Semiconductor laser and preparation method thereof

Abstract

The invention discloses a semiconductor laser and a preparation method thereof. The semiconductor laser comprises a substrate, a first DBR layer, an active layer and a second DBR layer, wherein the first DBR layer, the active layer and the second DBR layer are located on one side of the substrate and stacked in sequence. The first DBR layer and the second DBR layer comprise a DBR structure, and the DBR structure comprises a plurality of first material layers and second material layers which are alternately stacked; the first DBR layer and / or the second DBR layer further comprises at least one layer of sampling structure, and the sampling structure is located on one side of the DBR structure or located between two adjacent periodic structures of the DBR structure; wherein the thickness of the sampling structure is an integral multiple of a half of the target wavelength of the semiconductor laser. According to the semiconductor laser provided by the invention, under the condition that the reflectivity of the reflecting layer is not influenced, the forbidden bandwidth is reduced, and the transmissivity of non-target wavelength is increased, so that stable single-mode lasing is realized.

Description

Technical Field

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

[0002] Vertical-Cavity Surface-Emitting Lasers (VCSELs) have advantages such as circular light spots, low threshold currents, and easy array integration, and have become ideal light sources for next-generation lidars. In order to achieve higher power density output, the industry has gradually adopted a multi-junction structure design, that is, multiple active regions are connected in series through tunnel junctions to achieve a multiple increase in the output light power. At the same time, in order to reduce the far-field divergence angle of the device, a filtering layer structure needs to be integrated near the active region to regulate the mode.

[0003] When the number of junctions and the filtering layer continue to increase, the cavity length of the device also continues to increase, continuously compressing the longitudinal mode interval, resulting in multi-longitudinal mode lasing, which will reduce the device power and also reduce the signal-to-noise ratio at the usage end. Therefore, how to improve the wavelength stability of VCSELs and achieve single-mode lasing within a larger temperature and current density range is an urgent problem to be solved. Summary of the Invention

[0004] The present invention provides a semiconductor laser. By inserting a sampling structure into the original DBR structure, the bandgap width can be reduced without affecting the reflectivity of the reflective layer of the semiconductor laser, filtering out non-target lasing wavelengths, and achieving stable single-mode lasing of the semiconductor laser.

[0005] According to a first aspect of the present invention, there is provided a semiconductor laser, comprising: a substrate, and a first DBR layer, an active layer, and a second DBR layer sequentially stacked on one side of the substrate;

[0006] The first DBR layer and the second DBR layer include a DBR structure, and the DBR structure includes a plurality of first material layers and second material layers alternately stacked;

[0007] The first DBR layer and / or the second DBR layer further includes at least one sampling structure, the sampling structure is located on one side of the DBR structure or the sampling structure is located between two adjacent grating periods of the DBR structure; wherein, the thickness of the sampling structure is an integer multiple of half of the target wavelength of the semiconductor laser.

[0008] Optionally, the refractive index of the first material layer is greater than the refractive index of the second material layer.

[0009] Optionally, the number of layers of the sampling structure is greater than or equal to 2, and between any two adjacent sampling structures, there are n first material layers and second material layers alternately stacked, where n is a positive integer greater than or equal to 1.

[0010] Optionally, the sampling period of the sampling structure is the ratio of a grating period to a first period; where the grating period is the sum of the thicknesses of one first material layer and one second material layer, and the first period is the sum of the thicknesses of n first material layers, n second material layers, and one sampling structure.

[0011] Optionally, the sampling period is less than or equal to 0.5.

[0012] Optionally, it further includes a first spatial layer and a second spatial layer;

[0013] The first spatial layer is located between the first DBR layer and the active layer;

[0014] The second spatial layer is located between the active layer and the second DBR layer.

[0015] Optionally, it further includes an oxide layer;

[0016] The oxide layer is located between the second spatial layer and the second DBR layer.

[0017] Optionally, it further includes a current diffusion layer;

[0018] The current diffusion layer is located on the side of the second DBR layer away from the active layer.

