Multi-wavelength semiconductor laser

Abstract

The invention relates to the technical field of semiconductor lasers, in particular to a multi-wavelength semiconductor laser. Comprising a semiconductor PN junction, and an inclined array waveguide region, a beam splitting MMI structure, a gain array waveguide, a beam combining MMI structure and a super-symmetric waveguide array which are sequentially arranged on the surface of the semiconductor PN junction in the longitudinal mode light beam transmission direction; the inclined array waveguide region comprises Bragg reflection gratings and inclined array waveguides, the Bragg reflection gratings are arranged on ridge surfaces of inlet ends of the inclined array waveguides, cavity lengths of waveguides in the inclined array waveguides are different, and the Bragg reflection gratings are parallel; seed sources output by the inclined array waveguide region are injected into the beam splitting MMI structure, and the seed sources are uniformly distributed and coupled into each waveguide of the gain array waveguide; the gain array waveguide is a parallel waveguide; the super-symmetric waveguide array is used for providing further gain to a fundamental mode and loss to a high-order mode. The antenna has the advantages of simple preparation, high gain, high single-mode performance, small size and high integration.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor lasers, and in particular to a multi-wavelength semiconductor laser. Background Art

[0002] Semiconductor lasers are an important light source technology. Due to their small size, low power consumption, and long lifespan, they are well-suited for integration into LiDAR systems. LiDARs using semiconductor lasers as light sources are widely used in laser beam ranging and perception, autonomous driving, environmental perception, and target detection and tracking.

[0003] Advances in technology and market demand are driving higher demands on LiDAR for fast-moving target detection and high-precision distance measurement. As the core light source for LiDAR, semiconductor lasers require faster frequency response, narrower wavelength linewidth, and a wider wavelength tunable range to achieve high-speed, high-precision measurement and detection. Narrow linewidth improves measurement accuracy and interference resistance, while wide tunability enables multifunctional and multimodal LiDAR systems.

[0004] Semiconductor multi-wavelength lasers offer significant advantages in addressing these requirements. Multi-wavelength lasers can achieve widely tunable output by integrating multiple laser sources with different wavelengths. By tuning lasers of different wavelengths, more measurement data and spectral information can be obtained, thereby improving the performance and functionality of lidar to adapt to diverse detection scenarios and application requirements.

[0005] In terms of narrow linewidth, multi-wavelength lasers can achieve narrower linewidth output through reasonable design and control. This is very important for improving measurement accuracy, suppressing stray signals, and improving anti-interference capabilities.

[0006] The structures of multi-wavelength tunable lasers currently used in the field of lidar mainly include the following: tunable lasers based on external cavity structures, tandem tunable lasers, semiconductor lasers based on sampled gratings, and on-chip integrated multi-wavelength laser arrays.

[0007] The multi-wavelength semiconductor laser based on the external cavity structure contains multiple optical components. The operating wavelength is mainly changed by adjusting the parameters of the external cavity structure. Therefore, it relies on multiple optical components for tuning. Not only is the manufacturing and packaging method complicated, but it also takes up more space and is not suitable for the field of small-size, integrated on-chip semiconductor lidar.

[0008] The tunable distributed feedback multi-wavelength semiconductor laser based on the series structure is more compact in size and more convenient for on-chip integration than the external cavity device. However, the tuning principle of this type of device is achieved through the joint operation of multiple laser units with different wavelengths, so additional crosstalk will be introduced between each unit, increasing the complexity and uncertainty of the device operation.

