Tilted waveguide semiconductor laser with compound microstructure

Abstract

This application relates to the field of semiconductor optoelectronic device technology and discloses a tilted waveguide semiconductor laser with a composite microstructure. The semiconductor laser includes a tilted waveguide, and the base-side mode forms a zigzag resonant path within the tilted waveguide cavity. This ensures high end-face coupling efficiency of the base-side mode within the tilted waveguide semiconductor laser at different etching depths. An internal microstructure is disposed in the region within the tilted waveguide cavity that does not overlap with the zigzag resonant path; external microstructures are disposed in the regions on both sides of the tilted waveguide that overlap with the zigzag resonant path. Both the internal and external microstructures are used to increase the loss of higher-order side modes, improving the lateral beam quality, and have broad application prospects in fields such as pump sources and space communication.

Description

Technical Field

[0001] This application relates to the field of semiconductor optoelectronic device technology, specifically to a tilted waveguide semiconductor laser with a composite microstructure. Background Technology

[0002] Traditional wide-ridge waveguide semiconductor lasers are prone to filamentary emission and lasing of higher-order side modes due to nonlinear effects, resulting in large divergence angles and poor lateral beam quality, which limits their direct application. To suppress higher-order side modes and improve lateral beam quality, tilted waveguide semiconductor lasers have been proposed.

[0003] Tilted waveguide semiconductor lasers form tilted waveguides through etching in the etched region, and the cavity length of the tilted waveguide is determined by geometric relationships, so that the fundamental mode satisfies a zigzag resonance within the tilted waveguide. This zigzag resonance can suppress filamentary emission caused by uneven refractive index distribution within the tilted waveguide. However, existing tilted waveguide semiconductor lasers still have the following shortcomings:

[0004] 1. The strongly refractive index guiding structure of the etched region extending directly to the N-type waveguide layer results in a large number of non-radiative recombination centers on the tilted waveguide sidewalls. This causes additional absorption losses and reduces electro-optical conversion efficiency. Furthermore, as the etching depth decreases, the influence of the Gus-Hanshin displacement on the base-side modes during reflection from the tilted waveguide sidewalls increases, causing the cavity length determined by existing formulas to be less than the optimal cavity length. This results in the base-side modes failing to satisfy the zigzag resonance condition, leading to a decrease in the laser's threshold characteristics and lateral beam quality.

[0005] 2. Due to the zigzag resonance, the base-side modes in the tilted waveguide semiconductor laser have isosceles triangular non-overlapping regions with the tilted waveguide sidewalls. These regions allow higher-order side modes to meet the superradiation condition, and above the threshold, they are refracted at the front face of the tilted waveguide semiconductor laser and form side lobes on both sides of the main lobe of the optical field, which reduces the lateral beam quality of the tilted waveguide semiconductor laser.

[0006] 3. Tilted waveguide semiconductor lasers have a large ridge width. For higher-order side modes near the base mode, such as first-order and second-order side modes, their effective refractive index is close to that of the base mode, allowing them to satisfy selective resonance even at high injection levels. Therefore, tilted waveguides alone have limited filtering capability for higher-order side modes near the base mode at high injection levels. Summary of the Invention

[0007] This application provides a tilted waveguide semiconductor laser with a composite microstructure to solve the problems in the prior art where the base-side mode cannot meet the zigzag resonance condition under weak refractive index guidance, resulting in a decrease in the threshold characteristics and side beam quality of the laser; the formation of side lobes on both sides of the main lobe of the optical field by higher-order side modes; and the limited filtering capability of higher-order side modes near the base-side mode at high injection levels.

[0008] To address the aforementioned technical problems, this application discloses a tilted waveguide semiconductor laser with a composite microstructure. The semiconductor laser includes a tilted waveguide, and the base-side mode forms a zigzag resonant path within the tilted waveguide cavity. An internal microstructure is disposed in the region within the tilted waveguide cavity that does not overlap with the zigzag resonant path. An external microstructure is disposed in the regions on both sides of the tilted waveguide that overlap with the zigzag resonant path. Both the internal and external microstructures are used to increase the loss of higher-order side modes.