[0019] Optionally, the active layer includes a multiple quantum well layer or a quantum well layer.

[0020] According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor laser for manufacturing any one of the semiconductor lasers in the first aspect of the present invention, the manufacturing method including:

[0021] Providing a substrate;

[0022] Successively forming a first DBR layer, an active layer, and a second DBR layer stacked on one side of the substrate;

[0023] Wherein, the first DBR layer and the second DBR layer include a DBR structure, and the DBR structure includes a plurality of first material layers and second material layers alternately stacked;

[0024] The first DBR layer and / or the second DBR layer further includes at least one sampling structure, and the sampling structure is located on one side of the DBR structure or the sampling structure is located between two adjacent DBR structures of the DBR structure;

[0025] Wherein, the thickness of the sampling structure is an integer multiple of half of the target wavelength of the semiconductor laser.

[0026] The present invention discloses a semiconductor laser and a preparation method thereof. The semiconductor laser includes: a substrate, and a first DBR layer, an active layer, and a second DBR layer that are sequentially stacked on one side of the substrate; the first DBR layer and the second DBR layer include a DBR structure, and the DBR structure includes a plurality of first material layers and second material layers that are alternately stacked; the first DBR layer and / or the second DBR layer further include at least one sampling structure, and the sampling structure is located on one side of the DBR structure or the sampling structure is located between two adjacent periodic structures of the DBR structure; wherein, the thickness of the sampling structure is an integer multiple of half of the target wavelength of the semiconductor laser. The semiconductor laser provided by the present invention inserts a sampling structure into the original DBR structure, which can reduce the bandgap width without affecting the reflectivity of the reflective layer of the semiconductor laser, filter out non-target lasing wavelengths, and achieve stable single-mode lasing of the semiconductor laser.

[0027] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 is a schematic structural diagram of a semiconductor laser provided by an embodiment of the present invention;

[0030] Figure 2 is a schematic diagram of a DBR structure in a semiconductor laser provided by an embodiment of the present invention;

[0031] Figure 3 is a schematic structural diagram of a first DBR layer in a semiconductor laser provided by an embodiment of the present invention;

[0032] Figure 4 is a schematic structural diagram of a first DBR layer in another semiconductor laser provided by an embodiment of the present invention;

[0033] Figure 5 is a schematic structural diagram of a first DBR layer in another semiconductor laser provided by an embodiment of the present invention;

[0034] Figure 6 It is a schematic diagram for comparing the reflectivity-wavelength curves of distributed Bragg reflectors in a semiconductor laser structure provided by an embodiment of the present invention;

[0035] Figure 7 It is a schematic diagram of the structure of the first DBR layer in another semiconductor laser provided by an embodiment of the present invention;

[0036] Figure 8 It is a schematic diagram of the structure of the first DBR layer in another semiconductor laser provided by an embodiment of the present invention;

[0037] Figure 9 It is a schematic diagram of the structure of another semiconductor laser provided by an embodiment of the present invention;

[0038] Figure 10 It is a schematic diagram of the structure of another semiconductor laser provided by an embodiment of the present invention;

[0039] Figure 11 It is a schematic diagram of the structure of another semiconductor laser provided by an embodiment of the present invention;

[0040] Figure 12 It is a flowchart of a method for fabricating a semiconductor laser provided by an embodiment of the present invention. Detailed implementation manners

[0041] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order different from those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0043] It should be understood that various forms of the processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is imposed herein.

[0044] For a semiconductor laser, the longitudinal mode spacing is Δv = c / 2nl, where Δv is the longitudinal mode spacing, c is the speed of light, n is the refractive index, and l is the cavity length. For a traditional single-junction device, the longitudinal mode spacing is often greater than the bandgap width of a Distributed Bragg Reflector (DBR). However, as the cavity length continuously increases, the mode spacing is less than 15 nm, and may even be less than 10 nm. Within such a small longitudinal mode spacing, changes in the device operating temperature or injection density will cause lasing of non-primary modes, which will result in greater absorption losses and reduce device performance.

