A gallium nitride-based diffractive surface emitting semiconductor laser

Abstract

The application relates to a gallium nitride-based diffraction surface-emitting semiconductor laser, which comprises an upper cladding layer, an upper waveguide layer, an active layer, a lower waveguide layer and a lower cladding layer, the active layer emits light when carriers are injected into the active layer, at least one side of the active layer is provided with an optical modulation structure, and the optical modulation structure is located in the upper cladding layer and / or the lower cladding layer; wherein the optical modulation structure is a ring structure; and a base material of the optical modulation structure comprises InGaN. The application contains InGaN in the base material of the optical modulation structure, improves the freedom degree of light field regulation of the device in the direction perpendicular to the epitaxial layer, and solves the problem that the light field regulation is limited in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser, in particular to a gallium nitride-based diffraction facet emitting semiconductor laser. BACKGROUND

[0002] The gallium nitride-based diffraction facet emitting semiconductor laser belongs to horizontal cavity facet emitting structure, that is, an upper cladding layer, an upper waveguide layer, an active layer, a lower waveguide layer and a lower cladding layer are made in a direction perpendicular to an epitaxial layer, and a waveguide is formed in a direction parallel to the epitaxial layer to limit the propagation of a light field in a horizontal plane. The facet emission is realized by the diffraction of a second-order or higher-order grating / photonic crystal.

[0003] In order to limit the propagation of the light field in the horizontal plane, a refractive index difference is formed between the upper cladding layer and the upper waveguide layer or between the lower cladding layer and the lower waveguide layer, that is, the refractive index of the upper cladding layer is smaller than that of the upper waveguide layer, and the refractive index of the lower cladding layer is smaller than that of the lower waveguide layer. In the gallium nitride-based semiconductor laser, in order to realize the refractive index difference between the cladding layer and the waveguide layer, AlGaN or GaN is usually used as the upper cladding layer or the lower cladding layer, as described in document 1 and document 2.

[0004] For the diffraction facet emitting semiconductor laser, the grating / photonic crystal layer is usually arranged in the upper cladding layer or the lower cladding layer to reduce etching damage and non-radiative recombination. However, based on the flat waveguide structure, the confinement factor (that is, the ratio of the light field intensity in the cladding layer to the entire light field intensity in the direction perpendicular to the epitaxial layer) in the upper cladding layer and the lower cladding layer is small, and after the grating / photonic crystal is made, the confinement factor of the grating / photonic crystal layer is smaller, the lasing threshold is increased, and the emission intensity is lower.

[0005] Based on the GaN-based laser structure disclosed in document 1 and document 2, the grating / photonic crystal layer made by etching reduces the average refractive index of the layer, which causes the light field to shift to the other side. If the confinement factor of the grating / photonic crystal layer is to be increased, the Al content in the AlGaN cladding layer on the other side needs to be increased. However, in the GaN-based laser, the lattice constant of the AlGaN decreases with the increase of the Al content, which causes compressive stress, and the thicker the AlGaN material, the more the compressive stress accumulates. Too high compressive stress will cause cracks in the material, resulting in device failure, so the Al component and thickness need to be controlled within a suitable range. And such an epitaxial structure cannot effectively increase the light field intensity of the grating / photonic crystal layer, making it difficult for the device to lase. At the same time, the above laser structure also has the problem of limited light field regulation.

[0006] Prior art documents:

[0007] Document 1: S. W. Chen, T. T. Kao, T. T. Wu, et al., The Lasing Characteristics of GaN-based Two-dimensional Photonic Crystal Surface Emitting Lasers, Proc. SPIE Vol. 7602, 2010;

[0008] Document 2: K. Emoto, T. Koizumi, M. Hirose, et al., Wide-bandgap GaN-based watt-class photonic-crystal lasers, Communications Materials, Vol. 3, 2022. SUMMARY

[0009] Based on this, it is necessary to provide a gallium nitride-based diffraction type surface emitting semiconductor laser, in which the base material of the optical modulation structure contains InGaN, which improves the degree of freedom of light field regulation in the direction perpendicular to the epitaxial layer, and solves the problem of limited light field regulation in the prior art.

