A gallium nitride-based semiconductor laser having a graded optical field waveguide layer

Abstract

This invention proposes a gallium nitride-based semiconductor laser with a gradient optical field waveguide layer. The fitting curves of the In ion intensity distribution or In atom concentration distribution, refractive index distribution, and optical absorption coefficient distribution obtained from SIMS testing of both the upper and lower waveguide layers satisfy any one of the ExpGro1, ExpGro2, ExpGro3, and Shah functions. This allows for the synergistic control of optical field confinement, loss suppression, and carrier distribution, thereby regulating the laser's optical field distribution. The fabricated gradient refractive index waveguide layer, satisfying the relevant function distribution, confines photons generated by the active layer within the waveguide, smoothing the optical field within the waveguide layer. This eliminates reflection and scattering losses caused by abrupt refractive index differences at the interface, reduces light field penetration into the confinement layer, lowers optical leakage and threshold losses, suppresses the excitation of higher-order transverse modes, achieves stable fundamental mode output, improves the laser's mode stability and beam quality factor, and reduces the horizontal divergence angle.

Description

Technical Field

[0001] This application relates to the field of semiconductor optoelectronic devices, and more particularly to a gallium nitride-based semiconductor laser with a gradient optical field waveguide layer. Background Technology

[0002] Lasers are widely used in laser displays, laser TVs, laser projectors, communications, medical applications, weaponry, guidance, ranging, spectral analysis, cutting, precision welding, and high-density optical storage. There are many types of lasers, and they can be classified in various ways, mainly including solid-state, gas, liquid, semiconductor, and dye lasers. Compared with other types of lasers, all-solid-state semiconductor lasers have advantages such as small size, high efficiency, light weight, good stability, long lifespan, simple and compact structure, and miniaturization.

[0003] Lasers and nitride semiconductor light-emitting diodes (LEDs) differ significantly:

[0004] 1) Lasers are generated by stimulated emission of charge carriers. They have a small half-width at half-maximum and very high brightness. The output power of a single laser can be in the W range. In contrast, nitride semiconductor light-emitting diodes are generated by spontaneous emission. The output power of a single light-emitting diode is in the mW range.

[0005] 2) The operating current density of lasers reaches KA / cm2, which is more than two orders of magnitude higher than that of nitride light-emitting diodes. This results in stronger electron leakage, more severe Auger recombination, stronger polarization effect, and more severe electron-hole mismatch, leading to more severe efficiency degradation and the Droop effect.

[0006] 3) Light-emitting diodes emit spontaneous transition radiation, which is incoherent light that transitions from a high energy level to a low energy level without external influence. In contrast, lasers emit stimulated transition radiation, where the energy of the induced photon should be equal to the energy difference of the electron transition, producing coherent light that is identical to the induced photon.

[0007] 4) Different principles: Light emission diodes emit light by electrons and holes jumping to the active layer or pn junction under the action of external voltage to generate radiative recombination, while lasers require certain lasing conditions to be met before they can emit light. This requires the carriers in the active region to be reversed, the stimulated emission light to oscillate back and forth in the resonant cavity, and the propagation in the gain medium to amplify the light. When the threshold condition is met, the gain is greater than the loss, and finally, laser light is output.

[0008] Nitride semiconductor lasers suffer from the following problems: The laser field exhibits dissipation, and leakage of the light field modes into the substrate, forming standing waves, leads to low substrate mode suppression efficiency. This results in a small laser beam divergence angle, and the far-field image does not satisfy a Gaussian pattern along the c-axis of the laser epitaxial layer, leading to poor beam quality, inability to focus, and poor far-field image FFP quality. Refractive index dispersion, particularly high carrier concentration fluctuations, affects the refractive index of the active layer, causing the confinement factor to decrease with increasing wavelength, thus reducing the laser's mode gain. The laser beam pattern can be divided into transverse and longitudinal modes. The intensity distribution of transverse modes perpendicular to the optical axis is determined by the waveguide structure of the semiconductor laser; if the transverse modes are complex and unstable, the output light coherence is poor. Longitudinal modes exhibit a standing wave distribution along the resonant cavity propagation direction; if many longitudinal modes are simultaneously emitted or inter-mode variations exist, high temporal coherence cannot be achieved, resulting in poor far-field image FFP quality. Summary of the Invention

[0009] To address one of the aforementioned technical problems, this invention provides a gallium nitride-based semiconductor laser with a gradient optical field waveguide layer.

[0010] This invention provides a gallium nitride-based semiconductor laser with a gradient optical field waveguide layer, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, a first upper confinement layer, an electron blocking layer, a second upper confinement layer, and a contact layer. The lower waveguide layer includes a first lower waveguide layer and a second lower waveguide layer, with the first lower waveguide layer located below the second lower waveguide layer. The first lower waveguide layer is GaN, and the second lower waveguide layer is a gradient optical field lower waveguide layer. The upper waveguide layer includes a first upper waveguide layer and a second upper waveguide layer, with the first upper waveguide layer located below the second upper waveguide layer. The first upper waveguide layer is a gradient optical field upper waveguide layer, and the second upper waveguide layer is GaN.

[0011] The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the refractive index distribution, and the fitting curve of the optical absorption coefficient distribution of the waveguide layer in the gradient optical field under SIMS testing all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function, and Shah function.

[0012] The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the refractive index distribution, and the fitting curve of the optical absorption coefficient distribution of the waveguide layer under the gradient optical field under SIMS testing all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function, and Shah function.

