Semiconductor laser and design method thereof

Abstract

The invention relates to the technical field of lasers, in particular to a semiconductor laser and a design method thereof.The design method of the semiconductor laser comprises the steps that simulation analysis is conducted on the basis of the effective refractive index # imgabs0 #, the lasing wavelength # imgabs1 #, the channel refractive index difference # imgabs2 #, the lateral component k0 of a fundamental mode wave vector and the lateral component k1 of a first-order mode wave vector; obtaining a second corresponding relation among the channel refractive index difference # imgabs3 #, the central waveguide width WR and the channel width range; and selecting a first central waveguide width, a first channel depth and a first channel width satisfying a second corresponding relationship, taking the first central waveguide width as a target central waveguide width, taking the first channel depth as a target channel depth, and taking the first channel width as a target channel width. The method is at least beneficial to reducing the difficulty of designing and obtaining the semiconductor laser with better light beam quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of lasers, and in particular relates to a semiconductor laser and a design method thereof. Background Art

[0002] The brightness of a semiconductor laser is proportional to the ratio of power to beam quality, and the brightness of a semiconductor laser is usually expressed as laser power per unit solid angle. In practical applications, it is often desired that semiconductor lasers have high output power and excellent beam quality, that is, high brightness. However, the lateral modes of a semiconductor laser will reduce the overall brightness and beam quality of the semiconductor laser, and as the injection current increases, the lateral beam quality will also deteriorate rapidly, mainly reflected in the increase in the lateral far-field divergence angle caused by the lasing of high-order modes. Existing methods are mostly to reduce the waveguide width of the semiconductor laser, thereby reducing the number of lateral modes, or to achieve the purpose of improving the beam quality through external cavity technology, regulating carrier injection, etc. However, since reducing the waveguide width also reduces the area of the gain region, the output power is also greatly reduced, and the technology is complex, increasing the volume and cost of the semiconductor laser, which is very unfavorable for the industrial preparation of high-power semiconductor lasers.

[0003] In related technologies, the distribution characteristics of lateral high-order modes are changed by channels on both sides of the central waveguide without affecting the fundamental mode, making it difficult for the high-order modes to obtain gain, while the fundamental mode obtains maximum gain, thereby obtaining high-power single lateral mode output and improving beam quality. However, how to reasonably set the central waveguide and channel to maximize the improvement of beam quality while reducing the difficulty of determining the parameters of the central waveguide and the channels on both sides has not yet been solved. Therefore, how to reduce the difficulty of designing semiconductor lasers with better beam quality has become a problem that needs to be solved urgently. Summary of the Invention

[0004] In view of this, the present invention aims to provide a semiconductor laser and a design method thereof, which at least helps to reduce the difficulty of designing a semiconductor laser with better beam quality.

[0005] To achieve the above object, the technical solution created by the present invention is implemented as follows: The present invention provides a method for designing a semiconductor laser. The method for designing a semiconductor laser includes an epitaxial structure having a surface waveguide. The surface waveguide includes a central waveguide and channels located on both sides of the central waveguide. The method for designing a semiconductor laser includes: determining an effective refractive index according to the epitaxial structure. and lasing wavelength ; Determine the channel depth and channel refractive index difference The first correspondence of, and the determination of the lateral component of the fundamental mode wave vectorκ 0 and the lateral components of the first-order mode wave vector κ 1; Based on the effective refractive index , laser wavelength , channel refractive index difference , the lateral component of the fundamental mode wave vector κ 0 and the lateral components of the first-order mode wave vector κ 1 Perform simulation analysis to obtain the channel refractive index difference , central waveguide width W R and a second correspondence between the channel width range; selecting a first center waveguide width, a first channel depth, and a first channel width that satisfy the second correspondence, using the first center waveguide width as the target center waveguide width, the first channel depth as the target channel depth, and the first channel width as the target channel width.

[0006] Furthermore, obtaining the second corresponding relationship includes: obtaining the channel refractive index difference , central waveguide width W R and a curve graph of the correspondence between the channel width range; selecting the first center waveguide width, the first channel depth and the first channel width that satisfy the second correspondence includes: knowing the first center waveguide width and the first channel depth, determining the target channel width range based on the curve graph, and selecting the first channel width within the target channel width range; or, knowing the first center waveguide width, determining the target channel width range based on the curve graph, selecting the first channel width within the target channel width range, and determining the first channel depth according to the first channel width.

