Semiconductor laser structure capable of reducing hole burning effect

Abstract

The invention relates to a semiconductor laser structure capable of reducing a hole burning effect, which comprises a lower electrode layer, a substrate layer, a lower cover layer, a lower waveguide layer, a multi-quantum well layer, an upper waveguide layer, an upper cover layer, a ridge layer, a graphical contact layer and an upper electrode layer which are sequentially stacked from bottom to top, the graphical contact layer is formed by alternately arranging a plurality of contact strips and a plurality of insulating strips at intervals, the sizes of the contact strips in the arrangement direction are gradually increased from the contact strip in the middle to the contact strips at the two ends in the arrangement direction, and the sizes of the insulating strips in the arrangement direction are equal. According to the semiconductor laser structure capable of reducing the hole burning effect, the patterned contact layer is utilized to form a non-uniform grid structure, current injection is customized for the upper electrode layer and the lower electrode layer through non-uniform grids, the hole burning effect caused by heat accumulation in the center area of the semiconductor laser structure and high photon density is reduced, and finally the stability of the laser is improved; leakage current is further reduced, high-temperature characteristics are improved, and reliability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of lasers, and in particular to a semiconductor laser structure capable of reducing hole burning effect. Background Art

[0002] Semiconductor lasers have the advantages of small size, long life, low energy consumption, simple manufacturing, easy mass production, low cost, wide wavelength coverage, and high electro-optical conversion efficiency. They are widely used in the fields of optical fiber communication, optical storage, CD laser record players, laser printers, etc. Quantum well high-power semiconductor lasers are used in precision machining, printing industry, medical field, solid pump source field, etc. Laser technology has become one of the irreplaceable technologies in modern life. Whether it is industrial processing, medical beauty, optical fiber communication, or the unmanned driving and intelligent robots that have been popular in recent years, they are all closely related to laser technology.

[0003] The current research direction of quantum well lasers is mainly focused on three types of materials: InGaAlP-GaAs, GaAlAs-GaAs and InGaAsP-InP. The concept of strained quantum wells was proposed, which optimized the valence band characteristics inside the material and improved the performance of semiconductor light-emitting devices. The photoelectric conversion efficiency of high-power GaAs-based semiconductor lasers can reach 50%, and up to 70%. The practicality has been enhanced, and the application field has been greatly expanded. Semiconductor lasers have ushered in vigorous development in the field of industrial processing. The growth momentum has been strong in recent years, and it is expected to occupy a larger share in the future.

[0004] At present, existing high-power semiconductor lasers often encounter working instability problems, mainly due to instability problems caused by local high temperatures, such as spatial hole burning effects, which can lead to unstable modes and power outputs. Summary of the invention

[0005] The object of the present invention is to provide a semiconductor laser structure capable of reducing the hole burning effect so as to improve the high temperature characteristics and enhance the stability and reliability.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A semiconductor laser structure capable of reducing hole burning effect, characterized in that it comprises a lower electrode layer, a substrate layer, a lower cover layer, a lower waveguide layer, a multi-quantum well layer, an upper waveguide layer, an upper cover layer, a ridge stripe layer, a patterned contact layer and an upper electrode layer which are stacked in sequence from bottom to top, wherein the patterned contact layer is formed by a plurality of contact strips and a plurality of insulating strips which are alternately arranged at intervals, wherein the size of the contact strips along the arrangement direction gradually increases from the middle contact strip to the contact strips at both ends of the arrangement direction, and the sizes of the insulating strips along the arrangement direction are equal.

[0008] In one embodiment of the present application, along the arrangement direction of the contact strips and the insulating strips, the sizes of the ridge strip layer, the patterned contact layer and the upper electrode layer are smaller than the sizes of the lower electrode layer, the substrate layer, the lower cover layer, the lower waveguide layer, the multi-quantum well layer, the upper waveguide layer and the upper cover layer.

[0009] In one embodiment of the present application, the contact strip is an InGaAs contact strip that has been subjected to P-type modulation doping, the size of the middle contact strip along the arrangement direction is 0.5 microns to 1 micron, and the size of the contact strip along the stacking direction is 0.2 microns to 0.4 microns.

[0010] In one embodiment of the present application, the insulating strip is a silicon oxide insulating strip or a silicon nitride insulating strip, the size of the insulating strip along the arrangement direction is 1 micron to 3 microns, and the size of the insulating strip along the stacking direction is the same as that of the contact strip.

