An antireflection semiconductor laser chip and a method for manufacturing the same

Abstract

The present application relates to a kind of anti-reflection semiconductor laser chips and its preparation method, including the active region and anti-reflection window region being arranged above substrate, active region is configured with straight strip active region ridge waveguide, anti-reflection window region is configured with anti-reflection ridge waveguide structure, anti-reflection ridge waveguide structure includes light loss ridge waveguide and light outlet ridge waveguide, light outlet ridge waveguide is configured as straight strip, light outlet ridge waveguide is parallel with active region ridge waveguide, and it is arranged with each other staggered, the both ends of light loss ridge waveguide are connected with active region ridge waveguide and light outlet ridge waveguide respectively, light loss ridge waveguide is as light loss area, light outlet ridge waveguide is as output light guide area.This chip, structure is simpler, growth preparation is easier, can obtain more excellent anti-reflection performance, not only can effectively reduce cost, and the requirement of patch package precision is greatly reduced, can realize high tolerance patch package and the high coupling efficiency of butt joint optical fiber, facilitate batch production import.

Description

Technical Field

[0001] This invention relates to the field of semiconductor laser technology, and more specifically to an anti-reflective semiconductor laser chip and its fabrication method. Background Technology

[0002] In existing fiber optic communication networks, DFB single-mode output lasers are widely used for transmission distances greater than ten kilometers. This type of semiconductor laser is susceptible to resonance disturbances from reflected light in the system link, which degrades the system's receiving sensitivity. Optical isolators must typically be added to optical devices to block reflected light; however, optical isolators are mainly imported, are expensive, and significantly increase the cost of optical modules, thus reducing the competitiveness of optical chips.

[0003] Currently, achieving inherent anti-reflection capabilities in optical chips has gradually become a key factor in enhancing chip competitiveness. The chip's inherent anti-reflection capability is related to both the stability of its resonant modes and the waveguide design in the vertical and horizontal directions at the light-emitting end. Major domestic optical chip manufacturers have some patents in this area. For example, Chinese patents CN 209993866 U and CN 111541149 A disclose a 10G anti-reflection laser and its fabrication process, which designs a gradually varying thickness of the optical waveguide layer in the vertical direction of the light-emitting end face to reduce the loss of reflected light within the waveguide layer. Another example is Chinese patent CN 209993868 U, which discloses a 25G anti-reflection distributed feedback laser, which designs a separation between the optical waveguide layer and the active layer in the vertical direction of the light-emitting end face to reduce the loss of externally reflected light. Yet another example is Chinese patent CN112290382 A, which discloses a semiconductor laser and its fabrication method, which designs a double-layer waveguide layer in the vertical direction of the light-emitting end face to optimize the divergence angle and the chip's anti-reflection capability. For example, Chinese patent CN115621843A discloses a semiconductor laser and its fabrication method. By setting an isolation layer between the waveguide layer and the active layer, and ensuring that the waveguide layer and the active layer are not directly connected, a better anti-reflection light effect can be achieved, significantly improving the chip's own anti-reflection capability.

[0004] The aforementioned anti-reflection design schemes for semiconductor laser chips each have their own advantages. However, existing anti-reflection designs for semiconductor laser chips generally suffer from more complex structures and more difficult fabrication, resulting in high costs. Furthermore, existing anti-reflection designs for semiconductor laser chips have higher precision requirements for surface mount packaging and lower tolerances, leading to low yields and making them unsuitable for mass production. These issues urgently need to be addressed. Summary of the Invention

[0005] The first aspect of this invention addresses the problems of high cost, high precision requirements for surface mount packaging, and low tolerance in existing anti-reflection designs for semiconductor laser chips, which lead to low yields and unsuitability for mass production. It provides a semiconductor laser chip with a simpler structure, easier growth and fabrication, and superior anti-reflection performance. This not only effectively reduces costs but also significantly lowers the precision requirements for surface mount packaging, enabling high-tolerance surface mount packaging and high coupling efficiency with optical fibers. This facilitates mass production adoption and is suitable for mass production. The main concept is as follows:

[0006] An anti-reflection semiconductor laser chip includes a substrate, on which an active region and an anti-reflection window region are disposed. The anti-reflection window region is located at the light-emitting end face, and the active region is connected to the anti-reflection window region. The active region is used to provide a laser resonant cavity environment.

[0007] The active region is constructed with a straight active region ridge waveguide, which includes an active layer and a grating layer located above the active layer, for realizing single-mode laser output.

[0008] The anti-reflection window region is constructed with an anti-reflection ridge waveguide structure, which includes an optical loss ridge waveguide and an output ridge waveguide. The output ridge waveguide is constructed as a straight strip and is parallel to the active region ridge waveguide, but staggered with each other. The two ends of the optical loss ridge waveguide are respectively connected to the active region ridge waveguide and the output ridge waveguide. The optical loss ridge waveguide serves as the optical loss region, and the output ridge waveguide serves as the output light guiding region. In this scheme, the output ridge waveguide and the active ridge waveguide are staggered, and an optical loss ridge waveguide connects the active and output ridge waveguides. This causes the optical loss ridge waveguide to bend compared to both the active and output ridge waveguides. On one hand, the optical loss ridge waveguide acts as a loss region, where reflected light is effectively attenuated, preventing disturbances to the active resonant cavity and ensuring laser mode stability. This results in excellent anti-reflection performance and significantly improves the chip's anti-reflection capability. On the other hand, while the output light is attenuated at the optical loss ridge waveguide, proper design ensures that the output light intensity remains sufficient for the optical module application after passing through the anti-reflection window region, while the reflected light intensity does not affect the module's transmission performance. By constructing the output ridge waveguide as a straight strip parallel to the active region ridge waveguide, the output ridge waveguide can serve as the output light guiding region, enabling effective control over the laser emission direction and divergence angle. This not only enhances the chip's anti-reflection capability but also effectively reduces the precision requirements of surface mount packaging, achieving high-tolerance surface mount packaging and high coupling efficiency with optical fibers. This not only significantly improves the yield of semiconductor laser chips but also facilitates mass production. Furthermore, compared to existing semiconductor laser chip anti-reflection designs, this anti-reflection semiconductor laser chip has a simpler structure and is easier to grow and fabricate. While achieving superior anti-reflection performance, it also effectively reduces costs, further facilitating mass production.

[0009] Furthermore, the grating layer employs a phase-shifting grating, which facilitates the realization of high-power single-mode laser output.

[0010] Preferably, the distance H1 between the centerline of the output ridge waveguide and the centerline of the active region ridge waveguide is 1μm to 30μm.

[0011] Preferably, the width of the active region ridge waveguide is 1.2 μm to 2.5 μm.

[0012] Preferably, the depth of the active region ridge waveguide reaches the grating layer, and the depth of the anti-reflection ridge waveguide structure within the anti-reflection window region is the same as the depth of the active region ridge waveguide. This not only facilitates better anti-reflection performance but also simplifies the process, increases fabrication efficiency, lowers costs, and makes it more suitable for mass production.

[0013] Preferably, the length L1 of the anti-reflection ridge waveguide structure is 30μm to 70μm.