[0007] Furthermore, based on the effective refractive index , laser wavelength , channel refractive index difference , the lateral component of the fundamental mode wave vector κ 0 and the lateral components of the first-order mode wave vector κ 1. The simulation analysis includes: the effective refractive index , laser wavelength , channel refractive index difference , the lateral component of the fundamental mode wave vector κ 0 and the lateral components of the first-order mode wave vector κ 1 is substituted into formula 1 for simulation analysis to obtain the curve graph; formula 1 is as follows: , where W is the channel width.

[0008] Further, when the size of the target channel width range is smaller than that of the preset channel width range, the value of the target channel depth is decreased to increase the size of the target channel width range. If the target channel depth is smaller than the preset channel depth, an ion implanted insulating layer is provided. The ion implanted insulating layer extends from the bottom surface of the channel away from the channel into the epitaxial structure. The epitaxial structure includes an active region layer, and there is a spacing distance between the active region layer and the ion implanted insulating layer.

[0009] Further, determine the lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ 1, including: based on the channel refractive index difference , the central waveguide width W R and the lasing wavelength Adopt the Colin graphical method to solve the transcendental equation of the waveguide mode to obtain the lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ 1.

[0010] On the other hand, the present invention provides a semiconductor laser, including: an epitaxial structure having a surface waveguide, the surface waveguide including a central waveguide and channels located on both sides of the central waveguide. The semiconductor laser is designed by using the design method of the aforementioned semiconductor laser. The width of the central waveguide is the target central waveguide width, the depth of the channel is the target channel depth, and the width of the channel is the target channel width.

[0011] Further, the semiconductor laser further includes: an ion implanted insulating layer, which extends from the bottom surface of the channel away from the channel into the epitaxial structure. The epitaxial structure includes an active region layer, and there is a spacing distance between the active region layer and the ion implanted insulating layer.

[0012] Further, the width of the channel at any position is the same in the direction pointing from the central waveguide to any channel.

[0013] Further, the width of the central waveguide at any position is the same in the direction pointing from the central waveguide to any channel; or, at least one side of the central waveguide facing the channel is non-linear.

[0014] Further, the width of the central waveguide gradually increases along the extending direction of the central waveguide, and the width of the channel gradually increases along the extending direction of the central waveguide; or, the width of the central waveguide gradually increases from the middle position of the central waveguide to both ends of the central waveguide, and the width of the channel gradually increases from the middle position of the channel to both ends of the channel.

[0015] Compared with the prior art, the present invention can achieve the following beneficial effects: By using the design method of the semiconductor laser provided by the present invention, the reasonable center waveguide width, channel width, and channel depth can be directly and efficiently determined, avoiding the use of multiple repeated experiments to determine parameters, reducing the difficulty of designing a semiconductor laser with better beam quality, and the optimal parameters of the semiconductor laser can be determined. Furthermore, the channel can effectively suppress the high-order lateral modes, change the mode distribution in the device cavity, play a role in controlling the carrier injection, weaken the lateral carrier accumulation effect, thereby improving the optoelectronic performance of the device, increasing the beam brightness of the device output, stabilizing the far field, ensuring that the center waveguide has a larger width, increasing the injection gain area, increasing the power on the premise of ensuring the beam quality, and improving the beam brightness. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 FIG. is a schematic structural diagram of a semiconductor laser according to an embodiment of the present invention; Figure 2 FIG. is a relationship curve diagram of the channel depth and the refractive index difference caused by the channel according to an embodiment of the present invention ; Figure 3 FIG. is a corresponding relationship curve diagram of the channel refractive index difference , the center waveguide width W R and the channel width range according to an embodiment of the present invention; Figure 4 FIG. is a schematic structural diagram of a semiconductor laser according to another embodiment of the present invention; Figure 5 FIG. is a top view of a semiconductor laser according to an embodiment of the present invention; Figure 6 FIG. is a top view of three different semiconductor lasers according to another embodiment of the present invention; Figure 7 FIG. is a top view of three different semiconductor lasers according to still another embodiment of the present invention; Figure 8 FIG. is a top view of three different semiconductor lasers according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

[0018] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0019] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0021] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0022] Referring to Figures 1 to 8 , on the one hand, the present invention provides a design method for a semiconductor laser. The design method for a semiconductor laser is used to design a semiconductor laser, and the semiconductor laser includes an epitaxial structure having a surface waveguide. The surface waveguide includes a central waveguide 203 and channels 202 located on both sides of the central waveguide 203.

