Semiconductor laser with inclined cavity surface in vertical plane and manufacturing method

Abstract

The invention provides a semiconductor laser with an inclined cavity surface in a vertical plane and a manufacturing method. The semiconductor laser comprises a laminated structure; the main oscillator region, the power pre-amplifier region and the conical power amplifier region are sequentially integrated on the stacked structure in the extension direction of the axis of the waveguide optical path; the laminated structure is formed on the substrate; the substrate has a preset offset cutting angle, and the preset offset cutting angle is larger than or equal to 12 degrees and smaller than 17 degrees; wherein the semiconductor laser is provided with an output cavity surface formed by cleavage along the cleavage direction of the substrate at the output end of the conical power amplifier region, and the output cavity surface is obliquely arranged relative to the direction vertical to the axis of the waveguide light path in a vertical plane. The semiconductor laser effectively solves the technical problems of parasitic oscillation and light beam quality degradation induced by residual reflection of an output cavity surface of a monolithic integrated MOPA semiconductor laser in the prior art.

Description

Technical Field

[0001] This invention relates to the field of semiconductor laser technology, and more specifically to a semiconductor laser having an inclined cavity surface in a vertical plane and a method for manufacturing it. Background Technology

[0002] High-power, high-brightness, and spectrally pure semiconductor lasers have significant application value in cutting-edge fields such as LiDAR, nonlinear frequency conversion, and free-space optical communication. Monolithic integrated semiconductor laser chips based on the Master Oscillator Power Amplifier (MOPA) architecture are considered one of the key technological paths to meet these requirements because they can simultaneously achieve narrow-linewidth seed sources and high-power amplification.

[0003] However, the performance potential of monolithic MOPA lasers has long been limited by a core physical bottleneck: the parasitic feedback effect caused by residual reflections at the output cavity surface of the power amplifier (PA). Although an anti-reflection (AR) film is typically deposited on this cavity surface to suppress reflections, under practical fabrication conditions, the residual reflectivity is still difficult to reduce to below a certain level. to On the order of magnitude. Under high-gain operating conditions, this weak reflection is sufficient to form a parasitic Fabry-Pérot (FP) resonant cavity with the internal structure of the chip, thereby inducing a series of serious negative effects: Beam quality degradation: Parasitic oscillations lead to higher-order transverse mode lasing or filamentation effects, resulting in increased output beam divergence angle, uneven energy distribution, and decreased beam quality factor (M). 2 () deteriorated significantly; Spectral instability: The modes of the parasitic FP cavity will be superimposed on the main spectrum, resulting in spectral broadening, multimode appearance, or even mode jumps; Power saturation and damage: Parasitic oscillations can prematurely consume carriers in the amplification region, limiting the power extraction efficiency of the useful signal light and potentially causing catastrophic optical cavity surface damage (COD).

[0004] To address these challenges, existing technologies mainly follow two paths: one is to continuously optimize AR coating processes to further reduce reflectivity; the other is to avoid feedback light coupling back to the waveguide through structural design. Among these, the laterally Angled Facet scheme is the most representative. This design refers to forming a physical end face at a non-90° angle to the waveguide axis in the horizontal plane at the end of a flat waveguide structure through methods such as tilted etching or cleavage, so as to guide the reflected light away from the waveguide in the horizontal plane.

[0005] For example, Zah of Bell Communications Research in the United States proposed a "sloping-facet flared-waveguide traveling-wave laser amplifier" in his patent US4965525A. The core idea of ​​this invention is to tilt the waveguide (gain region) relative to the cleaved cavity surface on a flat epitaxial growth plane. This tilting design of the waveguide in the horizontal plane is intended to deflect the reflected light from the cavity surface off its original path, thereby suppressing the formation of feedback. (Zah, C.-E., US Patent No. 4,965,525, "Angled-facet flared-waveguide traveling-wave laser amplifiers," 1990). Similarly, Zink et al. from the Ferdinand-Braun Institute in Germany reported a monolithic MOPA structure in 2020, in which the tapered power amplifier (41) section is tilted at 4° relative to the axis of the master oscillator (MO) in the epitaxial plane to achieve horizontal feedback suppression (Zink, C., et al., “Monolithic Master Oscillator Tilted Tapered Power Amplifier Emitting 9.5 W at 1060 nm,” IEEE Photonics Technology Letters, Vol. 32, 2020).

[0006] Although the above-mentioned horizontal tilting scheme alleviates the feedback problem to some extent, it still has obvious limitations: on the one hand, the design of using tilted waveguides significantly increases the complexity of device layout and places higher demands on mode matching between the master oscillator and the power amplifier; on the other hand, even with a horizontally tilted cavity surface, the reflected light is still confined to propagation within the epitaxial layer plane, making it difficult to effectively avoid its recoupling from the waveguide mode and thus failing to achieve complete feedback suppression.

[0007] Therefore, existing technologies still need further development. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a semiconductor laser with an inclined cavity surface in a vertical plane and a manufacturing method thereof, so as to solve the technical problems of parasitic oscillations and beam quality degradation induced by residual reflections at the output cavity surface in monolithically integrated MOPA semiconductor lasers in the prior art.

[0009] To achieve the above-mentioned technical objectives, according to one aspect of the present invention: a semiconductor laser having an inclined cavity surface in a vertical plane is provided, comprising: a stacked structure; a master oscillator region, a power preamplifier region, and a tapered power amplifier region, wherein the master oscillator region, the power preamplifier region, and the tapered power amplifier region are sequentially integrated on the stacked structure along the extension direction of the waveguide optical path axis; a substrate, wherein the stacked structure is formed on the substrate; the substrate has a preset offset angle, the preset offset angle being greater than or equal to 12° and less than 17°; wherein the semiconductor laser has an output cavity surface formed by cleaving along the cleaving direction of the substrate at the output end of the tapered power amplifier region, the output cavity surface being inclined in a vertical plane relative to a direction perpendicular to the waveguide optical path axis, and the tilt angle of the output cavity surface being equal to the preset offset angle.

[0010] Furthermore, the preset offset angle of the substrate is 15°.

[0011] Furthermore, the stacked structure includes a P-type contact layer, a confinement layer, a waveguide layer, and an active layer; the confinement layer, waveguide layer, and active layer are located between the substrate and the P-type contact layer.

[0012] Furthermore, the confinement layer includes an N-type lower confinement layer and a P-type upper confinement layer, the waveguide layer includes a lower waveguide layer and an upper waveguide layer, and the active layer includes a quantum well active layer; the N-type lower confinement layer is disposed on the substrate, the lower waveguide layer is disposed on the N-type lower confinement layer, the quantum well active layer is disposed on the lower waveguide layer, the upper waveguide layer is disposed on the quantum well active layer, the P-type upper confinement layer is disposed on the upper waveguide layer, and the P-type contact layer is disposed on the P-type upper confinement layer.