[0009] General sampled grating DFB lasers use single grating layer feedback to change the duty cycle and period of each grating in the grating layer, thereby directly changing the actual refractive index of the grating. Another method is to modulate the refractive index by injecting current into different gratings. The ultimate goal is to change the feedback ability of the Bragg grating for different wavelengths and achieve tuned output of different wavelengths. Some sampled gratings are divided into two layers, each controlling two different active regions, so that two output ports can be tuned simultaneously. Sampled Bragg grating lasers based on reconstruction-equivalent chirp technology change the real phase shift of the grating through reconstruction-equivalent chirp technology to achieve laser lasing of different Bragg wavelengths. This type of device mostly uses a buried grating structure, and the duty cycle and period of the grating are not fixed. It has strict requirements for lithography, etching and epitaxial growth processes, and the preparation process is complex. The complex grating structure has very high requirements for process precision, which is difficult to meet with the commonly used micron-level grating preparation process.

[0010] Tunable semiconductor laser arrays based on a parallel structure achieve multi-wavelength lasing by combining and amplifying laser beams of different wavelengths. Multi-wavelength narrow-linewidth semiconductor laser array chips have garnered increasing attention as core optoelectronic devices in wavelength division multiplexing and dense wavelength division multiplexing systems. Semiconductor laser array chips, with their compact structure, stable performance, relatively low cost, independent operation of multiple fixed-wavelength resonators at different wavelengths, and suitability for monolithic integration, have become an ideal solution for multi-wavelength tunable light sources. This on-chip integrated module encompasses all laser systems, including the laser source, feedback structure, gain structure, and beam combining mechanism. All structures are fabricated on a single epitaxial wafer using photolithographic processes, eliminating the need for splicing or coupling systems and combining the advantages of modularity and miniaturization. Because all tuning structures are arranged in a parallel array, the light waves within each waveguide are independent of each other, significantly improving interference immunity and wavelength stability. Parallel gratings require micron-level precision for the grating or other mode-selective feedback structures, eliminating the need for deliberately fabricating low-order gratings and effectively improving device yield. Summary of the Invention

[0011] In order to solve the above problems, the present invention provides a multi-wavelength semiconductor laser.

[0012] The present invention aims to provide a multi-wavelength semiconductor laser, comprising a semiconductor PN junction, and an inclined array waveguide region, a beam splitting MMI structure, a gain array waveguide, a beam combining MMI structure, and a supersymmetric waveguide array sequentially arranged on the surface of the semiconductor PN junction along the longitudinal mode light beam propagation direction;

[0013] The tilted array waveguide region includes a Bragg reflection grating and a tilted array waveguide, wherein the Bragg reflection grating is provided on a ridge surface at an entrance end of the tilted array waveguide; each waveguide in the tilted array waveguide has a different cavity length and is used to provide a narrow linewidth laser seed source; all the Bragg reflection gratings in the tilted array waveguide region are parallel and are used to control the single longitudinal mode wavelength of the laser output by each waveguide;

[0014] The seed source outputted from the tilted array waveguide region is injected into the beam splitting MMI structure, and the beam splitting MMI structure evenly distributes and couples the seed source into each waveguide of the gain array waveguide;

[0015] The gain array waveguide is a parallel waveguide used to amplify power and ensure that the output power is sufficient for the application requirements; the beam-combining MMI structure couples the light output by the gain array waveguide into the supersymmetric waveguide array; the supersymmetric waveguide array is used to provide further gain to the fundamental mode and loss to the higher-order modes, ensuring that the final output laser light is in a single longitudinal mode state.

[0016] Preferably, the supersymmetric waveguide array includes an active waveguide and a passive waveguide, wherein the passive waveguide is located on both sides of the active waveguide; the active waveguide is a gain waveguide with current injection, which is used to achieve the fundamental mode gain of the final lasing; the passive waveguide does not inject current and is used to achieve laser loss.

[0017] Preferably, the beam-splitting MMI structure and the beam-combining MMI structure have the same row width; the beam-splitting MMI structure includes multiple entrance ends for connecting to the inclined array waveguide area and multiple exit ends for connecting to the gain array waveguide; the beam-combining MMI structure includes multiple entrance ends for connecting to the gain array waveguide and multiple exit ends for connecting to the supersymmetric waveguide array.