[0013] Preferably, when the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient optical field measured by SIMS satisfies the ExpGro1 function, the ExpGro1 function is y1=A*exp(x1 / B)+C, where y1 is the In ion intensity distribution or In atom concentration of the waveguide layer in the gradient optical field measured by SIMS, and x1 is the thickness of the waveguide layer in the gradient optical field, wherein -7E30≤A≤0, -4000000≤B≤0, and 7E14≤C≤7E34;

[0014] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient optical field measured by SIMS satisfies the ExpGro2 function, the ExpGro2 function is y2=D1*exp(x1 / E1)+ D2*exp(x1 / E2)+F, where y2 is the In ion intensity distribution or In atom concentration of the waveguide layer in the gradient optical field measured by SIMS, x1 is the thickness of the waveguide layer in the gradient optical field, and -9E30≤D1≤0, -9E30≤D2≤0, -8000≤E1≤0, -8000≤E2≤0, 2E12≤F≤2E32;

[0015] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient optical field measured by SIMS satisfies the ExpGro3 function, the ExpGro3 function is y3=G1*exp(x1 / H1)+ G2*exp(x1 / H2) + G3*exp(x1 / H3)+I, where y3 is the In ion intensity distribution or In atom concentration of the waveguide layer in the gradient optical field measured by SIMS, and x1 is the thickness of the waveguide layer in the gradient optical field, where: -4E30≤G1≤0, -4E30≤G2≤0, -4E30≤G3≤0, -5000≤H1≤0, -5000≤H2≤0, -5000≤H3≤0, 1E12≤I≤1E32;

[0016] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient optical field measured by SIMS satisfies the Shah function, the Shah function is y4=J+K*x1+L*M^x1, where y4 is the In ion intensity distribution or In atom concentration of the waveguide layer in the gradient optical field measured by SIMS, and x1 is the thickness of the waveguide layer in the gradient optical field, wherein: -1E30≤J≤0, 3E12≤K≤3E32, 1E14≤L≤1E34, 0.0009≤M≤900.

[0017] Preferably, when the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the SIMS test under the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y5=N*exp(x2 / P)+Q, where y5 is the In ion intensity distribution or In atom concentration of the waveguide layer under the SIMS test under the gradient optical field, and x2 is the thickness of the waveguide layer under the gradient optical field, wherein: -2E34≤N≤0, 10≤P≤1000000, 2E14≤Q≤2E34;

[0018] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the SIMS test under the gradient optical field satisfies the ExpGro2 function, the ExpGro2 function is y6=R1*exp(x2 / S1)+ R2*exp(x2 / S2)+T, where y6 is the In ion intensity distribution or In atom concentration of the waveguide layer under the SIMS test under the gradient optical field, and x2 is the thickness of the waveguide layer under the gradient optical field, where: -2E32≤R1≤0, -2E32≤R2≤0, 0.01≤S1≤10000, 0.01≤S2≤10000, 2E12≤T≤2E32;

[0019] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the SIMS test under the gradient optical field satisfies the ExpGro3 function, the ExpGro3 function is y7=U1*exp(x2 / V1)+U2*exp(x2 / V2) + U3*exp(x2 / V3)+W, where y7 is the In ion intensity distribution or In atom concentration of the waveguide layer under the SIMS test under the gradient optical field, x2 is the thickness of the waveguide layer under the gradient optical field, and the values ​​are: -4E30≤U1≤0, -4E30≤U2≤0, -4E30≤U3≤0, 0.006≤V1≤600, 0.006≤V2≤600, 0.006≤V3≤600, 1E12≤W≤1E32;

[0020] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the gradient optical field meets the Shah function, the Shah function is y8=a+b*x2+c*d^x2, where y8 is the In ion intensity distribution or In atom concentration of the waveguide layer under the gradient optical field, x2 is the thickness of the waveguide layer under the gradient optical field, and y8 is the In ion intensity distribution or In atom concentration of the waveguide layer under the gradient optical field.

[0021] Preferably, when the fitting curve of the refractive index distribution of the waveguide layer in the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y9=f*exp(x1 / g)+h, where y9 is the refractive index of the waveguide layer in the gradient optical field, x1 is the thickness of the waveguide layer in the gradient optical field, and -7000000≤f≤0, -10000000≤g≤0, 60≤h≤6000000;

[0022] When the fitted curve of the refractive index distribution of the waveguide layer in the gradient optical field satisfies the Shah function, the Shah function is y 10 =j+k*x1+m*n^x1,y 10 Let x be the refractive index of the waveguide layer in the gradient optical field, and x1 be the thickness of the waveguide layer in the gradient optical field, where: 0.002≤j≤2000, 0.007≤k≤7000, 0.001≤m≤1000, and 0.000009≤n≤90.

[0023] Preferably, when the fitting curve of the refractive index distribution of the waveguide layer under the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y 11 =p*exp(x2 / q)+r,y 11 x2 is the refractive index of the waveguide layer under the gradient optical field, and x3 is the thickness of the waveguide layer under the gradient optical field, where: -800000≤p≤0, 10≤q≤1000000, 0.08≤r≤800000;

[0024] When the fitted curve of the refractive index distribution of the waveguide layer under the gradient optical field satisfies the Shah function, the Shah function is y 12 =s+t*x2+u*v^x2,y 12 x1 is the refractive index of the waveguide layer under the gradient optical field, and x2 is the thickness of the waveguide layer under the gradient optical field, where: 0.002≤s≤2000, -600≤t≤0, 10≤u≤10000, 7E-20≤v≤700.

[0025] Preferably, when the fitting curve of the optical absorption coefficient distribution of the waveguide layer on the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y 13 =A3*exp(x1 / B3)+C3, y 13 Let x1 be the light absorption coefficient of the waveguide layer in the gradient light field, and x1 be the thickness of the waveguide layer in the gradient light field, where: 9E3≤A3≤9E18, -10000000≤B3≤0, -9E18≤C3≤0;

[0026] When the fitted curve of the optical absorption coefficient distribution of the waveguide layer on the gradient optical field satisfies the Shah function, the Shah function is y 14=D3+F3*x1+G3*H3^x1,y 14 denoted as the optical absorption coefficient of the waveguide layer in the gradient optical field, and x1 as the thickness of the waveguide layer in the gradient optical field, wherein: 100≤D3≤10000000, -60000000≤F3≤0, -8000000≤G3≤0, 2E-12≤H3≤200.

