror group (6 and 7), a fast axis compression mirror 9, a slow axis compression mirror 10 and an adjustable optical beam filtering and modulation device 11; the optical path adjustment mirror group (6 and 7) is composed of N pairs of parabolic reflectors, and is used to adjust the optical path, spacing and light spot between each light beam; the fast axis compression mirror 9 and the slow axis compression mirror 10 respectively perform fast and slow axis compression on the reflected blue light laser array, and converge the light beams to the adjustable optical beam filtering and modulation device 11, so as to modulate each light beam separately and filter out clutter;

[0047] The line width compression system performs data analysis on the modulated light beam, and adjusts the optical path adjustment mirror group (6 and 7) and the adjustable light beam filtering and modulation device 11 according to the analysis result.

[0048] In this embodiment, a high-power power supply 20 is connected to a brass base 1, and is used to provide power to multiple blue light single tube arrays 2. The arrays in the multiple blue light single tube arrays 2 include N TO-packaged blue light single tubes, and the single tubes are closely arranged to excite blue light laser beams with equal spacing and power. In this embodiment, the high-power power supply 20 uses a power supply of hundreds of watts. The blue light laser beam passes through the fast and slow axis collimator lens group 3 to reduce the divergence angle of the blue light laser beam so that it can be compressed by the subsequent system. Among them, the number of fast and slow axis collimators 3 is the same as the number of blue light single tubes. Each blue light single tube is correspondingly provided with a fast and slow axis collimator lens group 3. A single collimator is an integrated fast and slow axis collimator lens, and has the functions of a slow axis collimator (Slow Axis Collimator, SAC) and a fast axis collimator (Fast Axis Collimator Lenses, FAC), which collimates the light spots with inconsistent fast and slow axis divergence angles into collimated light that can be approximately regarded as collimated light without divergence angles. Among them, referring to Figure 1 , Figure 2 In the preferred embodiment, the blue light single tube array 2 is composed of 10 450nm blue light single tubes with a rated output power of 5W, and the spacing between each single tube is the same, and the 10 single tubes are closely arranged in the brass base 1 on the same straight line.

[0049] refer to Figure 1 and Figure 3 , the blue laser beam passing through the fast and slow axis collimator lens group 3 passes through the reflector group 4 and the triangular prism 5 in turn, wherein the reflector group 4 is composed of N identical rectangular reflectors arranged in a zigzag shape, the rectangular reflectors are placed in front of each collimator lens group, and are arranged one by one with the blue light single tubes, the rectangular reflectors are at an angle of 45 degrees to the blue laser beam, and are used to reflect the blue laser beam array, deflecting it 90 degrees to form an equally spaced beam; the triangular prism 5 is arranged in parallel with the reflector group 4, and deflects the passing blue laser beam 90 degrees, which is the same direction as the blue laser beam excited by the blue light single tube array, so that the blue laser beams in each array are closely arranged with equal spacing in the horizontal direction and are consistent in the vertical direction; the light spots between arrays are consistent in size in the horizontal direction and have equal height differences in the vertical direction. In a preferred embodiment, refer to Figure 1 , Figure 3, the reflector group 3 is composed of 10 identical rectangular reflectors, which are arranged in a zigzag shape on the aluminum plate in front of the brass tube holder 1, corresponding to the blue light tubes one by one. The surface of the rectangular reflector is coated with a reflection enhancement film suitable for 450nm. The rectangular reflector not only compresses the light path, but also changes the direction of 10 light beams at the same time and converges them on the full reverse surface of the triangular prism 5. The position setting of the reflector group 4 and the triangular prism 5, on the one hand, reduces the optical path difference as much as possible, that is, the distance from the blue light tube to the reflector is negatively correlated with the distance from the reflector to the triangular prism; on the other hand, the light path is compressed under the premise of ensuring that the light beams reflected by each reflector are not blocked, so that the spacing between adjacent light beams in a single array is changed from the spacing between single tubes to the spacing between reflectors, and they are parallel to each other, which greatly reduces the total width of the light beam in the fast axis direction.

