Semiconductor laser with on-chip composite cavity structure and preparation method thereof
By designing an on-chip composite cavity structure, the beam quality of the array semiconductor laser was improved, the problem of optical field control was solved, and a narrow divergence angle and high power output were achieved, making it suitable for laser communication and optical detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
- Filing Date
- 2026-01-16
- Publication Date
- 2026-05-08
AI Technical Summary
The beam quality enhancement structure of array semiconductor lasers has limitations in terms of compactness and power adaptability. It is difficult to achieve precise phase correction in optical field manipulation, resulting in a large divergence angle in the lateral far field, which cannot meet the application requirements of narrow divergence angle.
The design employs an on-chip composite cavity structure, including first and second confinement layers, waveguide layers, active regions, electrodes, and groove structures. The optical field is precisely controlled through components such as phase-locked waveguide arrays, phase-locked cavities, and amplitude modulation cavities. Buffer layers and insulating layers are combined to reduce resistance and losses.
It achieves stable optical mode formation, reduces far-field sidelobe energy, increases central main lobe energy density, lowers far-field divergence angle, supports narrow linewidth and high-power output, and is suitable for laser communication and optical detection.
Smart Images
Figure CN122000789A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor laser technology, and more specifically, to a semiconductor laser with an on-chip composite cavity structure and a method for fabricating the same. Background Technology
[0002] The application of arrayed semiconductor lasers relies on stable, high-quality beam output. To meet practical application requirements, narrow divergence angle laser output is necessary. This necessitates precise control of the laser beam field to ensure uniform phase in the near-field and, consequently, high beam concentration in the far-field. This is directly related to the core structural design of the laser, including phase-locked loop, transmission, and phase correction.
[0003] Currently, beam quality enhancement structures for array semiconductor lasers have limitations in terms of compactness and power adaptability; precise phase correction is difficult to achieve through optical field manipulation, resulting in large lateral far-field divergence angles in array semiconductor lasers. As the operating current increases, the beam quality is further reduced, making it impossible to meet the application requirements for narrow divergence angles. Summary of the Invention
[0004] In view of the above problems, this application provides a semiconductor laser with an on-chip composite cavity structure and a method for fabricating the same.
[0005] This application provides a semiconductor laser, comprising: a first electrode, a substrate, a first confinement layer, a first waveguide layer, an active region, a second waveguide layer, and a second confinement layer arranged sequentially from bottom to top; the upper surface of the second confinement layer having a first groove structure; a second electrode disposed on the second confinement layer and covering the first groove structure, the lower surface of the second electrode having a second groove structure, the first groove structure and the second groove structure being partially interlocked; wherein, after applying a forward bias voltage to the first electrode and the second electrode, charge carriers are injected, driving the charge carriers to be injected into the active region for recombination; the active region generates radiation light and forms an optical field during the recombination process; the first confinement layer and the second confinement layer restrict the diffusion of the optical field; the first waveguide layer and the second waveguide layer constrain the confined optical field to form a stable optical mode.
[0006] According to an embodiment of this application, the semiconductor laser further includes a buffer layer disposed between the first confinement layer and the substrate for mitigating lattice mismatch between the first confinement layer and the substrate.
[0007] According to an embodiment of this application, the semiconductor laser further includes an insulating layer disposed between the groove portion of the first groove structure and the second electrode, for insulating the interlocking portion of the second electrode and the second limiting layer.
[0008] According to an embodiment of this application, the semiconductor laser further includes: a capping layer disposed between the second electrode and the protrusion of the first groove structure, for forming an ohmic contact, reducing the series resistance between the second electrode and the second confinement layer, and reducing current injection loss.
[0009] According to an embodiment of this application, the semiconductor laser further includes: a phase-locked waveguide array disposed on a second confinement layer, comprising a plurality of equally spaced and equally wide first ridge waveguides for beam splitting and phase modulation of the confined optical field, wherein the plurality of ridge waveguides are parallel to each other, and the extension direction of the first ridge waveguides is parallel to the light output direction of the optical field.
[0010] According to an embodiment of this application, the semiconductor laser further includes a phase-locked cavity disposed on the second confinement layer, one side of which is connected to the output end of the phase-locked waveguide array for phase locking of the phase-modulated optical field.