[0011] In one embodiment of the present application, the upper electrode layer includes a titanium layer and a first gold layer stacked from bottom to top, the size of the titanium layer along the stacking direction is 50nm~100nm, and the size of the first gold layer along the stacking direction is not less than 300nm.

[0012] In one embodiment of the present application, the ridge stripe layer is an InP ridge stripe layer or an AlGaAs ridge stripe layer that has been subjected to P-type modulation doping, and the size of the ridge stripe layer along the stacking direction is 0.4 microns to 0.6 microns.

[0013] In one embodiment of the present application, the upper cover layer is an InP upper cover layer or an AlGaAs upper cover layer that has been subjected to P-type modulation doping, and the size of the upper cover layer along the stacking direction is 0.8 micrometers to 1 micrometer.

[0014] In one embodiment of the present application, the upper waveguide layer is an InGaAsP waveguide layer or an AlGaInAs waveguide layer, the size of the upper waveguide layer along the stacking direction is 0.2 microns to 0.8 microns, the refractive index of the upper waveguide layer gradually decreases from bottom to top, and the minimum refractive index is not less than 3.0.

[0015] In one embodiment of the present application, the multi-quantum well layer is an InGaAsP multi-quantum well layer or an AlGaInAs multi-quantum well layer, the size of the multi-quantum well layer along the stacking direction is 10nm~100nm, the multi-quantum well layer includes 1-10 quantum wells, the well layer thickness is 4nm~10nm, the barrier layer thickness is 4nm~10nm, the barrier confinement structure of the multi-quantum well layer adopts double barrier layer confinement, wherein the electron energy band step between the first barrier layer and the adjacent well layer is greater than 0.3 electron volts, the hole energy band step between the second barrier layer and the adjacent well layer is greater than 0.3 electron volts, and the double barrier layer thickness of the multi-quantum well layer is different.

[0016] In one embodiment of the present application, the lower waveguide layer is an InGaAsP waveguide layer or an AlGaInAs waveguide layer, the size of the lower waveguide layer along the stacking direction is 0.2 microns to 0.8 microns, the refractive index of the lower waveguide layer gradually increases from bottom to top, and the minimum refractive index is not less than 3.6.

[0017] In one embodiment of the present application, the lower cover layer is an InP lower cover layer or an AlGaAs lower cover layer that has been subjected to N-type modulation doping, and the size of the lower cover layer along the stacking direction is 1.0 micrometer to 1.5 micrometer.

[0018] In one embodiment of the present application, the substrate layer is a GaAs substrate layer or an InP substrate layer that has been subjected to N-type modulation doping, and the size of the substrate layer along the stacking direction is 70 microns to 90 microns.

[0019] In one embodiment of the present application, the lower electrode layer comprises a second gold layer and a gold-germanium-nickel layer stacked from bottom to top, the size of the second gold layer along the stacking direction is not less than 1000nm, and the surface of the second gold layer is covered with pits, the periodic size of the pits is 5 microns to 10 microns, the depth is 200nm to 600nm, the surface particle size of the second gold layer is 8000 mesh to 10000 mesh, and the size of the gold-germanium-nickel layer along the stacking direction is 50nm to 100nm.

[0020] It can be seen from the above technical scheme that the present invention discloses a semiconductor laser structure capable of reducing the hole burning effect. The semiconductor laser structure capable of reducing the hole burning effect comprises a lower electrode layer, a substrate layer, a lower cover layer, a lower waveguide layer, a multi-quantum well layer, an upper waveguide layer, an upper cover layer, a ridge stripe layer, a patterned contact layer and an upper electrode layer which are stacked in sequence from bottom to top. The patterned contact layer is formed by a plurality of contact strips and a plurality of insulating strips which are alternately arranged at intervals. The size of the contact strips along the arrangement direction increases gradually from the middle contact strip to the contact strips at both ends of the arrangement direction, and the sizes of the insulating strips along the arrangement direction are equal.