[0045] Taking a typical 940 nm semiconductor laser structure as an example, a traditional DBR structure uses a high-low Al composition design to form a refractive index difference, such as Al0.9Ga0.1As / Al0.1Ga0.9As, and their thicknesses respectively need to satisfy 1 / 4 of the target lasing wavelength, i.e., 78 nm / 67.5 nm, and the corresponding bandgap widths are 899 nm - 983.3 nm.

[0046] Therefore, the semiconductor laser provided by an embodiment of the present invention reduces the bandgap width by inserting a sampling structure without affecting the DBR reflectivity.

[0047] Figure 1 is a schematic structural diagram of a semiconductor laser provided by an embodiment of the present invention. Refer to Figure 1 , 1, the semiconductor laser provided by an embodiment of the present invention includes: a substrate 1, and a first DBR layer 2, an active layer 3, and a second DBR layer 4 sequentially stacked on one side of the substrate 1; Figure 2 is a schematic diagram of a DBR structure in a semiconductor laser provided by an embodiment of the present invention. Refer to Figure 1 and Figure 2 , the first DBR layer 2 and the second DBR layer 4 include a plurality of first material layers 201 and second material layers 202 with different refractive indices alternately stacked, and the DBR layer includes a plurality of DBR structures formed by the first material layer 201 and the second material layer 202; Figure 3 is a schematic structural diagram of a first DBR layer in a semiconductor laser provided by an embodiment of the present invention. Refer to Figure 1 and Figure 3 , the first DBR layer 2 and / or the second DBR layer 4 further includes at least one sampling structure 5, Figure 4This is a schematic diagram of the structure of the first DBR layer in another semiconductor laser provided by an embodiment of the present invention. The sampling structure 5 is located on one side of the DBR structure A (as Figure 3 shown. Exemplarily, Figure 3 only shows that the DBR structure A has a first material layer 201 and a second material layer 202, that is, the sampling structure 5 is located on the upper side of the DBR structure A, or, referring to Figure 4 , Figure 4 only shows that the DBR structure A has a first material layer 201 and a second material layer 202, that is, the sampling structure 5 is located on the lower side of the DBR structure A) or,

[0048] Figure 5 This is a schematic diagram of the structure of the first DBR layer in another semiconductor laser provided by an embodiment of the present invention. Referring to Figure 5 , the sampling structure 5 is located between two adjacent grating periods of the DBR structure A (exemplarily, that is, the sampling structure 5 is located between the upper grating period A1 and the lower grating period A2); wherein, the thickness of the sampling structure 5 is an integer multiple of half of the target wavelength of the semiconductor laser.

[0049] Among them, referring to Figure 2 , the DBR structure A is a kind of optical element with periodic arrangement, usually composed of material layers with refractive index differences (that is, the first material layer 201 and the second material layer 202) alternately, or has a periodically varying refractive index. It can be understood that the material layer with refractive index difference can be that the first material layer 201 is a high refractive index material and the second material layer 202 is a low refractive index material, or the first material layer 201 is a low refractive index material and the second material layer 202 is a high refractive index material. The main function of the DBR structure A is to control the propagation direction, intensity distribution and phase of light waves through reflection and transmission effects. Exemplarily, the DBR is a typical DBR structure, and the embodiments of the present invention are described by taking the DBR as an example; the active layer 3 is responsible for the generation, recombination and modulation of photons or electrons, provides a gain medium, and realizes stimulated emission. Among them, the material of the active layer 3 can be indium gallium arsenide (InGaAs) and gallium arsenide (GaAs).

[0050] Specifically, continuing to refer to Figure 1 , the semiconductor laser provided by the embodiment of the present invention includes a substrate 1, a first DBR layer 2 located on one side of the substrate (that is, Figure 1 the first DBR layer 2 on the upper layer of the substrate 1 in Figure 1 and Figure 2 ), an active layer 3 and a second DBR layer 4. Referring to Figure 2It is only shown as being composed of a single layer of a first material layer 201 and a single layer of a second material layer 202; alternatively, the DBR layer includes a plurality of DBR structures A formed by the first material layer 201 and the second material layer 202.

