A semiconductor laser device based on a tilted grating and a method of manufacturing the same

Abstract

This invention discloses a semiconductor laser device based on a tilted grating and its fabrication method. In the fabrication of the semiconductor laser's optical waveguide grating, the tilt angle of the waveguide grating is controlled by adjusting the waveguide tilt angle, forming a tilted grating composed of a tilted seed grating and a tilted sampling structure. A phase-shifting structure is introduced into the tilted grating, and phase matching of the laser resonator cavity at the phase-shifting structure is achieved through microstructure quasi-phase matching technology. Single-wavelength lasing output of a laser at a specific wavelength is formed by energizing a single electrode. This invention provides a laser source with precise wavelength control, simple structure, low power consumption, and high integration.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more specifically to a semiconductor laser device based on a tilted grating and its fabrication method. Background Technology

[0002] Distributed feedback (DFB) lasers with uniform Bragg gratings have been widely used in communication and sensing fields due to their advantages such as single longitudinal mode and low threshold voltage. However, the fabrication of fine micro- and nano-structures in the grating region of DFB lasers heavily relies on high-precision photolithography techniques, such as phase-shifting regions and chirped gratings. Electron beam lithography provides a feasible method for these requirements, but it also suffers from problems such as splicing errors and long manufacturing times. To reduce the fabrication cost of Bragg gratings and improve phase-shift control accuracy, the reconstructed equivalent chirp (REC) technique has been proposed, which involves designing the period of the sampling grating to control the Bragg wavelength. This technique fabricates one-dimensional sampling structures using micrometer-scale photolithography and has been widely applied in multi-wavelength source DFB lasers, laser arrays, and microwave photonics. To date, research and applications of two-dimensional sampling structures for DFB lasers are limited, representing a promising area for further exploration.

[0003] Compared to traditional reconstruction equivalent chirp techniques based on one-dimensional sampling structures, two-dimensional schemes offer greater flexibility in optimizing wavelength selection performance, going beyond simply adjusting the sampling period on a one-dimensional scale. While two-dimensional sampling grating designs based on MSQPM technology have been proposed for some time, they have not yet been widely applied in the field of DFB lasers. Therefore, realizing DFB lasers based on two-dimensional gratings is of great significance. Tilted Bragg gratings are a typical two-dimensional structure, with their grating plane at an angle to the waveguide's longitudinal axis. They have been extensively studied in polarizers, fiber lasers, optical sensing, and mode converters. Composed of uniform Bragg gratings, a two-dimensional sampling structure, namely the tilted sampling Bragg grating, has been proposed to meet the requirements of changing the propagation path in photonic integration. To meet the requirements of multi-wavelength lasers, partially tilted gratings and tilted sampling structure lasers with the same angle have been implemented. However, the tilted sampling grating in the middle section only serves to control the grating phase shift or period. Furthermore, this design greatly limits the flexibility of tilted sampling grating design, and its drawbacks ultimately manifest in the threshold current. Meanwhile, with the development of photonic integration and silicon-based electrical technology, various requirements have been put forward for the design of on-chip light sources. However, the design of traditional DBF lasers based on equivalent reconstructed chirp only focuses on one-dimensional structures. Therefore, research on tilted structures needs to be further carried out. At present, there is a lack of a light source based on tilted gratings that has high integration, simple structure, and low power consumption. Summary of the Invention

[0004] The purpose of this invention is to address the problems raised in the background art by providing a semiconductor laser device based on a tilted grating that can achieve precise wavelength control, has a simple structure, low power consumption, and high integration, as well as a method for fabricating the same.

[0005] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0006] A semiconductor laser device based on a tilted grating, wherein the waveguide grating of the semiconductor laser is a tilted grating composed of a tilted seed grating and a tilted sampling structure; the tilted grating has a phase-shifting structure, and the laser resonator cavity is phase-matched at the phase-shifting structure by a microstructure quasi-phase-matching technique.

[0007] The tilted seed grating of the tilted grating is tilted and has a uniform period, and the tilt angle is determined by the waveguide tilt angle; the tilt angle of the tilted grating is less than 7 degrees; the lasing wavelength control and wavelength interval selection are achieved by controlling the equivalent period change of the tilted sampling structure.

[0008] The tilted grating contains multiple shadow gratings, with one of the shadow gratings serving as the target equivalent grating. Through microstructure quasi-phase matching technology, the target equivalent grating becomes a uniform grating whose grating vector direction is consistent with the propagation of the light wave, and the wave vector direction corresponding to the target equivalent grating is the same as the optical waveguide direction of the laser.