[0013] Furthermore, the main oscillator region includes: a first protruding structure integrally formed by a stacked structure, wherein the first protruding structure sequentially includes a first DBR grating, a ridge waveguide, and a second DBR grating along the extension direction of the waveguide optical path axis, wherein the ridge waveguide is located between the first DBR grating and the second DBR grating.

[0014] Furthermore, the power preamplifier region includes: a second protrusion structure integrally formed by the stacked structure, the second protrusion structure forming a power preamplifier, the power preamplifier being located on the side of the second DBR grating away from the ridge waveguide.

[0015] Furthermore, the tapered power amplifier region includes: a third protrusion structure integrally formed by the stacked structure, the third protrusion structure forming a tapered power amplifier, the tapered power amplifier being located on one side of the output end of the power preamplifier; the width of the third protrusion structure in the extension direction perpendicular to the waveguide optical path axis gradually increases along the direction from the input end of the third protrusion structure to the output end of the third protrusion structure.

[0016] Furthermore, the semiconductor laser also includes: an electrically insulating film layer covering the P-type contact layer; the electrically insulating film layer having a first opening, a second opening, and a third opening, the first opening being located above the ridge waveguide, the second opening being located above the second protrusion structure, and the third opening being located above the third protrusion structure; a first electrode layer, a second electrode layer, and a third electrode layer, the first electrode layer being embedded in the first opening and electrically connected to the upper surface of the ridge waveguide; the second electrode layer being embedded in the second opening and electrically connected to the upper surface of the second protrusion structure; and the third electrode layer being embedded in the third opening and electrically connected to the upper surface of the third protrusion structure.

[0017] Furthermore, the semiconductor laser also includes: an anti-reflection film disposed on the output cavity surface; and / or an N-plane electrode layer disposed on the bottom surface of the substrate.

[0018] According to another aspect of the present invention, a method for manufacturing a semiconductor laser with an inclined cavity surface in a vertical plane is provided for fabricating the aforementioned semiconductor laser. The method includes: S1. Selecting a substrate with a preset offset angle; and forming a stacked structure on the substrate in one step by an epitaxial growth process; S2. Forming a master oscillator region, a power preamplifier region, and a tapered power amplifier region sequentially arranged along the waveguide optical path axis on the stacked structure by photolithography and etching processes; S3. Depositing an electrically insulating film layer on the top layer of the stacked structure, opening windows in the electrically insulating film layer by photolithography and etching processes, and fabricating mutually electrically isolated P-side electrode layers on the windows, while simultaneously fabricating a uniform N-side electrode layer on the bottom surface of the substrate; S4. Cleaving the wafer along the cleaving direction of the substrate to form an independent laser chip; wherein, since the substrate has a preset offset angle, the output cavity surface formed by cleaving is inclined in the vertical plane relative to the direction perpendicular to the waveguide optical path axis, and the tilt angle of the output cavity surface is equal to the preset offset angle.

[0019] Beneficial effects: According to the technical solution of this invention, a semiconductor laser with an in-plane tilted cavity surface is provided, comprising: a stacked structure, a master oscillator region, a power preamplifier region, a tapered power amplifier region, and a substrate. The stacked structure is formed on the substrate, and the master oscillator region, power preamplifier region, and tapered power amplifier region are integrated on the stacked structure, and are arranged sequentially along the extension direction of the waveguide optical path axis. The master oscillator region, power preamplifier region, and tapered power amplifier region are located in the top region of the stacked structure. The master oscillator region is used to generate a high-stability, narrow-linewidth seed laser. The power preamplifier region is located between the master oscillator region and the tapered power amplifier region, and is used to perform preliminary power boosting on the seed light from the master oscillator region to optimize the injection conditions of the main power amplifier stage. The tapered power amplifier region serves as the main power amplifier stage of the laser, supporting high-power output. The substrate is a skewed substrate with a preset skew angle greater than or equal to 12° and less than 17°. The semiconductor laser has an output cavity surface formed by cleaving along the cleaving direction of the substrate at the output end of the tapered power amplifier region. The output cavity surface is tilted in the vertical plane relative to the direction perpendicular to the waveguide optical path axis, and the tilt angle of the output cavity surface is equal to the preset tangent angle.

[0020] Therefore, this invention employs a substrate with a tangent angle of 12° to 17° and utilizes the crystal cleavage properties of the substrate to automatically form a tilt angle equal to the preset tangent angle of the substrate relative to the extension direction of the waveguide optical path axis during wafer cleavage. The tilted output cavity surface guides the reflected light from the end face to a direction deviating from the original optical path, effectively preventing the reflected light from returning to the main oscillator region, thereby significantly suppressing parasitic oscillations and intensity noise, mode jumps, and frequency drift caused by external optical feedback. Since parasitic oscillations are completely suppressed, the semiconductor laser can still maintain a stable single-mode, single-frequency operating state under high injection current conditions, achieving high beam quality close to the diffraction limit and stable narrow linewidth spectral output. At the same time, the elimination of optical feedback effectively improves the power extraction efficiency of the active region, reduces the risk of heat accumulation and optical damage, and further enhances the long-term operational reliability of the device. Meanwhile, this invention monolithically integrates the main oscillator region, power preamplifier region, and tapered power amplifier region along the extension direction of the waveguide optical path axis on the top of the stacked structure, constructing a complete MOPA main oscillator power amplifier architecture. The master oscillator region generates a highly stable, narrow-linewidth seed laser; the power preamplifier region provides initial power boosting for the seed laser and optimizes injection conditions; the tapered power amplifier region achieves high power amplification through a waveguide structure with a gradually increasing width along the propagation direction, while simultaneously reducing power density to suppress nonlinear effects and catastrophic optical damage. These three functional regions work together to significantly improve output power while maintaining excellent beam quality, avoiding insertion loss, spatial alignment errors, and system complexity inherent in traditional discrete device solutions. Furthermore, this invention fully utilizes the inherent cleavage properties of semiconductor materials and the geometric design advantages of offset substrates, eliminating the need for complex additional processes such as oblique etching, ion beam milling, or cavity surface polishing. A standard cleavage operation is sufficient to directly form an output cavity surface with an angle precisely equal to the preset offset angle of the substrate on the chip end face. Combined with one-time epitaxial growth and conventional photolithography and etching processes, the entire device can be efficiently integrated on existing semiconductor manufacturing platforms. This approach significantly simplifies the fabrication process, reduces manufacturing costs, and ensures high consistency in device performance, exhibiting high yield, good repeatability, and excellent industrialization prospects. This semiconductor laser with an in-plane tilted cavity effectively solves the technical problems of parasitic oscillations and beam quality degradation induced by residual reflections at the output cavity surface in existing monolithically integrated MOPA semiconductor lasers. Attached Figure Description

[0021] Figure 1 A schematic diagram of a semiconductor laser provided according to the present invention is shown from a first-viewpoint structure. Figure 2 A schematic diagram of a second-view structure of a semiconductor laser provided according to the present invention is shown; Figure 3A schematic diagram of a semiconductor laser provided according to the present invention from a third-view perspective is shown; Figure 4 A schematic diagram of the substrate and stacked structure in a semiconductor laser provided according to the present invention is shown. Figure 5 A schematic diagram of FDTD simulation results of the optical field distribution at the output end of a semiconductor laser provided according to the present invention is shown. Figure 6 A graph showing the total effective reflectivity of the output cavity surface of a semiconductor laser provided according to the present invention as a function of tilt angle is shown. Figure 7 A schematic diagram of a semiconductor laser provided according to the present invention, disposed on a heat sink and a base, is shown.