[0014] Preferably, along the length direction of the active region ridge waveguide, in the anti-reflection ridge waveguide structure, the length L2 of the optical loss ridge waveguide is 15μm to 35μm, and the width is 1.2μm to 2.5μm.

[0015] Preferably, the length L3 of the output ridge waveguide is 15μm to 35μm and the width is 1.2μm to 6.0μm.

[0016] To address the issue of further improving anti-reflection performance, some solutions employ an arc-shaped optical loss ridge waveguide. In this solution, by constructing the optical loss ridge waveguide as an arc, the radius of curvature of the waveguide can be configured according to requirements, which helps to balance optical loss and anti-reflection capability.

[0017] Preferably, the radius of curvature of the optical loss ridge waveguide changes continuously from one end to the other. This allows for the connection between the active region ridge waveguide and the output ridge waveguide through the optical loss ridge waveguide with a continuously changing radius of curvature. The structure with a changing radius of curvature can effectively balance optical loss and anti-reflection capability.

[0018] To further improve anti-reflection performance, some solutions include an optical loss ridge waveguide comprising at least two series-connected oblique-straight ridge waveguides. The oblique-straight ridge waveguides at the ends are connected to the active region ridge waveguide and the output ridge waveguide, respectively. This allows for the configuration of the number and angle of the oblique-straight ridge waveguides as needed, facilitating a balance between optical loss and anti-reflection capability.

[0019] Preferably, the angle between two adjacent inclined straight ridge waveguide segments is 1° to 4°. This can effectively reduce optical loss and improve anti-reflection capability.

[0020] To address the issue of further improving anti-reflection performance, some solutions incorporate a section of obliquely straight ridge waveguide into the optical loss ridge waveguide. The two ends of this obliquely straight ridge waveguide are connected to the active region ridge waveguide and the exit ridge waveguide, respectively. The obliquely straight ridge waveguide is constructed in a straight strip shape. This extreme structural form maximizes the loss of reflected light, thereby further improving anti-reflection performance.

[0021] The second aspect of this invention addresses the problem of further improving product yield. Specifically, along the direction away from the optical loss ridge waveguide, the width of the output ridge waveguide gradually widens. This allows for the modulation of near-field optical energy distribution through the gradually widened output ridge waveguide, which not only further improves anti-reflection performance but also effectively reduces the divergence angle. This, in turn, effectively reduces the precision requirements for surface mount packaging, enabling high-tolerance surface mount packaging and high coupling efficiency with optical fibers, thus improving the yield of semiconductor laser chips.

[0022] In some designs, the anti-reflection ridge waveguide structure along the vertical direction is identical to the active region ridge waveguide structure along the vertical direction. This simplifies MOCVD epitaxy and chip fabrication processes.

[0023] A third aspect of the present invention addresses the problem in fabricating the aforementioned semiconductor laser by providing a method for fabricating such a semiconductor laser chip, comprising:

[0024] Step S1: On the substrate, a primary epitaxial structure is formed by MOCVD;

[0025] Step S2: Based on the epitaxial structure, a grating layer is formed by electron beam exposure and dry etching.

[0026] Step S3: A secondary epitaxial structure is formed on the grating layer by MOCVD;

[0027] Step S4: On the secondary epitaxial structure, etching is performed using dry etching and wet etching processes until the grating layer is etched to form a ridge waveguide structure. The ridge waveguide structure includes an active region ridge waveguide located in the active region, an optical loss ridge waveguide located in the anti-reflection window region, and an output ridge waveguide. The two ends of the optical loss ridge waveguide are respectively connected to the active region ridge waveguide and the output ridge waveguide.

[0028] Step S5: A silicon oxide protective film is formed on the ridge waveguide structure using PECVD.

[0029] Step S6: On the active region ridge waveguide, a window is opened in the silicon oxide protective film layer by dry etching, and a front metal electrode structure is formed by magnetron sputtering.

[0030] Step S7 involves grinding and polishing the back side of the substrate, and then forming a back metal electrode structure via magnetron sputtering. This method not only provides a simpler and more convenient way to obtain semiconductor laser chips with better anti-reflection performance, but also offers simple fabrication methods, controllable quality, and easier mass production.

[0031] A fourth aspect of this invention addresses the problem of further enhancing the anti-reflection capability of the chip itself. In some solutions, the vertical structure of the anti-reflection ridge waveguide differs from the vertical structure of the active region ridge waveguide. This invention aims to further enhance the chip's anti-reflection capability by configuring anti-reflection ridge waveguide structures with different vertical structures.

[0032] Preferably, the anti-reflection window region includes an InP cladding layer one, a PQ waveguide layer, and an InP cladding layer two arranged sequentially along the height direction. One end of the InP cladding layer one extends to the light-emitting end face, and the other end extends at least along the direction away from the substrate above the grating layer. The PQ waveguide layer is disposed above the InP cladding layer one, with one end extending to the light-emitting end face and the other end extending at least along the direction away from the substrate above the grating layer. The InP cladding layer two is disposed above the PQ waveguide layer. The active layer is connected to the side of the InP cladding layer one and corresponds to the PQ waveguide layer. The InP cladding layer one isolates the active layer and the PQ waveguide layer. In this scheme, by configuring the InP cladding layer one in the anti-reflection window region, the active layer and the PQ waveguide layer are isolated, preventing direct contact between the active layer and the PQ waveguide layer. This significantly increases the loss of external back-reflected light coupling into the active region. Meanwhile, by extending one end of the PQ waveguide layer to the light-emitting end face and the other end to the grating layer at least in the direction away from the substrate, the PQ waveguide layer can guide the reflected light entering the waveguide layer from the light-emitting end face to exit from the other end of the PQ waveguide layer, effectively preventing the reflected light from entering the active region, and can simultaneously achieve reflected light loss in the vertical direction, which is conducive to further improving the chip's own anti-reflection capability.

[0033] Furthermore, the depth of the active region ridge waveguide reaches the grating layer, and the depth of the anti-reflection ridge waveguide structure within the anti-reflection window region reaches at least the PQ waveguide layer. This not only facilitates better anti-reflection performance but also simplifies the process, increases fabrication efficiency, lowers costs, and makes it more suitable for mass production.

[0034] Furthermore, the depth of the active region ridge waveguide reaches the grating layer, and the depth of the anti-reflection ridge waveguide structure within the anti-reflection window region reaches the InP cladding layer. This extreme form of structure can maximize the reflected light loss within the optical loss ridge waveguide region, thereby further improving anti-reflection performance.

[0035] Preferably, the PQ waveguide layer is made of InGaAsP material. This is more conducive to dissipating reflected light along the vertical direction, thereby improving the chip's own anti-reflection capability.

[0036] Preferably, the thickness of the PQ waveguide layer is 30nm to 150nm. This ensures effective loss of reflected light and achieves better anti-reflection performance.

[0037] A fifth aspect of the present invention addresses the problem in fabricating the aforementioned semiconductor laser by providing a method for fabricating such a semiconductor laser chip, comprising:

[0038] Step S1: On the substrate, a primary epitaxial structure is formed by MOCVD;

[0039] Step S2: Based on the epitaxial structure, a grating layer is formed by electron beam exposure and dry etching.