[0009] The semiconductor laser is composed of a substrate, a buffer layer, a lower confinement layer, a multiple quantum well layer, an upper confinement layer, a grating layer, a buried layer, an etch barrier layer, a waveguide layer, and a contact layer stacked from bottom to top. The grating layer is composed of a tilted grating.

[0010] The semiconductor laser uses a multi-quantum well layer as the gain medium; the tilted grating wavelength is located near the center of the gain bandwidth; the substrate is an n-type doped substrate; the lower confinement layer is a confinement layer composed of n-type doping and undoped layers; and the multi-quantum well layer is an InGaAlAs multi-quantum well.

[0011] A method for fabricating a semiconductor laser device based on a tilted grating includes the following steps:

[0012] In the fabrication of optical waveguide gratings for semiconductor lasers, the tilt angle of the optical waveguide grating is controlled by controlling the waveguide tilt angle, forming a tilted grating composed of a tilted seed grating and a tilted sampling structure.

[0013] A phase-shifting structure is introduced into the tilted grating, and the laser resonator at the phase-shifting structure is phase-matched by microstructure quasi-phase matching technology. A single-wavelength laser is generated by energizing a single electrode to produce a single-wavelength laser output.

[0014] The aforementioned method of introducing a phase-shift structure into a tilted grating and achieving phase matching of the laser resonator cavity at the phase-shift structure using microstructure quasi-phase matching technology specifically involves:

[0015] The grating structure of the optical waveguide of the semiconductor laser is divided into two segments, and a phase shift structure is introduced between the two segments. The phase shift structure is located in the middle of the grating region of the tilted grating. The structural parameters of the phase shift structure are designed using microstructure quasi-phase matching technology so that the laser resonator at the phase shift point achieves the phase matching condition and realizes stable single-mode output.

[0016] Using a shadow grating in a tilted grating as the target equivalent grating, the target equivalent grating is made into a uniform grating with the grating vector direction consistent with the light wave propagation through microstructure quasi-phase matching technology, and the wave vector direction corresponding to the target equivalent grating is the same as the optical waveguide direction of the laser; by controlling the sampling pattern and shape to change the refractive index distribution of the target equivalent grating, the tilted refractive index modulation period and intensity of the equivalent target grating are adjusted, and the refractive index distribution of the equivalent target grating is obtained according to Fourier analysis.

[0017] The tilted sampling structure is based on a tilted seed grating and designed using semiconductor photolithography technology, employing tilted refractive index modulation. The formula is expressed as follows:

[0018]

[0019] Where Δn represents the basic grating refractive index modulation. C represents the spatial location of the sampling structure. m Represented as Fourier coefficients, where m is the Fourier series; seed grating and sampling structure The vector satisfies and in and Let Λ0 represent the period of the seed grating, and Λ represent the unit direction vector. S The period of the sampling structure is represented by j, exp, and cc, which represent the imaginary part.

[0020] Positive Level 1 Shadow Raster Seed grating With sampling structure The vector relationship is represented as follows:

[0021]

[0022] The fabrication of a semiconductor laser device specifically includes the following steps:

[0023] A buffer layer and a lower confinement layer are sequentially grown on a substrate by metal-organic compound vapor deposition. A multi-quantum well layer is grown on the lower confinement layer, and an upper confinement layer is grown on the multi-quantum well layer. A tilted grating with a tilted seed grating and a tilted sampling structure is deposited above the upper confinement layer as a grating layer.

[0024] A phase-shifting structure is introduced into the tilted sampling grating of the tilted grating. The tilt angle and sampling period of the tilted sampling grating with the introduced phase-shifting structure are controlled by the microstructure quasi-phase matching technology to achieve phase matching.

[0025] A buried layer is grown above the grating layer, and a corrosion barrier layer, a waveguide layer, and a contact layer are grown sequentially on the buried layer.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] This invention utilizes reconstructed equivalent chirp technology combined with microstructure quasi-phase matching technology (MSPQM) to fabricate a tilted grating with a phase shift structure, so that the laser resonator cavity at the phase shift structure achieves phase matching, thereby obtaining a stable single-wavelength laser output of a specific wavelength.

[0028] By adopting a tilted sampling structure to increase the bandgap and Bragg wavelength group delay, optical feedback is enhanced and the threshold current of laser lasing is reduced. A phase shift structure is introduced in the center of the overall tilted grating to achieve stable lasing of a single wavelength at the phase shift position, avoiding the introduction of higher-order modes that increase losses and ensuring the normal operation of the laser.