[0023] Specifically, in some embodiments, the epitaxial structure includes an N-side electrode 110, a substrate 101, an N-type cladding layer 102, an N-type waveguide layer 103, an active region layer 104, a P-type waveguide layer 105, a P-type cladding layer 106, a P-type capping layer 107, an insulating layer 108, and a P-side electrode 109 stacked in sequence from bottom to top. The N-type waveguide layer 103, the active region layer 104, and the P-type waveguide layer 105 form a laser waveguide layer. The refractive index of the laser waveguide layer is greater than that of the N-type cladding layer 102 and greater than that of the P-type cladding layer 106, thereby forming a total reflection waveguide. The central waveguide 203 and the channels 202 are disposed on the P-type cladding layer 106 and the P-type capping layer 107. The two channels 202 are arranged at intervals, and the central waveguide 203 is located between the two channels 202. Each channel 202 penetrates through the P-type capping layer 107 and a part of the P-type cladding layer 106. On one side of each channel 202 away from the central waveguide 203 is a non-injection region 201. The insulating layer 108 is located on the top surface of the non-injection region 201 and the surface of the channels 202. The P-side electrode 109 is located on the top surface of the insulating layer 108 and the top surface of the central waveguide 203. The distance between the bottom surface of the channel 202 and the P-type waveguide layer 105 is less than the length of the evanescent wave of the laser waveguide layer. In some embodiments, the gain medium of the active region may include at least one of quantum wells, quantum dots, quantum wires, and quantum cascade superlattice structures. The channels 202 are used to effectively suppress high-order lateral modes, change the mode distribution in the device cavity, and can also play a role in controlling carrier injection, weakening the lateral carrier accumulation effect, thereby improving the optoelectronic performance of the device, increasing the device brightness, and stabilizing the far field.

[0024] The design method of the semiconductor laser provided by the present invention is used to determine the width of the channel (target channel width), the depth of the channel (target channel depth), and the width of the central waveguide (target central waveguide width) so that the width of the channel, the depth of the channel, and the width of the central waveguide satisfy: the channel can effectively suppress high-order lateral modes, change the mode distribution in the device cavity, play a role in controlling carrier injection, weaken the lateral carrier accumulation effect, thereby improving the optoelectronic performance of the device, increasing the brightness of the light beam output by the device, and stabilizing the far field. The central waveguide has a larger width, increasing the injection gain area and increasing the power on the premise of ensuring the beam quality.

[0025] The design method of the semiconductor laser includes: determining the effective refractive index according to the epitaxial structure and the lasing wavelength ; determining the first correspondence relationship between the channel depth and the channel refractive index difference and determining the lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ 1; based on the effective refractive index , the lasing wavelength and the channel refractive index difference , the lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ 1 are simulated and analyzed to obtain the channel refractive index difference , the central waveguide width W R and the second corresponding relationship of the channel width range; select the first central waveguide width, the first channel depth, and the first channel width that satisfy the second corresponding relationship, use the first central waveguide width as the target central waveguide width, the first channel depth as the target channel depth, and the first channel width as the target channel width. Among them, the target channel width refers to the width of a single channel.

[0026] It should be noted that for determining the first corresponding relationship between the channel depth and the channel refractive index difference , regardless of the epitaxial structure, the relationship between the channel depth and the channel refractive index difference is the same, as Figure 2 shown, and the channel refractive index difference increases with the increase of the channel depth. For how to determine the first corresponding relationship between the channel depth and the channel refractive index difference , in some embodiments, related technologies can be referred to (for example, Tianfang Wang, Chengao Yang, etc. Promotion of Specifc Single-Transverse-Mode Beam Characteristics for GaSb-Based Narrow Ridge Waveguide Lasers Via Customized Parameter Design[J]. Nanoscale Research Letters, 2022.17:116, https: / / doi.org / 10.1186 / s11671-022-03758-5, Page 3 of 10), which will not be elaborated here.