[0011] According to an embodiment of this application, the semiconductor laser further includes: a one-dimensional transmission array disposed on the second confinement layer and connected to the other side of the phase-locked cavity, for transmitting the phase-locked optical field. The one-dimensional transmission array includes multiple second ridge waveguides with equal spacing and width. The spacing between the multiple first ridge waveguides is equal to the spacing between the multiple second ridge waveguides. The width of the first ridge waveguide is equal to the width of the second ridge waveguide. The projections of the multiple first ridge waveguides and the multiple second ridge waveguides along the light output direction are alternately distributed.
[0012] According to an embodiment of this application, the semiconductor laser further includes an amplitude modulation cavity disposed on the second confinement layer, one side of which is connected to the output end of a one-dimensional transmission array for amplitude modulation of the transmitted optical field.
[0013] According to an embodiment of this application, the semiconductor laser further includes: n long ridge waveguides and n-1 short ridge waveguides disposed on the second confinement layer, where n > 1 and n is an integer; the n long ridge waveguides and n-1 short ridge waveguides are arranged alternately; the input ends of the n long ridge waveguides and the input ends of the n-1 short ridge waveguides are both connected to the other side of the amplitude modulation cavity; the n long ridge waveguides and n-1 short ridge waveguides constitute a correction structure to perform phase correction on the amplitude-modulated optical field.
[0014] Another aspect of this application provides a method for fabricating a semiconductor laser with an on-chip composite cavity structure, comprising: obtaining a substrate; sequentially growing a buffer layer, a first confinement layer, a first waveguide layer, an active region, a second waveguide layer, a second confinement layer, and a capping layer on the substrate; etching the grown epitaxial structure to form a first groove structure on the upper surface of the second confinement layer; growing an insulating layer on the surface of the first groove structure, partially etching the insulating layer to expose the capping layer, forming a second groove structure, and partially fitting the second groove structure and the first groove structure; forming a second electrode on the surface of the insulating layer and the second groove structure; and thinning and polishing the substrate to form a first electrode on its surface.
[0015] The semiconductor laser with an on-chip composite cavity structure and its fabrication method provided in this application can achieve the following beneficial effects:
[0016] (1) By calculating the length and width of the phase-locked cavity, the light field incident on the phase-locked waveguide array is diffracted and coupled in the phase-locked cavity. By precisely controlling the position of the one-dimensional transmission array, the fundamental mode can be perfectly incident on the one-dimensional transmission array, while the higher-order modes are filtered out, thus realizing mode gain control, thereby reducing the energy of the far-field sidelobe and increasing the energy density of the central main lobe.
[0017] (2) By flexibly adjusting the cavity length of the amplitude modulation cavity, the distance of optical field diffraction coupling can be controlled, achieving uniform distribution of near-field amplitude, effectively reducing the intensity of far-field side lobes caused by the non-lasing region between the ridge waveguide arrays, and reducing the far-field divergence angle.
[0018] (3) The semiconductor laser can be monolithically integrated with distributed feedback laser (DFB) structure, taper structure (i.e. tapered active waveguide design) to realize narrow linewidth, high power device. Attached Figure Description
[0019] The above and other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:
[0020] Figure 1 This schematically illustrates a structural diagram of a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application;
[0021] Figure 2 A schematic side view of a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application is shown.
[0022] Figure 3 A schematic top view of a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application is shown.
[0023] Figure 4 This schematically illustrates a comparison of the intensity distribution in the lateral far field of a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application;
[0024] Figure 5 A flowchart illustrating a method for fabricating a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application is shown.
[0025] Explanation of reference numerals in the attached figures:
[0026] 1-Second electrode; 2-Insulating layer; 3-Cap layer; 4-Second confinement layer; 5-Second waveguide layer; 6-Active region; 7-First waveguide layer; 8-First confinement layer; 9-Buffer layer; 10-Substrate; 11-First electrode. Detailed Implementation
[0027] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.
[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.
[0029] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.
[0030] Figure 1 This schematically illustrates a structural diagram of a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application; Figure 2 A schematic side view of a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application is shown.