[0021] The semiconductor laser structure that can reduce the hole burning effect utilizes a patterned contact layer to form a non-uniform grid structure. The upper and lower electrode layers are customized to inject current through the non-uniform grid, thereby reducing the heat accumulation in the central area of ​​the semiconductor laser structure and the hole burning effect caused by high photon density, thereby ultimately improving the laser stability, further reducing leakage current, improving high-temperature characteristics, and improving reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic structural diagram of a semiconductor laser structure capable of reducing hole burning effect provided by an embodiment of the present invention.

[0024] In the figure:

[0025] 1 is the lower electrode layer; 2 is the substrate layer; 3 is the lower cover layer; 4 is the lower waveguide layer; 5 is the multi-quantum well layer; 6 is the upper waveguide layer; 7 is the upper cover layer; 8 is the ridge layer; 9 is the patterned contact layer; 901 is the contact strip; 902 is the insulating strip; 10 is the upper electrode layer. DETAILED DESCRIPTION

[0026] The core of the present invention is to provide a semiconductor laser structure capable of reducing the hole burning effect. The structural design of the semiconductor laser structure enables it to improve high temperature characteristics, stability and reliability.

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] See also Figure 1 , Figure 1 A schematic structural diagram of a semiconductor laser structure capable of reducing hole burning effect provided by an embodiment of the present invention.

[0029] A semiconductor laser structure capable of reducing hole burning effect is disclosed in an embodiment of the present invention. The semiconductor laser structure capable of reducing hole burning effect includes a lower electrode layer 1, a substrate layer 2, a lower cover layer 3, a lower waveguide layer 4, a multi-quantum well layer 5, an upper waveguide layer 6, an upper cover layer 7, a ridge layer 8, a patterned contact layer 9 and an upper electrode layer 10 which are stacked in sequence from bottom to top.

[0030] The patterned contact layer 9 is composed of a plurality of contact strips 901 and a plurality of insulating strips 902 arranged alternately. The size of the contact strips 901 along the arrangement direction increases gradually from the middle contact strip 901 to the contact strips 901 at both ends of the arrangement direction. The sizes of the insulating strips 902 along the arrangement direction are equal.

[0031] Compared with the prior art, the semiconductor laser structure that can reduce the hole burning effect provided by the embodiment of the present invention utilizes a patterned contact layer 9 to form a non-uniform grid structure, and the upper and lower electrode layers 1 customize current injection through the non-uniform grid, thereby reducing the heat accumulation in the central area of ​​the semiconductor laser structure and the hole burning effect caused by the high photon density, thereby ultimately improving the laser stability, further reducing the leakage current, improving the high temperature characteristics, and improving the reliability.

[0032] Along the arrangement direction of the contact strips 901 and the insulating strips 902, the ridge strip layer 8, the patterned contact layer 9 and the upper electrode layer 10 have the same size and are smaller than the sizes of the lower electrode layer 1, the substrate layer 2, the lower cover layer 3, the lower waveguide layer 4, the multi-quantum well layer 5, the upper waveguide layer 6 and the upper cover layer 7. The sizes of the lower electrode layer 1, the substrate layer 2, the lower cover layer 3, the lower waveguide layer 4, the multi-quantum well layer 5, the upper waveguide layer 6 and the upper cover layer 7 along the arrangement direction of the contact strips 901 and the insulating strips 902 are the same, which is used for lateral mode selection control.

[0033] The contact strip 901 is an InGaAs contact strip that has been subjected to P-type modulation doping, and the P-type doping concentration is greater than 1×10 19 cm -3 Up to 2×10 19 cm -3 The size of the middle contact strip 901 along the arrangement direction is 0.5 microns to 1 micron, and the sizes of the contact strips 901 on both sides of the middle contact strip 901 along the arrangement direction increase with the increase of the distance from the middle contact strip 901. The size of the contact strip 901 along the stacking direction is 0.2 microns to 0.4 microns.

[0034] The insulating strip 902 is a silicon oxide insulating strip or a silicon nitride insulating strip. An insulating strip 902 is arranged between two adjacent contact strips 901. The size of the insulating strip 902 along the arrangement direction is 1 micron to 3 microns. The size of the insulating strip 902 along the stacking direction is the same as that of the contact strip 901, and the sizes of each insulating strip 902 along the arrangement direction are the same.

[0035] The upper electrode layer 10 is a double-layer structure, which includes a titanium layer and a first gold layer stacked from bottom to top. The size of the titanium layer along the stacking direction is 50nm-100nm, and the size of the first gold layer along the stacking direction is not less than 300nm.