[0009] In this embodiment, the semiconductor laser includes a tilted waveguide, with the base-side mode forming a zigzag resonant path within the tilted waveguide cavity. This ensures high end-face coupling efficiency of the base-side mode within the tilted waveguide semiconductor laser at different etching depths. Internal microstructures are disposed in the region within the tilted waveguide cavity that does not overlap with the zigzag resonant path; external microstructures are disposed in the regions on both sides of the tilted waveguide that overlap with the zigzag resonant path. Both internal and external microstructures are used to increase the loss of higher-order side modes, improving lateral beam quality and showing broad application prospects in fields such as pump sources and space communication.

[0010] Preferably, the length, width, and tilt angle of the tilted waveguide relative to the output end face satisfy the following relationship:

[0011]

[0012] Where L is the length of the tilted waveguide; m is a positive integer; W is the width of the tilted waveguide; δ GH θ is the Gus-Hanshin displacement of the base-side mode when reflected from the sidewall of the tilted waveguide; θ is the tilt angle of the tilted waveguide relative to the output end face; the output end face is the exit surface of the base-side mode on the tilted waveguide.

[0013] Through δ GH The introduction of the factor enables the length L of the tilted waveguide to satisfy the zigzag resonance condition of the base-side mode in the tilted waveguide at different etching depths of the 202 region.

[0014] Preferably, the region within the tilted waveguide cavity that does not overlap with the zigzag resonant path is in the shape of an isosceles triangle; the isosceles triangle has the same isosceles angle as the tilt angle of the tilted waveguide relative to the output end face; the height of the isosceles triangle is 30%-40% of the width of the tilted waveguide.

[0015] This ensures that the introduction of internal microstructures has little impact on the zigzag oscillation of the base-side mode, while suppressing the side lobes on both sides of the main lobe in the output light spot.

[0016] Preferably, the external microstructure is located in a region on both sides of the tilted waveguide with a width of 5%-10% of the width of the tilted waveguide end face, and at the position where the zigzag resonant path overlaps with the sidewall of the tilted waveguide.

[0017] The above structure can ensure that the introduction of external microstructures has little impact on the zigzag oscillation of the base-side mode, while increasing the filtering capability of higher-order side modes near the base-side mode.

[0018] Preferably, the semiconductor laser further includes a stacked structure; the stacked structure includes, from bottom to top, an N-face electrode, a substrate, an N-type confinement layer, an N-type waveguide layer, an active gain layer, a P-type waveguide layer, a P-type confinement layer, and a P-type capping layer; the tilted waveguide is formed by etching the stacked structure from top to bottom.

[0019] Preferably, etched regions are formed on the upper surfaces of the stacked structures on both sides of the tilted waveguide; the effective refractive index of the etched regions, the effective refractive index of the tilted waveguide, and the tilt angle of the tilted waveguide relative to the output end face satisfy the following relationship:

[0020] n eff,ET ≤n eff,WG ×sinθ

[0021] Where, n eff,ET n is the effective refractive index of the etched region. eff,WG θ is the effective refractive index of the tilted waveguide; θ is the tilt angle of the tilted waveguide relative to the output end face; the output end face is the exit surface of the base-side mode on the tilted waveguide.

[0022] By tilting the waveguide at different tilt angles θ relative to the output end face, sufficient optical field confinement can be provided for the base-side mode.

[0023] Preferably, the surface shape of the internal microstructure is any one of the first custom shapes; the first custom shapes include triangles, quadrilaterals, circles, arrow shapes, and fishbone shapes.

[0024] Preferably, the shape of the surface of the external microstructure is any one of the second custom shapes; the second custom shapes include triangles, quadrilaterals, serrated shapes, and gear shapes.

[0025] Additional aspects and advantages of the embodiments of this application will be set forth in the following description, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0026] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 A schematic diagram of a conventional tilted waveguide semiconductor laser structure provided in this application embodiment;

[0028] Figure 2 A schematic diagram of a tilted waveguide semiconductor laser with a composite microstructure provided in an embodiment of this application;

[0029] Figure 3 A top view of a tilted waveguide semiconductor laser with a composite microstructure provided in an embodiment of this application;

[0030] Figure 4 A comparison of the internal loss of higher-order side modes in the tilted waveguide between a tilted waveguide semiconductor laser with an introduced internal microstructure and a tilted waveguide semiconductor laser without an internal microstructure, obtained through simulation for embodiments of this application.