[0022] The above figures include the following reference numerals: 1. Stacked structure; 11. P-type contact layer; 12. N-type lower confinement layer; 13. P-type upper confinement layer; 14. Lower waveguide layer; 15. Upper waveguide layer; 16. Quantum well active layer; 2. Master oscillator region; 21. First DBR grating; 22. Ridge waveguide; 23. Second DBR grating; 3. Power preamplifier region; 31. Power preamplifier; 4. Tapered power amplifier region; 41. Tapered power amplifier; 5. Substrate; 6. First electrode layer; 7. Second electrode layer; 8. Third electrode layer; 9. N-face electrode layer; 10. Output cavity surface; 100. Heat sink; 200. Base. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0024] Please see Figures 1 to 7According to an embodiment of the present invention, a semiconductor laser with an inclined cavity surface in a vertical plane is provided, comprising: a stacked structure 1, a master oscillator region 2, a power preamplifier region 3, a tapered power amplifier region 4, and a substrate 5. The master oscillator region 2, the power preamplifier region 3, and the tapered power amplifier region 4 are sequentially integrated on the stacked structure 1 along the extension direction of the waveguide optical path axis. The stacked structure 1 is formed on the substrate 5. The substrate 5 has a preset offset angle, which is greater than or equal to 12° and less than 17°. The semiconductor laser has an output cavity surface 10 formed by cleaving along the cleaving direction of the substrate 5 at the output end of the tapered power amplifier region 4. The output cavity surface 10 is inclined in the vertical plane relative to the direction perpendicular to the waveguide optical path axis, and the tilt angle of the output cavity surface 10 is equal to the preset offset angle.

[0025] As can be seen, the present invention provides a semiconductor laser with an in-plane tilted cavity surface, comprising: a stacked structure 1, a master oscillator region 2, a power preamplifier region 3, a tapered power amplifier region 4, and a substrate 5. The stacked structure 1 is formed on the substrate 5, and the master oscillator region 2, the power preamplifier region 3, and the tapered power amplifier region 4 are integrated on the stacked structure 1, and are arranged sequentially along the extension direction of the waveguide optical path axis. The master oscillator region 2, the power preamplifier region 3, and the tapered power amplifier region 4 are located in the top region of the stacked structure 1. The master oscillator region 2 is used to generate a seed laser with high stability and narrow linewidth. The power preamplifier region 3 is located between the master oscillator region 2 and the tapered power amplifier region 4, and is used to perform preliminary power boosting on the seed light from the master oscillator region 2 to optimize the injection conditions of the main power amplifier stage. The tapered power amplifier region 4 serves as the main power amplifier stage of the laser, supporting high power output. The substrate 5 is a cleaved substrate with a preset cleaving angle greater than or equal to 12° and less than 17°. The semiconductor laser has an output cavity surface 10 formed by cleaving along the cleaving direction of the substrate 5 at the output end of the tapered power amplifier region 4. The output cavity surface 10 is inclined in a vertical plane relative to a direction perpendicular to the waveguide optical path axis, and the inclination angle of the output cavity surface 10 is equal to the preset cleaving angle.

[0026] Therefore, this invention employs a substrate 5 with a tangent angle of 12° to 17° and utilizes the crystal cleavage characteristics of the substrate 5 to automatically tilt the output cavity surface 10 relative to the waveguide optical path axis at a pre-set tangent angle equal to the substrate 5 during wafer cleavage. The tilted output cavity surface 10 guides the reflected light from the end face to a direction deviating from the original optical path, effectively preventing the reflected light from returning to the main oscillator region 2, thereby significantly suppressing parasitic oscillations and intensity noise, mode jumps, and frequency drift caused by external optical feedback. Because parasitic oscillations are completely suppressed, the semiconductor laser can maintain a stable single-mode, single-frequency operating state even under high injection current conditions, achieving near-diffraction-limited high beam quality and stable narrow-linewidth spectral output. Simultaneously, the elimination of optical feedback effectively improves the power extraction efficiency of the active region, reduces the risk of heat accumulation and optical damage, and further enhances the long-term operational reliability of the device. Meanwhile, this invention monolithically integrates the master oscillator region 2, the power preamplifier region 3, and the tapered power amplifier region 4 along the waveguide optical path axis on the top of the stacked structure 1, constructing a complete MOPA (master oscillator power amplifier) ​​architecture. The master oscillator region 2 is used to generate a highly stable, narrow-linewidth seed laser; the power preamplifier region 3 performs initial power enhancement on the seed laser and optimizes the injection conditions; the tapered power amplifier region 4 achieves high power amplification through a waveguide structure whose width gradually increases along the propagation direction, while reducing power density to suppress nonlinear effects and catastrophic optical damage. The three functional regions work together to significantly improve output power while maintaining excellent beam quality, avoiding insertion loss, spatial alignment errors, and system complexity in traditional discrete device solutions. In addition, this invention fully utilizes the inherent cleavage characteristics of semiconductor materials and the geometric design advantages of the offset substrate 5, eliminating the need for complex additional processes such as oblique etching, ion beam milling, or cavity surface polishing. The output cavity surface 10 with an tilt angle precisely equal to the preset offset angle of the substrate 5 can be directly formed on the chip end face through standard cleavage operations. By combining one-step epitaxial growth with conventional photolithography and etching processes, the entire device can be efficiently integrated on existing semiconductor manufacturing platforms. This approach significantly simplifies the fabrication process, reduces manufacturing costs, and ensures high consistency in device performance, exhibiting high yield, good reproducibility, and excellent industrialization prospects. This semiconductor laser with an in-plane tilted cavity effectively solves the technical problems of parasitic oscillations and beam quality degradation induced by residual reflections at the output cavity surface in existing monolithically integrated MOPA semiconductor lasers.

[0027] The aforementioned "waveguide optical path axis" refers to the straight line formed by connecting the center points of the ridge waveguide cross-section sequentially along the length of the device; its extension direction is the propagation direction of the laser within the device. Meanwhile, as... Figure 2In the diagram, arrow A indicates the direction of the extension of the waveguide optical path axis, which is also the arrangement direction of the main oscillator region 2, the power preamplifier region 3, and the tapered power amplifier region 4.