[0018] Preferably, a beam-splitting spatial modulation electrode window is provided in the beam-splitting MMI structure, and the beam-splitting spatial modulation electrode window is used to inject a periodic current to form a periodic carrier distribution inside the beam-splitting MMI structure.

[0019] Preferably, a beam-combining spatial modulation electrode window is provided in the beam-combining MMI structure, and the beam-combining spatial modulation electrode window is used for beam combining so that the combined laser beam is coupled to the supersymmetric waveguide array.

[0020] Preferably, the semiconductor PN junction includes a layered N-type substrate, an N-type cladding, an N-waveguide, an active area, a P-waveguide, a P-type cladding, and a P-type cap layer; the side of the N-type substrate facing away from the N-type cladding is connected to an N-electrode, and the side of the P-type cap layer facing away from the P-type cladding is connected to a P-electrode.

[0021] Preferably, the semiconductor PN junction is in the shape of an elongated strip; the sum of the column lengths of the inclined array waveguide region, the beam splitting MMI structure, the gain array waveguide, the beam combining MMI structure and the supersymmetric waveguide array is equal to the length of the semiconductor PN junction.

[0022] Preferably, the Bragg reflection grating is a micron-scale high-order grating, which is prepared by one-time etching.

[0023] Preferably, the etching depths of the inclined array waveguide region, the gain array waveguide and the supersymmetric waveguide array do not exceed the active region.

[0024] Preferably, the etching depths of the inclined array waveguide region, the gain array waveguide and the supersymmetric waveguide array all exceed the active region.

[0025] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0026] The present invention provides a multi-wavelength semiconductor laser with simple preparation, high gain, and high single-mode performance. All laser source, beam combining, gain, mode selection, and other structures are fabricated on a single epitaxial wafer through photolithography and etching processes. The seed laser emitted by the array is evenly distributed to the gain array through the MMI beam combining structure. The laser amplified by the gain array is beam combined again into a supersymmetric gain waveguide, and the loss waveguide is used to filter out high-order modes to achieve high-power, narrow-linewidth, single-longitudinal-mode laser output. This can effectively overcome the problems of low integration of multi-wavelength laser systems, crosstalk between different wavelengths, poor output single-longitudinal-mode performance, and difficulty in preparation. It is an important driving force for the development of semiconductor lasers in wide-tuning and multi-wavelength fields such as lidar.

[0027] Compared with external cavity multi-wavelength semiconductor lasers, the present invention has a smaller size, meets the requirements of integration, does not require a complex optical path adjustment system, and does not have coupling problems between the various parts caused by misalignment of the transmission optical path. Moreover, the parallel grating of the present invention plays the reflection function of the bottom DBR through reasonable design, and does not require an external reflector to improve the intracavity oscillation.

[0028] Compared with the series-type multi-wavelength semiconductor laser, the present invention adopts parallel array waveguides. Each waveguide generates lasers of different wavelengths and is separately controlled by separate control electrodes. The laser optical path of each wavelength is different, so there is no wavelength interference problem caused by the shared optical path of the series type. There is no need to prepare multiple gratings. Only a simple two-step lithography is required, one to prepare parallel gratings and the second to prepare tilted waveguides, to achieve multi-wavelength lasing.

[0029] Compared with the sampled Bragg grating laser, the present invention does not require the design of nm-level low-order gratings. The parallel grating can prepare micron-level high-order gratings, which are surface gratings. There is no need to prepare buried gratings or secondary epitaxy, which simplifies the grating preparation process and improves the device yield.

[0030] Compared with other array-type multi-wavelength semiconductor lasers, the present invention integrates all the structures required for multi-wavelength lasing on a single epitaxial wafer, and can achieve lasing, gain, and mode selection without bonding epitaxial structures of other materials. The present invention has a higher degree of integration.