[0040] Step S3: A secondary epitaxial structure is formed on the grating layer by MOCVD;

[0041] Step S4: Form a mask pattern for the anti-reflection window area on the secondary epitaxial structure;

[0042] Step S5: Isotropic etching is performed on the light-emitting end along the vertical direction to form an anti-reflection window area;

[0043] Step S6: Perform protective treatment on the end face etching area of ​​the anti-reflection window area;

[0044] Step S7: Perform three epitaxial growths in the end face etching area of ​​the anti-reflection window region, sequentially growing InP cladding layer one, PQ waveguide layer and InP cladding layer two.

[0045] Step S8: Perform a fourth epitaxial growth on the three-epiaxial structure;

[0046] Step S9: On the four-epitaxial structure, etching is performed by dry etching and wet etching processes to form a ridge waveguide structure. This includes etching the active region onto the grating layer to form an active region ridge waveguide, and simultaneously etching the anti-reflection window region onto the PQ waveguide layer to form an optical loss ridge waveguide and an output ridge waveguide. The two ends of the optical loss ridge waveguide are connected to the active region ridge waveguide and the output ridge waveguide, respectively.

[0047] Step S10: A silicon oxide protective film is formed on the ridge waveguide structure using PECVD.

[0048] Step S11: On the active region ridge waveguide, a window is opened in the silicon oxide protective film layer by dry etching, and a front metal electrode structure is formed by magnetron sputtering.

[0049] Step S12 involves grinding and polishing the back side of the substrate, and forming a back metal electrode structure by magnetron sputtering. This not only makes it simpler and more convenient to obtain the aforementioned semiconductor laser chip with better anti-reflection performance, but also facilitates mass production. Furthermore, the obtained semiconductor laser chip can simultaneously achieve reflected light loss in both the horizontal and vertical directions, thereby effectively dissipating reflected light in two mutually perpendicular directions and further improving the chip's anti-reflection performance.

[0050] A sixth aspect of the present invention addresses the problem in fabricating the aforementioned semiconductor laser by providing a method for fabricating such a semiconductor laser chip, comprising:

[0051] Step S1: On the substrate, a primary epitaxial structure is formed by MOCVD;

[0052] Step S2: Based on the epitaxial structure, a grating layer is formed by electron beam exposure and dry etching.

[0053] Step S3: A secondary epitaxial structure is formed on the grating layer by MOCVD;

[0054] Step S4: Form a mask pattern for the anti-reflection window area on the secondary epitaxial structure;

[0055] Step S5: Isotropic etching is performed on the light-emitting end along the vertical direction to form an anti-reflection window area;

[0056] Step S6: Perform protective treatment on the end face etching area of ​​the anti-reflection window area;

[0057] Step S7: Perform three epitaxial growths in the end face etching area of ​​the anti-reflection window region, sequentially growing InP cladding layer one, PQ waveguide layer and InP cladding layer two.

[0058] Step S8: Based on the three-stage epitaxial structure, perform a fourth epitaxial growth.

[0059] Step S9: On the four-epitaxial structure, etching is performed using dry etching and wet etching processes to form a preliminary ridge waveguide structure. This includes etching the active region onto the grating layer to form an active region ridge waveguide, and simultaneously etching the anti-reflection window region onto the PQ waveguide layer to form a preliminary optical loss ridge waveguide and a preliminary light exit ridge waveguide. The two ends of the optical loss ridge waveguide are connected to the active region ridge waveguide and the light exit ridge waveguide, respectively.

[0060] Step S10: Continue etching the anti-reflection window area using dry etching and wet etching processes. Continue etching the anti-reflection window area down along the initial optical loss ridge waveguide and the initial light outlet ridge waveguide to the InP cladding layer 1 to form the required ridge waveguide structure.

[0061] Step S11: A silicon oxide protective film is formed on the ridge waveguide structure using PECVD.

[0062] Step S12: On the active region ridge waveguide, a window is opened in the silicon oxide protective film layer by dry etching, and a front metal electrode structure is formed by magnetron sputtering.

[0063] Step S13 involves grinding and polishing the back side of the substrate, and then forming a back metal electrode structure via magnetron sputtering. This process not only allows for the fabrication of anti-reflection semiconductor laser chips with further improved anti-reflection performance, but also simplifies the process and makes it more suitable for mass production.

[0064] Compared with existing technologies, the anti-reflection semiconductor laser chip and its fabrication method provided by this invention have a simpler structure and are easier to grow and prepare, resulting in superior anti-reflection performance. This not only effectively reduces costs but also significantly lowers the requirements for surface mount packaging precision, enabling high-tolerance surface mount packaging and high coupling efficiency with optical fibers. This facilitates mass production and is suitable for mass production. Attached Figure Description

[0065] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0066] Figure 1 This is a schematic diagram of step S1, a primary epitaxial structure, in a method for fabricating an anti-reflection semiconductor laser chip according to Embodiment 1 of the present invention.

[0067] Figure 2 This is a schematic diagram of the structure of the grating layer in step S2 of the method for fabricating an anti-reflection semiconductor laser chip provided in Embodiment 1 of the present invention.

[0068] Figure 3 This is a schematic diagram of the secondary epitaxial structure in step S3 of the method for fabricating an anti-reflection semiconductor laser chip provided in Embodiment 1 of the present invention.

[0069] Figure 4 This is a top view of an anti-reflection semiconductor laser chip according to the present invention, and also a top view of a ridge waveguide structure obtained in step S4 of the fabrication method of an anti-reflection semiconductor laser chip provided in Embodiment 1 of the present invention.

[0070] Figure 5 This is a top view of another anti-reflection semiconductor laser chip according to the present invention, and also a top view of another ridge waveguide structure obtained in step S4 of the fabrication method of an anti-reflection semiconductor laser chip provided in Embodiment 1 of the present invention.

[0071] Figure 6 This is a top view of another anti-reflection semiconductor laser chip according to the present invention, and also a top view of another ridge waveguide structure obtained in step S4 of the fabrication method of an anti-reflection semiconductor laser chip provided in Embodiment 1 of the present invention.

[0072] Figure 7This is a schematic diagram of the structure of the semiconductor laser chip obtained in step S8 of the method for fabricating an anti-reflection semiconductor laser chip provided in Embodiment 1 of the present invention.

[0073] Figure 8 This is a schematic diagram of the structure after three epitaxial growths in step S7 of the method for fabricating an anti-reflection semiconductor laser chip provided in Embodiment 3 of the present invention.

[0074] Figure 9 This is a schematic diagram of the structure after four epitaxial growths in step S8 of the method for fabricating an anti-reflection semiconductor laser chip provided in Embodiment 3 of the present invention.

[0075] Figure 10 This is a top view after etching in step S9 of the method for fabricating an anti-reflection semiconductor laser chip provided in Embodiment 3 of the present invention.

[0076] Figure 11 This is a top view after etching in step S10 of the method for fabricating an anti-reflection semiconductor laser chip provided in Embodiment 4 of the present invention.