[0028] The semiconductor laser of the present invention integrates the aforementioned multiple functional regions sequentially along the extension direction of the waveguide optical path axis on the top of the same stacked structure 1. This layout facilitates electrode extraction and also benefits the design and optimization of the optical waveguide structure. Therefore, in the context of the present invention, the waveguide optical path axis can be equivalently regarded as the propagation axis of the laser within the device.

[0029] The offset angle of substrate 5 can be understood as follows: when preparing a semiconductor laser, the selected substrate 5 is not strictly cut along the main crystal plane (such as the (001) plane), but its physical surface is tilted towards a certain crystal direction (such as the

[111] A direction) by a preset angle (e.g., 15°). This angle directly determines the tilt angle of the output cavity surface relative to the waveguide optical path axis after cleavage.

[0030] Furthermore, the preset offset angle of substrate 5 is 15°. With this structural setup, when the preset offset angle of substrate 5 is 15°, the output cavity surface 10 formed by cleaving is tilted at exactly 15° relative to the extension direction of the waveguide optical path axis. The choice of this angle is a key engineering decision balancing feedback suppression effect and process feasibility: on the one hand, the 15° tilt is sufficient to effectively guide the reflected light from the end face away from the main oscillator region 2, significantly suppressing intensity noise, mode jumps, and frequency drift caused by external optical feedback; on the other hand, this angle avoids excessive beam deflection, which is beneficial for efficient coupling of laser with fiber or free-space optical systems. More importantly, 15° provides sufficient process tolerance, ensuring robustness of feedback suppression in manufacturing processes such as substrate cutting, epitaxial growth, and cleaving alignment, while being compatible with mature processes of GaAs-based material systems, facilitating large-scale production with high consistency and high yield.

[0031] Optionally, the substrate 5 is a semiconductor substrate made of gallium arsenide (GaAs) single crystal material. Furthermore, the semiconductor substrate is an N-type semiconductor substrate.

[0032] For example, when using a GaAs substrate with a physical surface offset 15° from the (001) main crystal plane towards the

[111] A direction, after completing epitaxial growth and all device processes on the substrate, the wafer only needs to be cleaved along the natural cleavage plane of the GaAs crystal (e.g., the {110} crystal plane perpendicular to the (001) crystal plane) to naturally form the output cavity surface 10 at the chip output end.

[0033] Since the substrate surface already has a preset 15° cleavage angle, and the cleavage direction is determined by the inherent crystal structure (i.e., along the {110} plane), the resulting output cavity surface 10 will automatically tilt 15° relative to the direction perpendicular to the waveguide optical path axis. In other words, the angle between the output cavity surface 10 and the principal plane of the epitaxial structure is 75°, but its tilt angle relative to the vertical direction is 15°—this is the key design parameter for suppressing optical feedback.

[0034] This tilted output cavity surface can effectively guide the reflected light from the end face away from the original optical path without the need for additional complex processes such as oblique etching, ion milling or precision polishing, thus preventing it from returning to the resonant cavity, thereby significantly improving the spectral purity, output stability and anti-external feedback capability of the laser.

[0035] Optionally, the angle between the output cavity surface 10 and the vertical direction is 15°. This angle is directly derived from the offset design of the GaAs substrate used: its physical surface is offset by 15° relative to the (001) main crystal plane in the

[111] A direction, so that after cleaving, an output cavity surface 10 with a 15° tilt angle is automatically formed, achieving a balance between process simplification and performance optimization.

[0036] It should be noted that the "tilted cavity surface" scheme of this invention is fundamentally different from the "tilted waveguide" scheme in the prior art. In the prior art, feedback suppression is usually achieved by tilting the waveguide axis relative to a standard, vertical cavity surface; however, this invention adopts a completely different technical approach: the waveguide optical path axis can be normally arranged along a standard crystal orientation (such as the

[001] direction), consistent with the epitaxial layer structure, without any deflection; what is actually tilted is the output cavity surface itself—that is, the cavity surface has a preset tilt angle relative to the waveguide optical path axis and the epitaxial plane. Thus, this invention, through a novel device geometry, effectively guides the reflected light from the end face away from the original optical path from the structural root, thereby achieving highly efficient suppression of external optical feedback. This scheme avoids a series of problems caused by tilted waveguides, such as mode mismatch, beam quality degradation, increased coupling loss, and increased complexity of epitaxial and etching processes.

[0037] Specifically, the stacked structure 1 includes a P-type contact layer 11, a confinement layer, a waveguide layer, and an active layer; the confinement layer, waveguide layer, and active layer are located between the substrate 5 and the P-type contact layer 11.

[0038] With the above-mentioned structural configuration, the stacked structure 1 rationally arranges the active layer, waveguide layer, and confinement layer between the substrate 5 and the P-type contact layer 11. This ensures effective confinement and low-loss transmission of the optical field in the active region, and facilitates uniform current injection through the top P-type contact layer 11. At the same time, the positional relationship of each functional layer conforms to the standard epitaxial growth sequence, which is beneficial to improving material quality and device consistency, and provides a structural basis for the high-efficiency, high-stability, and high-reliability operation of the laser.

[0039] Specifically, such as Figure 4 As shown, the confinement layer includes an N-type lower confinement layer 12 and a P-type upper confinement layer 13, the waveguide layer includes a lower waveguide layer 14 and an upper waveguide layer 15, and the active layer includes a quantum well active layer 16. The N-type lower confinement layer 12 is disposed on the substrate 5, the lower waveguide layer 14 is disposed on the N-type lower confinement layer 12, the quantum well active layer 16 is disposed on the lower waveguide layer 14, the upper waveguide layer 15 is disposed on the quantum well active layer 16, the P-type upper confinement layer 13 is disposed on the upper waveguide layer 15, and the P-type contact layer 11 is disposed on the P-type upper confinement layer 13.

[0040] Using the above-described structure, a stacked structure 1, comprising an N-type lower confinement layer 12, a lower waveguide layer 14, a quantum well active layer 16, an upper waveguide layer 15, a P-type upper confinement layer 13, and a P-type contact layer 11, is epitaxially grown sequentially on the substrate 5 to effectively confine carriers and the optical field. This structure forms a carrier confinement barrier through the N-type lower confinement layer 12 and the P-type upper confinement layer 13, efficiently injecting and confining electrons and holes within the quantum well active layer 16, significantly improving radiative recombination efficiency. Simultaneously, the lower waveguide layer 14 and the upper waveguide layer 15, together with the upper and lower confinement layers, constitute a refractive index-guided optical waveguide, tightly confining the optical field near the quantum well active layer 16, reducing light propagation loss and enhancing optical gain. The P-type contact layer 11, located on the top layer, facilitates the fabrication of low-resistance ohmic electrodes, enables uniform vertical current injection, and facilitates efficient heat dissipation from the active region to the surface electrodes, thereby improving the thermal stability and reliability of the device under high-power operating conditions. The entire stacked structure 1 can be completed in one step using standard epitaxial processes such as MOCVD or MBE. The interfaces of each functional layer are clear and the lattice matching is good, which significantly improves the electro-optical conversion efficiency, output power and long-term working stability of the semiconductor laser.