[0031] Compared with existing multi-wavelength semiconductor lasers, the present invention does not require bonding, external optical path adjustment, or deliberate preparation of low-order gratings. While improving the degree of integration, it can achieve many requirements such as a narrow enough line width of the light beam, a high enough gain, a large enough high-order mode loss, and a simpler adjustment method. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the overall structure of a multi-wavelength semiconductor laser provided according to an embodiment of the present invention.

[0033] Figure 2 FIG. 4 is a top view of a multi-wavelength semiconductor laser provided according to an embodiment of the present invention.

[0034] Figure 3 4 is a front view of a multi-wavelength semiconductor laser provided according to an embodiment of the present invention.

[0035] Figure 4 FIG. 4 is a side view of a multi-wavelength semiconductor laser provided according to an embodiment of the present invention.

[0036] Figure 5 It is a partially enlarged view of a multi-wavelength semiconductor laser provided according to an embodiment of the present invention.

[0037] Reference numerals:

[0038] 1. Bragg reflection grating; 2. Tilted waveguide array; 3. Beam-splitting MMI structure; 4. Beam-splitting spatial modulation electrode window; 5. Gain array waveguide; 6. Beam-combining MMI structure; 7. Beam-combining spatial modulation electrode window; 8. Supersymmetric waveguide array; 9. N-electrode; 10. N-type substrate; 11. N-type cladding; 12. N-waveguide; 13. Active region; 14. P-waveguide; 15. P-type cladding; 16. P-type cap layer; 17. P-electrode;

[0039] 801. Active waveguide; 802. Passive waveguide. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, identical modules are denoted by identical reference numerals. In the case of identical reference numerals, their names and functions are also identical. Therefore, their detailed description will not be repeated.

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying 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 of the present invention.

[0042] The present invention provides a multi-wavelength semiconductor laser, comprising a semiconductor PN junction, and an inclined array waveguide region, a beam splitting MMI structure, a gain array waveguide, a beam combining MMI structure and a supersymmetric waveguide array, which are sequentially arranged on the surface of the semiconductor PN junction along the longitudinal mode light beam transmission direction;

[0043] The semiconductor PN junction includes a layered N-type substrate, an N-type cladding, an N-waveguide, an active region, a P-waveguide, a P-type cladding, and a P-type cap layer; the N-type substrate is connected to an N-electrode on the side facing away from the N-type cladding, and the P-type cap layer is connected to a P-electrode on the side facing away from the P-type cladding;

[0044] The tilted array waveguide region includes a Bragg reflection grating and a tilted array waveguide, wherein the Bragg reflection grating is provided on a ridge surface at an entrance end of the tilted array waveguide; each waveguide in the tilted array waveguide has a different cavity length and is used to provide a narrow linewidth laser seed source; all the Bragg reflection gratings in the tilted array waveguide region are parallel and are used to control the single longitudinal mode wavelength of the laser output by each waveguide;

[0045] The seed source output from the tilted array waveguide region is injected into the beam splitting MMI structure, and the beam splitting MMI structure evenly distributes and couples the seed source into each waveguide of the gain array waveguide;

[0046] The gain array waveguide is a parallel waveguide used to amplify power and ensure that the output power is sufficient for the application requirements; the beam-combining MMI structure couples the light output by the gain array waveguide into the supersymmetric waveguide array; the supersymmetric waveguide array is used to provide further gain to the fundamental mode and loss to the higher-order modes, ensuring that the final output laser light is in a single longitudinal mode state.

[0047] The supersymmetric waveguide array includes active waveguides and passive waveguides, with the passive waveguides located on both sides of the active waveguide. The active waveguide is a gain waveguide with current injection, used to achieve the fundamental mode gain of the final lasing; the passive waveguide does not inject current and is used to achieve laser loss.