[0029] The laser of this invention employs a tilted grating and tilted sampling structure. The period and tilt angle of the tilted sampling structure are adjusted and adapted according to the tilt angle and period of the seed grating, thereby enhancing grating feedback, increasing the bandgap of the laser, and precisely controlling the lasing wavelength. The entire grating structure is divided into two segments, and a phase shift is introduced between the two segments. The grating structure is identical between each segment, and the laser resonator at the phase shift point achieves phase matching conditions, realizing single-mode output. Each laser uses a single electrode for power application, and all phase shift points share a single laser resonator, achieving single-wavelength output.

[0030] The wavelengths of each output light wave in this invention can be controlled by the angle and period of the sampling structure, and the wavelength interval is designed using microstructure quasi-phase matching technology; the threshold of the tilted grating laser can be reduced and single-wavelength operation can be achieved by a single laser, realizing precise wavelength output of a single laser, which can reduce the threshold of the laser and optimize the wavelength selection characteristics.

[0031] This invention provides a laser light source with features such as precise wavelength control, simple structure, low power consumption, and high integration, offering another option for integrated optical light source design. Attached Figure Description

[0032] Figure 1This is a schematic diagram of the phase matching condition of the semiconductor laser grating based on the tilted grating of the present invention, where K0 is the seed grating vector, K s Let G be the vector of the sampling structure, α be the sampling tilt angle, β be the seed grating tilt angle, and G be the sampling grating vector.

[0033] Figure 2 This is a schematic diagram of the laser seed grating and sampling structure based on the tilted grating of the present invention.

[0034] Figure 3 This is a schematic diagram of the semiconductor laser structure based on a tilted grating according to the present invention.

[0035] Figure 4 The image shows the actual spectrum of the 5-channel laser in the embodiment, where 401 is the first wavelength lasing peak, 402 is the second wavelength lasing peak, 403 is the third wavelength lasing peak, 404 is the fourth wavelength lasing peak, and 405 is the fifth wavelength lasing peak. Detailed Implementation

[0036] The present invention will be further described in detail below through embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0037] This invention provides a semiconductor laser device based on a tilted grating. The waveguide grating of the semiconductor laser is a tilted grating composed of a tilted seed grating and a tilted sampling structure. The tilted grating has a phase-shifting structure, and the laser resonator cavity achieves phase matching at the phase-shifting structure through microstructure quasi-phase matching technology.

[0038] The grating structure of the semiconductor laser of the present invention adopts a tilted grating. The period and tilt angle of the tilted sampling structure are adjusted and adapted according to the tilt angle and period of the tilted seed grating, thereby enhancing grating feedback, increasing the bandgap of the laser, and precisely controlling the lasing wavelength.

[0039] The seed waveguide grating within the tilted grating is tilted and has a uniform period, with the tilt angle determined by the waveguide tilt angle. The overall grating exhibits uniform period and equal tilt angle within the laser cavity. Laser wavelength control and wavelength spacing selection are achieved by controlling the equivalent period variation of the tilted sampling structure.

[0040] In some implementations, the tilt angle of the tilt grating is less than 7 degrees to ensure compatibility with existing semiconductor laser fabrication processes. This invention controls the angle of the equivalent tilted seed grating by controlling the waveguide tilt angle, thereby enabling the fabrication of a tilted sampling grating using existing tilted sampling structure fabrication processes.

[0041] The tilted grating contains multiple shadow gratings, with one of the shadow gratings serving as the target equivalent grating. Through microstructure quasi-phase matching technology, the target equivalent grating becomes a uniform grating whose grating vector direction is consistent with the propagation of the light wave, making the laser equivalent to a distributed feedback (DFB) laser. The wave vector direction corresponding to the target equivalent grating is the same as the optical waveguide direction of the laser. A positive or negative first-order shadow grating can be selected as the target equivalent grating.

[0042] In some implementations, the semiconductor laser is composed of, from bottom to top, a substrate, a buffer layer, a lower confinement layer, a multiple quantum well layer, an upper confinement layer, a grating layer, an InP layer, an etching barrier layer, a waveguide layer, and a contact layer, wherein the grating layer is composed of a tilted grating.

[0043] The quantum well layer, as a gain medium, encompasses the operating wavelength range of the tilted grating-based semiconductor laser device. The tilted grating wavelength is located near the center of the gain bandwidth to improve output power.