[0041] Specifically, such as Figures 1 to 3 As shown, the main oscillator region 2 includes: a first protruding structure integrally formed by the stacked structure 1, the first protruding structure including a first DBR grating 21, a ridge waveguide 22 and a second DBR grating 23 in sequence along the extension direction of the waveguide optical path axis, wherein the ridge waveguide 22 is located between the first DBR grating 21 and the second DBR grating 23.

[0042] With the above-described structure, the main oscillator region 2 adopts a first protruding structure integrally formed by the stacked structure 1. Along the waveguide optical path axis, a first DBR grating 21, a ridge waveguide 22, and a second DBR grating 23 are sequentially integrated, with the ridge waveguide 22 located between the first DBR grating 21 and the second DBR grating 23, forming a monolithically integrated distributed Bragg reflection (DBR) laser resonator. This structure integrates high reflectivity, narrow bandwidth wavelength selection feedback with low-loss optical waveguide transmission, significantly improving the mode stability and wavelength accuracy of the resonator. Simultaneously, the ridge waveguide 22, as the active gain region, is effectively confined within the resonator from both ends by the first DBR grating 21 and the second DBR grating 23, enhancing the interaction efficiency between the optical field and the active region, and effectively suppressing the lasing of higher-order transverse modes, thereby achieving stable single longitudinal and single transverse mode output. Furthermore, the entire structure is formed from the same epitaxial layer through a single etching process, resulting in continuous interfaces between regions and low parasitic optical loss, which is beneficial for improving device manufacturing yield and long-term operational reliability.

[0043] Optionally, the first DBR grating 21, the ridge waveguide 22, and the second DBR grating 23 can be precisely fabricated on the stacked structure 1 using standard micro-nano fabrication processes such as electron beam lithography (EBL) and reactive ion etching (RIE), achieving high-precision pattern definition and integrated design. The process is mature and highly compatible.

[0044] Specifically, during the etching process, only the portion of the P-type contact layer 11 and the underlying epitaxial layer outside the ridge waveguide 22 and the DBR grating regions on both sides is removed. The upper surface of the area containing the first DBR grating 21, the ridge waveguide 22, and the second DBR grating 23 remains flush with the original top surface of the pre-etched stacked structure 1, while the surrounding area is etched to form trenches, thus forming an integral raised ridge structure on the device surface. This structure not only constitutes a complete resonant cavity and waveguide path but also simultaneously achieves lateral optical field confinement and current injection confinement, improving mode stability and electro-optical conversion efficiency.

[0045] Specifically, such as Figures 1 to 3 As shown, the power preamplifier region 3 includes a second protrusion structure integrally formed by the stacked structure 1, the second protrusion structure forming a power preamplifier 31, the power preamplifier 31 being located on the side of the second DBR grating 23 away from the ridge waveguide 22.

[0046] With the above-described structural configuration, the seed light generated in the main oscillator region 2 can be directly coupled into the power preamplifier 31 for single-pass amplification without the need for reflection or foldback paths, effectively avoiding self-excited oscillation and mode instability. At the same time, since the power preamplifier 31 and the main oscillator region 2 share the same epitaxial stacked structure 1 and are manufactured using an integrated molding process, they are naturally matched in terms of materials, waveguide modes, and optical axis alignment, which significantly improves coupling efficiency and overall output power. It also simplifies the fabrication process and improves device integration and reliability.

[0047] Optionally, the power preamplifier 31 is also precisely fabricated on the stacked structure 1 using standard micro / nano fabrication processes such as electron beam lithography (EBL) and reactive ion etching (RIE). Employing these mature micro / nano fabrication technologies not only enables high-precision pattern definition of the power preamplifier 31 but also ensures seamless integration and efficient optical coupling between it and the main oscillator region 2. Since all key components are integrally formed on the same stacked structure 1, complex alignment steps and potential interface mismatch problems are avoided, significantly improving the overall device performance and manufacturing yield. Furthermore, this integrated design simplifies the manufacturing process, reduces production costs, and enhances the product's market competitiveness.

[0048] Specifically, such as Figures 1 to 3 As shown, the tapered power amplifier region 4 includes: a third protrusion structure integrally formed by the stacked structure 1, the third protrusion structure forming a tapered power amplifier 41, the tapered power amplifier 41 being located on one side of the output end of the power preamplifier 31; the width of the third protrusion structure in the extension direction perpendicular to the waveguide optical path axis gradually increases along the direction from the input end of the third protrusion structure to the output end of the third protrusion structure.

[0049] With the above-described structure, the tapered power amplifier 41 can gradually expand the lateral dimension of the optical field during amplification, effectively reducing the power density of the active region, thereby suppressing nonlinear effects and thermal lensing effects, supporting higher output power, and avoiding optical damage and mode degradation. Furthermore, its waveguide width gradually changes along the light propagation direction, smoothly guiding the expansion of the optical field, significantly reducing diffraction loss and the excitation of higher-order transverse modes, thus improving the near-field and far-field distribution of the output beam and enhancing beam quality (characterized by the M² factor). Further, since the tapered power amplifier 41, the main oscillator region 2, and the power preamplifier 31 are all integrally formed based on the same stacked structure 1, the three are naturally aligned in terms of material system, waveguide mode, and optical axis direction, requiring no additional alignment process. This not only ensures efficient cascaded amplification performance but also enhances the overall stability and reliability of the device.

[0050] Alternatively, the tapered power amplifier 41 is also precisely fabricated on the stacked structure 1 using standard micro-nano fabrication processes such as electron beam lithography (EBL) and reactive ion etching (RIE).

[0051] Specifically, such as Figure 2 As shown, the semiconductor laser further includes: an electrically insulating film layer, a first electrode layer 6, a second electrode layer 7, and a third electrode layer 8. The electrically insulating film layer covers the P-type contact layer 11. The electrically insulating film layer has a first opening, a second opening, and a third opening. The first opening is located above the ridge waveguide 22, the second opening is located above the second protrusion structure, and the third opening is located above the third protrusion structure. The first electrode layer 6 is embedded in the first opening and is electrically connected to the upper surface of the ridge waveguide 22. The second electrode layer 7 is embedded in the second opening and is electrically connected to the upper surface of the second protrusion structure. The third electrode layer 8 is embedded in the third opening and is electrically connected to the upper surface of the third protrusion structure.