[0010] To solve the above technical problems, the technical solution adopted by the present application is:

[0011] A gallium nitride-based diffraction type surface emitting semiconductor laser, comprising an upper cladding layer, an upper waveguide layer, an active layer, a lower waveguide layer, and a lower cladding layer, the active layer emits light when carriers are injected into the active layer, at least one side of the active layer is provided with an optical modulation structure, and the optical modulation structure is located in the upper cladding layer and / or the lower cladding layer.

[0012] The optical modulation structure is a ring structure.

[0013] The base material of the optical modulation structure contains InGaN.

[0014] Preferably, the molar percentage content of In component in InGaN is less than or equal to 10%.

[0015] Preferably, the molar percentage content of In component in InGaN is greater than or equal to 0.5%.

[0016] Preferably, the optical modulation structure is a ring grating structure or a ring hole structure.

[0017] Preferably, the optical modulation structure is a ring grating structure.

[0018] The ring grating structure adopts a second-order grating structure or a higher-order grating structure.

[0019] Preferably, the annular air hole structure or the annular grating structure is distributed in the radial direction according to the period of the Bessel function;

[0020] The Bessel function is 0 order or 1 order.

[0021] Preferably, the annular grating structure adopts a second-order grating structure, and the period a= λ / n eff ; or

[0022] The annular grating structure adopts a third-order grating structure, and the period a=3 λ / 2 n eff ; or

[0023] The annular grating structure adopts a fourth-order grating structure, and the period a=2 λ / n eff ;

[0024] wherein, λ is the wavelength of the laser, n eff is the refractive index of the optical field mode.

[0025] Preferably, the period a= λ / n eff of the annular grating structure, the groove width of the grating is w1, the duty cycle d c1 = w1 / a, and the duty cycle d c1 is greater than or equal to 0.3 and less than or equal to 0.6;

[0026] The period a= λ / n eff of the annular air hole structure, the width in the radial direction is w2, the duty cycle d c2 = w2 / a, and the duty cycle d c2 is greater than or equal to 0.3 and less than or equal to 0.6.

[0027] Preferably, the base material of the optical modulation structure includes at least one InGaN layer and at least one GaN layer.

[0028] Preferably, the base material of the optical modulation structure is a three-layer structure including two InGaN layers and one GaN layer, and the GaN layer is located between the two InGaN layers.

[0029] By adopting the above technical solutions, the present application has the following advantages compared with the prior art:

[0030] 1. The present application is improved based on a gallium nitride-based diffraction type surface emitting semiconductor laser, wherein the base material of the optical modulation structure contains InGaN, thereby improving the freedom degree of light field regulation in the direction perpendicular to the epitaxial layer of the device;

[0031] 2. The substrate material of the optical modulation structure in this application includes InGaN, which improves the confinement factor of the optical modulation structure and reduces the lasing threshold.

[0032] 3. This application further improves emission efficiency by adjusting the duty cycle of the optical modulation structure to achieve low in-plane feedback. Attached Figure Description

[0033] To more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 A cross-sectional schematic diagram of a gallium nitride-based diffractive surface-emitting semiconductor laser structure provided by the present invention;

[0035] Figure 2 This is a schematic diagram of the annular grating structure provided by the present invention;

[0036] Figure 3 The following are the scanning results of Example 1, where: (a) is a graph showing the relationship between the limiting factor of the optical modulation structure and the duty cycle dc1 of the ring structure and the In content in InGaN; (b) is a graph showing the relationship between the in-plane feedback coefficient of the optical modulation structure and the duty cycle dc1 of the ring structure and the In content in InGaN; (c) is a graph showing the relationship between the emission coefficient of the optical modulation structure and the duty cycle dc1 of the ring structure and the In composition in InGaN; and (d) is a graph showing the relationship between the in-plane feedback coefficient / emission coefficient of the optical modulation structure and the duty cycle dc1 of the ring structure and the In composition in InGaN.