[0031] like Figure 1 and Figure 2As shown, the semiconductor laser with an on-chip composite cavity structure in this embodiment includes: a first electrode 11, a substrate 10, a first confinement layer 8, a first waveguide layer 7, an active region 6, a second waveguide layer 5, and a second confinement layer 4 arranged sequentially from bottom to top. The upper surface of the second confinement layer 4 is provided with a first groove structure. A second electrode 1 is disposed on the second confinement layer 4 and covers the first groove structure. The lower surface of the second electrode 1 is provided with a second groove structure. The first groove structure and the second groove structure are partially interlocked. After applying a forward bias voltage to the first electrode 11 and the second electrode 1, charge carriers are injected and driven to be injected into the active region 6 for recombination.
[0032] The active region 6 generates radiated light and forms an optical field during the recombination process. The first confinement layer 8 and the second confinement layer 4 restrict the diffusion of the optical field. The first waveguide layer 7 and the second waveguide layer 5 constrain the confined optical field to form a stable optical mode.
[0033] For example, the material of the second electrode 1 may include Ti, Pt, or Au.
[0034] For example, the material of the second confinement layer 4 can be p-type doped. .
[0035] For example, the second waveguide layer 5 and the first waveguide layer 7 can be made of the same material, which is undoped. .
[0036] For example, the active region 6 may include m quantum wells and m-1 barrier layers, where m > 1 and m is an integer; the material of the quantum wells can be... The material of the barrier layer can be .
[0037] For example, the material of the first confinement layer 8 can be N-type doped. .
[0038] For example, the material of substrate 10 can be GaSb.
[0039] For example, the material of the first electrode 11 can be Ni, AuGe, or Au.
[0040] The semiconductor laser with an on-chip composite cavity structure based on the embodiments of this application increases the contact area between the electrode and the device through the interlocking design of the first groove structure and the second groove structure, reduces the contact resistance, improves the current injection efficiency, ensures uniform injection of charge carriers into the active region, and reduces the current crowding effect. The synergistic effect of the dual confinement layers (i.e., the first confinement layer and the second confinement layer) and the dual waveguide layers (i.e., the first waveguide layer and the second waveguide layer) can effectively confine the optical field, avoid optical field diffusion loss, and improve the beam quality.
[0041] In embodiments of this application, the semiconductor laser having an on-chip composite cavity structure further includes a buffer layer 9 disposed between the first confinement layer 8 and the substrate 10, for mitigating lattice mismatch between the first confinement layer 8 and the substrate 10.
[0042] For example, the material of buffer layer 9 can be N-type doped GaSb.
[0043] In embodiments of this application, the semiconductor laser further includes an insulating layer 2 disposed between the groove portion of the first groove structure and the second electrode 1, for insulating the interlocking portion of the second electrode 1 and the second limiting layer 4.
[0044] For example, the material of insulating layer 2 can be or .
[0045] In embodiments of this application, the semiconductor laser further includes: a capping layer 3 disposed between the second electrode 1 and the protrusion of the first groove structure, for forming an ohmic contact, reducing the series resistance between the second electrode and the second confinement layer, and reducing current injection loss.
[0046] For example, the material of capping layer 3 can be P-type heavily doped GaSb.
[0047] In embodiments of this application, the semiconductor laser further includes: a phase-locked waveguide array disposed on the second confinement layer 4, comprising a plurality of equally spaced and equally wide first ridge waveguides for beam splitting and phase modulation of the confined optical field, wherein the plurality of ridge waveguides are parallel to each other, and the extension direction of the first ridge waveguide is parallel to the light output direction of the optical field.
[0048] For example, the width of the first ridge waveguide can be set to The spacing between each first ridge waveguide can be set to The length of each first ridge waveguide can be set to .
[0049] The following is combined Figure 3 The phase-locked waveguide array structure of this embodiment is described in detail.
[0050] Figure 3 A schematic top view of a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application is shown.
[0051] like Figure 3As shown, the phase-locked waveguide array comprises multiple sets of parallel first ridge waveguides. These first ridge waveguides are arranged in strips of equal width and spacing. One end of the phase-locked waveguide array is flush with the edge of the upper surface of the semiconductor laser, and the extension direction of the ridge waveguides is parallel to the output light direction. This allows for uniform beam splitting of the input light field. Furthermore, through the phase coordination effect of the phase-locked waveguide array, the phase of the light field within each first ridge waveguide is controlled to be the same, ultimately resulting in a phase-synchronized laser output.