[0027] Preferably, when the fitting curve of the optical absorption coefficient distribution of the waveguide layer under the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y 15 =J3*exp(x2 / K3)+L3, y 15 denoted as , where is the light absorption coefficient of the waveguide layer under a gradient light field, and x2 is the thickness of the waveguide layer under a gradient light field, where: 7E2≤J3≤7E17, 10≤K3≤1000000, -7E17≤L3≤0;

[0028] When the fitted curve of the optical absorption coefficient distribution of the waveguide layer under the gradient optical field satisfies the Shah function, the Shah function is y 16 =M3+N3*x2+P3*Q3^x2,y 16 denoted as M3, where M3 is the light absorption coefficient of the waveguide layer under a gradient light field, and x2 is the thickness of the waveguide layer under a gradient light field, wherein: 500≤M3≤50000000, 60≤N3≤6000000, 0.08≤P3≤8000000, and 0.00009≤Q3≤900.

[0029] Preferably, the substrate is a GaN single crystal substrate;

[0030] The lower waveguide layer is any one or any combination of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, and GaN.

[0031] The active layer is an InGaN / GaN quantum well;

[0032] The upper waveguide layer is any one or any combination of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, and GaN.

[0033] The electron blocking layer is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, and AlN.

[0034] Preferably, the lower waveguide layer is a combination of GaN and InGaN;

[0035] The upper waveguide layer is an InGaN / GaN combination;

[0036] The upper confinement layer is an AlGaN / AlGaN combination;

[0037] The electron blocking layer is AlGaN;

[0038] The lower confinement layer is an AlGaN / AlGaN or a combination of AlGaN / InGaN / AlGaN.

[0039] Preferably, the thickness of the lower waveguide layer is 300 angstroms to 8000 angstroms;

[0040] The thickness of the upper waveguide layer is 300 angstroms to 8000 angstroms;

[0041] The thickness of the upper confinement layer is 500 angstroms to 9000 angstroms;

[0042] The thickness of the electron blocking layer is from 5 angstroms to 800 angstroms.

[0043] The beneficial effects of the present invention are as follows: The lower waveguide layer of the gallium nitride-based semiconductor laser in the present invention includes a first lower waveguide layer and a second lower waveguide layer, and the second lower waveguide layer is a gradient optical field lower waveguide layer; the upper waveguide layer includes a first upper waveguide layer and a second upper waveguide layer, and the first upper waveguide layer is a gradient polarization upper waveguide layer. In this invention, the fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the refractive index distribution, and the fitting curve of the optical absorption coefficient distribution obtained by SIMS testing of the waveguide layer under a gradient optical field all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function, and Shah function. Similarly, the fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the refractive index distribution, and the fitting curve of the optical absorption coefficient distribution obtained by SIMS testing of the waveguide layer under a gradient optical field all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function, and Shah function. This allows for the synergistic control of optical field confinement, loss suppression, and carrier distribution, thereby regulating the optical field distribution of the laser. By fabricating a gradient refractive index waveguide layer that satisfies the correlation function distribution, photons generated by the active layer are confined within the optical waveguide, and the optical field is more gently confined within the waveguide layer, eliminating… The reflection and scattering losses caused by the abrupt interface refractive index difference reduce the penetration of the light field into the confinement layer, lowering optical leakage loss and threshold loss, and suppressing the excitation of higher-order transverse modes, achieving stable fundamental mode output, improving the laser's mode stability and beam quality factor, and reducing the horizontal divergence angle. Simultaneously, through precise control of the free carrier absorption coefficient, composition, and defect concentration, the light absorption coefficient of the waveguide layer satisfies the designed functional distribution, precisely matching the light field peak with the active layer thickness and position, allowing the light field peak to coincide with the active region, increasing the overlap factor between photons and carriers, improving stimulated emission efficiency, and reducing the probability of photons being absorbed by free carriers or defects, lowering the threshold current density, absorbing stray photons leaking into the waveguide layer, reducing stray photon interference on stimulated emission of the active layer, forming an optical field filter, further stabilizing the laser's fundamental mode output and intermode variations, and improving the laser's mode stability, focused beam resolution coherence, and beam quality factor. Attached Figure Description

[0044] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0045] Figure 1 This is a schematic diagram of the structure of a gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention;

[0046] Figure 2This is a SIMS secondary ion mass spectrum and a schematic diagram of x and y coordinates of a gallium nitride-based semiconductor laser with a gradient optical field waveguide layer as described in an embodiment of the present invention.

[0047] Figure 3 The image shows the SIMS secondary ion mass spectrum of the waveguide layer in the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention, and its ExpGro1 function fitting curve.

[0048] Figure 4 The image shows the SIMS secondary ion mass spectrum of the waveguide layer in the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention, and its ExpGro2 function fitting curve.

[0049] Figure 5 The image shows the SIMS secondary ion mass spectrum of the waveguide layer in the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention, and its ExpGro3 function fitting curve.

[0050] Figure 6 The image shows the SIMS secondary ion mass spectrum of the waveguide layer in the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention, and its Shah function fitting curve.

[0051] Figure 7 The image shows the SIMS secondary ion mass spectrum of the waveguide layer of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer under the gradient optical field, as described in the embodiments of the present invention, and its ExpGro1 function fitting curve.

[0052] Figure 8 The image shows the SIMS secondary ion mass spectrum of the waveguide layer of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer under a gradient optical field, as described in the embodiments of the present invention, and its ExpGro2 function fitting curve.

[0053] Figure 9 The image shows the SIMS secondary ion mass spectrum of the waveguide layer of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer under a gradient optical field, as described in the embodiments of the present invention, and its ExpGro3 function fitting curve.

[0054] Figure 10 The image shows the SIMS secondary ion mass spectrum of the waveguide layer and its Shah function fitting curve under the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention.

[0055] Figure 11The diagram shows the refractive index distribution of the waveguide layer in the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention, and its ExpGro1 function fitting curve.