[0037] Figure 4 The following are the scanning results of Example 2, where: (a) is a graph showing the relationship between the confinement factor of the optical modulation structure and the duty cycle dc1 of the ring structure and the thickness of InGaN; (b) is a graph showing the relationship between the in-plane feedback coefficient of the optical modulation structure and the duty cycle dc1 of the ring structure and the thickness of InGaN; (c) is a graph showing the relationship between the emission coefficient of the optical modulation structure and the duty cycle dc1 of the ring structure and the thickness of InGaN; and (d) is a graph showing the relationship between the in-plane feedback coefficient / emission coefficient of the optical modulation structure and the duty cycle dc1 of the ring structure and the thickness of InGaN.

[0038] Figure 5 This is a scan result image of Example 3.

[0039] Among them: 1. Lower electrode; 2. Lower cladding; 3. Lower waveguide layer; 4. Active layer; 5. Upper waveguide layer; 6. Upper cladding; 7. Upper electrode; 8. Optical modulation structure. Detailed Implementation

[0040] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0041] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0044] "Multiple" means two or more, unless otherwise explicitly specified. " / " means "or".

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0046] Currently, in GaN-based laser structures, the average refractive index of the grating / photonic crystal layer, fabricated through etching, decreases, causing the light field to shift to one side. To improve the confinement factor of the grating / photonic crystal layer, the Al content in the AlGaN cladding layer needs to be increased. However, in GaN-based lasers, the lattice constant of AlGaN decreases with increasing Al content, leading to compressive stress, which accumulates as the AlGaN material thickens. Excessive compressive stress can cause cracks in the material, leading to device failure. Therefore, the Al composition and thickness need to be controlled within a suitable range. Furthermore, this epitaxial structure cannot effectively increase the light field intensity of the grating / photonic crystal layer, making lasing difficult. Additionally, the aforementioned laser structure also suffers from limited light field manipulation.

[0047] Based on this, the present invention provides a gallium nitride-based diffractive surface-emitting semiconductor laser, comprising an upper cladding layer, an upper waveguide layer, an active layer, a lower waveguide layer, and a lower cladding layer. When charge carriers are injected into the active layer, the active layer emits light. An optical modulation structure is disposed on at least one side of the active layer, and the optical modulation structure is located in the upper cladding layer and / or the lower cladding layer. The optical modulation structure is a ring structure. The substrate material of the optical modulation structure comprises InGaN.

[0048] This invention incorporates InGaN into the substrate material of the optical modulation structure, thereby increasing the degree of freedom in optical field modulation in the direction perpendicular to the epitaxial layer and solving the problem of limited optical field modulation in the prior art.

[0049] In some specific embodiments, the optical modulation structure can be disposed on one side of the active layer or on both sides of the active layer. That is, the optical modulation structure can be disposed on the upper side or the lower side of the active layer, or it can be disposed on both the upper and lower sides of the active layer at the same time.

[0050] In some specific embodiments, an upper electrode may be disposed on the upper cladding layer, and a lower electrode may be disposed on the lower cladding layer. The upper electrode, upper cladding layer, upper waveguide layer, active layer, lower waveguide layer, lower cladding layer, and lower electrode are all conventional configurations of semiconductor lasers and are not considered inventive features of this invention; therefore, they will not be described in detail here.

[0051] In some specific embodiments, the molar percentage content of In component in InGaN is greater than or equal to 0.5%, specifically, it can also be greater than or equal to 0.8%, or greater than or equal to 1%, or greater than or equal to 1.3%, or greater than or equal to 1.7%, or greater than or equal to 2%, or greater than or equal to 2.4%, or greater than or equal to 2.6%, or greater than or equal to 3%, or greater than or equal to 3.5%, or greater than or equal to 4%, or greater than or equal to 4.6%.

[0052] In some specific embodiments, the molar percentage content of In component in InGaN is less than or equal to 10%. Specifically, it can also be less than or equal to 9.6%, or less than or equal to 9%, or less than or equal to 8.7%, or less than or equal to 8.3%, or less than or equal to 8%, or less than or equal to 7.8%, or less than or equal to 7.4%, or less than or equal to 7%, or less than or equal to 6.5%, or less than or equal to 6%, or less than or equal to 5.4%.