[0027] In some embodiments, obtaining the second corresponding relationship includes: obtaining the channel refractive index difference , the central waveguide width W R and the curve graph of the corresponding relationship of the channel width range.

[0028] In some embodiments, the simulation analysis based on the effective refractive index , the lasing wavelength , the channel refractive index difference , the lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ 1 includes: taking the effective refractive index , lasing wavelength , channel refractive index difference , lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ Substitute 0 and 1 into Equation 1 for simulation analysis to obtain a curve; Equation 1 is as follows: , where W is the channel width.

[0029] In some embodiments, the derivation process of Equation 1 is as follows: For a waveguide composed of a laser waveguide layer and a surface waveguide, when total internal reflection occurs, a Goos-Hänchen shift will be generated, which is manifested as an evanescent wave generated when the optical field enters from the high refractive index layer to the low refractive index layer, and the limit distance Z of the evanescent wave transmitted to the low refractive index layer can be expressed as: , where is the lasing wavelength, is the effective refractive index of the transmission mode, is the refractive index of the low refractive index layer material; For a semiconductor device with an edge-emitting structure, the channel depth determines the effective refractive index distribution of the waveguide in the lateral direction. Assume that the effective refractive index of the channel is defined as , and the effective refractive index of the ridge structure is (the effective refractive index determined according to the epitaxial structure), where is determined by the epitaxial structure adopted by the device. The effective refractive index of the transmission mode is . To confine the mode in the waveguide, it is necessary to satisfy the channel width W > Z, so there is . In fact, in this waveguide, if the nth-order lateral mode can exist and its effective refractive index is , then the effective refractive indices of each order of mode satisfy the following relationship: . Therefore, the channel width W corresponding to different modes is different, and the width required for the fundamental mode is the smallest. Therefore, to ensure that only the fundamental mode is output, generally the channel width W needs to satisfy: , that is, , where κ 0 is the component of the wave vector of the fundamental mode in the lateral direction, κ 1 is the component of the wave vector of the first-order mode in the lateral direction, κ 0 and κ 1 are related to the channel depth and the center waveguide width W R and can be obtained by solving the transcendental equation of the waveguide mode to obtain an accurate numerical solution. Since , where is the refractive index difference generated by the channel 202, and usually the refractive index difference is about 10 -2 ​~10 -4 within the range of, thus, the previous formula can be approximately simplified to: , that is, Formula 1.

[0030] In some embodiments, determining the lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ 1 includes: based on the channel refractive index difference , the center waveguide width W R and the lasing wavelength using the Colin graphical method to solve the transcendental equation of the waveguide mode to obtain the lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ 1. Specifically, the specific method of using the Colin graphical method to solve the transcendental equation of the waveguide mode can refer to the related technology (Jiang Jianping, Semiconductor Lasers [M]. Publishing House of Electronics Industry, 2000, pages 66 to 67), which will not be elaborated here.

[0031] In some embodiments, selecting the first center waveguide width, the first channel depth, and the first channel width that satisfy the second correspondence relationship includes: knowing the first center waveguide width and the first channel depth, based on the curve graph, determining the target channel width range, and selecting the first channel width within the target channel width range; or, knowing the first center waveguide width, based on the curve graph, determining the target channel width range, selecting the first channel width within the target channel width range, and determining the first channel depth according to the first channel width.

[0032] In some embodiments, when the size of the target channel width range is smaller than the size of the preset channel width range, reducing the value of the target channel depth to increase the size of the target channel width range. If the target channel depth is less than the preset channel depth, an ion-implanted insulating layer 120 is provided. The ion-implanted insulating layer 120 extends from the bottom surface of the channel 202 into the epitaxial structure in a direction away from the channel 202. The epitaxial structure includes an active region layer 104, and there is a spacing distance between the active region layer 104 and the ion-implanted insulating layer 120. That is to say, as the width of the center waveguide 203 increases, the optional value interval of the channel width will rapidly decrease. At this time, the value interval of the channel width can be increased by reducing the channel depth. However, as the channel depth decreases, carrier diffusion will cause a significant power reduction in the device. Therefore, it is necessary to form an insulating layer 108 by ion implantation at the bottom of the channel 202 to alleviate the power reduction phenomenon caused by carrier diffusion, so as to design a device with a wider center waveguide 203.