[0048] In a specific embodiment, the beam-splitting MMI structure and the beam-combining MMI structure have the same row width; the beam-splitting MMI structure includes multiple inlet ports for connecting to the tilted array waveguide region and multiple outlet ports for connecting to the gain array waveguide; and the beam-combining MMI structure includes multiple inlet ports for connecting to the gain array waveguide and multiple outlet ports for connecting to the supersymmetric waveguide array. A beam-splitting spatial modulation electrode window is provided within the beam-splitting MMI structure, and is used to inject a periodic current to form a periodic carrier distribution within the beam-splitting MMI structure. A beam-combining spatial modulation electrode window is provided within the beam-combining MMI structure, and is used to combine the beams, coupling the combined laser beams to the supersymmetric waveguide array.

[0049] In a specific embodiment, the semiconductor PN junction is in the shape of an elongated strip; the sum of the column lengths of the inclined array waveguide region, the beam splitting MMI structure, the gain array waveguide, the beam combining MMI structure and the supersymmetric waveguide array is equal to the length of the semiconductor PN junction.

[0050] In a specific embodiment, the Bragg reflection grating is a micron-scale high-order grating, which is prepared by one-time etching.

[0051] In a specific embodiment, the etching depths of the inclined array waveguide region, the gain array waveguide, and the supersymmetric waveguide array do not exceed the active region, or the etching depths all exceed the active region.

[0052] Example 1

[0053] like Figure 1-4 As shown, a multi-wavelength semiconductor laser includes a semiconductor PN junction, and an inclined array waveguide region, a beam splitting MMI structure 3, a gain array waveguide 5, a beam combining MMI structure 6 and a supersymmetric waveguide array 8 arranged in sequence on the surface of the semiconductor PN junction along the longitudinal mode light beam transmission direction.

[0054] The semiconductor PN junction includes a layered N-type substrate 10, an N-type cladding 11, an N-waveguide 12, an active area 13, a P-waveguide 14, a P-type cladding 15, and a P-type cap layer 16; the side of the N-type substrate 10 facing away from the N-type cladding 11 is connected to an N-electrode 9, and the side of the P-type cap layer 16 facing away from the P-type cladding 15 is connected to a P-electrode 17; the inclined array waveguide region, the beam splitting MMI structure 3, the gain array waveguide 5, the beam combining MMI structure 6, and the supersymmetric waveguide array 8 are all arranged on the surface of the P-type cap layer 16.

[0055] The tilted array waveguide area mainly provides a narrow-linewidth laser seed source, including a tilted waveguide array 2 and a Bragg reflection grating 1. The Bragg reflection grating 1 is arranged on the ridge surface of the entrance end of the tilted array waveguide 2. All Bragg reflection gratings are parallel, are micron-level high-order gratings, and are surface gratings. No buried gratings are required and no secondary epitaxy is required. They are used to control the wavelength of the laser output from each tilted waveguide. Different tilt angles are used to change the cavity length of the tilted waveguide, and the Bragg reflection gratings 1 on each tilted waveguide are parallel and are all prepared by one etching. Due to the different cavity lengths, the actual duty cycle and period of the Bragg reflection grating 1 on each tilted waveguide are different, and the selected single longitudinal mode wavelength is also different. By regulating the lasing state of the tilted waveguides with different electrodes, narrow-linewidth seed source lasers of different wavelengths can be obtained.

[0056] The beam-splitting MMI structure 4 evenly distributes and couples the seed source injected from each port into each waveguide of the gain array waveguide 5; the surface electrode of the beam-splitting MMI structure 4 is a beam-splitting spatial modulation electrode window 4, which is used to inject periodic current to form a periodic distribution of carriers inside the beam-splitting MMI structure 4. The carrier concentration is changed by different injected currents. Different carrier concentrations will cause the imaginary part of the refractive index inside the material to change periodically, forming a refractive index difference, thereby achieving the purpose of modulation, ensuring that the seed source laser injected by the tilted waveguide array 2 can be evenly coupled into the gain array waveguide 5 when passing through the beam-splitting MMI structure 4.

[0057] The gain array waveguide 5 is a parallel waveguide that acts as a power amplifier to ensure that the final output power is sufficient to meet application requirements.