[0051] Reference Figure 1 、 Figures 3 to 5 The first DBR layer 2 and / or the second DBR layer 4 further includes a sampling structure 5, and the sampling structure 5 is located on one side of the DBR structure A (that is, Figure 3 the sampling structure 5 shown in Figure 4 is located on the upper side of the DBR structure A or Figure 3 the sampling structure 5 shown in Figure 4 is located on the lower side of the DBR structure A), the sampling structure 5 can be located on the upper side of the DBR structure A (as shown in

[0052] ), the sampling structure 5 can also be located on the lower side of the DBR structure A (as shown in Figure 5 ), or

[0053] Optionally, the first DBR layer 2 is an N-type semiconductor DBR, and the second DBR layer 4 is a P-type semiconductor DBR, and its reflectivity can reach more than 99%.

[0054] Figure 6 is a schematic diagram of the comparison of the reflectivity-wavelength curves of the BDR mirror in a semiconductor laser structure provided by an embodiment of the present invention. Reference Figure 6 wherein, the red waveform is the reflectivity-wavelength curve of the DBR in the prior art, and from Figure 6 it can be known the bandgap width of the DBR in the prior art. It can be clearly seen that it is concentrated between 899 nm and 983.3 nm. The black waveform is the reflectivity-wavelength curve of the DBR provided by the embodiment of the present invention. From Figure 6 it can be known the bandgap width of the DBR adopted in the embodiment of the present invention. It can be clearly seen that the bandgap width is reduced to between 920.5 nm and 960 nm, and lasing cannot be achieved for the longitudinal modes outside the sub-wavelength. The bandgap width can be further reduced as the sampling period of the sampling structure decreases.

[0055] By inserting a sampling structure into the original DBR structure of the semiconductor laser provided by the embodiment of the present invention, the bandgap width can be reduced without affecting the reflectivity of the semiconductor laser, filtering out non-target lasing wavelengths, and realizing stable single-mode lasing of the semiconductor laser.

[0056] Optionally, the refractive index of the first material layer 201 is greater than that of the second material layer 202.

[0057] Specifically, in the DBR structure A of the semiconductor laser provided by the embodiment of the present invention, the refractive index of the first material layer 201 is greater than that of the second material layer 202. It can be understood that the first material layer 201 is composed of a material with a high refractive index, such as gallium arsenide (GaAs), gallium nitride (GaN), etc., and the second material layer 202 is composed of a material with a low refractive index, such as silicon dioxide (SiO2), silicon nitride (Si3N4), etc.

[0058] Figure 7 is a schematic structural diagram of the first DBR layer in another semiconductor laser provided by the embodiment of the present invention. Refer to Figure 7 , optionally, the number of layers of the sampling structure 5 is greater than or equal to 2 layers. Between any two adjacent sampling structures A, there are n alternately stacked first material layers 201 and second material layers 202, where n is a positive integer greater than or equal to 1.

[0059] Specifically, as Figure 7 shown, the number of layers of the sampling structure 5 is greater than or equal to 2 layers ( Figure 6 only shows 2 layers of the sampling structure 5 in the figure). Between any two adjacent sampling structures A, there are n alternately stacked first material layers 201 and second material layers 202. Exemplarily, Figure 6 in the figure, n is 2. It can be understood that Figure 6 the first DBR layer 2 shown in the figure is stacked from top to bottom in sequence as the sampling structure 5, the second material layer 202, the first material layer 201, the sampling structure 5, the second material layer 202, and the first material layer 201. Wherein, n is a positive integer greater than or equal to 1.

[0060] Figure 8 is a schematic structural diagram of the first DBR layer in another semiconductor laser provided by the embodiment of the present invention. Refer to Figure 8 , n can also be 3. In the embodiment of the present invention, n can be set according to actual needs and will not be enumerated here.