[0044] The substrate is an n-type doped substrate, the lower confinement layer is a confinement layer composed of n-type doped and undoped layers, and the multi-quantum well layer is an InGaAlAs multi-quantum well.

[0045] By using microstructure quasi-phase matching technology and reconstructed equivalent chirp technology to fabricate tilted gratings, the threshold current of the laser is reduced and the wavelength selectivity is optimized, thereby improving the group delay of the grating structure to reduce the threshold current.

[0046] The present invention also provides a method for fabricating a semiconductor laser device based on a tilted grating, comprising the following steps:

[0047] To fabricate an optical waveguide grating for a semiconductor laser, the tilt angle of the optical waveguide grating is controlled by controlling the waveguide tilt angle, forming a tilted grating composed of a tilted seed grating and a tilted sampling structure.

[0048] A phase-shifting structure is introduced into the tilted grating, and the laser resonator at the phase-shifting structure is phase-matched by microstructure quasi-phase matching technology. A single-wavelength laser is generated by energizing a single electrode to produce a single-wavelength laser output.

[0049] When a phase-shifting structure is introduced, the grating structure of the laser's optical waveguide is divided into two segments. A phase-shifting structure is introduced in the center of the grating region between the two segments. The grating structures are the same between each segment. The laser resonator at the phase-shifting structure reaches the phase-matching condition, realizing single-mode output. The presence of a phase-shifting structure in the laser enables stable single-longitudinal-mode lasing output.

[0050] Using a shadow grating in a tilted grating as the target equivalent grating, the target equivalent grating is made into a uniform grating with the grating vector direction consistent with the light wave propagation through microstructure quasi-phase matching technology, and the wave vector direction corresponding to the target equivalent grating is the same as the optical waveguide direction of the laser; by controlling the sampling pattern and shape to change the refractive index distribution of the target equivalent grating, the tilted refractive index modulation period and intensity of the equivalent target grating are adjusted, and the refractive index distribution of the equivalent target grating is obtained according to Fourier analysis.

[0051] The tilted sampling structure is based on a tilted seed grating and is designed using semiconductor photolithography technology to achieve tilted refractive index modulation. The formula is expressed as follows:

[0052]

[0053] Where Δn represents the basic grating refractive index modulation. C represents the spatial location of the sampling structure. m Represented as Fourier coefficients, where m is the Fourier series; seed grating and sampling structure The vector satisfies and in and Let Λ0 represent the period of the seed grating, and Λ represent the unit direction vector. S The period of the sampling structure is represented by j, exp, and cc, which represent the imaginary part.

[0054] Positive Level 1 Shadow Raster Seed grating With sampling structure The vector relationship is represented as follows:

[0055]

[0056] In some implementations, fabricating a semiconductor laser device specifically includes the following steps:

[0057] A buffer layer and a lower confinement layer are sequentially grown on a substrate by metal-organic compound vapor deposition. A multi-quantum well layer is grown on the lower confinement layer, and an upper confinement layer is grown on the multi-quantum well layer. A tilted grating with a tilted seed grating and a tilted sampling structure is deposited above the upper confinement layer as a grating layer.

[0058] A phase-shifting structure is introduced into the tilted sampling grating of the tilted grating. The tilt angle and sampling period of the tilted sampling grating with the introduced phase-shifting structure are controlled by the microstructure quasi-phase matching technology to achieve phase matching.

[0059] An InP layer for burying the grating layer is grown above the grating layer, and an etch barrier layer, a waveguide layer, and a contact layer are grown sequentially on the InP layer.

[0060] This invention is based on microstructure quasi-phase matching (MSPQM) technology. In laser design, phase matching is achieved by controlling the tilt angle and sampling period of the sampling structure. A phase shift structure exists in the middle of the laser grating region, enabling lasing output at a specific wavelength. A single laser uses a single electrode for power application, and all phase shifts share a single laser resonant cavity, achieving single-wavelength output.

[0061] The structural parameters of the tilted sampling grating of this invention are designed using microstructure quasi-phase matching technology, ensuring that the wave vector direction corresponding to the target equivalent grating is the same as the optical waveguide direction of the laser. The target equivalent grating is a uniform grating whose grating vector direction is consistent with the light wave propagation. The laser based on this target equivalent grating is equivalent to a conventional distributed feedback (DFB) laser. A phase shift structure is set in the middle of the grating region of the tilted sampling grating. The phase shift structure is realized using the tilted sampling grating structure. In the grating layer, the phase shift structure in the center of the tilted grating structure can be realized using the reconstructed equivalent chirp technology and microstructure quasi-phase matching technology proposed by Chen Xiangfei et al. By using microstructure quasi-phase matching technology to achieve phase matching, the semiconductor laser device based on the tilted grating has a specific tilt morphology and periodic sampling structure, thereby realizing single-wavelength lasing output.