[0058] The beam-combining MMI structure 6 couples the light output by the gain array waveguide 5 into the supersymmetric waveguide array 8; the beam-combining spatial modulation electrode window 7 has the same mechanism as the beam-splitting spatial modulation electrode window 4, but the spatial modulation electrode window 7 is used for beam combining to ensure that the light from the gain array waveguide 5 can be combined and coupled into the active waveguide of the supersymmetric waveguide array 8.

[0059] The structure of the supersymmetric waveguide array 8 provides further gain for the fundamental mode and loss for higher-order modes, ensuring that the final lasing light is in a single longitudinal mode state. The supersymmetric waveguide array 8 includes active waveguides and passive waveguides. The passive waveguides are lossy waveguides on both sides of the active waveguide. Figure 5This is an enlarged schematic diagram of a supersymmetric waveguide array 8. The active waveguide 801 is a gain waveguide with current injection, ensuring sufficiently high fundamental mode gain for the final lasing. The passive waveguide 802 does not require current injection, and higher-order modes appear within the passive waveguide. Without carrier injection, these higher-order modes entering the passive waveguide are simply lost, suppressing lasing. This embodiment shows only one active waveguide 801 and two passive waveguides 802 on either side. In practice, multiple active and passive waveguides can be used, and the number can be increased depending on the specific situation.

[0060] The etching depths of the tilted array waveguide region, the gain array waveguide 5 and the supersymmetric waveguide array 8 do not exceed the active region 13 .

[0061] Example 2

[0062] A multi-wavelength semiconductor laser comprises a semiconductor PN junction, and an inclined array waveguide region, a beam splitting MMI structure, a gain array waveguide, a beam combining MMI structure and a supersymmetric waveguide array which are sequentially arranged on the surface of the semiconductor PN junction along the longitudinal mode light beam transmission direction.

[0063] The difference from the first embodiment is that the tilted arrayed waveguide region, the beam splitting MMI structure, the gain arrayed waveguide, the beam combining MMI structure and the supersymmetric waveguide array are all provided on the surface of the N-type substrate 10 .

[0064] The different positions of the on-chip structures will only change the main affected light field. The on-chip structure on the N-side has a greater impact on the N-side light field, and will not change the essential influence of structures such as gratings and supersymmetry on mode selection.

[0065] Example 3

[0066] A multi-wavelength semiconductor laser comprises a transistor laser, and an inclined array waveguide region, a beam splitting MMI structure, a gain array waveguide, a beam combining MMI structure and a supersymmetric waveguide array which are sequentially arranged on the surface of the transistor laser along the longitudinal mode light beam transmission direction.

[0067] The difference from Example 1 is that the tilted arrayed waveguide region, beam-splitting MMI structure, gain array waveguide, beam-combining MMI structure, and supersymmetric waveguide array are arranged on the surface electrodes of the transistor laser. Regardless of which electrode the multi-wavelength array structure is formed on, it is a modified design of the present invention.

[0068] Example 4

[0069] The difference between this embodiment and embodiment 1 is that the etching depths of the inclined array waveguide region, the gain array waveguide, and the supersymmetric waveguide array all exceed the active region.

[0070] Alternatively, different etching depths can be achieved for each section by performing separate photolithography, both of which are variations of the present invention. However, due to the high degree of integration in the present invention, different etching depths can affect the optical path during laser transmission, potentially causing the optical path to be at different heights. Therefore, the additional losses introduced by optical path propagation must be considered when determining the etching depth.

[0071] Example 5

[0072] Based on the multi-wavelength semiconductor laser provided in Example 1, a buried grating is added near the tilted waveguide or the P-type cladding, or the line width is further narrowed based on the existing surface grating to improve the single longitudinal mode yield of the device.

[0073] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved. This is not limited herein.