[0050] The blue laser beams with equal spacing in the horizontal direction pass through the optical path adjustment lens group, such as Figure 1 and Figure 4 As shown, the first optical path adjustment mirror 6 and the second optical path adjustment mirror 7 are arranged opposite to each other to form N pairs of small parabolic reflectors. The adaptive adjustment base 9 is arranged at the bottom of the first or second optical path adjustment mirror 7. The servo motor is controlled by inputting adjustment instructions through the external computer 18 to adjust the relative position and angle of the two optical path adjustment mirrors (6 and 7), change the optical path of each light spot and fine-tune the output angle, so that the optical path of each blue laser beam is equal and the optical path is parallel, thereby achieving precise fine-tuning.

[0051] Exemplarily, in this embodiment, the position of the first optical path adjustment mirror 6 is basically fixed after the optical path is reflected, and the adjustment of the optical path difference and the optical fiber propagation direction is mainly completed by the second optical path adjustment mirror 7 placed on the adaptive adjustment base 8. There are springs and top screws behind the adaptive adjustment base 8. By adjusting the spring length and the top screw position, the second optical path adjustment mirror 7 can be controlled to achieve the purpose of making the optical path difference of each group of light beams zero and the optical paths basically parallel. The spring and the top screw are controlled by a servo motor 17, and the motor receives a signal 18 from a computer to operate automatically.

[0052] like Figure 4 As shown in the figure, for each adjustment lens group, collimated light is still output after passing through, and each adjustment lens group adjusts the optical path, spacing and spot between each light beam. The optical path between each light beam is the same, the spacing is consistent, the spot size is consistent, and the fast and slow axes should be equal in the overall spot width, forming a square spot, so as to facilitate subsequent line width compression. Figure 1 and Figure 5The focusing lens group is composed of a fast-axis compression lens 9 and a slow-axis compression lens 10, which are two cylindrical lenses placed front and back, with different focal lengths and perpendicular to each other. Different focal lengths are selected according to the total width of the fast and slow axes of the light beam. They are placed in a suitable position so that the light spot after the fast and slow axis compression can just pass through the adjustable beam filter device 1 to filter out the side lobe clutter. In the preferred embodiment, the selection of focal length is related to both the fast and slow axis widths after passing through the reflector group 4 and the size of the grating 12 selected later. In order to control costs, this example selects the finished cylindrical lenses available on the market. After calculation, since the focal length of the cylindrical lens in the fast axis direction needs to be greater than 26.82mm, a plano-convex cylindrical lens with a focal length of 50mm is selected from Hengyang Optics as the fast-axis direction beam focusing lens. The focal length of the cylindrical lens in the slow axis direction needs to be greater than 15.91mm, and a plano-convex cylindrical lens with a focal length of 20mm is selected from Hengyang Optics as the slow-axis direction beam compression lens.

[0053] Optionally, the adjustable beam filtering and modulation device 11 is connected to a computer 18, and the computer 18 performs phase modulation on each input beam, filters out side lobes, and feeds back the output beam signal to the computer for adaptive adjustment.

[0054] Furthermore, the spot size between each array should be adjusted as much as possible to make the total width of the slow axis of the spot close to the total width of the fast axis of the spot and in the same direction. The adjustable beam filter modulation device 11 modulates each beam separately, filters out the side lobes, and feeds the output beam signal back to the computer 18 for adaptive adjustment.

[0055] Reference Figure 1 and Figure 6 The line width compression system in this example is composed of an adjustable beam filter modulation device 11, a grating 12, a spectroscope 13, a power meter 14, a CDD camera 15 and a spectrometer 16. The beam filter adjustment device 11 is a straight cylinder, in which a spatial light modulator is placed, which can be programmed by a computer 18 to modulate the phase of each light to obtain the best light beam. The size of the filter adjustment device 11 can be freely adjusted to filter out stray light without losing power. The grating 12 can receive the light beam and separate the light beam to select light of a specific wavelength. There are two M6 standard threaded holes at the bottom of the filter adjustment device to fix the device to keep it stable and prevent the optical fiber from burning due to vibration or other reasons causing the position of the device to change.