[0077] The markings in the diagram are as follows: 00, active region ridge waveguide; 01, optical loss ridge waveguide; 011, oblique straight ridge waveguide; 02, light outlet ridge waveguide.

[0078] 10. InP buffer layer, 11. n-type cladding, 12. Active layer, 13. p-type cladding, 14. Raster layer, 15. p-type capping layer one, 16. p-type capping layer two.

[0079] 20. InP substrate; 21. p-type contact layer.

[0080] 30. Antireflective coating; 31. High reflective coating.

[0081] 40. InP cladding layer one; 41. PQ waveguide layer; 42. InP cladding layer two. Detailed Implementation

[0082] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0083] Example 1

[0084] Please see Figure 1 This embodiment provides a method for fabricating an anti-reflection semiconductor laser chip, including the following main steps:

[0085] Step S1: A primary epitaxial structure is formed on the indium phosphide substrate 20. Specifically, an InP buffer layer 10, an n-type cladding layer 11, an active layer 12, a p-type cladding layer 13, and a grating layer 14 can be sequentially deposited on the indium phosphide (InP) substrate 20 using metal-organic chemical vapor deposition (MOCVD). Figure 1 As shown.

[0086] Step S2: Based on the epitaxial structure, a grating layer 14 is formed using electron beam lithography or inductively coupled plasma dry etching, such as... Figure 1 As shown, grating layer 14 is used to achieve single-mode laser output. In implementation, grating layer 14 can preferably be constructed as a phase-shifting grating, such as a λ / 4 phase-shifting grating, which is beneficial for achieving high-power single-mode laser output. Alternatively, grating layer 14 can also employ a partial grating structure.

[0087] Step S3: On the grating layer 14, a p-type capping layer 15 is deposited using the MOCVD method to form a secondary epitaxial structure, such as... Figure 2 As shown. The secondary epitaxial structure may also include a second p-type capping layer 16 and a p-type contact layer 21 deposited on the first p-type capping layer 15 using MOCVD, as shown. Figure 3 As shown.

[0088] Step S4: On the secondary epitaxial structure, a ridge waveguide structure is formed using dry etching and wet etching processes, such as... Figure 4 As shown. In implementation, existing photolithography processes can be used, and different ridge waveguide structure morphologies can be obtained by fabricating different mask patterns. In this embodiment, the ridge waveguide structure includes an active region ridge waveguide 00 located in the active region and an anti-reflection ridge waveguide structure located in the anti-reflection window region. The anti-reflection ridge waveguide structure includes an optical loss ridge waveguide 01 and an output ridge waveguide 02. The two ends of the optical loss ridge waveguide 01 are respectively connected to the active region ridge waveguide 00 and the output ridge waveguide 02, as shown. Figure 4As shown, the region near the light-emitting end face is called the anti-reflection window region. The active region is adjacent to the anti-reflection window region and is used to provide the laser resonant cavity environment. In this embodiment, along the direction perpendicular to the substrate 20, the anti-reflection ridge waveguide structure in the anti-reflection window region is the same as the structure of the active region ridge waveguide 00 in the active region in the vertical direction, which can simplify the MOCVD epitaxy and chip process. In implementation, the ridge waveguide structure can be preferentially etched to the grating layer, and in implementation, the etching depth of the active region ridge waveguide 00, the optical loss ridge waveguide 01, and the light-emitting port ridge waveguide 02 can be the same. As an example, in this embodiment, both the active region and the anti-reflection window region are etched to the grating layer, as shown in the figure. That is, the depth of the active region ridge waveguide reaches the grating layer, and the depth of the anti-reflection ridge waveguide structure in the anti-reflection window region is the same as the depth of the active region ridge waveguide. This not only achieves better anti-reflection effect, but also simplifies the process and reduces costs.

[0089] In implementation, the active region ridge waveguide 00 is constructed as a straight strip, such as... Figure 4 As shown, the width of the active region ridge waveguide 00 can preferably be 1.2μm to 2.5μm. For example, the width of the active region ridge waveguide 00 can preferably be 1.5μm, 2.0μm, or 2.5μm, etc. Meanwhile, the output ridge waveguide 02 can also be constructed as a straight strip, such as... Figure 4 As shown, the width of the output ridge waveguide 02 can preferably be between 1.2 μm and 6.0 μm. For example, the width of the output ridge waveguide 02 can preferably be 2.0 μm, 3.0 μm, 4.0 μm, or 5.0 μm, etc., and the width of the output ridge waveguide 02 can be larger than the width of the active region ridge waveguide 00, which is beneficial for controlling the divergence angle. Figure 4 As shown, the output ridge waveguide 02 is parallel to the active ridge waveguide 00 and is staggered relative to it. The spacing of the stagger can be determined according to actual needs. For example, the spacing H1 between the centerline of the output ridge waveguide 02 and the centerline of the active ridge waveguide 00 can preferably be 1μm to 30μm. Figure 4 As shown.

[0090] In implementation, the length of the anti-reflection ridge waveguide structure (i.e., the length along the horizontal direction) can be determined according to actual needs. To achieve better anti-reflection effects, the length of the anti-reflection ridge waveguide structure can preferably be 30μm to 70μm. For example, the length of the anti-reflection ridge waveguide structure can preferably be 30μm, 40μm, 50μm, 60μm, or 70μm. In implementation, the length L3 of the light-emitting ridge waveguide 02 can preferably be 15μm to 35μm. For example, the length L3 of the light-emitting ridge waveguide 02 can preferably be 20μm, 25μm, or 30μm. Similarly, in implementation, along the length direction of the active region ridge waveguide 00, the length L2 of the optical loss ridge waveguide 01 in the anti-reflection ridge waveguide structure can preferably be 15μm to 35μm. For example, the length L2 of the optical loss ridge waveguide 01 can preferably be 20μm, 25μm, or 30μm.

[0091] In this embodiment, the optical loss ridge waveguide 01 serves as the optical loss region, and the output ridge waveguide 02 serves as the output optical guiding region. Since the active region ridge waveguide 00 and the output ridge waveguide 02 are parallel to each other and staggered, and the two ends of the optical loss ridge waveguide 01 are the active region ridge waveguide 00 and the output ridge waveguide 02 respectively, the optical loss ridge waveguide 01 will inevitably be bent compared to the active region ridge waveguide 00 and the output ridge waveguide 02. In implementation, the shape of the optical loss ridge waveguide 01 can be determined according to actual needs. As an example, the optical loss ridge waveguide 01 can be constructed as an arc-shaped structure to allow for the configuration of the radius of curvature of the optical loss ridge waveguide 01 according to requirements, which is beneficial for balancing optical loss and anti-reflection capability. The arc-shaped structure can be a circular arc structure, such as... Figure 5 As shown, the radius of curvature of the optical loss ridge waveguide 01 remains constant at this time. In implementation, the optical loss ridge waveguide 01 can also be a non-circular arc structure, such as an elliptical arc structure, so that the radius of curvature of the optical loss ridge waveguide 01 can continuously change from one end to the other. This allows the connection between the active region ridge waveguide 00 and the output ridge waveguide 02 to be achieved through the optical loss ridge waveguide 01 with a continuously changing radius of curvature. By adopting a structure with a changing radius of curvature, optical loss and anti-reflection capability can be effectively balanced.