[0061] Optionally, the sampling period of the sampling structure A is the ratio of a grating period to a first period; wherein, the grating period is the sum of the thicknesses of one first material layer and one second material layer, and the first period is the sum of the thicknesses of n first material layers, n second material layers, and 1 sampling structure.

[0062] Specifically, exemplarily, refer to Figure 7 shown, the sampling period of the sampling structure 5 is the ratio of a grating period (i.e., the sum of the thicknesses of one first material layer 201 and one second material layer 202) to the first period (inFigure 7 Among them, the first period is the total thickness of 2 first material layers 201, 2 second material layers 202, and 1 sampling structure 5).

[0063] Again, for example, referring to Figure 8 As shown, the sampling period of the sampling structure 5 is the ratio of one grating period (i.e., the total thickness of one first material layer 201 and one second material layer 202) to the first period (in Figure 8 Among them, it is the total thickness of 3 first material layers 201, 3 second material layers 202, and 1 sampling structure 5).

[0064] Optionally, the sampling period is less than or equal to 0.5.

[0065] Figure 9 It is another schematic diagram of a semiconductor laser structure provided by an embodiment of the present invention. Referring to Figure 9 Optionally, it further includes a first spatial layer 61 and a second spatial layer 62;

[0066] The first spatial layer 61 is located between the first DBR layer 2 and the active layer 3;

[0067] The second spatial layer 62 is located between the active layer 3 and the second DBR layer 4.

[0068] Specifically, the semiconductor laser provided by the embodiment of the present invention further includes a first spatial layer 61 and a second spatial layer 62. By setting spatial layers in the semiconductor laser, the optical cavity length can be adjusted to ensure that the resonant wavelength matches the gain peak and reduce leakage current. For example, the materials of the first spatial layer 61 and the second spatial layer 62 are gallium arsenide (GaAs).

[0069] Figure 10 It is another schematic diagram of a semiconductor laser structure provided by an embodiment of the present invention. Referring to Figure 10 The semiconductor laser provided by the embodiment of the present invention further includes an oxide layer 7; the oxide layer 7 is located between the second spatial layer 62 and the second DBR layer 4.

[0070] Specifically, the oxide layer 7 insulates the current by oxidizing high-aluminum (Al) components to form aluminum oxide (Al2O3) during the device processing, reducing the threshold current density of the device.

[0071] Figure 11 It is another schematic diagram of a semiconductor laser structure provided by an embodiment of the present invention. Referring to Figure 11 Optionally, the semiconductor laser provided by the embodiment of the present invention further includes a current diffusion layer 8; the current diffusion layer 8 is located on the side of the second DBR layer 4 away from the active layer 3.

[0072] Specifically, the current diffusion layer 8 is located on the side of the second DBR layer 4 away from the active layer 3 (ie Figure 11 The top layer in the device) is highly doped to achieve uniform dispersion of the injected current at various locations in the device, and by reducing the series resistance of the device, the uniformity of the current distribution is improved, thereby improving the performance and reliability of the entire device.

[0073] Optionally, the active layer 3 includes a multi-quantum well layer or a quantum well layer.

[0074] Among them, the multi-quantum well layer is a thin film structure formed by alternating two or more materials. The thickness of each layer of material is about several nanometers to tens of nanometers, which is much smaller than the wavelength of light. For example, there are multi-quantum well layers composed of material systems such as GaAs / AlGaAs and InGaAs / InP. The quantum well layer is composed of a barrier layer of material with a larger band gap and a well layer with a smaller band gap.

[0075] According to the same inventive concept, Figure 12 is a flow chart of a semiconductor laser manufacturing method provided by an embodiment of the present invention, refer to Figure 12 The present invention provides a method for preparing a semiconductor laser, which is used to prepare the semiconductor laser in the above invention embodiment. The preparation method includes:

[0076] S101. Provide a substrate.