[0056] Figure 12 The diagram shows the refractive index distribution of the waveguide layer in the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention, and its Shah function fitting curve.

[0057] Figure 13 The graph shows the optical absorption coefficient distribution of the waveguide layer in the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention, and its ExpGro1 function fitting curve.

[0058] Figure 14 The graph shows the optical absorption coefficient distribution of the waveguide layer in the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention, and its Shah function fitting curve.

[0059] Figure 15 The diagram shows the refractive index distribution of the waveguide layer and its ExpGro1 function fitting curve of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer as described in the embodiments of the present invention.

[0060] Figure 16 The diagram shows the refractive index distribution of the waveguide layer and its Shah function fitting curve under the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention.

[0061] Figure 17 The graph shows the distribution of the optical absorption coefficient of the waveguide layer and its ExpGro1 function fitting curve of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer under the gradient optical field according to the embodiments of the present invention.

[0062] Figure 18 The diagram shows the distribution of the optical absorption coefficient of the waveguide layer and its Shah function fitting curve under the gradient optical field of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to an embodiment of the present invention.

[0063] Figure label:

[0064] 100. Substrate; 101. Lower confinement layer; 102. Lower waveguide layer; 103. Active layer; 104. Upper waveguide layer; 105. Electron blocking layer; 106. Upper confinement layer; 107. Contact layer.

[0065] 102a, First lower waveguide layer; 102b, Second lower waveguide layer;

[0066] 104a, First upper waveguide layer; 104b, Second upper waveguide layer;

[0067] 106a, First upper confinement layer; 106b, Second upper confinement layer. Detailed Implementation

[0068] To make the technical solutions and advantages of the embodiments of this application clearer, the exemplary embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0069] like Figure 1 and Figure 2 As shown, this embodiment proposes a gallium nitride-based semiconductor laser with a gradient optical field waveguide layer, including a substrate 100, a lower confinement layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, an electron blocking layer 105, an upper confinement layer 106, and a contact layer 107 arranged sequentially from bottom to top.

[0070] Specifically, in this embodiment, the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer is provided from bottom to top with a substrate 100, a lower confinement layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, an electron blocking layer 105, an upper confinement layer 106, and a contact layer 107. The upper confinement layer 106 includes a first upper confinement layer 106a and a second upper confinement layer 106b, which are located below and above the electron blocking layer 105, respectively.

[0071] In this embodiment, the lower waveguide layer 102 includes a first lower waveguide layer 102a and a second lower waveguide layer 102b, with the first lower waveguide layer 102a located below the second lower waveguide layer 102b. The first lower waveguide layer 102a is GaN, and the second lower waveguide layer 102b is a gradient optical field lower waveguide layer. The upper waveguide layer 104 includes a first upper waveguide layer 104a and a second upper waveguide layer 104b, with the first upper waveguide layer 104a located below the second upper waveguide layer 104b. The first upper waveguide layer 104a is a gradient optical field upper waveguide layer, and the second upper waveguide layer 104b is GaN.

[0072] Both the waveguide layer above and below the gradient optical field exhibit the In ion intensity distribution or In atom concentration distribution characteristics, refractive index distribution characteristics, and optical absorption coefficient distribution characteristics as measured by SIMS. Specifically, they are as follows:

[0073] The fitting curves of In ion intensity distribution or In atom concentration distribution, refractive index distribution and optical absorption coefficient distribution of the waveguide layer in the gradient optical field by SIMS testing all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function and Shah function.

[0074] The fitting curves of In ion intensity distribution or In atom concentration distribution, refractive index distribution and optical absorption coefficient distribution of the waveguide layer under the SIMS test under the gradient optical field all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function and Shah function.

[0075] Specifically, in this embodiment, for the waveguide layer with a gradient optical field, the fitting curve of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the waveguide layer with a gradient optical field can be specifically represented as follows:

[0076] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS on a graded optical field satisfies the ExpGro1 function, the ExpGro1 function is y1=A*exp(x1 / B)+C, where y1 is the In ion intensity distribution or In atom concentration of the waveguide layer measured by SIMS on a graded optical field, and x1 is the thickness of the waveguide layer on the graded optical field, where -7E30≤A≤0, -4000000≤B≤0, and 7E14≤C≤7E34. Figure 3 As shown, when the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient optical field meets the ExpGro1 function, the ExpGro1 function can be y1=-6.96483E24*exp(x1 / -3377.62864)+6.96402E24.

[0077] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS on a graded optical field satisfies the ExpGro2 function, the ExpGro2 function is y2=D1*exp(x1 / E1)+ D2*exp(x1 / E2)+F, where y2 is the In ion intensity distribution or In atom concentration of the waveguide layer measured by SIMS on a graded optical field, and x1 is the thickness of the waveguide layer on a graded optical field, where -9E30≤D1≤0, -9E30≤D2≤0, -8000≤E1≤0, -8000≤E2≤0, and 2E12≤F≤2E32. Figure 4As shown, when the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS on the gradient optical field satisfies the ExpGro2 function, the ExpGro2 function can be y2=-9.72267E21*exp(x1 / -8.92879)+ (-9.72267E21)*exp(x1 / -8.92368)+1.86019E22.

[0078] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS on a graded optical field satisfies the ExpGro3 function, the ExpGro3 function is y3=G1*exp(x1 / H1)+ G2*exp(x1 / H2) + G3*exp(x1 / H3)+I, where y3 is the In ion intensity distribution or In atom concentration of the waveguide layer measured by SIMS on a graded optical field, and x1 is the thickness of the waveguide layer on a graded optical field, where: -4E30≤G1≤0, -4E30≤G2≤0, -4E30≤G3≤0, -5000≤H1≤0, -5000≤H2≤0, -5000≤H3≤0, 1E12≤I≤1E32. Figure 5 As shown, when the fitting curves of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS on the gradient optical field satisfy the ExpGro3 function, the ExpGro3 function can be y3=-4.26269E21*exp(x1 / -5.68625)+(-4.2626E21)*exp(x1 / -5.70813) + (-4.26263E21)*exp(x1 / -5.67361)+1.1928E22.