[0092] As another example, the optical loss ridge waveguide 01 may include at least two series-connected oblique ridge waveguides. The oblique ridge waveguides at the ends are connected to the active region ridge waveguide 00 and the output ridge waveguide 02, respectively, to allow for the configuration of the number and angle of the oblique ridge waveguides as needed, which is beneficial for balancing optical loss and anti-reflection capability. In implementation, the number of oblique ridge waveguides can be determined according to actual needs; for example, the oblique ridge waveguides may include two, three, or four oblique ridge waveguides. The angle between two adjacent oblique ridge waveguides can be determined according to actual needs, such as... Figure 6As shown. In implementation, the included angle between two adjacent oblique straight ridge waveguide segments can preferably be 1° to 4°, which can effectively reduce optical loss and improve anti-reflection capability. For example, the included angle between two adjacent oblique straight ridge waveguide segments can be 1°, 2°, 3°, or 4°, etc. In this case, the width of the optical loss ridge waveguide 01 can preferably be 1.2μm to 2.5μm.

[0093] As another example, the optical loss ridge waveguide 01 can also consist of only a section of oblique straight ridge waveguide, such as... Figure 4 As shown, the two ends of the oblique straight ridge waveguide are connected to the active region ridge waveguide 00 and the output ridge waveguide 02, respectively, and the oblique straight ridge waveguide is constructed in a straight strip shape. This extreme form structure can maximize the loss of reflected light, thereby helping to further improve anti-reflection performance. In implementation, the width of the optical loss ridge waveguide 01 can preferably be 1.2μm to 2.5μm. For example, the width of the optical loss ridge waveguide 01 can preferably be 1.5μm or 2μm, etc. In this embodiment, the width of the optical loss ridge waveguide 01 is the same as the width of the active region ridge waveguide 00, such as... Figure 4 As shown.

[0094] Step S5: A silicon oxide protective film is formed on the ridge waveguide structure using PECVD.

[0095] Step S6: On the active region ridge waveguide 00, a window is opened in the silicon oxide protective film layer by dry etching, and a front metal electrode structure is formed by magnetron sputtering, for example, by depositing a p-metal electrode.

[0096] Step S7: Grinding and polishing are performed on the back side of the substrate 20 to thin and polish the back side of the InP substrate 20 to 100μm±10μm, and then a back metal electrode structure is formed by magnetron sputtering, for example, by depositing an n-metal electrode.

[0097] A more refined solution also includes step S8, where, after the wafer is separated by the bar strip, an anti-reflection coating layer 30 is deposited on the light-emitting end face, such as... Figure 7 As shown, simultaneously, a high-reflectivity film layer 31 is deposited on the other side of the active region, such as... Figure 7 As shown, the process is now complete. This not only makes it easier and more convenient to obtain the aforementioned semiconductor laser chip with better anti-reflection performance, but also makes the preparation method simple, the quality controllable, and easier for mass production.

[0098] Specifically, the anti-reflection semiconductor laser chip provided in this embodiment has two main advantages. First, the optical loss ridge waveguide 01 can serve as an optical loss region, where reflected light is effectively attenuated, preventing disturbances to the active region resonant cavity and affecting laser mode stability. This achieves excellent anti-reflection performance and significantly enhances the chip's anti-reflection capability. Second, while the output light experiences loss at the optical loss ridge waveguide 01, proper design ensures that the output light intensity remains sufficient to meet the requirements of the optical module after passing through the anti-reflection window region, while the reflected light intensity does not affect the transmission performance requirements of the optical module. Third, by constructing the output ridge waveguide 02 as a straight strip parallel to the active region ridge waveguide 00, the output ridge waveguide 02 can serve as an output light guide region, enabling effective control of the laser output direction and divergence angle. This not only improves the chip's anti-reflection capability but also effectively reduces the precision requirements of surface mount packaging, achieving high-tolerance surface mount packaging and high coupling efficiency with optical fibers. This not only effectively improves the yield of the semiconductor laser chip but also facilitates mass production.

[0099] Example 2

[0100] To further improve product yield, the main difference between this embodiment 2 and embodiment 1 is that in the anti-reflection semiconductor laser chip provided in this embodiment, the width of the output ridge waveguide 02 gradually widens along the direction away from the optical loss ridge waveguide 01, as shown below. Figures 4-6 As shown, the near-field light energy distribution can be controlled by gradually widening the ridge waveguide 02 at the output port. This not only helps to further improve the anti-reflection performance, but also effectively reduces the divergence angle, thereby effectively reducing the precision requirements of the surface mount packaging, achieving high-tolerance surface mount packaging and high coupling efficiency of the docking optical fiber, which is beneficial to improving the yield of semiconductor laser chips.

[0101] In implementation, the output ridge waveguide 02 can gradually widen only at one end near the optical loss ridge waveguide 01, such as... Figures 4-6 As shown, the remaining portion of the light-emitting ridge waveguide 02 is in the form of straight strips, such as... Figures 4-6 As shown, this effectively controls the near-field light energy distribution, which not only improves anti-reflection performance but also does not affect the output light, achieving effective control over the laser emission direction and divergence angle. Of course, in practice, the width of the emission port ridge waveguide 02 can gradually increase along the direction from the optical loss ridge waveguide 01 to the emission end face; that is, it is narrowest at the end near the optical loss ridge waveguide 01 and widest at the end near the emission end face.

[0102] like Figures 4-6As shown, in this embodiment, the width of the optical loss ridge waveguide 01 is the same as the width of the active region ridge waveguide 00, and the width of the light outlet ridge waveguide 02 is greater than the width of the optical loss ridge waveguide 01 and the width of the active region ridge waveguide 00. This is beneficial for achieving better anti-reflection effect and for reducing the precision requirements of surface mount packaging, thereby achieving high-tolerance surface mount packaging.

[0103] Example 3

[0104] To address the issue of further enhancing the anti-reflection capability of the chip itself, this embodiment 3 provides a semiconductor laser chip with an alternative structure. The main difference between this embodiment and embodiments 1 and 2 is that, in this semiconductor laser chip, along the direction perpendicular to the substrate 20, the vertical structure of the anti-reflection ridge waveguide in the anti-reflection window region differs from the vertical structure of the active region ridge waveguide 00 in the active region. For example... Figure 8 and Figure 9 As shown, the anti-reflection capability of the chip can be further improved by configuring anti-reflection ridge waveguide structures with different vertical structures. For example, in implementation, the structure of the anti-reflection ridge waveguide structure along the direction perpendicular to the substrate 20 (vertical direction) can be the same as the structure along the vertical direction in the anti-reflection window region disclosed in Chinese Patent CN 209993866 U, so as to achieve loss of reflected light along the vertical direction (direction perpendicular to the substrate 20) and prevent reflected light from entering the active region. Through the processing of steps S4-S7 in Embodiment 1, a semiconductor laser chip that can lose reflected light both vertically and horizontally can be obtained, thereby further improving the chip's anti-reflection capability. At this time, the structure of the anti-reflection ridge waveguide structure along the vertical direction is different from the structure of the active region ridge waveguide 00 in the active region along the vertical direction. Similarly, in implementation, the anti-reflection ridge waveguide structure along the direction perpendicular to the substrate 20 (vertical direction) can be the same as the vertical structure in the anti-reflection window region disclosed in Chinese Patent CN 209993868 U. This makes the vertical structure of the anti-reflection ridge waveguide structure different from the vertical structure of the active region ridge waveguide 00 in the active region, further enhancing the chip's anti-reflection capability. Furthermore, the vertical structure of the anti-reflection ridge waveguide structure along the direction perpendicular to the substrate 20 can also be the same as the vertical structure in the anti-reflection window region disclosed in Chinese Patent CN 112290382 A, etc.