[0033] It should be noted that the size of the preset channel width range is related to the process window of the channel width. The larger the size of the preset channel width range, the larger the process window of the channel width, and the easier it is to fabricate a channel that meets the channel width range. Therefore, on the premise of better device performance, it is generally desirable that the preset channel width range be as large as possible. The preset channel depth is the limit value of the channel depth where carrier diffusion occurs, that is, when the channel depth is less than the preset channel depth, the power reduction caused by carrier diffusion is more obvious, and when the channel depth is greater than or equal to the preset channel depth, the influence of carrier diffusion on power reduction is smaller. The present invention does not limit the preset channel width range and the preset channel depth, and the preset channel width range and the preset channel depth can be determined according to the actual application requirements of the device.

[0034] In some examples, assume that the effective refractive index determined by the epitaxial structure is 3.413, the lasing wavelength is 0.976 μm, and the relationship between the channel depth and the channel refractive index difference is as Figure 2 shown. Substituting the effective refractive index , the lasing wavelength , the channel refractive index difference , the lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ 1 into Equation 1 gives the curve graph as Figure 3 shown. Among them, the dotted line of the corresponding color represents the upper limit curve of the channel width, and the solid line of the corresponding color represents the lower limit curve of the channel width. Different colors represent different channel refractive index differences. According to the curve graph, the first channel width, the first channel depth, and the first center waveguide width that satisfy Equation 1 can be determined, and then a device with higher lateral beam quality can be designed. For example, when the refractive index difference is 5×10 -4 , the corresponding channel depth is about 0.86 μm. If the selected center waveguide width W R is 18 μm, then the channel width W is in the range of 2.8 μm to 3.7 μm.

[0035] According to Figure 3 it can be seen that as the center waveguide width W R increases, the selectable value range of the channel width W rapidly decreases. Therefore, the method of reducing the channel depth can be used to increase the value range of the channel width W to increase the fabrication window of the channel width. However, since as the channel depth decreases, carrier diffusion will cause a strong power reduction in the device, at this time, the problem of power reduction in the device caused by carrier diffusion can be solved by forming an ion implantation insulating layer 120 at the bottom of the channel 202 through ion implantation, and a device with high beam quality and high output power can be effectively obtained.

[0036] In some embodiments, the epitaxial structure is an edge-emitting quantum well epitaxy, the channel width ranges from 2 μm to 5 μm, the channel depth ranges from 0.7 μm to 1.0 μm, the center waveguide width ranges from 10 μm to 20 μm, and the bottom of the channel 202 does not have an ion implantation insulating layer 120; in other embodiments, the epitaxial structure is an edge-emitting quantum well epitaxy, the channel width ranges from 2 μm to 5 μm, the channel depth ranges from 0.4 μm to 0.7 μm, the center waveguide width ranges from 20 μm to 50 μm, and the bottom of the channel 202 has an ion implantation insulating layer 120.

[0037] On the other hand, the present invention provides a semiconductor laser, comprising: an epitaxial structure having a surface waveguide, the surface waveguide including a center waveguide 203 and channels 202 located on both sides of the center waveguide 203. The semiconductor laser is designed by using the design method of the aforementioned semiconductor laser. The width of the center waveguide 203 is the target center waveguide width, the depth of the channel 202 is the target channel depth, and the width of the channel 202 is the target channel width. The target center waveguide width, the target channel width, and the target channel depth satisfy Formula 1.

[0038] Specifically, in some embodiments, the epitaxial structure includes an N-side electrode 110, a substrate 101, an N-type cladding layer 102, an N-type waveguide layer 103, an active region layer 104, a P-type waveguide layer 105, a P-type cladding layer 106, a P-type capping layer 107, an insulating layer 108, and a P-side electrode 109, which are stacked in sequence from bottom to top. The center waveguide 203 and the channels 202 are disposed on the P-type cladding layer 106 and the P-type capping layer 107. The two channels 202 are arranged at intervals, the center waveguide 203 is located between the two channels 202, each channel 202 penetrates through the P-type capping layer 107 and a part of the P-type cladding layer 106, the non-implantation region 201 is on the side of each channel 202 away from the center waveguide 203, the insulating layer 108 is located on the top surface of the non-implantation region 201 and the surface of the channel 202, and the P-side electrode 109 is located on the top surface of the insulating layer 108 and the top surface of the center waveguide 203.