[0056] Reference Figure 1 and Figure 7After the light beam is emitted from the beam filter modulation device 11, each light beam will pass through the grating 12 for line width compression. The output light beam passes through the 99% spectroscope 13 and is divided into a first light beam and a second light beam. The high-power first light beam is received by the power meter 14, and the low-power second light beam is captured by the CCD camera 15. The CCD camera 15 transfers the light waveform to the spectrometer 16 for observation, analyzes the line width and whether the wavelength is what you want, and then transfers the data to the servo motor 17 for processing. The computer transmits instructions to the motor to change the data of the beam adjustment mirror group and the beam filter modulation device. The spectrometer obtains the next set of data, and the computer compares them. In this way, the best result is finally obtained, and the computer issues an end instruction.

[0057] On the basis of the above embodiment, the fast and slow axis collimation system includes three blue light single tube arrays (2, 21, 22), the three blue light single tube arrays completely overlap in the horizontal direction, and the spacing between the blue light single tube arrays in the vertical direction is equal. Correspondingly, it includes three fast and slow axis collimation lens groups (3, 31, 32), three optical path adjustment lens groups, the second optical path adjustment lens group 23 and the third optical path adjustment lens group 24 are adjustment lens groups that are consistent with the first optical path adjustment lens group (6 and 7) except for the height direction, and the principle is also consistent with the first optical path adjustment lens group. After being output by the three optical path adjustment lens groups, 3N light beams should be an array of light beams with equal optical path and strict parallelism.

[0058] The technical solution of the present invention can be used to solve the problem of insufficient power of blue light semiconductor lasers and a small number of single tubes participating in spatial beam combining by superimposing multiple layers of arrays in the slow axis direction, while making the light beams as parallel and equal in optical path as possible, filtering out sidelobe clutter, and better performing line width compression, improving compression efficiency, reducing compression difficulty, and preventing the problem of grating damage caused by too low efficiency. The modulation device can be programmed to perform phase modulation on each optical fiber to ensure the line width compression effect. A power detection system and a spectrometer are installed at the light output end to obtain specific data such as line width compression efficiency and compression effect. According to the feedback data, the servo motor can be used to drive the gear to flexibly adjust the angle and front and rear position of the beam adjustment mirror to achieve the best line width compression effect.

[0059] Furthermore, at high power, laser wavelength drift is also a problem that cannot be ignored, and a good water cooling system is also necessary. Common water cooling systems generally cool the entire structure with water from one side, which often leads to uneven cooling.

[0060] On the basis of the above embodiment, optionally, a water cooling system is further included; the water cooling system includes a brass tube seat 1, a water cooling tube 25 and an external water cooling machine 19;

[0061] Each of the brass tube holders 1 is integrated and wraps one of the blue light single tube arrays 2;

[0062] The water cooling pipe 25 connects the plurality of brass tube holders 1 and the external water cooling machine 19 and is used to dissipate heat from the filter device.

[0063] The brass tube base 1 completely surrounds the blue light single tube array 2. The base of the brass base 1 has a water trough and two standard threaded holes on one side. An external water cooler 19 can be connected to control the blue light single tube to work at a relatively stable temperature, thereby ensuring stable output power. A water cooling system (not shown) is installed below the device of the line width compression system. Through the external water cooler, water can pass through the two threaded holes directly below and through the water pipes distributed inside the device, thereby achieving the effect of cooling the device. A water cooling pipe (not shown) is also connected to the light modulation and filtering device to reduce the device temperature.

[0064] It will be easily understood by those skilled in the art that the above description is only 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 in the protection scope of the present invention.