[0062] This invention utilizes an equivalent grating structure to introduce an equivalent phase shift at the center of the grating. The laser wavelength control depends on the design of the sampling structure angle and period, enabling precise control of the laser wavelength. A single electrode structure can be used to achieve carrier injection.

[0063] The present invention will be further described in detail below with reference to specific embodiments:

[0064] Example 1

[0065] A semiconductor laser device based on a tilted grating, wherein the grating phase matching condition of the tilted sampling grating design for a single laser is as follows: Figure 1 As shown.

[0066] The laser includes a tilted grating and a tilted sampling structure, such as Figure 2 , 3 As shown, a phase-shifting structure exists at the center of the grating region. The light source enhances the continuity within the bandgap of the tilted grating through a tilted sampling structure, thereby improving the group delay of the sampling grating at the corresponding operating wavelength.

[0067] The laser uses an n-type doped substrate. An n-type doped InP buffer layer, an n-type doped confinement layer, and an undoped confinement layer are sequentially grown on the substrate by metal-organic compound vapor deposition. The confinement layers are used to confine the optical field and bind the charge carriers. Subsequently, an InGaAlAs multi-quantum-well structure is grown.

[0068] A confinement layer is designed above the quantum well, and an InGaAsP grating layer is grown on top of the confinement layer. Its structure is a tilted grating superimposed with a tilted sampling structure. The equivalent uniform grating is designed using reconstruction equivalent chirp technology and microstructure quasi-phase matching technology, and its equivalent grating period is uniform.

[0069] A p-type InP layer is grown above the grating layer for burial, and an etch barrier layer, a waveguide layer, and a contact layer are grown sequentially on the InP layer.

[0070] A tilted grating was designed and fabricated using microstructure quasi-phase matching technology to match the period and angle of the tilted sampling structure with the parameters of the tilted seed grating. A phase shift structure was introduced on the tilted grating, and the wavelength variation of the Bragg grating of the entire laser was determined by the angle of the tilted seed grating and the angle of the tilted sampling structure, with a 1-degree interval to achieve different wavelength designs.

[0071] There are two types of tilted gratings, 3 degrees and 4 degrees, with tilted sampling structures ranging from 38 degrees to 42 degrees and 46 degrees to 50 degrees, respectively. A phase shift structure is introduced in the middle of the tilted sampling structure to realize tilted grating lasers with multiple wavelengths.

[0072] The test results related to the above design embodiments are as follows: Figure 4 As shown, the spectral test results indicate that five wavelengths can be emitted separately during actual use, with uniform channel spacing, stable output optical power, and high side-mode suppression. Therefore, it can be determined that the designed laser based on the tilted grating can be applied to the aforementioned related application fields.

[0073] In summary, this invention provides a laser design scheme based on a tilted grating. It adopts a tilted sampling structure to increase the bandgap and Bragg wavelength group delay, enhances optical feedback, and reduces the threshold current of laser lasing. A phase shift structure is introduced in the center of the overall tilted grating to achieve stable lasing of a single wavelength at the phase shift position, avoids the introduction of higher-order modes to increase losses, and ensures normal operation of the laser.

[0074] This invention ultimately achieves single-wavelength output from a single laser, with flexible structural design, low threshold current, and high integration.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the technical solution of the present invention, based on the technical essence of the present invention, shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A semiconductor laser device based on a tilted grating, characterized in that: The waveguide grating of the semiconductor laser is a tilted grating composed of a tilted seed grating and a tilted sampling structure. The tilted grating has a phase-shifting structure, and the laser resonator cavity achieves phase matching at the phase-shifting structure using microstructure quasi-phase matching technology. The tilted seed grating of the tilted grating is tilted and has a uniform period, with the tilt angle determined by the waveguide tilt angle. The tilt angle of the tilted grating is less than 7 degrees. Laser wavelength control and wavelength spacing selection are achieved by controlling the equivalent period variation of the tilted sampling structure. The tilted grating contains multiple shadow gratings, with one of the shadow gratings serving as the target equivalent grating. Microstructure quasi-phase matching technology ensures that the target equivalent grating becomes a uniform grating with the grating vector direction consistent with the light wave propagation, and the wave vector direction corresponding to the target equivalent grating is the same as the laser's waveguide direction.