[0036] The ridge stripe layer 8 is an InP ridge stripe layer or an AlGaAs ridge stripe layer that has been subjected to P-type modulation doping, and the P-type doping concentration is greater than 1×10 18 cm -3 Up to 8×10 18 cm -3 The size of the ridge layer 8 along the stacking direction is 0.4 microns to 0.6 microns.

[0037] The upper cap layer 7 is an InP upper cap layer or an AlGaAs upper cap layer that has been subjected to P-type modulation doping, and the P-type doping concentration is 1×10 18 cm -3 Up to 8×10 18 cm -3 Gradual change, the size of the upper cover layer 7 along the stacking direction is 0.8 micron~1 micron.

[0038] The upper waveguide layer 6 is an InGaAsP waveguide layer or an AlGaInAs waveguide layer, and the unintentional doping concentration is less than 2×10 17 cm -3 The size of the upper waveguide layer 6 along the stacking direction is 0.2 microns to 0.8 microns, and the refractive index of the upper waveguide layer 6 gradually decreases from bottom to top, and the lowest refractive index is not less than 3.0.

[0039] The multi-quantum well layer 5 is an InGaAsP multi-quantum well layer or an AlGaInAs multi-quantum well layer, the size of the multi-quantum well layer 5 along the stacking direction is 10nm~100nm, the multi-quantum well layer 5 includes 1-10 quantum wells, the well layer thickness is 4nm~10nm, the barrier layer thickness is 4nm~10nm, the barrier confinement structure of the multi-quantum well layer 5 adopts double barrier layer confinement, wherein the electron energy band step between the first barrier layer and the adjacent well layer is greater than 0.3 electron volts, the hole energy band step between the second barrier layer and the adjacent well layer is greater than 0.3 electron volts, the double barrier layer thickness of the multi-quantum well layer 5 is different, the multi-quantum well layer 5 has a high barrier difference, and can improve the high temperature characteristics of the semiconductor laser structure that can reduce the hole burning effect.

[0040] The lower waveguide layer 4 is an InGaAsP waveguide layer or an AlGaInAs waveguide layer, and the unintentional doping concentration is less than 2×10 17 cm -3 The size of the lower waveguide layer 4 along the stacking direction is 0.2 microns to 0.8 microns, and the refractive index of the lower waveguide layer 4 gradually increases from bottom to top, and the lowest refractive index is not less than 3.6.

[0041] The lower cap layer 3 is an InP lower cap layer or an AlGaAs lower cap layer that has been modulated and doped with N-type, and the N-type doping concentration is 1×10 18 cm -3 , the size of the lower cover layer 3 along the stacking direction is 1.0 micron to 1.5 micron.

[0042] The substrate layer 2 is a GaAs substrate layer or an InP substrate layer that has been subjected to N-type modulation doping, and the size of the substrate layer 2 along the stacking direction is 70 microns to 90 microns.

[0043] Furthermore, a buffer layer is provided between the substrate layer 2 and the lower cover layer 3. The buffer layer is a GaAs buffer layer that has been modulated and doped with N-type. The size of the buffer layer along the stacking direction is 0.4 micrometers to 1 micrometer, and the N-type doping concentration is 5×10 17 cm -3 Up to 1×10 18 cm -3 .

[0044] The lower electrode layer 1 is stacked from bottom to top with a second gold layer and a gold-germanium-nickel layer, the size of the second gold layer along the stacking direction is not less than 1000nm, and the surface of the second gold layer is covered with pits, the periodic size of the pits is 5 microns to 10 microns, the depth is 200nm to 600nm, the surface particle size of the second gold layer is 8000 mesh to 10000 mesh, and the size of the gold-germanium-nickel layer along the stacking direction is 50nm to 100nm.

[0045] The semiconductor laser structure that can reduce the hole burning effect adopts MOCVD equipment, and the MO sources used are TMGa, TMAl and TMIn. The doping sources used are SiH4, CF4, etc., and the special gases used are AsH3 and PH3. Specifically, a GaAs buffer layer is grown on the GaAs substrate layer 2 at a temperature of 710°C, and an N-AlGaAs lower cap layer 3 is grown on the N-GaAs buffer layer at 710°C with a thickness of 1.0 micron to 1.5 micron, and the N-type doping concentration is 1×10 18 cm -3 .