Claims

1. A filter device for line width compression of a multilayer blue light semiconductor laser array, characterized in that: include: The fast and slow axis collimation system, optical path spatial beam combining system, beam filtering and modulation system and line width compression system placed along the optical path; The fast-slow axis collimation system comprises a combination of a plurality of blue light single tube arrays and a fast-slow axis collimation lens group, wherein the blue light single tube array is used to excite blue light laser beams of equal spacing and power, and the fast-slow axis collimation lens group is used to reduce the divergence angle of the blue light laser beam; The optical path space beam combining system comprises: a reflector group and a triangular prism, wherein the reflector group and the triangular prism are combined to reflect the blue laser beam array output after passing through the fast and slow axis collimator group, so that the blue laser beams in each array are closely arranged with equal spacing in the horizontal direction and are consistent in the vertical direction; the light spots between arrays are consistent in size in the horizontal direction and have equal height differences in the vertical direction; The optical beam filtering and modulation system comprises: an optical path adjustment mirror group, a fast axis compression mirror, a slow axis compression mirror and an adjustable optical beam filtering and modulation device; the optical path adjustment mirror group is composed of N pairs of parabolic reflectors, and is used to adjust the optical path, spacing and light spot between each light beam; the fast axis compression mirror and the slow axis compression mirror respectively perform fast and slow axis compression on the reflected blue light laser array, and converge the light beams to the adjustable optical beam filtering and modulation device, so as to modulate each light beam separately and filter out stray light; The line width compression system performs data analysis on the modulated light beam, and adjusts the optical path adjustment mirror group and the adjustable light beam filtering and modulation device according to the analysis result.

2. The filtering device according to claim 1, characterized in that The blue light single tube array comprises N TO-packaged blue light single tubes, and each of the blue light single tubes is correspondingly provided with a fast-slow axis collimating lens group.

3. The filtering device according to claim 2, characterized in that The reflector group includes N identical rectangular reflectors, which are arranged in a zigzag pattern and are arranged one by one with the blue light single tubes; the rectangular reflectors are at an angle of 45 degrees to the blue light laser beam; The triangular prism is arranged in parallel with the reflector group and is used to deflect the passing blue laser beam by 90 degrees.

4. The filtering device according to claim 1, characterized in that The optical path adjustment mirror group includes: a first optical path adjustment mirror, a second optical path adjustment mirror and an adaptive adjustment base, wherein the first optical path adjustment mirror and the second optical path adjustment mirror are arranged opposite to each other to form N pairs of parabolic reflectors; the adaptive adjustment base is arranged at the bottom of the first or second optical path adjustment mirror and is controlled by a servo motor to adjust the relative position and angle of the two optical path adjustment mirrors so that the optical path of each blue light laser beam is equal and the optical path is parallel.

5. The filtering device according to claim 4, characterized in that The fast-axis compression mirror and the slow-axis compression mirror have different focal lengths. The two compression mirrors are arranged front and back along the optical path. The focal length is selected according to the total width of the light beam so that the light spot after passing through the fast-axis compression mirror and the slow-axis compression mirror just passes through the adjustable beam filtering and modulation device.

6. The filtering device according to claim 5, characterized in that The adjustable beam filtering and modulation device is connected to a computer, and phase modulates each input beam through the computer to filter out side lobes, and feeds back the output beam signal to the computer for adaptive adjustment.

7. The filtering device according to claim 1, characterized in that The number of the blue light single tube arrays is the same as the number of the optical path adjustment lens groups.

8. The filtering device according to claim 1, characterized in that The line width compression system comprises: a grating, a spectroscope, a power meter, a CCD camera and a spectrometer; the grating is used to compress the line width of a modulated light beam, the output light beam is divided into a first light beam and a second light beam by the spectroscope, the first light beam is received by the power meter, the second light beam is captured by the CCD camera, and the waveform of the light is transferred to the spectrometer for observation, the line width and waveform are analyzed, the data of the light beam is transferred to a computer for data analysis, and the computer adjusts the optical path adjustment mirror group and the adjustable light beam filtering and modulation device according to the analysis results.

9. The filtering device according to claim 1, characterized in that It also includes a water cooling system; the water cooling system includes a brass pipe seat, a water cooling pipe and an external water cooling machine; Each of the brass tube holders is of an integrated type and wraps around one of the blue light single tube arrays; The water cooling pipe is connected to a plurality of the brass tube holders and the external water cooling machine, and is used for dissipating heat from the filter device.

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