[0053] In some specific embodiments, the thickness of the optical modulation structure is less than or equal to 175 nm and greater than or equal to 25 nm, specifically 165 nm, 150 nm, 130 nm, 120 nm, 115 nm, 105 nm, 100 nm, 95 nm, 75 nm, 60 nm, 45 nm, and 30 nm.

[0054] In some specific embodiments, the optical modulation structure is located in the upper cladding and / or the lower cladding, that is, the optical modulation structure may be located in the upper cladding, or the optical modulation structure may be located in the lower cladding, or the optical modulation structure may be located in both the upper and lower cladding.

[0055] In some specific embodiments, the optical modulation structure is a ring grating structure or a ring aperture structure. Preferably, the optical modulation structure is a ring grating structure, such as... Figure 2 As shown.

[0056] In some specific embodiments, the annular grating structure adopts a second-order grating structure or a higher-order grating structure.

[0057] In some specific embodiments, the annular aperture structure or annular grating structure is radially distributed according to the periodicity of a Bessel function. Preferably, the Bessel function is of order 0 or 1.

[0058] In some specific embodiments, the annular grating structure adopts a second-order grating structure, that is, the phase difference between two adjacent rings is 2π, and the period a = λ / n eff ;or

[0059] The ring grating structure uses a third-order grating structure, meaning that the phase difference between two adjacent rings is 3π, and the period a=3. λ / 2n eff ;or

[0060] The ring grating structure uses a fourth-order grating structure, meaning that the phase difference between two adjacent rings is 4π, and the period a=2. λ / n eff ;

[0061] in, λ n is the laser wavelength. eff is the refractive index of the light field mode.

[0062] Preferably, the annular grating structure or the annular aperture structure adopts a second-order grating structure, that is, the phase difference between two adjacent rings is 2π, and the period a = λ / n eff The grating has a slot width of w1, a duty cycle of dc1 = w1 / a, and a duty cycle of dc1 greater than or equal to 0.3 and less than or equal to 0.6. Specifically, the duty cycle dc1 can also be greater than or equal to 0.32 and less than or equal to 0.58, or greater than or equal to 0.34 and less than or equal to 0.57, or greater than or equal to 0.37 and less than or equal to 0.55, or greater than or equal to 0.4 and less than or equal to 0.55. Preferably, it is greater than or equal to 0.35 and less than or equal to 0.55. The radial width of the annular hole structure is w2, the duty cycle dc2 = w2 / a, and the duty cycle dc2 is greater than or equal to 0.3 and less than or equal to 0.6. Specifically, the duty cycle dc2 can also be greater than or equal to 0.32 and less than or equal to 0.58, or greater than or equal to 0.34 and less than or equal to 0.57, or greater than or equal to 0.37 and less than or equal to 0.55, or greater than or equal to 0.4 and less than or equal to 0.55. Preferably, it is greater than or equal to 0.35 and less than or equal to 0.55.

[0063] In some specific embodiments, the substrate material of the optical modulation structure includes at least one InGaN layer and at least one GaN layer. Specifically, the substrate material of the optical modulation structure is a three-layer structure, including two InGaN layers and one GaN layer, with the GaN layer located between the two InGaN layers, i.e., InGaN-GaN-InGaN. Inserting a GaN layer into the InGaN optical modulation structure can increase the adjustment space of the confinement factor of the optical modulation structure.

[0064] The following is in conjunction with the appendix Figures 1-5 The present invention will be described in detail below with reference to specific embodiments.

[0065] Example 1

[0066] Taking GaN-based semiconductor lasers as an example, as shown in the attached document... Figure 1As shown, the epitaxial structure of the diffractive surface-emitting semiconductor laser in this embodiment includes, from top to bottom, an upper electrode 7, an upper cladding layer 6, an upper waveguide layer 5, an active layer 4, a lower waveguide layer 3, a lower cladding layer 2, and a lower electrode 1. Depending on actual performance requirements, the diffractive surface-emitting semiconductor laser in this embodiment can also incorporate structures such as an electron blocking layer, a buffer layer, and an ohmic contact layer.