[0046] The lower waveguide layer 4 is grown on the lower cap layer 3 at 710°C. The material is InGaAsP or AlGaInAs. The size along the stacking direction is 0.2 microns to 0.8 microns. The unintentional doping concentration is less than 2×10 17 cm -3 The refractive index of the lower waveguide layer 4 is gradually distributed, the refractive index gradually increases from bottom to top, and satisfies the raised cosine distribution, and the maximum refractive index does not exceed 3.6.

[0047] A multi-quantum well layer 5 is grown on the lower waveguide layer 4 at 700°C. The material of the multi-quantum well layer 5 is InGaAsP or AlGaInAs, with a thickness of 10nm~100nm and an unintentional doping concentration of less than 2×10 17 cm -3 .

[0048] The upper waveguide layer 6 is grown on the multi-quantum well layer 5 at 700°C. The material of the upper waveguide layer 6 is InGaAsP or AlGaInAs. The size along the stacking direction is 0.2 microns to 0.8 microns. The unintentional doping concentration is less than 2×10 17 cm -3The refractive index of the upper waveguide layer 6 is gradually distributed, the refractive index gradually decreases from bottom to top, and satisfies the falling cosine distribution, and the minimum refractive index value is not less than 3.0.

[0049] The upper cap layer 7 and the ridge stripe layer 8 are grown on the upper waveguide layer 6 at 700°C. The materials of the upper cap layer 7 and the ridge stripe layer 8 are InP or AlGaAs. The total size of the upper cap layer 7 and the ridge stripe layer 8 along the stacking direction is 1.2 microns to 1.6 microns. The upper cap layer 7 and the ridge stripe layer 8 are both P-type modulated doped, and the P-type doping concentration is 1×10 18 cm -3 Up to 8×10 18 cm -3 Gradient.

[0050] A contact layer is grown on the unetched ridge layer 8 at 710° C. The material of the contact layer is InGaAs, and the size along the stacking direction is 0.2 μm to 0.4 μm. The contact layer is P-type modulated doped, and the P-type doping concentration is greater than 1×10 19 cm -3 Up to 2×10 19 cm -3 .

[0051] Then the upper cover layer 7 and the contact layer are patterned, and the ridge layer 8 is patterned by photolithography and etching, with a depth of 0.4 microns to 0.6 microns. The contact layer is patterned by photolithography and etching, such as the contact strips 901 are strips distributed according to a certain rule. The contact strip 901 in the middle has the smallest size along the arrangement direction, and the size of the contact strips 901 at both ends along the arrangement direction gradually widens as the distance from the middle contact strip 901 increases, with the smallest point being 1 micron and the middle being the zero point. The gradual width of the contact strip 901 satisfies multiple relationships such as the e exponential curve and the raised cosine. An insulating strip 902 is filled between two adjacent contact strips 901. The insulating strip 902 is made of silicon oxide or silicon nitride, has the same height as the contact strip 901, and has a size of 1 micron to 3 microns along the arrangement direction.

[0052] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0053] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A semiconductor laser structure capable of reducing hole burning effect, characterized in that: The invention comprises a lower electrode layer, a substrate layer, a lower cover layer, a lower waveguide layer, a multi-quantum well layer, an upper waveguide layer, an upper cover layer, a ridge stripe layer, a patterned contact layer and an upper electrode layer which are stacked in sequence from bottom to top. The patterned contact layer is formed by a plurality of contact strips and a plurality of insulating strips which are alternately arranged at intervals. The size of the contact strips along the arrangement direction increases gradually from the middle contact strip to the contact strips at both ends of the arrangement direction, and the sizes of the insulating strips along the arrangement direction are equal.

2. The semiconductor laser structure capable of reducing hole burning effect according to claim 1, characterized in that: Along the arrangement direction of the contact strips and the insulating strips, the sizes of the ridge strip layer, the patterned contact layer and the upper electrode layer are smaller than the sizes of the lower electrode layer, the substrate layer, the lower cover layer, the lower waveguide layer, the multi-quantum well layer, the upper waveguide layer and the upper cover layer.

3. The semiconductor laser structure capable of reducing hole burning effect according to claim 1, characterized in that: The contact strips are P-type modulation-doped InGaAs contact strips, the size of the middle contact strip along the arrangement direction is 0.5 micrometer to 1 micrometer, and the size of the contact strip along the stacking direction is 0.2 micrometer to 0.4 micrometer.