[0031] Figure 5 A comparison diagram of the near field of the first-order side mode in a tilted waveguide semiconductor laser with an external microstructure and without an external microstructure, obtained by simulation according to an embodiment of this application.

[0032] Among them, 100-stacked structure; 101-N-face electrode; 102-substrate; 103-N-type confinement layer; 104-N-type waveguide layer; 105-active gain layer; 106-P-type waveguide layer; 107-P-type confinement layer; 108-P-type capping layer; 109-P-face electrode; 201-tilted waveguide; 202-etched region; 203-isosceles triangular region; 204-internal microstructure; 205-regions on both sides of the tilted waveguide with a width of 5%-10% of the width of the tilted waveguide end face; 206-external microstructure. Detailed Implementation

[0033] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0034] Those skilled in the art will understand that, unless explicitly stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this application means the presence of features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0035] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0036] In view of the technical problems existing in the prior art, this application provides a tilted waveguide semiconductor laser with a composite microstructure, which aims to solve at least one of the technical problems of the prior art.

[0037] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0038] Figure 1 A schematic diagram of a conventional tilted waveguide semiconductor laser structure is shown. Figure 1As shown, the stacked structure 100, from bottom to top, consists of an N-type electrode 101, a substrate 102, an N-type confinement layer 103, an N-type waveguide layer 104, an active gain layer 105, a P-type waveguide layer 106, a P-type confinement layer 107, and a P-type capping layer 108. An inclined waveguide 201 is formed at the middle position of the upper part of the stacked structure 100 by etching from the surface of the stacked structure 100. A P-type electrode 109 is formed on the upper surface of the inclined waveguide 201. To achieve total internal reflection of the base-side modes on the sidewalls of the tilted waveguide 201, most tilted waveguide semiconductor lasers currently employ a high refractive index guiding structure. The etched region 202 often extends directly to the N-type waveguide layer 104. The cavity length is determined through geometric relationships, enabling the base-side modes to achieve a zigzag resonance within the tilted waveguide 201. This zigzag resonance can suppress filamentary emission caused by uneven refractive index distribution within the tilted waveguide 201. Simultaneously, within the tilted waveguide 201, due to the different effective refractive indices of each order of side modes, higher-order side modes cannot achieve the zigzag resonance and face greater losses. Compared to traditional wide-ridge semiconductor lasers, the lateral beam quality can be significantly improved under high-power laser output conditions.

[0039] Based on the above, this application provides a possible implementation method. Figure 2 A schematic diagram of a tilted waveguide semiconductor laser with a composite microstructure is provided.

[0040] like Figure 2 As shown, the semiconductor laser includes a tilted waveguide 201, in which the base-side mode forms a zigzag resonant path within the cavity of the tilted waveguide 201; an internal microstructure 204 is disposed in the region within the cavity of the tilted waveguide 201 that does not overlap with the zigzag resonant path; and an external microstructure 206 is disposed in the regions on both sides of the tilted waveguide that overlap with the zigzag resonant path; both the internal microstructure 204 and the external microstructure 206 are used to increase the loss of higher-order side modes.

[0041] In this embodiment, the semiconductor laser further includes a stacked structure 100; the stacked structure 100, from bottom to top, includes an N-type electrode 101, a substrate 102, an N-type confinement layer 103, an N-type waveguide layer 104, an active gain layer 105, a P-type waveguide layer 106, a P-type confinement layer 107, and a P-type capping layer 108; the tilted waveguide 201 is formed by etching the stacked structure 100 from top to bottom, and a P-type electrode 109 is formed on the upper surface of the tilted waveguide 201 in the region other than the composite microstructure. In this embodiment, by designing the etching depth and the cavity length of the tilted waveguide 201, the base-side mode forms a zigzag resonant path within the cavity of the tilted waveguide 201.