[0067] Because the grating area of ​​a ring grating structure is several times larger than that of a ring-shaped aperture structure and a photonic crystal structure, the confinement factor of the ring grating structure is smaller than that of the ring-shaped aperture structure and the photonic crystal structure under the same epitaxial structure. This makes it difficult for existing gallium nitride-based diffractive surface-emitting lasers to be electrically injected into the laser when a ring grating structure is used on one or both sides of the active layer 4. During the research and development process, the applicant discovered that by setting an optical modulation structure 8 on at least one side of the active layer 4, and the optical modulation structure 8 being located in the upper cladding layer 6 and / or the lower cladding layer 2; wherein the optical modulation structure 8 is a ring structure, and the substrate material of the optical modulation structure 8 contains InGaN, this problem can be effectively improved.

[0068] Specifically, in this embodiment, the optical modulation structure 8 is located in the upper cladding 6 and has a thickness of 100 nm. The thickness of the optical modulation structure 8 can be adjusted according to actual needs, and there is no limitation on the thickness of the optical modulation structure 8 here.

[0069] The substrate material of the optical modulation structure 8 is InGaN, and the optical modulation structure 8 is a second-order ring grating structure, such as... Figure 2 As shown, the annular grating structure is radially distributed according to a periodic Bessel function, where the Bessel function is of order 0 and the period a = λ / n eff ,in, λ n is the laser wavelength. eff is the refractive index of the light field mode.

[0070] By scanning the duty cycle dc1 (i.e., the ratio of the grating's slot width w1 to its period a) and the molar percentage of In in InGaN (In_doping) of the annular grating structure using a Python program, the confinement factor (g_pc) of the corresponding optical modulation structure 8 is obtained. Figure 3 As shown in (a) of the paper. When the molar percentage of In is constant, the larger dc1 is, the smaller g_pc is; when dc1 is constant, the higher the molar percentage of In, the larger g_pc is. Therefore, controlling the molar percentage of In can compensate for the decrease in g_pc caused by an excessively large dc1, i.e., increase g_pc. Because if dc1 is too small, the function of the grating disappears; for example, dc1=0, which is equivalent to no grating. Therefore, the structure of this application is particularly suitable for ring grating structures.

[0071] For a ring structure, two coefficients, h1 and h2, can be calculated. h1.real is the real part of h1, representing the surface emission output coefficient; h1.imag is the imaginary part of h1, and h1.imag + h2 represents the in-plane feedback coefficient. The closer the in-plane feedback coefficient is to 0, the weaker the in-plane feedback, making it more suitable for lasing single-mode control of large-area devices; the larger the output coefficient, the greater the surface-emitted laser intensity and the higher the slope efficiency.

[0072] like Figure 3 As shown in (d), the area marked in red represents the region where |h1.imag+h2| / h1.real ≤ 0.15, meaning the in-plane feedback coefficient is close to 0. Combined with... Figure 3 As shown in (c), when dc1=0.4 and the molar percentage content of In component in InGaN is 0.1, its emission intensity will be about 20% higher than when the molar percentage content of In component is 0.05.

[0073] Example 2

[0074] Based on Example 1, the molar percentage content of In component in InGaN was fixed at 0.05.

[0075] By scanning the duty cycle dc1 of the annular grating structure and the InGaN thickness of the optical modulation structure 8 using a Python program, the confinement factor (g_pc) of the corresponding optical modulation structure 8 is obtained, such as... Figure 4 As shown in (a) of the diagram. When the InGaN thickness is constant, the larger dc1 is, the smaller g_pc is; when dc1 is constant, the thicker the InGaN, the larger g_pc is. Therefore, controlling the InGaN thickness can compensate for the problem of g_pc decreasing due to excessively large dc1.

[0076] like Figure 4 As shown in (d), the area marked in red represents the region where |h1.imag+h2| / h1.real≤0.2, meaning the in-plane feedback coefficient is close to 0. Combined with... Figure 4 As shown in (c), for this model structure, when dc1≈0.45 and the InGaN thickness is approximately 50 nm-75 nm, the in-plane feedback is close to 0, while the emission is strongest. Considering the difference between the theoretical calculation model and the actual device fabrication process, the InGaN thickness should be greater than or equal to 25 nm and less than or equal to 175 nm.

[0077] Example 3

[0078] Based on Example 1, the thickness of the fixed optical modulation structure is 100 nm, and the molar percentage content of In component in InGaN is 0.03.