[0105] Preferably, in this embodiment, the anti-reflection window region includes an InP cladding layer 40, a PQ waveguide layer 41, and an InP cladding layer 42 arranged sequentially along the height direction. One end of the InP cladding layer 40 extends to the light-emitting end face, and the other end extends at least along the direction away from the substrate 20 above the grating layer 14. Figure 8 and Figure 9As shown. The PQ waveguide layer 41 is disposed above the InP cladding layer 40. One end of the PQ waveguide layer 41 extends to the light-emitting end face, and the other end extends at least in the direction away from the substrate 20 above the grating layer 14, as shown. Figure 8 and Figure 9 As shown. In implementation, the PQ waveguide layer 41 can preferably be made of InGaAsP material, and its thickness can be 30nm to 150nm. This allows for simultaneous reduction of reflected light in the vertical direction, thereby further improving the chip's anti-reflection performance. For example... Figure 8 and Figure 9 As shown, the second InP cladding layer 42 is disposed above the PQ waveguide layer 41. The active layer 12 is connected to the side of the first InP cladding layer 40 and corresponds to the PQ waveguide layer 41 to facilitate light emission. The first InP cladding layer 40 can isolate the active layer 12 and the PQ waveguide layer 41. In this anti-reflection window region, by configuring the first InP cladding layer 40 in the anti-reflection window region, the active layer 12 and the PQ waveguide layer 41 are isolated by the first InP cladding layer 40, so that the active layer 12 and the PQ waveguide layer 41 do not directly contact each other, thereby greatly increasing the loss of external back-reflected light coupling into the active region. Meanwhile, by extending one end of the PQ waveguide layer 41 to the light-emitting end face and the other end to extend at least along the direction away from the substrate 20 above the grating layer 14, the PQ waveguide layer 41 can guide the reflected light entering the waveguide layer from the light-emitting end face to exit from the other end of the PQ waveguide layer 41, effectively preventing reflected light from entering the active region and simultaneously achieving reflected light loss in the vertical direction, thereby further improving the chip's anti-reflection capability. To fabricate a semiconductor laser chip with this structure, this embodiment provides a method for fabricating the semiconductor laser chip, including...

[0106] Step S1: A primary epitaxial structure is formed on the indium phosphide substrate 20. Specifically, an InP buffer layer 10, an n-type cladding layer 11, an active layer 12, a p-type cladding layer 13, and a grating layer 14 can be sequentially deposited on the indium phosphide (InP) substrate 20 using metal-organic chemical vapor deposition (MOCVD). Figure 1 As shown.

[0107] Step S2: Based on the primary epitaxial structure, a grating layer 14 is formed using electron beam lithography or inductively coupled plasma dry etching, such as... Figure 1 As shown, grating layer 14 is used to achieve single-mode laser output. In implementation, grating layer 14 can preferably be constructed as a λ / 4 phase-shift grating, which is beneficial for achieving high-power single-mode laser output.

[0108] Step S3: On the grating layer 14, a p-type capping layer 15 is deposited using the MOCVD method to form a secondary epitaxial structure, such as... Figure 2 As shown.

[0109] Step S4: On the secondary epitaxial structure, a mask pattern for the anti-reflection window region is formed; specifically, a SiO2 mask layer can be deposited on the surface of the p-type capping layer-15 using plasma-enhanced chemical vapor deposition (PECVD). The material of the mask layer can be Si3N4 or SiO2, and the mask pattern is fabricated using photolithography.

[0110] Step S5: Isotropic etching is performed on the light-emitting end along the vertical direction to form an anti-reflection window region, such as... Figure 8 or Figure 9 As shown.

[0111] Step S6: Protect the end face etching area of ​​the anti-reflection window region.

[0112] Step S7: Three epitaxial growths are performed on the end-face etching region of the anti-reflection window area, sequentially growing InP cladding layer 1 40, PQ waveguide layer 41, and InP cladding layer 2 42 to form a three-stage epitaxial structure, as shown below. Figure 8 As shown, one end of the InP cladding layer 40 extends to the light-emitting end face, and the other end extends at least in a direction away from the substrate 20 above the grating layer 14, as shown. Figure 8 As shown. The PQ waveguide layer 41 is disposed above the InP cladding layer 40. One end of the PQ waveguide layer 41 extends to the light-emitting end face, and the other end extends at least in a direction away from the substrate 20 above the grating layer 14, as shown. Figure 8 As shown. The second InP cladding layer 42 is disposed above the PQ waveguide layer 41. The active layer 12 is connected to the side of the first InP cladding layer 40 and corresponds to the PQ waveguide layer 41, as shown. Figure 8 As shown, this isolates the active layer 12 from the PQ waveguide layer 41.

[0113] Step S8: Based on the three-stage epitaxial structure, a fourth epitaxial growth is performed. Specifically, the MOCVD method can be used to sequentially deposit a p-type capping layer 16 and a p-type contact layer 21 above the p-type capping layer 15 and the InP cladding layer 42, as shown below. Figure 9 As shown.

[0114] Step S9: Perform chip fabrication. On the four-epilithography structure, a ridge waveguide structure is formed using dry etching and wet etching processes. The ridge waveguide structure includes an active region ridge waveguide 00 located in the active region and an anti-reflection ridge waveguide structure located in the anti-reflection window region. The anti-reflection ridge waveguide structure includes an optical loss ridge waveguide 01 located in the anti-reflection window region and an output ridge waveguide 02. The two ends of the optical loss ridge waveguide 01 are connected to the active region ridge waveguide 00 and the output ridge waveguide 02, respectively. Figure 10As shown. In implementation, the structure and dimensional parameters of the active region ridge waveguide 00, the optical loss ridge waveguide 01, and the output ridge waveguide 02 can be the same as in Embodiment 1, and will not be repeated here. In this embodiment, the p-type capping layer one and the InP cladding layer two are made of the same material. Therefore, in implementation, the p-type capping layer one and the InP cladding layer two can be etched away simultaneously, so that the active region can be etched onto the grating layer 14 (i.e., the active region is etched onto the upper surface of the grating layer) in one etching process to form the active region ridge waveguide 00. At the same time, the anti-reflection window region is etched onto the PQ waveguide layer 41 (i.e., the anti-reflection window region is etched onto the upper surface of the PQ waveguide layer 41) to form the optical loss ridge waveguide 01 and the output ridge waveguide 02, as shown. Figure 10 As shown, the two ends of the optical loss ridge waveguide are connected to the active region ridge waveguide and the output ridge waveguide, respectively. This method not only obtains the desired ridge waveguide structure morphology, which is beneficial for achieving better anti-reflection effects, but also has a simpler process, higher fabrication efficiency, and lower cost, making it more suitable for mass production.