[0079] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS on a graded optical field satisfies the Shah function, the Shah function is y4=J+K*x1+L*M^x1, where y4 is the In ion intensity distribution or In atom concentration of the waveguide layer measured by SIMS on a graded optical field, and x1 is the thickness of the waveguide layer on the graded optical field, where: -1E30≤J≤0, 3E12≤K≤3E32, 1E14≤L≤1E34, 0.0009≤M≤900. Figure 6 As shown, when the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient light field meets the Shah function, the Shah function can be y4=-1.21596E24+3.18114E22*x1+1.21522E24*0.97553^x1.

[0080] In this embodiment, for the waveguide layer under a gradient optical field, the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under a gradient optical field measured by SIMS can be specifically represented as follows:

[0081] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under a graded optical field, measured by SIMS, satisfies the ExpGro1 function, the ExpGro1 function is y5=N*exp(x2 / P)+Q, where y5 is the In ion intensity distribution or In atom concentration of the waveguide layer under a graded optical field, and x2 is the thickness of the waveguide layer under a graded optical field, where: -2E34≤N≤0, 10≤P≤1000000, 2E14≤Q≤2E34. Figure 7 As shown, when the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the SIMS test under the gradient light field satisfies the ExpGro1 function, the ExpGro1 function can be y5=-2.68377E24*exp(x2 / 1208.64152)+2.68552E24.

[0082] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS under a gradient optical field satisfies the ExpGro2 function, the ExpGro2 function is y6=R1*exp(x2 / S1)+ R2*exp(x2 / S2)+T, where y6 is the In ion intensity distribution or In atom concentration of the waveguide layer measured by SIMS under a gradient optical field, and x2 is the thickness of the waveguide layer under a gradient optical field, where: -2E32≤R1≤0, -2E32≤R2≤0, 0.01≤S1≤10000, 0.01≤S2≤10000, 2E12≤T≤2E32. Figure 8 As shown, when the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the SIMS test under the gradient light field satisfies the ExpGro2 function, the ExpGro2 function can be y6=-1.2054E22*exp(x2 / 11.53152)+(-1.20539E22)*exp(x2 / 11.52375)+2.58181E22.

[0083] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS under a gradient optical field satisfies the ExpGro3 function, the ExpGro3 function is y7=U1*exp(x2 / V1)+U2*exp(x2 / V2) + U3*exp(x2 / V3)+W, where y7 is the In ion intensity distribution or In atom concentration of the waveguide layer measured by SIMS under a gradient optical field, and x2 is the thickness of the waveguide layer under a gradient optical field, where: -4E30≤U1≤0, -4E30≤U2≤0, -4E30≤U3≤0, 0.006≤V1≤600, 0.006≤V2≤600, 0.006≤V3≤600, 1E12≤W≤1E32. Figure 9 As shown, when the fitting curves of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the SIMS test in the gradient optical field satisfy the ExpGro3 function, the ExpGro3 function can be y7=-4.50823E21*exp(x2 / 6.74404)+-4.50815E21*exp(x2 / 6.72844)+(-4.50808E21)*exp(x2 / 6.77793)+1.52034E22.

[0084] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS under a gradient optical field satisfies the Shah function, the Shah function is y8=a+b*x2+c*d^x2, where y8 is the In ion intensity distribution or In atom concentration of the waveguide layer measured by SIMS under a gradient optical field, and x2 is the thickness of the waveguide layer under a gradient optical field, where: 1E11≤a≤1E31, -2E30≤b≤0, -3E30≤c≤0, 0.0009≤d≤900. Figure 10 As shown, when the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the SIMS test under the gradient light field satisfies the Shah function, the Shah function can be y8=1.79198E21+(-2.22179E21)*x2+(-3.61233E19)*0.99921^x2.

[0085] In this embodiment, the fitting curve for the refractive index distribution of the waveguide layer in the gradient optical field can be specifically represented as follows:

[0086] When the fitted curve of the refractive index distribution of the waveguide layer in the graded optical field satisfies the ExpGro1 function, the ExpGro1 function is y9=f*exp(x1 / g)+h, where y9 is the refractive index of the waveguide layer in the graded optical field, x1 is the thickness of the waveguide layer in the graded optical field, and -7000000≤f≤0, -10000000≤g≤0, 60≤h≤6000000. Figure 11As shown, when the fitting curve of the refractive index distribution of the waveguide layer in the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function can be y9=-6891.13542*exp(x1 / -10502.41929)+6893.17571.

[0087] When the fitted curve of the refractive index distribution of the waveguide layer in a graded optical field satisfies the Shah function, the Shah function is y. 10 =j+k*x1+m*n^x1,y 10 Let be the refractive index of the waveguide layer in the graded optical field, and x1 be the thickness of the waveguide layer in the graded optical field, where: 0.002≤j≤2000, 0.007≤k≤7000, 0.001≤m≤1000, 0.000009≤n≤90. Figure 12 As shown, when the fitted curve of the refractive index distribution of the waveguide layer in the gradient optical field satisfies the Shah function, the Shah function is y. 10 =2.0031+0.70891*x1+0.10772*0.00945^x1.

[0088] In this embodiment, the fitting curve for the optical absorption coefficient distribution of the waveguide layer on the gradient optical field can be specifically represented as follows:

[0089] When the fitted curve of the optical absorption coefficient distribution of the waveguide layer in a graded optical field satisfies the ExpGro1 function, the ExpGro1 function is y. 13 =A3*exp(x1 / B3)+C3, y 13 Let x be the light absorption coefficient of the waveguide layer in the graded light field, and x1 be the thickness of the waveguide layer in the graded light field, where: 9E3≤A3≤9E18, -10000000≤B3≤0, -9E18≤C3≤0. For example... Figure 13 As shown, when the fitted curve of the optical absorption coefficient distribution of the waveguide layer in the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y. 13 =9.29206E8*exp(x1 / -14161.71539)+(-9.2908E8).