[0052] The semiconductor laser with an on-chip composite cavity structure based on the embodiments of this application can uniformly split the light field through the first ridge waveguide with equal width and equal spacing. With the cooperation of phase modulation, the phase synchronization of the light field in each waveguide can be achieved. Its extension direction is parallel to the light output direction, which ensures the stable transmission of the light field along the light output path and reduces transmission loss.
[0053] In embodiments of this application, the semiconductor laser further includes a phase-locked cavity disposed on the second confinement layer 4, one side of which is connected to the output end of the phase-locked waveguide array for phase locking of the phase-modulated optical field.
[0054] For example, the phase-locked cavity can be a rectangular structure, and the width of the phase-locked cavity can be set to... The length of the phase-locked cavity can be set to .
[0055] In embodiments of this application, the semiconductor laser further includes: a one-dimensional transmission array disposed on the second confinement layer 4 and connected to the other side of the phase-locked cavity, used to transmit the phase-locked light field. The one-dimensional transmission array includes multiple second ridge waveguides with equal spacing and width. The spacing between the multiple first ridge waveguides is equal to the spacing between the multiple second ridge waveguides. The width of the first ridge waveguide is equal to the width of the second ridge waveguide. The projections of the multiple first ridge waveguides and the multiple second ridge waveguides along the light output direction are alternately distributed.
[0056] For example, the width of the second ridge waveguide can be set to The spacing between each second ridge waveguide can be set to The length of each second ridge waveguide can be set to .
[0057] For example, the distance by which the one-dimensional transmission array is translated relative to the phase-locked waveguide array in the direction perpendicular to the light output direction can be set as... .
[0058] The semiconductor laser with an on-chip composite cavity structure based on the embodiments of this application uses a second ridge waveguide of equal width and spacing to match the structural parameters of the phase-locked waveguide array, ensuring the continuity and consistency of optical field transmission. The design of alternating projections of the first and second ridge waveguides continues the phase synchronization after phase locking, ensuring that the optical field maintains uniform amplitude and stable phase in the transmission path.
[0059] In embodiments of this application, the semiconductor laser further includes an amplitude modulation cavity disposed on the second confinement layer 4, one side of which is connected to the output end of the one-dimensional transmission array for amplitude modulation of the transmitted optical field.
[0060] For example, the amplitude control cavity can be a rectangular structure, and the width of the amplitude control cavity can be set to... The length of the amplitude control cavity can be set to .
[0061] In embodiments of this application, the semiconductor laser further includes: n long ridge waveguides and n-1 short ridge waveguides disposed on the second confinement layer 4, where n > 1 and n is an integer; the n long ridge waveguides and n-1 short ridge waveguides are arranged alternately; the input ends of the n long ridge waveguides and the input ends of the n-1 short ridge waveguides are both connected to the other side of the amplitude modulation cavity; the n long ridge waveguides and n-1 short ridge waveguides constitute a correction structure to perform phase correction on the amplitude-modulated optical field.
[0062] For example, the length of a long ridge waveguide can be set to The width can be set to The length of the short ridge waveguide is set to Width set to .
[0063] For example, the second groove is opened downwards to a depth that penetrates the insulating layer 2.
[0064] The semiconductor laser with an on-chip composite cavity structure based on the embodiments of this application achieves precise phase compensation through the optical path difference between the long ridge waveguide and the short ridge waveguide, which can perform phase correction on the amplitude-modulated optical field and eliminate phase distortion of the optical field.
[0065] Figure 4 The diagram schematically illustrates a comparison of the intensity distribution in the lateral far field of a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application.
[0066] like Figure 4 As shown, the horizontal axis represents the angular range of the semiconductor laser's lateral far field (the angular range covers -40° to 40°, i.e., the angular distribution in a plane space relative to the direction of light emission), and the vertical axis represents the intensity, reflecting the light intensity distribution at different angles in the far field.
[0067] The dashed line represents the far-field intensity distribution of a semiconductor laser without a correction structure. It can be seen that the intensity distribution in the far field is relatively dispersed, with peaks around -15°, -5°, 0°, 5°, and 15°, including multiple secondary peaks. The solid line represents the far-field intensity distribution of a semiconductor laser with a correction structure. The far-field intensity is concentrated around 0°, with only one main peak. Side lobes are suppressed, and the intensity is highest at approximately 0°, approaching 1.