[0052] By employing the above structural configuration, an electrically insulating film layer is placed on the P-type contact layer 11, and first, second, and third openings corresponding to the ridge waveguide 22, the second protrusion structure, and the third protrusion structure are respectively formed on it. This allows the first electrode layer 6, the second electrode layer 7, and the third electrode layer 8 to be embedded within each opening and to achieve local ohmic contact with the protrusion structure below. This enables independent electrical addressing and regional current injection for the main oscillator region 2, the power preamplifier region 3, and the tapered power amplifier region 4. This structure not only effectively avoids current crosstalk between regions but also allows for flexible adjustment of the drive current in each functional region according to actual operating requirements, optimizing the synergistic performance of seed light generation, preamplification, and power amplification. Simultaneously, the electrically insulating film layer covers the non-opening areas, providing good lateral current confinement, improving injection efficiency, and reducing Joule heat diffusion.

[0053] Optionally, the first electrode layer 6 serves as the electrode layer for the main oscillator region, the second electrode layer 7 serves as the electrode layer for the power preamplifier region, and the third electrode layer 8 serves as the electrode layer for the tapered power amplifier region. All three are located above the P-type contact layer 11, forming P-surface electrodes, which are used to independently drive the main oscillator region 2, the power preamplifier region 3, and the tapered power amplifier region 4, respectively.

[0054] In the actual fabrication process, after forming the raised structures of the main oscillator region 2, the power preamplifier region 3, and the tapered power amplifier region 4 by etching, an electrically insulating film layer is deposited on the chip surface. This insulating film layer covers the P-type contact layer 11 on the top of each raised structure and the surrounding etched trench area. Subsequently, windows are opened above the corresponding functional areas to expose the P-type contact layer 11 and form independent electrodes.

[0055] Specifically, the semiconductor laser also includes an anti-reflection film disposed on the output cavity surface 10. With this structural arrangement, by depositing an anti-reflection (AR) film on the output cavity surface 10, the Fresnel reflectivity of the output end face can be significantly reduced, effectively suppressing residual reflected light from returning to the resonant cavity, thereby further weakening external optical feedback and avoiding problems such as mode jumps, intensity noise, and self-oscillation. Simultaneously, the anti-reflection film and the tilted output cavity surface 10 in this invention form a synergistic effect: the tilted structure deflects the reflected light from the original optical path, while the anti-reflection film further suppresses interface reflection from an optical interference perspective. The combination of these two elements can reduce the end face reflectivity to a minimum. This significantly improves the spectral stability, output power linearity, and high-power operational reliability of lasers.

[0056] Optionally, the antireflective film is an Al2O3 thin film. To ensure uniform coverage on the large-angle topography of the tilted output cavity surface 10, the antireflective film is preferably prepared using electron beam evaporation (EB) or ion beam sputtering (IBS) techniques.

[0057] Specifically, such as Figure 4 As shown, the semiconductor laser also includes an N-plane electrode layer 9, which is disposed on the bottom surface of the substrate 5. This structural arrangement, by placing the N-plane electrode layer 9 on the bottom surface of the substrate 5, allows the formation of a common electrode, which, together with multiple independent electrodes on the P-plane (such as the first electrode layer 6, the second electrode layer 7, and the third electrode layer 8), constitutes a complete vertical current injection loop. This design not only ensures uniform and efficient carrier injection in the main oscillator region 2, the power preamplifier region 3, and the tapered power amplifier region 4, but also significantly reduces the series resistance of the device and improves the consistency of current spread. Furthermore, since the N-plane electrode layer 9 covers the back side of the highly conductive substrate 5, heat can be efficiently conducted from the active region through the substrate to the heat sink, thereby effectively improving the heat dissipation performance of the device and enhancing the overall electro-optical conversion efficiency, output power capability, and long-term operational stability of the laser.

[0058] Alternatively, the working process and principle of the semiconductor laser are as follows: During operation, a driving current above the threshold is injected into the first electrode layer 6 of the master oscillator region 2 to generate a stable single-mode seed laser. This seed light is then amplified in two stages through the power preamplifier region 3 and the tapered power amplifier region 4, and finally emitted at high power from the inclined output cavity surface 10.

[0059] like Figure 5The figure shows the FDTD simulation results of the optical field distribution at the output end of the MOPA-type semiconductor laser of the present invention. Inside the laser (the region x<0 in the figure), the laser beam is effectively confined in the form of the fundamental mode within the horizontally arranged epitaxial waveguide layer and propagates stably along the waveguide optical path axis. When the beam reaches the output cavity surface 10, which is tilted vertically at x≈0, the beam is refracted at the semiconductor-air interface due to the preset non-90° angle between the cavity surface and the waveguide axis. According to Snell's law, the propagation direction of the emitted laser beam (the region x>0 in the figure) will be significantly deflected, forming an out-of-plane emitted beam whose propagation direction is no longer parallel to the growth plane of the epitaxial layer. The simulation results clearly verify the technical effect of the present invention in achieving directional out-of-plane deflection of the laser beam by tilting the output cavity surface 10 vertically. This not only effectively suppresses the return of reflected light from the end face to the resonant cavity, but also provides favorable conditions for the efficient reception and utilization of the emitted beam by subsequent optical systems (such as collimating lenses, fiber coupling modules, etc.).

[0060] As can be seen, the core of this invention lies in the feedback suppression mechanism that occurs when light reaches the tilted output cavity surface 10. Because this cavity surface is tilted, any residual specular reflection light will have its propagation direction deflected at a large angle from the incident direction. The physical basis of this suppression mechanism lies in the total effective reflectivity... The ultimate compression can be understood as the reflectivity of the cavity surface specular surface. Efficiency of coupling back to waveguide mode with reflected light The product of.

[0061] First, when the beam is directed at the tilted cavity surface at a 15° angle, the main specular reflection beam will be directed at the waveguide interface at an off-axis angle of 30°. For a typical GaAs / AlGaAs material system, this angle is much smaller than the critical angle for total internal reflection (TIR) ​​(approximately 78.4°). Therefore, most of the reflected light will be directly refracted and escape from the waveguide layer, making it difficult to re-enter the active region.

[0062] Secondly, for the weak scattered light that may return, the mode mismatch between it and the waveguide fundamental mode leads to a significant reduction in coupling efficiency. Assuming that the single mode at the narrow input end of the PA can be well approximated by a Gaussian beam, according to the classical theory of Gaussian beam coupling efficiency by Nemoto and Makimoto (1979), in the case of pure angular misalignment (tilt angle θ...),... Coupling efficiency under ) It can be parsed as in, It is the tilt angle of the output cavity surface 10 in the vertical direction; The angle between the reflected beam and the incident beam; The effective refractive index of the waveguide; Let be the radius of the fundamental mode spot of the waveguide in the vertical direction; The center wavelength is .

[0063] The above formula shows that the coupling efficiency decreases exponentially with the increase of the tilt angle, thereby achieving efficient suppression of parasitic feedback.