[0090] When the fitted curve of the optical absorption coefficient distribution of the waveguide layer in a graded optical field satisfies the Shah function, the Shah function is y. 14 =D3+F3*x1+G3*H3^x1,y 14 Let be the optical absorption coefficient of the waveguide layer in the graded optical field, and x1 be the thickness of the waveguide layer in the graded optical field, where: 100≤D3≤10000000, -60000000≤F3≤0, -8000000≤G3≤0, 2E-12≤H3≤200. For example... Figure 14As shown, when the fitting curve of the optical absorption coefficient distribution of the waveguide layer in the gradient optical field satisfies the Shah function, this Shah function can be y 14 =127023.74438+(-67465.39319)*x1+(-89264.64386)*(1.20033E-6)^x1.

[0091] In this embodiment, the fitting curve for the refractive index distribution of the waveguide layer under a gradient optical field can be specifically represented as follows:

[0092] When the fitted curve of the refractive index distribution of the waveguide layer under a graded optical field satisfies the ExpGro1 function, the ExpGro1 function is y. 11 =p*exp(x2 / q)+r,y 11 Let be the refractive index of the waveguide layer under a graded optical field, and x2 be the thickness of the waveguide layer under a graded optical field, where: -800000≤p≤0, 10≤q≤1000000, 0.08≤r≤800000. Figure 15 As shown, when the fitted curve of the refractive index distribution of the waveguide layer under a gradient optical field satisfies the ExpGro1 function, this ExpGro1 function can be y 11 =-807.74679*exp(x2 / 1282.694)+810.54461.

[0093] When the fitted curve of the refractive index distribution of the waveguide layer under a graded optical field satisfies the Shah function, the Shah function is y. 12 =s+t*x2+u*v^x2,y 12 Let be the refractive index of the waveguide layer under a graded optical field, and x2 be the thickness of the waveguide layer under a graded optical field, where: 0.002≤s≤2000, -600≤t≤0, 10≤u≤10000, 7E-20≤v≤700. Figure 16 As shown, when the fitted curve of the refractive index distribution of the waveguide layer under a gradient optical field satisfies the Shah function, the Shah function is y. 12 =2.78337+(-0.61078)*x2+1380.34724*(7.82103E-10)^x2.

[0094] In this embodiment, the fitting curve for the optical absorption coefficient distribution of the waveguide layer under a gradient optical field can be specifically represented as follows:

[0095] When the fitted curve of the optical absorption coefficient distribution of the waveguide layer under a gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y. 15 =J3*exp(x2 / K3)+L3, y 15Let be the optical absorption coefficient of the waveguide layer under a graded optical field, and x2 be the thickness of the waveguide layer under a graded optical field, where: 7E2≤J3≤7E17, 10≤K3≤1000000, -7E17≤L3≤0. Figure 17 As shown, when the fitted curve of the optical absorption coefficient distribution of the waveguide layer under a gradient optical field satisfies the ExpGro1 function, this ExpGro1 function can be y 15 =7.88469E7*exp(x2 / 1252.09754)+(-7.87967E7).

[0096] When the fitted curve of the optical absorption coefficient distribution of the waveguide layer under a graded optical field satisfies the Shah function, the Shah function is y. 16 =M3+N3*x2+P3*Q3^x2,y 16 Let M be the optical absorption coefficient of the waveguide layer under a graded optical field, and x2 be the thickness of the waveguide layer under a graded optical field, where: 500≤M3≤50000000, 60≤N3≤6000000, 0.08≤P3≤8000000, 0.00009≤Q3≤900. Figure 18 As shown, when the fitted curve of the optical absorption coefficient distribution of the waveguide layer under a gradient optical field satisfies the Shah function, this Shah function can be y 16 =49344.35282+63007.60196*x2+861.28003*0.99924^x2.

[0097] In this embodiment, the lower waveguide layer 102 of the gallium nitride-based semiconductor laser includes a first lower waveguide layer 102a and a second lower waveguide layer 102b, and the second lower waveguide layer 102b is a gradient optical field lower waveguide layer. The upper waveguide layer 104 includes a first upper waveguide layer 104a and a second upper waveguide layer 104b, and the first upper waveguide layer 104a is a gradient polarization upper waveguide layer 104. In this invention, the fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the refractive index distribution, and the fitting curve of the optical absorption coefficient distribution obtained by SIMS testing of the waveguide layer under a gradient optical field all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function, and Shah function. Similarly, the fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the refractive index distribution, and the fitting curve of the optical absorption coefficient distribution obtained by SIMS testing of the waveguide layer under a gradient optical field all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function, and Shah function. This allows for the synergistic control of optical field confinement, loss suppression, and carrier distribution, thereby regulating the optical field distribution of the laser. By fabricating a gradient refractive index waveguide layer that satisfies the correlation function distribution, photons generated by the active layer 103 are confined within the optical waveguide, and the optical field is more smoothly confined within the waveguide layer, eliminating abrupt changes. The reflection and scattering losses caused by the varying refractive index difference at the interface reduce the penetration of the light field into the confinement layer, lowering optical leakage loss and threshold loss, and suppressing the excitation of higher-order transverse modes, achieving stable output of the fundamental mode, improving the mode stability and beam quality factor of the laser, and reducing the horizontal divergence angle. Simultaneously, by precisely controlling the absorption coefficient of free carriers, its composition, and defect concentration, the light absorption coefficient of the waveguide layer satisfies the designed functional distribution, accurately matching the peak of the light field with the thickness and position of the active layer 103, allowing the peak of the light field to coincide with the active region, improving the overlap factor between photons and carriers, improving stimulated emission efficiency, and reducing the probability of photons being absorbed by free carriers or defects, lowering the threshold current density, absorbing stray photons leaking into the waveguide layer, reducing the interference of stray photons on stimulated emission of the active layer 103, forming light field filtering, further stabilizing the fundamental mode output and intermode variation of the laser, and improving the mode stability, focused spot resolution coherence, and beam quality factor of the laser.