[0039] In some examples, the substrate 101 is a group III-V compound. For example, the material of the substrate 101 includes but is not limited to GaAs, InP, GaSb, GaN, etc. The substrate 101 is usually N-type doped. The substrate 101 includes a main body layer and a buffer layer, and the buffer layer is used to bury the defects of the substrate 101 itself. The N-type waveguide, the active region layer 104, and the P-type waveguide layer 105 form a laser waveguide layer. The refractive index of the laser waveguide layer is greater than that of the N-type cladding layer 102 and greater than that of the P-type cladding layer 106, thereby forming a total reflection waveguide. The optical mode transmitted in the laser resonator cavity is restricted within the laser waveguide layer. However, due to the evanescent wave effect, part of the light will still be transmitted in the N-type cladding layer 102 and the P-type cladding layer 106. Therefore, the optical field characteristics transmitted in the laser waveguide layer can be affected by controlling some characteristics of the N-type cladding layer 102 and the P-type cladding layer 106; the P-type capping layer 107 is heavily doped to facilitate ohmic contact; the P-side electrode 109 and the N-side electrode 110 serve as the electrodes of the semiconductor laser for current injection.

[0040] In some embodiments, the semiconductor laser further includes: an ion implantation insulating layer 120. The ion implantation insulating layer 120 extends from the bottom surface of the channel 202 into the epitaxial structure in a direction away from the channel 202. The epitaxial structure includes the active region layer 104, and there is a spacing distance between the active region layer 104 and the ion implantation insulating layer 120.

[0041] In some embodiments, the width of the channel 202 at any position is the same in the direction pointing from the central waveguide 203 to any channel 202. The high-order mode cannot be completely restricted in the central waveguide 203, thereby generating a higher loss, while the fundamental mode can be stably restricted within the central waveguide 203 structure, thereby realizing single-mode lasing.

[0042] In some embodiments, the width of the central waveguide 203 at any position is the same in the direction pointing from the central waveguide 203 to any channel 202. Similarly, the high-order mode cannot be completely restricted in the central waveguide 203, thereby generating a higher loss, while the fundamental mode can be stably restricted within the central waveguide 203 structure, thereby realizing single-mode lasing.

[0043] In some embodiments, the central waveguide 203 can be a straight waveguide, an inclined waveguide, a curved waveguide, a partially inclined waveguide, or a partially curved waveguide. For the inclined waveguide, through the inclined setting, the difference between the minimum channel width required for the high-order mode and the minimum channel width required for the fundamental mode is relatively large, which is more conducive to the process preparation.

[0044] In some embodiments, at least one side of the central waveguide 203 facing the channel 202 is non-linear. In this way, the higher-order modes are regulated by the free segments, the mode width increases, and it is more difficult to be completely confined in the central waveguide 203, resulting in higher losses. However, the fundamental mode can be stably confined within the central waveguide 203 structure, thus achieving single-mode lasing.

[0045] In some embodiments, the width of the central waveguide 203 gradually decreases along the extending direction of the central waveguide 203, and the width of the channel 202 gradually increases along the extending direction of the central waveguide 203; or, the width of the central waveguide 203 gradually increases from the middle position of the central waveguide 203 to both ends of the central waveguide 203, and the width of the channel 202 gradually decreases from the middle position of the channel 202 to both ends of the channel 202. That is, the central waveguide 203 is composed of a narrow ridge portion and a power amplification structure together. The fundamental mode can obtain higher gain, while the higher-order modes will be diffracted and have extremely strong leakage, resulting in higher losses for the higher-order modes. Finally, the fundamental mode output is obtained, which has relatively lower astigmatism compared to the traditional MOPA (Master Oscillator Power-Amplifier) structure.

[0046] It should be understood that the various forms of the processes shown above can be used, with steps reordered, added, or deleted. For example, the steps recited in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved. No limitation is imposed herein.