[0064] As an illustrative, non-restrictive example, such as Figure 6 The theoretical calculation results shown indicate that as the output cavity surface tilt angle increases, the total effective reflectivity decreases. Significantly reduced. Under typical operating conditions, when the tilt angle... At an angle of 15°, combined with an anti-reflective film and a tilted structure, the total effective reflectivity is... It can be suppressed to below On the order of magnitude. Further calculations based on the above mode mismatch theory formula show that, at this angle, the coupling efficiency between the scattered light and the waveguide fundamental mode is... Approximately This constitutes the physical basis for the efficient suppression of parasitic feedback.

[0065] It should be noted that, Figure 6 The "optimal antireflective coating thickness" indicated in the text refers to the physical thickness of the antireflective coating (AR film) optimized to achieve the lowest reflectivity under specific wavelength and incident conditions. This thickness is typically close to one-quarter of the target wavelength in the film material (λ / 4n) to minimize interface reflection by utilizing the principle of destructive interference.

[0066] However, it should be noted that the tilt angle of the output cavity surface is limited by the critical angle for total internal reflection. For GaAs-based materials (refractive index approximately 3.45), the critical angle for total internal reflection to air is approximately 17°. Figure 6 As shown, when the tilt angle approaches this critical angle (e.g., equal to 17°), although the feedback suppression effect is excellent, the energy of the beam emitted through the cavity surface will decrease sharply, and the coating process will become significantly more difficult. When the angle is greater than the critical angle, the beam will undergo total internal reflection and thus cannot be effectively emitted from the end face. Therefore, this invention requires controlling the tilt angle within the critical angle.

[0067] Furthermore, choosing 15° as the tilt angle of the output cavity surface is an engineering compromise that comprehensively considers both feedback suppression effectiveness and process feasibility. This angle provides strong feedback suppression while still having sufficient process tolerance to ensure that the device maintains robust performance during mass production.

[0068] This extremely low effective reflectivity means that reflected light cannot re-enter the waveguide and be amplified, thus fundamentally cutting off the feedback loop of parasitic oscillations and ensuring that the device can maintain high beam quality and a stable narrow linewidth spectrum even at high power. Furthermore, the application of the aforementioned anti-reflection coating further enhances this feedback suppression effect, enabling the laser to not only possess excellent spectral stability but also maintain long-term reliable performance in complex environments.

[0069] This invention also provides a method for manufacturing a semiconductor laser with an inclined cavity surface in a vertical plane, used to prepare the semiconductor laser of the above embodiment. The manufacturing method includes: S1. Selecting a substrate 5 with a preset offset angle; and forming a stacked structure 1 on the substrate 5 in one step by an epitaxial growth process; S2. Forming a master oscillator region 2, a power preamplifier region 3, and a tapered power amplifier region 4 arranged sequentially along the waveguide optical path axis on the stacked structure 1 by photolithography and etching processes; S3. Depositing an electrically insulating film layer on the top layer of the stacked structure 1, opening windows in the electrically insulating film layer by photolithography and etching processes, and fabricating mutually electrically isolated P-side electrode layers on the windows. At the same time, a uniform N-side electrode layer 9 is prepared on the bottom surface of the substrate 5; S4. Cleaving the wafer along the cleaving direction of the substrate 5 to form an independent laser chip; wherein, since the substrate 5 has a preset offset angle, the output cavity surface 10 formed by cleaving is inclined in the vertical plane relative to the direction perpendicular to the waveguide optical path axis, and the tilt angle of the output cavity surface 10 is equal to the preset offset angle.

[0070] Using the above manufacturing method, semiconductor lasers with tilted cavity surfaces in a vertical plane can be efficiently fabricated. By selecting a substrate 5 with a preset offset angle and epitaxially growing a complete stacked structure 1 on it in one step, followed by wafer cleaving along the crystal cleaving direction, a tilted output cavity surface 10 can be naturally formed. The tilt angle of this cavity surface is precisely equal to the offset angle of the substrate, and its tilt direction is strictly limited to a vertical plane perpendicular to the waveguide optical path axis. This method eliminates the need for additional complex post-processing techniques such as dry etching, ion milling, or cavity surface polishing, significantly simplifying the manufacturing process and reducing production costs. It also effectively avoids angle deviations and surface defects that may be introduced by manual processing, ensuring a smooth output cavity surface morphology and precise angles. Furthermore, thanks to this self-aligned cleaving process, the mass-produced laser chips have highly consistent cavity surface tilt angles, significantly improving the repeatability and reliability of device performance. Combining the design of independent addressing of multiple electrodes on the P-side and a common electrode on the N-side further achieves high integration and excellent electrothermal management capabilities. More importantly, the tilted output cavity surface and the anti-reflective film work together to suppress the total effective reflectivity to a minimum. Below the order of magnitude, the parasitic feedback loop is fundamentally cut off, enabling the device to stably output single-longitudinal-mode, narrow-linewidth, and high-beam-quality lasers even under high-power operating conditions, fully meeting the needs of high reliability and large-scale industrial applications.

[0071] The aforementioned "wafer" can be understood as: a whole semiconductor material that has undergone epitaxial growth and patterning processes based on a substrate 5 with a preset cleavage angle. Cleaving the wafer along its crystal cleavage direction is a standard process step for mass-producing high-precision tilted output cavity surfaces by utilizing the crystal anisotropy of the material.

[0072] Optionally, the method for manufacturing the semiconductor laser includes the following specific steps: Step S1: Substrate selection and epitaxial growth A semiconductor substrate with a preset offset angle is selected. For example, a GaAs substrate with a physical surface offset of 15° relative to the (001) main crystal plane along the

[111] A direction can be used. Subsequently, the stacked structure 1 is grown on the offset substrate in one step using epitaxial equipment such as metal-organic chemical vapor deposition (MOCVD).

[0073] Step S2: Grating and Waveguide Patterning This step aims to integrate the lateral optical structure of the device. First, during photolithographic alignment, the axis of the overall waveguide optical path, including the master oscillator region 2 (MO region), the power preamplifier region 3, and the tapered power amplifier region 4 (PA region), is precisely aligned with the natural cleavage direction of the substrate 5. Subsequently, using electron beam lithography (EBL) combined with reactive ion etching (RIE) and other micro-nano fabrication techniques, the first DBR grating 21, the second DBR grating 23, the ridge waveguide 22, the power preamplifier 31, and the tapered power amplifier 41 are simultaneously fabricated, achieving integrated construction of each functional region.

[0074] Step S3: Insulation and Electrode Preparation An electrically insulating film is deposited on the P-side of the chip, and windows are created on this insulating layer using photolithography and etching processes to define the current injection area. Next, using a combination of metal evaporation and lift-off processes, electrically isolated P-side electrodes are fabricated within each window: the first electrode layer 6 (main oscillator region electrode), the second electrode layer 7 (power preamplifier region electrode), and the third electrode layer 8 (tapered power amplifier region electrode). Finally, the back side of the substrate 5 is thinned and polished, and a uniform N-side electrode layer 9 is deposited on its bottom surface.