[0074] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A multi-wavelength semiconductor laser, characterized in that: It includes a semiconductor PN junction, and an inclined array waveguide region, a beam splitting MMI structure, a gain array waveguide, a beam combining MMI structure and a supersymmetric waveguide array sequentially arranged on the surface of the semiconductor PN junction along the longitudinal mode light beam transmission direction; The tilted array waveguide region includes a Bragg reflection grating and a tilted array waveguide, wherein the Bragg reflection grating is provided on a ridge surface at an entrance end of the tilted array waveguide; each waveguide in the tilted array waveguide has a different cavity length and is used to provide a narrow linewidth laser seed source; all the Bragg reflection gratings in the tilted array waveguide region are parallel and are used to control the single longitudinal mode wavelength of the laser output by each waveguide; The seed source outputted from the tilted array waveguide region is injected into the beam splitting MMI structure, and the beam splitting MMI structure evenly distributes and couples the seed source into each waveguide of the gain array waveguide; The gain array waveguide is a parallel waveguide used to amplify power and ensure that the output power is sufficient for the application requirements; the beam-combining MMI structure couples the light output by the gain array waveguide into the supersymmetric waveguide array; the supersymmetric waveguide array is used to provide further gain to the fundamental mode and loss to the higher-order modes, ensuring that the final output laser light is in a single longitudinal mode state.

2. The multi-wavelength semiconductor laser according to claim 1, wherein: The supersymmetric waveguide array includes active waveguides and passive waveguides, and the passive waveguides are located on both sides of the active waveguides; the active waveguides are gain waveguides with current injection, which are used to achieve the fundamental mode gain of the final lasing; the passive waveguides do not inject current and are used to achieve laser loss.

3. The multi-wavelength semiconductor laser according to claim 2, wherein: The beam-splitting MMI structure and the beam-combining MMI structure have the same row width; the beam-splitting MMI structure includes multiple entrance ends for connecting to the tilted array waveguide region and multiple exit ends for connecting to the gain array waveguide; the beam-combining MMI structure includes multiple entrance ends for connecting to the gain array waveguide and multiple exit ends for connecting to the supersymmetric waveguide array.

4. The multi-wavelength semiconductor laser according to claim 3, characterized in that: A beam-splitting spatial modulation electrode window is provided in the beam-splitting MMI structure. The beam-splitting spatial modulation electrode window is used to inject a periodic current to form a periodic carrier distribution in the beam-splitting MMI structure.

5. The multi-wavelength semiconductor laser according to claim 4, characterized in that: A beam-combining spatial modulation electrode window is provided in the beam-combining MMI structure. The beam-combining spatial modulation electrode window is used for beam combining so that the combined laser beam is coupled to the supersymmetric waveguide array.

6. A multi-wavelength semiconductor laser according to any one of claims 1 to 5, characterized in that: The semiconductor PN junction includes a layered N-type substrate, an N-type cladding, an N-waveguide, an active area, a P-waveguide, a P-type cladding, and a P-type cap layer; the N-type substrate is connected to an N-electrode on the side facing away from the N-type cladding, and the P-type cap layer is connected to a P-electrode on the side facing away from the P-type cladding.

7. The multi-wavelength semiconductor laser according to claim 6, characterized in that: The semiconductor PN junction is in the shape of an elongated strip; the sum of the column lengths of the inclined array waveguide region, the beam splitting MMI structure, the gain array waveguide, the beam combining MMI structure and the supersymmetric waveguide array is equal to the length of the semiconductor PN junction.

8. The multi-wavelength semiconductor laser according to claim 7, characterized in that: The Bragg reflection grating is a micron-level high-order grating and is prepared by one-time etching.

9. The multi-wavelength semiconductor laser according to claim 8, characterized in that: The etching depths of the inclined array waveguide region, the gain array waveguide, and the supersymmetric waveguide array do not exceed the active region.

10. The multi-wavelength semiconductor laser according to claim 8, characterized in that: The etching depths of the inclined array waveguide region, the gain array waveguide and the supersymmetric waveguide array all exceed the active region.

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