[0047] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A design method of a semiconductor laser, characterized in that, The semiconductor laser design method is used to design a semiconductor laser, wherein the semiconductor laser includes an epitaxial structure having a surface waveguide, wherein the surface waveguide includes a central waveguide and channels located on both sides of the central waveguide, and the semiconductor laser design method includes: Determine the effective refractive index based on the epitaxial structure and the lasing wavelength ; Determine the first correspondence between the channel depth and the channel refractive index difference and determine the lateral component of the fundamental mode wave vector κ 0 and the lateral component of the first-order mode wave vector κ 1; Based on the effective refractive index , lasing wavelength , channel refractive index difference , lateral component of the fundamental mode wave vector κ 0 and lateral component of the first-order mode wave vector κ 1 for simulation analysis to obtain the channel refractive index difference , central waveguide width W R and the second corresponding relationship of the channel width range; Select a first central waveguide width, a first channel depth, and a first channel width that satisfy the second corresponding relationship, use the first central waveguide width as the target central waveguide width, use the first channel depth as the target channel depth, and use the first channel width as the target channel width.

2. The design method of the semiconductor laser according to claim 1, wherein Obtaining the second corresponding relationship includes: obtaining the refractive index difference of the channel , the central waveguide width W R and a curve graph of the corresponding relationship of the channel width range; Selecting the first center waveguide width, the first channel depth, and the first channel width that satisfy the second corresponding relationship includes: knowing the first center waveguide width and the first channel depth, determining the target channel width range based on the curve graph, and selecting the first channel width within the target channel width range; or, knowing the first center waveguide width, determining the target channel width range based on the curve graph, selecting the first channel width within the target channel width range, and determining the first channel depth based on the first channel width.

3. The design method of the semiconductor laser according to claim 2, characterized in that Based on the effective refractive index , lasing wavelength , channel refractive index difference , lateral component of the fundamental mode wave vector κ 0 and lateral component of the first-order mode wave vector κ 1 for simulation analysis includes: taking the effective refractive index , lasing wavelength , channel refractive index difference , lateral component of the fundamental mode wave vector κ 0 and lateral component of the first-order mode wave vector κ 1 into formula 1 for simulation analysis to obtain the said curve graph; The formula 1 is as follows: , where W is the channel width.

4. The design method of the semiconductor laser according to claim 2, characterized in that, When the size of the target channel width range is smaller than the size of the preset channel width range, the value of the target channel depth is reduced to increase the size of the target channel width range. If the target channel depth is smaller than the preset channel depth, an ion implantation insulating layer is provided. The ion implantation insulating layer extends from the bottom surface of the channel in a direction away from the channel into the epitaxial structure. The epitaxial structure includes an active area layer. The active area layer is spaced apart from the ion implantation insulating layer.

5. The design method of the semiconductor laser according to claim 1, characterized in that, Determine the lateral component of the fundamental mode wave vector κ The lateral components of the wave vectors of the 0 and first-order modes κ 1 include: based on the channel refractive index difference , the center waveguide width W R and the lasing wavelength Use the Colin graphical method to solve the transcendental equation of the waveguide mode to obtain the lateral component of the fundamental mode wave vector κ The lateral components of the wave vectors of the 0 and first-order modes κ 1.

6. A semiconductor laser, characterized in that, include: An epitaxial structure having a surface waveguide, the surface waveguide including a central waveguide and channels located on both sides of the central waveguide, the semiconductor laser being designed using the semiconductor laser design method according to any one of claims 1 to 5, the width of the central waveguide being a target central waveguide width, the depth of the channel being a target channel depth, and the width of the channel being a target channel width.

7. The semiconductor laser according to claim 6, characterized in that, The semiconductor laser further comprises an ion-implanted insulating layer extending from the bottom surface of the channel into the epitaxial structure in a direction away from the channel. The epitaxial structure comprises an active region layer, and the active region layer is spaced apart from the ion-implanted insulating layer.

8. The semiconductor laser according to claim 6, wherein The width of the channel at any position along the direction pointing to any channel along the central waveguide is the same.

9. The semiconductor laser according to claim 8, characterized in that The width of the central waveguide at any position in the direction along the central waveguide pointing to any channel is the same; Alternatively, at least one side surface of the central waveguide facing the channel is non-linear.

10. The semiconductor laser according to claim 8, characterized in that, The width of the central waveguide gradually decreases along the extension direction of the central waveguide, and the width of the channel gradually increases along the extension direction of the central waveguide; Alternatively, the width of the central waveguide gradually increases from the middle position of the central waveguide to both ends of the central waveguide, and the width of the channel gradually decreases from the middle position of the channel to both ends of the channel.

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