[0075] Step S4: Cleavage, Passivation and Coating The entire wafer is diced and cleaved along the natural cleavage direction of substrate 5 to obtain individual laser chips. Since a substrate with a preset offset angle was used in step S1, and the waveguide optical path axis was precisely aligned with the cleavage direction in step S2, the output cavity surface 10 formed by cleaving will automatically have a tilted structure in the vertical plane, with a tilt angle equal to the offset angle of the substrate (e.g., 15°), requiring no additional cavity surface processing. After cleaving, the cavity surface is immediately passivated to reduce the interface state density; subsequently, an anti-reflective (AR) film is deposited on the tilted output cavity surface 10. To ensure uniform coverage at large angles, the anti-reflective film is preferably prepared using electron beam evaporation (EB) or ion beam sputtering (IBS) techniques.

[0076] Furthermore, in order to address the beam direction tilting issue caused by the tilted output cavity surface 10 and improve the device's practicality, during use, such as... Figure 7 As shown, the semiconductor laser chip is mounted on a standard heat sink 100, the upper surface of which is flat. The heat sink 100 and the laser chip it carries are then fixed as a whole to a specially designed base 200.

[0077] The base 200 is precisely designed with an inclined mounting surface. The inclination angle of this mounting surface complements the inclination angle of the output cavity surface 10 of the semiconductor laser chip. Through this compensatory design, when the flat heat sink 100 and the laser chip it supports are mounted together on the inclined base 200, the entire assembly allows the light beam, originally emitting at an inclination relative to the chip substrate, to be redirected in spatial orientation and ultimately emitted in a preset, standardized direction, such as horizontally (e.g., ...). Figure 7 (The direction indicated by the middle arrow B).

[0078] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0079] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0080] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0081] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0082] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A semiconductor laser having an in-plane tilted cavity surface, characterized in that, include: Layered structure (1); The main oscillator region (2), the power preamplifier region (3) and the tapered power amplifier region (4) are sequentially integrated on the stacked structure (1) along the extension direction of the waveguide optical path axis. Substrate (5), the stacked structure (1) is formed on the substrate (5); the substrate (5) has a preset offset angle, the preset offset angle is greater than or equal to 12° and less than 17°; The semiconductor laser has an output cavity surface (10) formed by cleaving along the cleaving direction of the substrate (5) at the output end of the tapered power amplifier region (4). The output cavity surface (10) is inclined in a vertical plane relative to the direction perpendicular to the waveguide optical path axis. The inclination angle of the output cavity surface (10) is equal to the preset offset angle.

2. The semiconductor laser according to claim 1, characterized in that, The preset offset angle of the substrate (5) is 15°.

3. The semiconductor laser according to claim 1, characterized in that, The stacked structure (1) includes a P-type contact layer (11), a confinement layer, a waveguide layer, and an active layer; the confinement layer, the waveguide layer, and the active layer are located between the substrate (5) and the P-type contact layer (11).

4. The semiconductor laser according to claim 3, characterized in that, The confinement layer includes an N-type lower confinement layer (12) and a P-type upper confinement layer (13), the waveguide layer includes a lower waveguide layer (14) and an upper waveguide layer (15), and the active layer includes a quantum well active layer (16). The N-type lower confinement layer (12) is disposed on the substrate (5), the lower waveguide layer (14) is disposed on the N-type lower confinement layer (12), the quantum well active layer (16) is disposed on the lower waveguide layer (14), the upper waveguide layer (15) is disposed on the quantum well active layer (16), the P-type upper confinement layer (13) is disposed on the upper waveguide layer (15), and the P-type contact layer (11) is disposed on the P-type upper confinement layer (13).

5. The semiconductor laser according to claim 3, characterized in that, The main oscillator region (2) includes: a first protruding structure integrally formed by the stacked structure (1), wherein the first protruding structure includes a first DBR grating (21), a ridge waveguide (22) and a second DBR grating (23) in sequence along the extension direction of the waveguide optical path axis, wherein the ridge waveguide (22) is located between the first DBR grating (21) and the second DBR grating (23).

6. The semiconductor laser according to claim 5, characterized in that, The power preamplifier region (3) includes a second protrusion structure integrally formed by the stacked structure (1), the second protrusion structure forming a power preamplifier (31), the power preamplifier (31) being located on the side of the second DBR grating (23) away from the ridge waveguide (22).

7. The semiconductor laser according to claim 6, characterized in that, The conical power amplifier region (4) includes: a third protrusion structure integrally formed by the stacked structure (1), the third protrusion structure forming a conical power amplifier (41), the conical power amplifier (41) being located on one side of the output end of the power preamplifier (31); the width of the third protrusion structure in the extension direction perpendicular to the waveguide optical path axis gradually increases along the direction from the input end of the third protrusion structure to the output end of the third protrusion structure.

8. The semiconductor laser according to claim 7, characterized in that, The semiconductor laser also includes: An electrically insulating film layer covers the P-type contact layer (11); the electrically insulating film layer has a first opening, a second opening and a third opening, the first opening being located above the ridge waveguide (22), the second opening being located above the second protrusion structure, and the third opening being located above the third protrusion structure. The structure comprises a first electrode layer (6), a second electrode layer (7), and a third electrode layer (8). The first electrode layer (6) is embedded in the first opening and is electrically connected to the upper surface of the ridge waveguide (22). The second electrode layer (7) is embedded in the second opening and is electrically connected to the upper surface of the second protrusion structure. The third electrode layer (8) is embedded in the third opening and is electrically connected to the upper surface of the third protrusion structure.

9. The semiconductor laser according to claim 1, characterized in that, The semiconductor laser also includes: An anti-reflective film is disposed on the output cavity surface (10); and / or, The N-side electrode layer (9) is disposed on the bottom surface of the substrate (5).

10. A method for manufacturing a semiconductor laser having an in-plane tilted cavity surface, characterized in that, The manufacturing method for preparing a semiconductor laser as described in any one of claims 1 to 9 comprises: S1. Select a substrate (5) with a preset offset angle; and form a stacked structure (1) on the substrate (5) in one step by epitaxial growth process. S2. Through photolithography and etching processes, a main oscillator region (2), a power preamplifier region (3), and a tapered power amplifier region (4) are formed on the stacked structure (1) in sequence along the waveguide optical path axis. S3. An electrically insulating film layer is deposited on the top layer of the stacked structure (1), and a window is made in the electrically insulating film layer by photolithography and etching process. P-side electrode layers that are electrically isolated from each other are made on the window. At the same time, a uniform N-side electrode layer (9) is prepared on the bottom surface of the substrate (5). S4. The wafer is cleaved along the cleavage direction of the substrate (5) to form an independent laser chip; Wherein, since the substrate (5) has a preset offset angle, the output cavity surface (10) formed by cleaving is inclined in the vertical plane relative to the direction perpendicular to the waveguide optical path axis, and the tilt angle of the output cavity surface (10) is equal to the preset offset angle.

Images