[0042] In a tilted waveguide semiconductor laser, the base-side modes suppress filamentary emission through zigzag resonance. However, non-overlapping regions exist between these regions and the sidewalls of the tilted waveguide 201. These regions, located outside the oscillation path of the base-side modes, can only provide gain to the base-side modes through carrier compensation, but can provide direct gain to higher-order side modes. This allows these higher-order side modes to satisfy the superradiative condition, refracting above a threshold at the front face of the tilted waveguide semiconductor laser and forming side lobes on both sides of the main lobe of the optical field, thus reducing the lateral beam quality of the tilted waveguide semiconductor laser. In this embodiment, by introducing an internal microstructure 204 into the region 203 of the tilted waveguide 201 that cannot provide direct gain to the base-side modes, while ensuring minimal loss to the base-side modes, the region directly providing gain to the higher-order side modes that contribute to the side lobes is disrupted, increasing the internal loss of the higher-order side modes and effectively suppressing the side lobes on both sides of the main lobe in the output optical field.

[0043] Since the energy of the base-side mode decreases from the center of the tilted waveguide 201 to both sides, while the higher-order side modes have a strong energy distribution on both sides of the tilted waveguide, in this embodiment, an external microstructure 206 is introduced as a loss region in the region where the tilted waveguide overlaps with the zigzag resonant path on both sides. This enhances the internal losses such as diffraction, scattering and absorption of the higher-order side modes, increases the threshold gain difference between them and the base-side mode, and thus improves the mode selectivity of the tilted waveguide semiconductor laser at high injection levels.

[0044] The tilted waveguide semiconductor laser with composite microstructure in the embodiments of this application is suitable for, for example, Figure 1 The original tilted waveguide semiconductor laser process shown is relatively inexpensive.

[0045] In this embodiment, the semiconductor laser includes a tilted waveguide 201. The base-side mode forms a zigzag resonant path within the cavity of the tilted waveguide 201, ensuring high end-face coupling efficiency of the base-side mode within the tilted waveguide semiconductor laser at different etching depths. Internal microstructures are disposed in the region within the cavity of the tilted waveguide 201 that does not overlap with the zigzag resonant path; external microstructures are disposed in the regions on both sides of the tilted waveguide that overlap with the zigzag resonant path. Both the internal and external microstructures are used to increase the loss of higher-order side modes. While ensuring high coupling efficiency of the base-side mode within the tilted waveguide 201 waveguide semiconductor laser, the lateral beam quality is further improved, showing broad application prospects in fields such as pump sources and space communication.

[0046] As a first example, the N-side electrode 101 is fabricated using Ti / Pt / Au material, the substrate 102 and the P-side capping layer 108 are grown from N-type doped and P-type doped GaAs with thicknesses of 0.1 μm, respectively, and the N-type confinement layer 103 and the P-type confinement layer 107 are grown from N-type doped and P-type doped Al with thicknesses of 1 μm, respectively.0.4 Ga 0.6 As, the growth material for the N-type waveguide layer 104 and the P-type waveguide layer 106 is Al with a thickness of 0.5 μm. 0.2 Ga 0.8 As, the active gain layer 105 is grown from In with a thickness of 0.006 / 0.014 μm. 0.29 Ga 0.71 As / GaAs single quantum well.

[0047] A tilted waveguide 201 is formed at the upper middle position of the stacked structure 100 by one-step etching on the surface of the stacked structure 100. The etched area on the surface of the stacked structure 100 forms an etched region 202. A P-surface electrode 109 is formed on the upper surface of the tilted waveguide 201, excluding the composite microstructure. The P-surface electrode 109 is made of Au / Ge / Ni material. Figure 3 A top view of a tilted waveguide semiconductor laser with a composite microstructure is provided. (See reference...) Figure 3 In an optional embodiment, the length, width, and tilt angle of the tilted waveguide 201 relative to the output end face satisfy the following relationship:

[0048]

[0049] Where L is the length of the tilted waveguide 201; m is a positive integer; W is the width of the tilted waveguide 201; δ GH θ is the Gus-Hanshin displacement of the base-side mode when reflected from the sidewall of the tilted waveguide 201; θ is the tilt angle of the tilted waveguide 201 relative to the output end face; the output end face is the exit surface of the base-side mode on the tilted waveguide 201.