[0068] It can be explained that without a correction structure, the laser has a wide angular distribution in the lateral direction (the plane perpendicular to the light output direction), and the energy is dispersed (i.e., there are many side lobes), which is not conducive to the directional transmission of the laser. After adding a correction structure, the laser energy is confined to a narrow angular range near 0°, the side lobes disappear, and a highly directional far-field distribution is achieved, which is crucial for scenarios that require a concentrated beam, such as laser communication and optical detection.
[0069] Figure 5 A flowchart illustrating a method for fabricating a semiconductor laser with an on-chip composite cavity structure according to an embodiment of this application is shown.
[0070] like Figure 5 As shown, the method for fabricating a semiconductor laser with an on-chip composite cavity structure in this embodiment includes steps S510 to S550.
[0071] In step S510, a substrate is obtained.
[0072] In step S520, a buffer layer, a first confinement layer, a first waveguide layer, an active region, a second waveguide layer, a second confinement layer, and a capping layer are sequentially grown on the substrate.
[0073] In step S530, the grown epitaxial structure is etched to form a first groove structure on the upper surface of the second confinement layer.
[0074] For example, wet etching or inductively coupled plasma dry etching can be used to etch the epitaxial structure after the growth of the buffer layer, the first confinement layer, the first waveguide layer, the active region, the second waveguide layer, the second confinement layer and the capping layer, so that the upper surface of the second confinement layer forms the first groove structure.
[0075] In step S540, an insulating layer is grown on the surface of the first groove structure, and the insulating layer is partially etched to expose the capping layer, forming a second groove structure, and the second groove structure and the first groove structure are partially fitted together.
[0076] For example, an insulating layer can be grown on the surface of the first groove structure using metal-organic chemical vapor deposition.
[0077] For example, inductively coupled plasma dry etching or reactive plasma etching can be used to etch away the insulating layer on the waveguide structure to form an electrical injection window, thereby exposing the capping layer.
[0078] In step S550, a second electrode is formed on the surface of the insulating layer and the second groove structure.
[0079] For example, the second electrode can be formed by magnetron sputtering or electron beam evaporation.
[0080] In step S560, after thinning and polishing the substrate, a first electrode is formed on its surface.
[0081] For example, the material formed after step S560 can be cleaved into laser array strips. Antireflection coatings and high-reflection coatings are then deposited on the laser array strips corresponding to the front and rear cavity surfaces of the semiconductor laser, respectively. Finally, the material is cleaved into individual dies to form a semiconductor laser, which is then mounted on a heat sink for testing. The size of a single semiconductor laser can be 500. 2000 Antireflective coating materials can be adopted. High-reflectivity film materials can be made of Si or .
[0082] In summary, the semiconductor laser with an on-chip composite cavity structure and its fabrication method provided in this application have the following beneficial effects:
[0083] (1) By calculating the length and width of the phase-locked cavity, the light field incident on the phase-locked waveguide array is diffracted and coupled in the phase-locked cavity. By precisely controlling the position of the one-dimensional transmission array, the fundamental mode can be perfectly incident on the one-dimensional transmission array, while the higher-order modes are filtered out, thereby achieving mode gain control, thereby reducing the energy of the far-field side lobes and increasing the energy density of the central main lobe.
[0084] (2) By flexibly adjusting the cavity length of the amplitude modulation cavity, the distance of the optical field diffraction coupling can be controlled, the near-field amplitude uniform distribution can be achieved, the far-field sidelobe intensity caused by the non-lasing region between the ridge waveguide arrays can be effectively reduced, and the far-field divergence angle can be reduced.
[0085] (3) The semiconductor laser can be monolithically integrated with distributed feedback laser (DFB) structure, taper structure (i.e. tapered active waveguide design) to realize narrow linewidth, high power device.
[0086] Those skilled in the art will understand that the features described in the various embodiments of this application can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this application. In particular, the features described in the various embodiments of this application can be combined or combined in various ways without departing from the spirit and teachings of this application. All such combinations or combinations fall within the scope of this application.
[0087] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of this application, those skilled in the art can make various substitutions and modifications, all of which should fall within the scope of this application.