[0079] In this embodiment, a GaN layer is inserted in the middle of the InGaN layers, and the inserted GaN layer is also fabricated into a ring structure. That is, the optical modulation structure 8 in this embodiment includes a three-layer structure, namely two InGaN layers and one GaN layer, with the GaN layer located between the two InGaN layers, i.e., inserted in the middle of the two InGaN layers. The inserted GaN layer is also used to fabricate a ring grating structure.

[0080] By changing the thickness of the inserted GaN layer and dc1, the confinement factor (g_pc) of the corresponding optical modulation structure 8 is obtained, such as... Figure 5 As shown in the figure. The results indicate that increasing the thickness of the inserted GaN layer can improve the confinement factor g_pc of the optical modulation structure 8.

[0081] Due to the addition of In, the lattice constant of InGaN increases with increasing In content, leading to tensile stress. Furthermore, the thicker the InGaN material, the more compressive stress accumulates. Excessive tensile stress can cause cracks in the material, resulting in device failure. Therefore, the In composition and thickness need to be controlled within appropriate ranges. In this embodiment, inserting a GaN layer into the InGaN layer avoids excessive tensile stress in the epitaxial wafer, while simultaneously controlling the thickness and confinement factor of the optical modulation structure 8.

[0082] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A gallium nitride-based diffractive surface-emitting semiconductor laser, comprising an upper cladding layer, an upper waveguide layer, an active layer, a lower waveguide layer, and a lower cladding layer, wherein when charge carriers are injected into the active layer, the active layer emits light, characterized in that, At least one side of the active layer is provided with an optical modulation structure, and the optical modulation structure is located in the upper cladding layer and / or the lower cladding layer; The optical modulation structure is a ring structure. The substrate material of the optical modulation structure comprises InGaN; The molar percentage content of In component in the InGaN is greater than or equal to 0.5%.

2. The gallium nitride-based diffractive surface-emitting semiconductor laser according to claim 1, characterized in that, The molar percentage content of In component in the InGaN is less than or equal to 10%.

3. The gallium nitride-based diffractive surface-emitting semiconductor laser according to claim 1, characterized in that, The optical modulation structure is a ring grating structure or a ring aperture structure.

4. The gallium nitride-based diffractive surface-emitting semiconductor laser according to claim 3, characterized in that, The optical modulation structure is a ring grating structure; The annular grating structure adopts a second-order grating structure or a higher-order grating structure.

5. The gallium nitride-based diffractive surface-emitting semiconductor laser according to claim 3, characterized in that, The annular aperture structure or the annular grating structure is distributed radially according to the periodic distribution of the Bessel function; The Bessel function is of order 0 or 1.

6. The gallium nitride-based diffractive surface-emitting semiconductor laser according to claim 4, characterized in that, The annular grating structure adopts a second-order grating structure with a period a= λ / n eff ;or The annular grating structure adopts a third-order grating structure with a period a=3. λ / 2 n eff ;or The annular grating structure adopts a fourth-order grating structure with a period a=2. λ / n eff ; in, λ n is the laser wavelength. eff is the refractive index of the light field mode.

7. The gallium nitride-based diffractive surface-emitting semiconductor laser according to claim 3, characterized in that, The period a of the annular grating structure = λ / n eff The grating has a slot width of w1 and a duty cycle of dc1 = w1 / a, wherein the duty cycle dc1 is greater than or equal to 0.3 and less than or equal to 0.

6. The period a of the annular hollow structure = λ / n eff The radial width is w2, and the duty cycle dc2 = w2 / a, wherein the duty cycle dc2 is greater than or equal to 0.3 and less than or equal to 0.

6.

8. The gallium nitride-based diffractive surface-emitting semiconductor laser according to claim 1, characterized in that, The substrate material of the optical modulation structure includes at least one InGaN layer and at least one GaN layer.

9. The gallium nitride-based diffractive surface-emitting semiconductor laser according to claim 8, characterized in that, The substrate material of the optical modulation structure is a three-layer structure, including two InGaN layers and one GaN layer, with the GaN layer located between the two InGaN layers.

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