4. The semiconductor laser structure capable of reducing hole burning effect according to claim 2, characterized in that: The insulating strips are silicon oxide insulating strips or silicon nitride insulating strips, the size of the insulating strips along the arrangement direction is 1 micron to 3 microns, and the size of the insulating strips along the stacking direction is the same as that of the contact strips.

5. The semiconductor laser structure capable of reducing hole burning effect according to any one of claims 1 to 4, characterized in that: The upper electrode layer includes a titanium layer and a first gold layer stacked from bottom to top, the size of the titanium layer along the stacking direction is 50nm-100nm, and the size of the first gold layer along the stacking direction is not less than 300nm.

6. The semiconductor laser structure capable of reducing hole burning effect according to any one of claims 1 to 4, characterized in that: The ridge stripe layer is an InP ridge stripe layer or an AlGaAs ridge stripe layer that has been subjected to P-type modulation doping, and the size of the ridge stripe layer along the stacking direction is 0.4 micrometers to 0.6 micrometers.

7. The semiconductor laser structure capable of reducing hole burning effect according to any one of claims 1 to 4, characterized in that: The upper cover layer is an InP upper cover layer or an AlGaAs upper cover layer that has been subjected to P-type modulation doping, and the size of the upper cover layer along the stacking direction is 0.8 micrometer to 1 micrometer.

8. The semiconductor laser structure capable of reducing hole burning effect according to any one of claims 1 to 4, characterized in that: The upper waveguide layer is an InGaAsP waveguide layer or an AlGaInAs waveguide layer, the size of the upper waveguide layer along the stacking direction is 0.2 microns to 0.8 microns, the refractive index of the upper waveguide layer gradually decreases from bottom to top, and the lowest refractive index is not less than 3.

0.

9. The semiconductor laser structure capable of reducing hole burning effect according to any one of claims 1 to 4, characterized in that: The multi-quantum well layer is an InGaAsP multi-quantum well layer or an AlGaInAs multi-quantum well layer, the size of the multi-quantum well layer along the stacking direction is 10nm~100nm, the multi-quantum well layer includes 1-10 quantum wells, the well layer thickness is 4nm~10nm, the barrier layer thickness is 4nm~10nm, the barrier confinement structure of the multi-quantum well layer adopts double barrier layer confinement, wherein the electron energy band step between the first barrier layer and the adjacent well layer is greater than 0.3 electron volts, the hole energy band step between the second barrier layer and the adjacent well layer is greater than 0.3 electron volts, and the double barrier layer thickness of the multi-quantum well layer is different.

10. The semiconductor laser structure capable of reducing hole burning effect according to any one of claims 1 to 4, characterized in that: The lower waveguide layer is an InGaAsP waveguide layer or an AlGaInAs waveguide layer, the size of the lower waveguide layer along the stacking direction is 0.2 microns to 0.8 microns, the refractive index of the lower waveguide layer gradually increases from bottom to top, and the lowest refractive index is not less than 3.

6.

11. The semiconductor laser structure capable of reducing hole burning effect according to any one of claims 1 to 4, characterized in that: The lower cover layer is an InP lower cover layer or an AlGaAs lower cover layer that has been subjected to N-type modulation doping, and the size of the lower cover layer along the stacking direction is 1.0 micrometer to 1.5 micrometer.

12. The semiconductor laser structure capable of reducing hole burning effect according to any one of claims 1 to 4, characterized in that: The substrate layer is a GaAs substrate layer or an InP substrate layer that has been subjected to N-type modulation doping, and the size of the substrate layer along the stacking direction is 70 microns to 90 microns.

13. The semiconductor laser structure capable of reducing hole burning effect according to any one of claims 1 to 4, characterized in that: The lower electrode layer is stacked from bottom to top with a second gold layer and a gold-germanium-nickel layer, the size of the second gold layer along the stacking direction is not less than 1000nm, and the surface of the second gold layer is covered with pits, the periodic size of the pits is 5 microns to 10 microns, the depth is 200nm to 600nm, the surface particle size of the second gold layer is 8000 mesh to 10000 mesh, and the size of the gold-germanium-nickel layer along the stacking direction is 50nm to 100nm.

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