[0115] Step S10: A silicon oxide protective film is formed on the ridge waveguide structure using PECVD.

[0116] Step S11: On the active region ridge waveguide 00, a window is opened in the silicon oxide protective film layer by dry etching, and a front metal electrode structure is formed by magnetron sputtering, for example, by depositing a p-metal electrode.

[0117] Step S12: Grinding and polishing are performed on the back side of the substrate 20 to thin and polish the back side of the InP substrate 20 to 100μm±10μm, and then a back metal electrode structure is formed by magnetron sputtering, for example, by depositing an n-metal electrode.

[0118] A more refined solution also includes step S13, where, after the wafer is separated by the bar strip, an anti-reflection coating layer 30 is deposited on the light-emitting end face, such as... Figure 9 As shown, a high-reflectivity film layer 31 is simultaneously deposited on the other side of the active region, such as... Figure 9 As shown, the process is now complete.

[0119] Using this preparation method, it is not only easier and more convenient to obtain the above-mentioned semiconductor laser chip with better anti-reflection performance, but also easier to mass-produce. Moreover, the obtained semiconductor laser chip can achieve reflected light loss simultaneously in both the horizontal and vertical directions, thereby effectively losing reflected light in two mutually perpendicular directions and further improving the anti-reflection performance of the chip.

[0120] Example 4

[0121] To further improve anti-reflection performance, Embodiment 4 provides a semiconductor laser chip with an alternative structure. The main difference from Embodiment 3 is the depth of the anti-reflection ridge waveguide structure along the vertical direction. Specifically, in this embodiment, the depth of the active region ridge waveguide extends to the grating layer 14, and the depth of the anti-reflection ridge waveguide structure within the anti-reflection window region reaches the InP cladding layer 40. Figure 11 As shown, this extreme form structure can maximize the reflected light loss in the optical loss ridge waveguide region, which is beneficial for further improving the anti-reflection performance.

[0122] Accordingly, this embodiment also provides a method for fabricating such a semiconductor laser chip. Steps S1-S8 of this method are the same as steps S1-S8 in Embodiment 3, and will not be repeated here. In addition, this method also includes step S9, which involves etching the four-stage epitaxial structure using dry etching and wet etching processes to form a preliminary ridge waveguide structure. This includes etching the active region onto the grating layer 14 (i.e., etching the active region onto the upper surface of the grating layer) to form the active region ridge waveguide 00. Figure 10 As shown, simultaneously, the anti-reflection window region is etched onto the PQ waveguide layer 41 (i.e., the anti-reflection window region is etched onto the upper surface of the PQ waveguide layer 41) to form a preliminary optical loss ridge waveguide 01 and a preliminary light exit ridge waveguide 02, as shown. Figure 10 As shown, the two ends of the optical loss ridge waveguide 01 are connected to the active region ridge waveguide 00 and the output ridge waveguide 02, respectively. The structure and size parameters of the active region ridge waveguide 00, the optical loss ridge waveguide 01 and the output ridge waveguide 02 can be the same as those in Example 1, and will not be repeated here.

[0123] Step S10: Continue etching the anti-reflection window region using dry and wet etching processes. The anti-reflection window region is etched downwards along the initial optical loss ridge waveguide and the initial output ridge waveguide to the InP cladding layer 40 (i.e., the anti-reflection window region is etched to the upper surface of the InP cladding layer 40), forming the required optical loss ridge waveguide 01 and output ridge waveguide 02, as shown below. Figure 11 As shown, the formed ridge waveguide structure includes an active region ridge waveguide 00 located in the active region and an anti-reflection ridge waveguide structure located in the anti-reflection window region. The anti-reflection ridge waveguide structure includes an optical loss ridge waveguide 01 located in the anti-reflection window region and an output ridge waveguide 02. The two ends of the optical loss ridge waveguide 01 are connected to the active region ridge waveguide 00 and the output ridge waveguide 02, respectively. Figure 11 As shown, the depth of the active region ridge waveguide reaches the grating layer, as... Figure 11 As shown, the depth of the anti-reflection ridge waveguide structure within the anti-reflection window region reaches the InP cladding layer one, as... Figure 11 As shown.

[0124] Step S11: A silicon oxide protective film is formed on the ridge waveguide structure using PECVD.

[0125] In step S12, on the active region ridge waveguide 00, a window is opened in the silicon oxide protective film layer by dry etching, and a front metal electrode structure is formed by magnetron sputtering, for example, by depositing a p-metal electrode.

[0126] Step S13: Grinding and polishing are performed on the back side of the substrate 20 to thin and polish the back side of the InP substrate 20 to 100μm±10μm, and then a back metal electrode structure is formed by magnetron sputtering, for example, by depositing an n-metal electrode.

[0127] A more refined solution also includes step S13, where, after the wafer is separated by the bar strip, an anti-reflection coating layer 30 is deposited on the light-emitting end face, such as... Figure 9 As shown, simultaneously, a high-reflectivity film layer 31 is deposited on the other side of the active region, such as... Figure 9 As shown, the process is now complete. This chip and its fabrication process not only effectively reduce costs but also significantly lower the requirements for surface mount packaging precision. It enables high-tolerance surface mount packaging and high coupling efficiency with optical fibers, facilitating mass production and making it suitable for mass production. The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this invention should be included within the scope of protection of this invention.

Claims

1. An anti-reflection semiconductor laser chip, comprising a substrate, wherein an active region and an anti-reflection window region are disposed on the substrate, the anti-reflection window region is located at the light-emitting end face, the active region is connected to the anti-reflection window region, and the active region is used to provide a laser resonant cavity environment, characterized in that, The active region is constructed with a straight active region ridge waveguide, which includes an active layer and a grating layer located above the active layer, for realizing single-mode laser output; The anti-reflection window region is constructed with an anti-reflection ridge waveguide structure, which includes an optical loss ridge waveguide and an output ridge waveguide. The output ridge waveguide is constructed as a straight strip and is parallel to the active region ridge waveguide, but staggered with each other. The two ends of the optical loss ridge waveguide are respectively connected to the active region ridge waveguide and the output ridge waveguide. The optical loss ridge waveguide serves as the optical loss region, and the output ridge waveguide serves as the output light guiding region. The distance H1 between the centerline of the optical output ridge waveguide and the centerline of the active region ridge waveguide is 1μm~30μm; The width of the active region ridge waveguide is 1.2μm~2.5μm; The width of the optical loss ridge waveguide is 1.2μm~2.5μm; The width of the ridge waveguide at the light output port is 1.2μm~6.0μm.