Claims
1. A semiconductor laser with an on-chip composite cavity structure, characterized in that, include: The first electrode (11), substrate (10), first confinement layer (8), first waveguide layer (7), active region (6), second waveguide layer (5), and second confinement layer (4) are arranged sequentially from bottom to top. The upper surface of the second confinement layer (4) is provided with a first groove structure. The second electrode (1) is disposed on the second limiting layer (4) and covers the first groove structure. The lower surface of the second electrode (1) is provided with a second groove structure, and the first groove structure and the second groove structure are partially fitted together. Among them, after applying a positive bias voltage to the first electrode (11) and the second electrode (1), carriers are injected and driven to be injected into the active region (6) for recombination; The active region (6) generates radiation light and forms an optical field during the recombination process. The first confinement layer (8) and the second confinement layer (4) restrict the diffusion of the optical field. The first waveguide layer (7) and the second waveguide layer (5) constrain the confined optical field to form a stable optical mode.
2. The semiconductor laser according to claim 1, characterized in that, The semiconductor laser also includes: A buffer layer (9) is disposed between the first confinement layer (8) and the substrate (10) to alleviate the lattice mismatch between the first confinement layer (8) and the substrate (10).
3. The semiconductor laser according to claim 3, characterized in that, The semiconductor laser also includes: An insulating layer (2) is disposed between the groove portion of the first groove structure and the second electrode (1) for insulating the mating portion of the second electrode (1) and the second limiting layer (4).
4. The semiconductor laser according to claim 1, characterized in that, The semiconductor laser also includes: The capping layer (3) is disposed between the second electrode (1) and the protruding portion of the first groove structure to form an ohmic contact, reduce the series resistance between the second electrode (1) and the second limiting layer (4), and reduce current injection loss.
5. The semiconductor laser according to claim 1, characterized in that, The semiconductor laser also includes: A phase-locked waveguide array is disposed on the second confinement layer (4) and includes multiple first ridge waveguides with equal spacing and equal width, which are used to split and phase-control the constrained optical field. The multiple ridge waveguides are parallel to each other, and the extension direction of the first ridge waveguide is parallel to the light output direction of the optical field.
6. The semiconductor laser according to claim 5, characterized in that, The semiconductor laser also includes: A phase-locked cavity is disposed on the second confinement layer (4). One side of the phase-locked cavity is connected to the output end of the phase-locked waveguide array and is used to phase-lock the optical field after phase modulation.
7. The semiconductor laser according to claim 6, characterized in that, The semiconductor laser also includes: A one-dimensional transmission array is disposed on the second confinement layer (4) and connected to the other side of the phase-locked cavity for transmitting the phase-locked optical field. The one-dimensional transmission array includes multiple second ridge waveguides with equal spacing and width. The spacing between the multiple first ridge waveguides is equal to the spacing between the multiple second ridge waveguides. The width of the first ridge waveguide is equal to the width of the second ridge waveguide. The projections of the multiple first ridge waveguides and the multiple second ridge waveguides along the light output direction are alternately distributed.
8. The semiconductor laser according to claim 7, characterized in that, The semiconductor laser also includes: An amplitude modulation cavity is disposed on the second confinement layer (4), and one side of the amplitude modulation cavity is connected to the output end of the one-dimensional transmission array for amplitude modulation of the transmitted optical field.
9. The semiconductor laser according to claim 8, characterized in that, The semiconductor laser also includes: n long ridge waveguides and n-1 short ridge waveguides are disposed on the second confinement layer (4), where n>1 and n is an integer. The n long ridge waveguides and the n-1 short ridge waveguides are arranged alternately. The input ends of the n long ridge waveguides and the input ends of the n-1 short ridge waveguides are connected to the other side of the amplitude modulation cavity. The n long ridge waveguides and the n-1 short ridge waveguides constitute a correction structure to perform phase correction on the amplitude-modulated optical field.
10. A method for fabricating a semiconductor laser with an on-chip composite cavity structure, characterized in that, include: Obtain the substrate (10); A buffer layer (9), a first confinement layer (8), a first waveguide layer (7), an active region (6), a second waveguide layer (5), a second confinement layer (4), and a capping layer (3) are sequentially grown on the substrate. The epitaxial structure after growth is etched to form a first groove structure on the upper surface of the second confinement layer (4); An insulating layer (2) is grown on the surface of the first groove structure, and the insulating layer (2) is partially etched to expose the cover layer (3) to form a second groove structure, and the second groove structure and the first groove structure are partially fitted together. A second electrode (1) is formed on the surface of the insulating layer (2) and the second groove structure; After the substrate (10) is thinned and polished, a first electrode (11) is formed on its surface.