[0098] In some alternative embodiments, the substrate 100 is a GaN single crystal substrate 100;

[0099] The lower waveguide layer 102 is any one or any combination of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, and GaN;

[0100] The active layer 103 is an InGaN / GaN quantum well;

[0101] The upper waveguide layer 104 is any one or any combination of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, and GaN;

[0102] The electron blocking layer 105 is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, and AlN.

[0103] In some alternative embodiments, the lower waveguide layer 102 is a combination of GaN and InGaN;

[0104] The upper waveguide layer 104 is an InGaN / GaN combination;

[0105] The upper confinement layer 106 is an AlGaN / AlGaN combination;

[0106] Electron blocking layer 105 is AlGaN;

[0107] The lower confinement layer 101 is an AlGaN / AlGaN or a combination of AlGaN / InGaN / AlGaN.

[0108] In some alternative embodiments, the thickness of the lower waveguide layer 102 is from 300 angstroms to 8000 angstroms;

[0109] The thickness of the upper waveguide layer 104 is 300 angstroms to 8000 angstroms;

[0110] The thickness of the upper confinement layer 106 is 500 angstroms to 9000 angstroms;

[0111] The thickness of the electron blocking layer 105 ranges from 5 angstroms to 800 angstroms.

[0112] The table below compares the performance of the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer proposed in this embodiment with that of a conventional laser, mainly through comparisons of beam quality factor, focused spot resolution, horizontal divergence angle, and threshold current:

[0113] Traditional lasers Laser in this embodiment range of change <![CDATA[Beam quality factor M 2 > 1.56 1.03 51% Focused spot resolution (nm) >100 <15 Horizontal divergence angle 18~40° 5~18° Threshold current (mA) 425 306 -28%

[0114] As can be seen from the table above, the gallium nitride-based semiconductor laser with a gradient optical field waveguide layer proposed in this embodiment improves the beam quality factor and reduces the threshold current compared with traditional lasers. It also shows significant improvements in focused beam resolution and horizontal divergence angle, and its performance is significantly better than that of traditional lasers.

[0115] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A gallium nitride-based semiconductor laser with a gradient optical field waveguide layer, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, a first upper confinement layer, an electron blocking layer, a second upper confinement layer, and a contact layer, characterized in that, The lower waveguide layer includes a first lower waveguide layer and a second lower waveguide layer, with the first lower waveguide layer located below the second lower waveguide layer. The first lower waveguide layer is made of GaN, and the second lower waveguide layer is a gradient optical field lower waveguide layer. The upper waveguide layer includes a first upper waveguide layer and a second upper waveguide layer, with the first upper waveguide layer located below the second upper waveguide layer. The first upper waveguide layer is a gradient optical field upper waveguide layer, and the second upper waveguide layer is made of GaN. The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the refractive index distribution, and the fitting curve of the optical absorption coefficient distribution of the waveguide layer in the gradient optical field under SIMS testing all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function, and Shah function. The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the refractive index distribution, and the fitting curve of the optical absorption coefficient distribution of the waveguide layer under the gradient optical field under SIMS testing all satisfy any one of the ExpGro1 function, ExpGro2 function, ExpGro3 function, and Shah function.

2. The gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to claim 1, characterized in that, When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient optical field measured by SIMS satisfies the ExpGro1 function, the ExpGro1 function is y1=A*exp(x1 / B)+C, where y1 is the In ion intensity distribution or In atom concentration of the waveguide layer in the gradient optical field measured by SIMS, and x1 is the thickness of the waveguide layer in the gradient optical field, where -7E30≤A≤0, -4000000≤B≤0, and 7E14≤C≤7E34; When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient optical field measured by SIMS satisfies the ExpGro2 function, the ExpGro2 function is y2=D1*exp(x1 / E1)+ D2*exp(x1 / E2)+F, where y2 is the In ion intensity distribution or In atom concentration of the waveguide layer in the gradient optical field measured by SIMS, x1 is the thickness of the waveguide layer in the gradient optical field, and -9E30≤D1≤0, -9E30≤D2≤0, -8000≤E1≤0, -8000≤E2≤0, 2E12≤F≤2E32; When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient optical field measured by SIMS satisfies the ExpGro3 function, the ExpGro3 function is y3=G1*exp(x1 / H1)+ G2*exp(x1 / H2) + G3*exp(x1 / H3)+I, where y3 is the In ion intensity distribution or In atom concentration of the waveguide layer in the gradient optical field measured by SIMS, and x1 is the thickness of the waveguide layer in the gradient optical field, where: -4E30≤G1≤0, -4E30≤G2≤0, -4E30≤G3≤0, -5000≤H1≤0, -5000≤H2≤0, -5000≤H3≤0, 1E12≤I≤1E32; When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer in the gradient optical field measured by SIMS satisfies the Shah function, the Shah function is y4=J+K*x1+L*M^x1, where y4 is the In ion intensity distribution or In atom concentration of the waveguide layer in the gradient optical field measured by SIMS, and x1 is the thickness of the waveguide layer in the gradient optical field, wherein: -1E30≤J≤0, 3E12≤K≤3E32, 1E14≤L≤1E34, 0.0009≤M≤900.