[0050] In conjunction with the first example above, the working optical wavelength corresponding to the above-mentioned stacked structure 100 is 1.06μm; the width W of the tilted waveguide 201 is 60μm, and the tilt angle of the tilted waveguide 201 relative to the output end face is a tilt angle of 7°.

[0051] In an optional embodiment, an etched region 202 is formed on the upper surface of the stacked structure 100 on both sides of the tilted waveguide;

[0052] The effective refractive index of the etched region 202, the effective refractive index of the tilted waveguide 201, and the tilt angle of the tilted waveguide 201 relative to the output end face satisfy the following relationship:

[0053] n eff,ET ≤n eff,WG ×sinθ

[0054] Where, n eff,ET n is the effective refractive index of etched region 202; eff,WGθ is the effective refractive index of the tilted waveguide 201; θ is the tilt angle of the tilted waveguide 201 relative to the output end face; the output end face is the exit surface of the base-side mode on the tilted waveguide 201.

[0055] In this embodiment, by using different tilt angles θ of the tilted waveguide 201 relative to the output end face, sufficient optical field confinement can be provided for the base-side mode.

[0056] As a second example, in order to reduce the etching depth while ensuring the coupling efficiency of the base-side mode on the front end of the tilted waveguide semiconductor laser, thereby reducing additional absorption loss and improving electro-optic conversion efficiency, the etching depth of the semiconductor laser region 202 is 1.1 μm when the sidewall of the tilted waveguide 201 is straightened, and the cavity length L after considering the Gus-Hanshin displacement is 1.02 mm.

[0057] In this embodiment of the application, δ GH The introduction of the factor ensures that the length L of the tilted waveguide 201 satisfies the zigzag resonance condition of the base-side mode within the tilted waveguide 201 at different etching depths of the etched region 202. Simultaneously, it mitigates the problem of reduced electro-optic conversion efficiency caused by additional absorption losses due to interface defects formed by deep etching.

[0058] In an optional embodiment, the region within the tilted waveguide 201 that does not overlap with the zigzag resonant path is in the shape of an isosceles triangle; the isosceles triangle has the same isosceles angle as the tilt angle of the tilted waveguide 201 relative to the output end face; the height of the isosceles triangle is 30%-40% of the width of the tilted waveguide 201.

[0059] As a third example, the internal microstructure 204 is located in an isosceles triangular region 203 that does not overlap with the zigzag resonant path of the base-side mode and the tilted waveguide 201. The isosceles triangular region 203 has a height of 24 μm and an equilateral angle of 7°.

[0060] In an optional embodiment, the surface shape of the internal microstructure is any of the first custom shapes; the first custom shapes include, but are not limited to, triangles, quadrilaterals, circles, arrow shapes, and fishbone shapes.

[0061] In conjunction with the third example above, the internal microstructure 204 is composed of several rectangular cylinders, which are used to increase the loss of higher-order side modes that directly gain the sidelobe. The width and adjacent spacing of each internal rectangle are 10 μm. The rectangle in the middle of the isosceles triangular region 203 has the largest length, and the length of the rectangles on both sides decreases from the isosceles triangular region 203 towards both ends.

[0062] Figure 4A comparison of simulation results for the internal loss of high-order side modes in tilted waveguide 201 is provided between tilted waveguide semiconductor lasers with and without internal microstructures. The horizontal axis represents the side mode order, and the vertical axis represents the normalized internal loss. (Refer to...) Figure 4 It can be seen that the introduction of the internal microstructure increases the internal loss of the 5th to 7th order side modes by 3%, 7% and 9% respectively. More importantly, the region that directly provides gain for the higher order side modes is cut off and destroyed, which plays an important role in suppressing the side lobes on both sides of the optical field of the tilted waveguide 201.

[0063] In summary, the above structure ensures that the introduction of the internal microstructure 204 has little impact on the zigzag oscillation of the base-side mode, while suppressing the side lobes on both sides of the main lobe in the output light spot.

[0064] In an optional embodiment, the external microstructure is located in a region 205 on both sides of the tilted waveguide, with a width of 5%-10% of the width of the tilted waveguide end face, and at the position where the zigzag resonant path overlaps with the sidewall of the tilted waveguide.