[0077] Specifically, a substrate required for preparing a semiconductor laser is provided. The substrate is the basis for constructing a semiconductor laser. Exemplarily, gallium arsenide (GaAs) can be selected as the material of the substrate.

[0078] S102 , forming a first DBR layer, an active layer, and a second DBR layer stacked in sequence on one side of the substrate.

[0079] Specifically, after providing the substrate in the above step S101, a first DBR layer is deposited on one side of the substrate, wherein the first DBR layer includes a plurality of first material layers, a plurality of second material layers and a plurality of sampling structures which are stacked, and the deposition method may be chemical process deposition. After the first DBR layer is deposited, an active layer is deposited on the side of the first DBR layer away from the substrate, wherein the active layer is generally composed of a quantum well or a multi-quantum well. After the active layer is deposited, a second DBR layer is deposited on the side of the active layer away from the first DBR layer, wherein the second DBR layer also includes a plurality of first material layers, a plurality of second material layers and a plurality of sampling structures which are stacked, wherein the plurality of first material layers and the plurality of second material layers which are stacked in the first DBR layer and the second DBR layer are DBR structures, and the sampling structure is located on one side of the DBR structure or the sampling structure is located between two adjacent periodic structures of the DBR structure; wherein the thickness of the sampling structure is an integer multiple of half the target wavelength of the semiconductor laser.

[0080] The above specific embodiments do not constitute a limitation on 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 semiconductor laser, characterized in that, include: A substrate and a first DBR layer, an active layer and a second DBR layer stacked in sequence on one side of the substrate; The first DBR layer and the second DBR layer include a DBR structure, and the DBR structure includes a plurality of first material layers and second material layers alternately stacked; The first DBR layer and / or the second DBR layer further includes at least one sampling structure, wherein the sampling structure is located on one side of the DBR structure or between two adjacent grating periods of the DBR structure; wherein the thickness of the sampling structure is an integer multiple of half the target wavelength of the semiconductor laser.

2. The semiconductor laser according to claim 1, characterized in that The refractive index of the first material layer is greater than the refractive index of the second material layer.

3. The semiconductor laser according to claim 1, characterized in that, The number of layers of the sampling structure is greater than or equal to 2, and any two adjacent sampling structures include n alternately stacked first material layers and second material layers, wherein n is a positive integer greater than or equal to 1.

4. The semiconductor laser according to claim 3, characterized in that, The sampling period of the sampling structure is the ratio of a grating period to a first period; wherein the grating period is the sum of the thicknesses of one first material layer and one second material layer, and the first period is the sum of the thicknesses of n first material layers, n second material layers and 1 sampling structure.

5. The semiconductor laser according to claim 3, characterized in that, The sampling period is less than or equal to 0.

5.

6. The semiconductor laser according to claim 1, wherein Also includes a first spatial layer and a second spatial layer; The first space layer is located between the first DBR layer and the active layer; The second space layer is located between the active layer and the second DBR layer.

7. The semiconductor laser according to claim 6, wherein Also includes oxide layer; The oxide layer is located between the second space layer and the second DBR layer.

8. The semiconductor laser according to claim 1, wherein Also including a current spreading layer; The current diffusion layer is located on a side of the second DBR layer away from the active layer.

9. The semiconductor laser according to claim 1, characterized in that, The active layer includes a multi-quantum well layer or a quantum well layer.

10. A method for preparing a semiconductor laser, characterized in that, Used to prepare the semiconductor laser according to any one of claims 1 to 9, the preparation method comprising: providing a substrate; A first DBR layer, an active layer, and a second DBR layer are sequentially stacked on one side of the substrate; Wherein, the first DBR layer and the second DBR layer comprise a DBR structure, and the DBR structure comprises a plurality of first material layers and second material layers alternately stacked; The first DBR layer and / or the second DBR layer further comprises at least one layer of sampling structure, wherein the sampling structure is located on one side of the DBR structure or between two adjacent grating periods of the DBR structure; Wherein, the thickness of the sampling structure is an integer multiple of half the target wavelength of the semiconductor laser.

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