2. The anti-reflection semiconductor laser chip according to claim 1, characterized in that, The grating layer is a phase-shifted grating; and / or, the depth of the active region ridge waveguide reaches the grating layer, and the depth of the anti-reflection ridge waveguide structure in the anti-reflection window region is the same as the depth of the active region ridge waveguide.

3. The anti-reflection semiconductor laser chip according to claim 1, characterized in that, The length L1 of the anti-reflection ridge waveguide structure is 30μm~70μm; And / or, along the length direction of the active region ridge waveguide, the length L2 of the optical loss ridge waveguide is 15μm~35μm; And / or, the length L3 of the output ridge waveguide is 15μm~35μm.

4. The anti-reflection semiconductor laser chip according to claim 1, characterized in that, The optical loss ridge waveguide is constructed as an arc structure; Alternatively, the optical loss ridge waveguide includes at least two cascaded oblique and straight ridge waveguides, with the oblique and straight ridge waveguides at the ends connected to the active region ridge waveguide and the output ridge waveguide, respectively. Alternatively, the optical loss ridge waveguide includes a section of oblique straight ridge waveguide, the two ends of which are connected to the active region ridge waveguide and the output ridge waveguide, respectively, and the oblique straight ridge waveguide is constructed in a straight strip shape.

5. The anti-reflection semiconductor laser chip according to any one of claims 1-4, characterized in that, The vertical structure of the anti-reflection ridge waveguide differs from that of the active region ridge waveguide.

6. The anti-reflection semiconductor laser chip according to claim 5, characterized in that, The anti-reflection window region includes an InP cladding layer one, a PQ waveguide layer, and an InP cladding layer two arranged sequentially along the height direction. One end of the InP cladding layer one extends to the light-emitting end face, and the other end of the InP cladding layer one extends at least in the direction away from the substrate above the grating layer. The PQ waveguide layer is disposed above the InP cladding layer one, with one end extending to the light-emitting end face and the other end extending at least in the direction away from the substrate above the grating layer. The InP cladding layer two is disposed above the PQ waveguide layer. The active layer is connected to the side of the InP cladding layer one and corresponds to the PQ waveguide layer. The InP cladding layer one isolates the active layer and the PQ waveguide layer. The depth of the active region ridge waveguide reaches the grating layer, and the depth of the anti-reflection ridge waveguide structure in the anti-reflection window region reaches at least the PQ waveguide layer.

7. A method for fabricating an anti-reflection semiconductor laser chip according to any one of claims 1-4, characterized in that, include, Step S1: On the substrate, a primary epitaxial structure is formed by MOCVD; Step S2: Based on the epitaxial structure, a grating layer is formed by electron beam exposure and dry etching. Step S3: A secondary epitaxial structure is formed on the grating layer by MOCVD; Step S4: On the secondary epitaxial structure, etching is performed using dry etching and wet etching processes until the grating layer is etched to form a ridge waveguide structure. The ridge waveguide structure includes an active region ridge waveguide located in the active region, an optical loss ridge waveguide located in the anti-reflection window region, and an output ridge waveguide. The two ends of the optical loss ridge waveguide are respectively connected to the active region ridge waveguide and the output ridge waveguide. Step S5: A silicon oxide protective film is formed on the ridge waveguide structure using PECVD. Step S6: On the active region ridge waveguide, a window is opened in the silicon oxide protective film layer by dry etching, and a front metal electrode structure is formed by magnetron sputtering. Step S7: Grind and polish the back side of the substrate, and form a back metal electrode structure by magnetron sputtering.

8. A method for fabricating the anti-reflection semiconductor laser chip as described in claim 6, characterized in that, include, Step S1: On the substrate, a primary epitaxial structure is formed by MOCVD; Step S2: Based on the epitaxial structure, a grating layer is formed by electron beam exposure and dry etching. Step S3: A secondary epitaxial structure is formed on the grating layer by MOCVD; Step S4: Form a mask pattern for the anti-reflection window area on the secondary epitaxial structure; Step S5: Isotropic etching is performed on the light-emitting end along the vertical direction to form an anti-reflection window area; Step S6: Perform protective treatment on the end face etching area of ​​the anti-reflection window area; Step S7: Perform three epitaxial growths in the end face etching area of ​​the anti-reflection window region, sequentially growing InP cladding layer one, PQ waveguide layer and InP cladding layer two. Step S8: Based on the three-stage epitaxial structure, perform a fourth epitaxial growth. Step S9: On the four-epitaxial structure, etching is performed by dry etching and wet etching processes to form a ridge waveguide structure. This includes etching the active region onto the grating layer to form an active region ridge waveguide, and simultaneously etching the anti-reflection window region onto the PQ waveguide layer to form an optical loss ridge waveguide and an output ridge waveguide. The two ends of the optical loss ridge waveguide are connected to the active region ridge waveguide and the output ridge waveguide, respectively. Step S10: A silicon oxide protective film is formed on the ridge waveguide structure using PECVD. Step S11: On the active region ridge waveguide, a window is opened in the silicon oxide protective film layer by dry etching, and a front metal electrode structure is formed by magnetron sputtering. Step S12: Grinding and polishing are performed on the back side of the substrate, and a back metal electrode structure is formed by magnetron sputtering.

9. A method for fabricating the anti-reflection semiconductor laser chip as described in claim 6, characterized in that, include, Step S1: On the substrate, a primary epitaxial structure is formed by MOCVD; Step S2: Based on the epitaxial structure, a grating layer is formed by electron beam exposure and dry etching. Step S3: A secondary epitaxial structure is formed on the grating layer by MOCVD; Step S4: Form a mask pattern for the anti-reflection window area on the secondary epitaxial structure; Step S5: Isotropic etching is performed on the light-emitting end along the vertical direction to form an anti-reflection window area; Step S6: Perform protective treatment on the end face etching area of ​​the anti-reflection window area; Step S7: Perform three epitaxial growths in the end face etching area of ​​the anti-reflection window region, sequentially growing InP cladding layer one, PQ waveguide layer and InP cladding layer two. Step S8: Based on the three-stage epitaxial structure, perform a fourth epitaxial growth. Step S9: On the four-epitaxial structure, etching is performed using dry etching and wet etching processes to form a preliminary ridge waveguide structure. This includes etching the active region onto the grating layer to form an active region ridge waveguide, and simultaneously etching the anti-reflection window region onto the PQ waveguide layer to form a preliminary optical loss ridge waveguide and a preliminary light exit ridge waveguide. The two ends of the optical loss ridge waveguide are connected to the active region ridge waveguide and the light exit ridge waveguide, respectively. Step S10: Continue etching the anti-reflection window area using dry etching and wet etching processes. Continue etching the anti-reflection window area down along the initial optical loss ridge waveguide and the initial light outlet ridge waveguide to the InP cladding layer 1 to form the required ridge waveguide structure. Step S11: A silicon oxide protective film is formed on the ridge waveguide structure using PECVD. Step S12: On the active region ridge waveguide, a window is opened in the silicon oxide protective film layer by dry etching, and a front metal electrode structure is formed by magnetron sputtering. Step S13: Grinding and polishing are performed on the back side of the substrate, and a back metal electrode structure is formed by magnetron sputtering.

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