[0065] In one optional embodiment, the surface shape of the external microstructure is any of the second custom shapes; the second custom shapes include, but are not limited to, triangles, quadrilaterals, serrated shapes, and gear shapes.

[0066] As a fourth example, such as Figure 2 and Figure 3 As shown, the external microstructures located on both sides of the tilted waveguide consist of several isosceles trapezoidal cylinders. The base width and adjacent spacing of each isosceles trapezoid are 10 μm, the equilateral angle is 107°, and the height is 16 μm.

[0067] Figure 5 A comparison of simulation results for the near field of the first-order side modes in a tilted waveguide semiconductor laser with and without external microstructures is provided. The horizontal axis represents the lateral position (in micrometers), and the vertical axis represents the normalized light intensity. (Refer to...) Figure 5 It can be observed that the introduction of the external microstructure reduces the normalized intensity of the first-order side mode within the tilted waveguide 201, resulting in a multi-lobed optical field distribution. This demonstrates that the introduction of the external microstructure effectively increases the loss of modes near the base-side mode, contributing to improved lateral beam quality at high injection levels.

[0068] In summary, the above structure ensures that the introduction of the external microstructure 206 has a small impact on the zigzag oscillation of the base-side mode, while increasing the filtering capability for higher-order side modes near the base-side mode.

[0069] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A tilted waveguide semiconductor laser with a compound microstructure, characterized in that, The semiconductor laser includes a tilted waveguide, and the base-side mode forms a zigzag resonant path within the tilted waveguide cavity; The region within the inclined waveguide cavity that does not overlap with the zigzag resonant path is provided with an internal microstructure; External microstructures are provided in the regions on both sides of the tilted waveguide that overlap with the zigzag resonant path. Both the internal and external microstructures are used to increase the loss of higher-order side modes; The region within the tilted waveguide cavity that does not overlap with the zigzag resonant path is in the shape of an isosceles triangle. The isosceles triangle has the same angle as the tilt angle of the tilted waveguide relative to the output end face. The height of the isosceles triangle is 30%-40% of the width of the tilted waveguide; The external microstructure is located in a region on both sides of the tilted waveguide with a width of 5%-10% of the width of the tilted waveguide end face, and at the position where the zigzag resonant path overlaps with the sidewall of the tilted waveguide.

2. The tilted waveguide semiconductor laser with compound microstructure according to claim 1, characterized in that, The length, width, and tilt angle of the tilted waveguide relative to the output end face satisfy the following relationship: wherein L is a length of the slanted waveguide; m is a positive integer; and W is a width of the slanted waveguide; is a Goos-Ha nchen displacement of the base side mode when reflected by the slanted waveguide sidewall; is a slanting angle of the slanted waveguide relative to an output end face; the output end face is an exit face of the base side mode on the slanted waveguide.

3. The tilted waveguide semiconductor laser with composite microstructure according to claim 1, characterized in that, The semiconductor laser also includes a stacked structure; The stacked structure, from bottom to top, includes an N-face electrode, a substrate, an N-type confinement layer, an N-type waveguide layer, an active gain layer, a P-type waveguide layer, a P-type confinement layer, and a P-type capping layer. The tilted waveguide is formed by etching the stacked structure from top to bottom.

4. The tilted waveguide semiconductor laser with composite microstructure according to claim 3, characterized in that, An etched region is formed on the upper surface of the stacked structure on both sides of the tilted waveguide; The effective refractive index of the etched region, the effective refractive index of the tilted waveguide, and the tilt angle of the tilted waveguide relative to the output end face satisfy the following relationship: in, The effective refractive index of the etched region; The effective refractive index of the tilted waveguide; The tilt angle of the tilted waveguide relative to the output end face; the output end face is the exit surface of the base-side mode on the tilted waveguide.

5. The tilted waveguide semiconductor laser with composite microstructure according to any one of claims 1-4, characterized in that, The surface shape of the internal microstructure can be any one of the first custom shapes; the first custom shape includes triangle, quadrilateral, circle, arrow, and herringbone.

6. The tilted waveguide semiconductor laser with composite microstructure according to any one of claims 1-4, characterized in that, The shape of the surface of the external microstructure is any one of the second custom shapes; the second custom shape includes triangle, quadrilateral, serrated shape, and gear shape.

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