3. The gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to claim 1, characterized in that, When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the gradient optical field meets the ExpGro1 function, the ExpGro1 function is y5=N*exp(x2 / P)+Q, where y5 is the In ion intensity distribution or In atom concentration of the waveguide layer under the gradient optical field, x2 is the thickness of the waveguide layer under the gradient optical field, and -2E34≤N≤0, 10≤P≤1000000, 2E14≤Q≤2E34; When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the SIMS test under the gradient optical field satisfies the ExpGro2 function, the ExpGro2 function is y6=R1*exp(x2 / S1)+ R2*exp(x2 / S2)+T, where y6 is the In ion intensity distribution or In atom concentration of the waveguide layer under the SIMS test under the gradient optical field, and x2 is the thickness of the waveguide layer under the gradient optical field, where: -2E32≤R1≤0, -2E32≤R2≤0, 0.01≤S1≤10000, 0.01≤S2≤10000, 2E12≤T≤2E32; When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the SIMS test under the gradient optical field satisfies the ExpGro3 function, the ExpGro3 function is y7=U1*exp(x2 / V1)+U2*exp(x2 / V2) + U3*exp(x2 / V3)+W, where y7 is the In ion intensity distribution or In atom concentration of the waveguide layer under the SIMS test under the gradient optical field, x2 is the thickness of the waveguide layer under the gradient optical field, and the values ​​are: -4E30≤U1≤0, -4E30≤U2≤0, -4E30≤U3≤0, 0.006≤V1≤600, 0.006≤V2≤600, 0.006≤V3≤600, 1E12≤W≤1E32; When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the gradient optical field meets the Shah function, the Shah function is y8=a+b*x2+c*d^x2, where y8 is the In ion intensity distribution or In atom concentration of the waveguide layer under the gradient optical field, x2 is the thickness of the waveguide layer under the gradient optical field, and y8 is the In ion intensity distribution or In atom concentration of the waveguide layer under the gradient optical field.

4. The gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to claim 1, characterized in that, When the fitting curve of the refractive index distribution of the waveguide layer in the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y9=f*exp(x1 / g)+h, where y9 is the refractive index of the waveguide layer in the gradient optical field, x1 is the thickness of the waveguide layer in the gradient optical field, and -7000000≤f≤0, -10000000≤g≤0, 60≤h≤6000000; When the fitted curve of the refractive index distribution of the waveguide layer in the gradient optical field satisfies the Shah function, the Shah function is y 10 =j+k*x1+m*n^x1,y 10 Let x be the refractive index of the waveguide layer in the gradient optical field, and x1 be the thickness of the waveguide layer in the gradient optical field, where: 0.002≤j≤2000, 0.007≤k≤7000, 0.001≤m≤1000, and 0.000009≤n≤90.

5. The gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to claim 1, characterized in that, When the fitted curve of the refractive index distribution of the waveguide layer under the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y 11 =p*exp(x2 / q)+r,y 11 x2 is the refractive index of the waveguide layer under the gradient optical field, and x3 is the thickness of the waveguide layer under the gradient optical field, where: -800000≤p≤0, 10≤q≤1000000, 0.08≤r≤800000; When the fitted curve of the refractive index distribution of the waveguide layer under the gradient optical field satisfies the Shah function, the Shah function is y 12 =s+t*x2+u*v^x2,y 12 x1 is the refractive index of the waveguide layer under the gradient optical field, and x2 is the thickness of the waveguide layer under the gradient optical field, where: 0.002≤s≤2000, -600≤t≤0, 10≤u≤10000, 7E-20≤v≤700.

6. The gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to claim 1, characterized in that, When the fitted curve of the optical absorption coefficient distribution of the waveguide layer on the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y 13 =A3*exp(x1 / B3)+C3, y 13 Let x1 be the light absorption coefficient of the waveguide layer in the gradient light field, and x1 be the thickness of the waveguide layer in the gradient light field, where: 9E3≤A3≤9E18, -10000000≤B3≤0, -9E18≤C3≤0; When the fitted curve of the optical absorption coefficient distribution of the waveguide layer on the gradient optical field satisfies the Shah function, the Shah function is y 14 =D3+F3*x1+G3*H3^x1,y 14 denoted as the optical absorption coefficient of the waveguide layer in the gradient optical field, and x1 as the thickness of the waveguide layer in the gradient optical field, wherein: 100≤D3≤10000000, -60000000≤F3≤0, -8000000≤G3≤0, 2E-12≤H3≤200.

7. The gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to claim 1, characterized in that, When the fitted curve of the optical absorption coefficient distribution of the waveguide layer under the gradient optical field satisfies the ExpGro1 function, the ExpGro1 function is y 15 =J3*exp(x2 / K3)+L3, y 15 denoted as , where is the light absorption coefficient of the waveguide layer under a gradient light field, and x2 is the thickness of the waveguide layer under a gradient light field, where: 7E2≤J3≤7E17, 10≤K3≤1000000, -7E17≤L3≤0; When the fitted curve of the optical absorption coefficient distribution of the waveguide layer under the gradient optical field satisfies the Shah function, the Shah function is y 16 =M3+N3*x2+P3*Q3^x2,y 16 denoted as M3, where M3 is the light absorption coefficient of the waveguide layer under a gradient light field, and x2 is the thickness of the waveguide layer under a gradient light field, wherein: 500≤M3≤50000000, 60≤N3≤6000000, 0.08≤P3≤8000000, and 0.00009≤Q3≤900.

8. The gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to claim 1, characterized in that, The substrate is a GaN single crystal substrate; The lower waveguide layer is any one or any combination of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, and GaN. The active layer is an InGaN / GaN quantum well; The upper waveguide layer is any one or any combination of InGaN, GaN / InGaN, GaN / InGaN / GaN, InGaN / GaN, and GaN. The electron blocking layer is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, and AlN.

9. The gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to claim 1, characterized in that, The lower waveguide layer is a combination of GaN / InGaN; The upper waveguide layer is an InGaN / GaN combination; The upper confinement layer is an AlGaN / AlGaN combination; The electron blocking layer is AlGaN.

10. The gallium nitride-based semiconductor laser with a gradient optical field waveguide layer according to claim 1, characterized in that, The thickness of the lower waveguide layer ranges from 300 angstroms to 8000 angstroms; The thickness of the upper waveguide layer is 300 angstroms to 8000 angstroms; The thickness of the upper confinement layer is 500 angstroms to 9000 angstroms; The thickness of the electron blocking layer is from 5 angstroms to 800 angstroms.

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