2. The semiconductor laser device based on a tilted grating according to claim 1, characterized in that: The semiconductor laser is composed of a substrate, a buffer layer, a lower confinement layer, a multiple quantum well layer, an upper confinement layer, a grating layer, a buried layer, an etch barrier layer, a waveguide layer, and a contact layer stacked from bottom to top. The grating layer is composed of a tilted grating.

3. The semiconductor laser device based on a tilted grating according to claim 2, characterized in that: The semiconductor laser uses a multi-quantum well layer as the gain medium; the tilted grating wavelength is located near the center of the gain bandwidth; the substrate is an n-type doped substrate; the lower confinement layer is a confinement layer composed of n-type doping and undoped layers; and the multi-quantum well layer is an InGaAlAs multi-quantum well.

4. A method for fabricating a semiconductor laser device based on a tilted grating as described in any one of claims 1 to 3, characterized in that, Includes the following steps: In the fabrication of optical waveguide gratings for semiconductor lasers, the tilt angle of the optical waveguide grating is controlled by controlling the waveguide tilt angle, forming a tilted grating composed of a tilted seed grating and a tilted sampling structure. A phase-shifting structure is introduced into the tilted grating, and the laser resonator at the phase-shifting structure is phase-matched by microstructure quasi-phase matching technology. A single-wavelength laser is generated by energizing a single electrode to produce a single-wavelength laser output.

5. The method for fabricating a semiconductor laser device based on a tilted grating according to claim 4, characterized in that: The aforementioned method of introducing a phase-shift structure into a tilted grating and achieving phase matching of the laser resonator cavity at the phase-shift structure using microstructure quasi-phase matching technology specifically involves: The grating structure of the optical waveguide of the semiconductor laser is divided into two segments, and a phase shift structure is introduced between the two segments. The phase shift structure is located in the middle of the grating region of the tilted grating. The structural parameters of the phase shift structure are designed using microstructure quasi-phase matching technology so that the laser resonator at the phase shift point achieves the phase matching condition and realizes stable single-mode output.

6. The method for fabricating a semiconductor laser device based on a tilted grating according to claim 4, characterized in that: Using a shadow grating in a tilted grating as the target equivalent grating, the target equivalent grating is made into a uniform grating with the grating vector direction consistent with the light wave propagation through microstructure quasi-phase matching technology, and the wave vector direction corresponding to the target equivalent grating is the same as the optical waveguide direction of the laser; by controlling the sampling pattern and shape to change the refractive index distribution of the target equivalent grating, the tilted refractive index modulation period and intensity of the equivalent target grating are adjusted, and the refractive index distribution of the equivalent target grating is obtained according to Fourier analysis.

7. The method for fabricating a semiconductor laser device based on a tilted grating according to claim 4, characterized in that: The tilted sampling structure is based on a tilted seed grating and designed using semiconductor photolithography technology, employing tilted refractive index modulation. The formula is expressed as follows: in, This indicates the modulation of the refractive index of the basic grating. Indicates the spatial location of the sampling structure. Represented as Fourier coefficients, where m is the Fourier series; seed grating and sampling structure The vector satisfies and ,in and Represents the unit direction vector. Indicates the period of the seed grating. Indicates the period of the sampling structure. j, exp, cc Indicates the imaginary part; Positive Level 1 Shadow Raster Seed grating With sampling structure The vector relationship is represented as follows: 。 8. The method for fabricating a semiconductor laser device based on a tilted grating according to claim 4, characterized in that, Specifically, the following steps are included: A buffer layer and a lower confinement layer are sequentially grown on a substrate by metal-organic compound vapor deposition. A multi-quantum well layer is grown on the lower confinement layer, and an upper confinement layer is grown on the multi-quantum well layer. A tilted grating with a tilted seed grating and a tilted sampling structure is deposited above the upper confinement layer as a grating layer. A phase-shifting structure is introduced into the tilted sampling grating of the tilted grating. The tilt angle and sampling period of the tilted sampling grating with the introduced phase-shifting structure are controlled by the microstructure quasi-phase matching technology to achieve phase matching. A buried layer is grown above the grating layer, and a corrosion barrier layer, a waveguide layer, and a contact layer are grown sequentially on the buried layer.

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