Dispersion-compensated ring reflector and method of manufacture

Abstract

This invention relates to a dispersion-compensated ring reflector and its fabrication method. It includes a substrate, a silicon waveguide core layer disposed on the substrate, and a first 1×2 multimode interferometer, a first curved tapered waveguide, a second curved tapered waveguide, a first mode converter, a second mode converter, and a first coupling waveguide disposed on the silicon waveguide core layer. The first 1×2 multimode interferometer has one port at its first end and two ports at its second end. The port at the first end is connected to the incident and exit waveguide cross-sections via a first single-mode waveguide. The two ports at the second end are connected to the inputs of the first and second mode converters via the first and second curved tapered waveguides, respectively. The outputs of the first and second mode converters are connected via the first coupling waveguide. The device provided by this invention is adaptable to various material platforms and has good integration with other devices.

Description

Technical Field

[0001] This invention relates to the technical field of photonic integrated chips, and more specifically, to a dispersion-compensating ring reflector and its fabrication method. Background Technology

[0002] The characteristic absorption peaks of most molecular bonds (such as CO, NH, CH, etc.) are concentrated in the mid-infrared band, making this band of significant value in molecular absorption spectroscopy sensing. By integrating optical systems onto a single chip, not only can the system be made more compact and reliable, but power consumption and optical losses can also be significantly reduced. The integration of on-chip sensing systems in the mid-infrared band has broad application prospects, covering multiple areas such as portable spectrometers, military applications, and biological detection.

[0003] The core of an on-chip spectral sensing system is a light source with a wide spectral range. Optical frequency combs generated based on nonlinear effects, due to their wide spectral advantage, show great potential, especially in dual-frequency comb sensing applications. Therefore, the efficient generation of mid-infrared optical frequency combs has become one of the current research hotspots. According to existing research, whether it is an efficient Kerr optical frequency comb, a supercontinuum, or a quantum cascade laser optical frequency comb, its resonant cavity must satisfy the key condition of small and flat negative group velocity dispersion. However, since the intracavity dispersion often cannot meet this requirement, additional dispersion compensation mechanisms must be introduced. Therefore, researching devices capable of achieving optical frequency comb dispersion compensation has significant scientific and practical value.

[0004] Dispersion compensation can be achieved through the following methods: (1) Adjusting the geometry of the optical waveguide: Dispersion characteristics can be adjusted by changing the geometric dimensions (such as the width) of the waveguide. However, for a given wafer, the waveguide thickness is fixed, and dispersion compensation can only be achieved by adjusting the waveguide width, which has limited adjustment capability. (2) Chirped Bragg grating: Dispersion compensation can be achieved by changing the grating width or designing a specific operating wavelength. However, this method requires the introduction of a fine grating structure, which has high requirements for processing technology and increases manufacturing complexity and cost. (3) Coupled waveguide: Dispersion compensation can be achieved by exciting a specific coupling mode. This method is simple and efficient to design and applicable to a variety of material platforms, with good versatility. However, coupled waveguides are difficult to integrate with other devices on-chip, which to some extent limits their application scenarios. In summary, the current dispersion compensation technologies each have their advantages and disadvantages, but how to meet the integration requirements of on-chip photonic systems while ensuring design efficiency and manufacturing feasibility is a key challenge. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing coupled waveguides, which are difficult to integrate on-chip with other devices, and to provide a dispersion-compensated ring reflector and its fabrication method, which can be adapted to a variety of material platforms and has good integration with other devices.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A dispersion-compensated ring reflector is provided, comprising a substrate, a silicon waveguide core layer disposed on the substrate, and a first 1×2 multimode interferometer, a first curved tapered waveguide, a second curved tapered waveguide, a first mode converter, a second mode converter, and a first coupling waveguide disposed on the silicon waveguide core layer; the first end and the second end of the first 1×2 multimode interferometer are respectively provided with one port and two ports, the port of the first end is connected to the incident and outgoing waveguide cross-sections through the first single-mode waveguide, the incident and outgoing waveguide cross-sections being the same cross-section; the two ports of the second end are respectively connected to the input ends of the first mode converter and the second mode converter through the first curved tapered waveguide and the second curved tapered waveguide, respectively, and the output ends of the first mode converter and the second mode converter are connected through the first coupling waveguide.

[0008] The present invention discloses a dispersion-compensated ring reflector, wherein a first 1×2 multimode interferometer is used to achieve 50:50 optical power beam splitting and combining; the light input to the first 1×2 multimode interferometer is split into two beams, and then the fundamental mode excitation is converted into a specific coupling mode by the first mode converter and the second mode converter, respectively; after the two beams achieve dispersion compensation in the first coupling waveguide, the specific coupling mode is converted back to the fundamental mode by the second mode converter and the first mode converter, respectively, and then the beams are combined in the first 1×2 multimode interferometer, and finally output from the first port of the first 1×2 multimode interferometer, thus completing the dispersion compensation and optical feedback functions. This invention provides a dispersion-compensating ring reflector that combines dispersion compensation and optical feedback functions. Its design is simple and effectively reduces process requirements. The coupling waveguide structure is versatile and adaptable to various material platforms (such as silicon-based, silicon nitride-based, and lithium niobate), expanding the application range of this invention in different on-chip photonic integrated systems. It also exhibits good integration with other devices; the structural design supports on-chip integration with other photonic devices (such as multimode interferometers and light sources), overcoming the limitations of traditional coupling waveguides and making it suitable for compact on-chip photonic systems.

[0009] Furthermore, the first mode converter and the second mode converter respectively convert the fundamental modes in the first and second curved tapered waveguides into specific coupling modes in the first coupled waveguide. These specific coupling modes have specific dispersion values ​​for dispersion compensation. Through the aforementioned first and second mode converters, specific coupling modes can be excited to achieve dispersion compensation. The length of the first coupled waveguide is selected based on the specific application.

[0010] Furthermore, both the first mode converter and the second mode converter include a first multimode waveguide and a third curved tapered waveguide, with the first multimode waveguide and the third curved tapered waveguide spaced apart to achieve mode conversion from the fundamental mode to a specific coupling mode in the first coupling waveguide.

[0011] Furthermore, the first coupling waveguide includes a second single-mode waveguide and a second multi-mode waveguide, the second single-mode waveguide and the second multi-mode waveguide are spaced apart, the two ends of the second multi-mode waveguide are respectively connected to the output ends of two first multi-mode waveguides, and the two ends of the second single-mode waveguide are respectively connected to the output ends of two third curved tapered waveguides.

[0012] Furthermore, the fundamental mode in the second single-mode waveguide couples with the higher-order modes in the second multimode waveguide to form a specific coupling mode. This specific coupling mode includes symmetric and antisymmetric modes, each with opposite dispersion compensation values. The first coupling waveguide operates in the weak phase-matching region. The first coupling waveguide can be used for coupling between the fundamental mode (e.g., TE0) and specific higher-order modes (e.g., TE1, TE2, TE3, etc.) to achieve dispersion compensation. The first and second mode converters can be designed to excite either the symmetric or antisymmetric modes in the first coupling waveguide, specifically by adjusting the width of the third tapered single-mode waveguide in the mode converter. The operating wavelength of the first coupling waveguide is designed in the weak coupling region adjacent to the phase-matching region to reduce power exchange between the single-mode and multimode waveguides, thereby avoiding mode jumps and reducing the power input from the single-mode waveguide coupling into the multimode waveguide.

[0013] Furthermore, the width of the first multimode waveguide is greater than the width of the third curved tapered waveguide, and the width of the input end of the third curved tapered waveguide is less than the width of the output end of the third curved tapered waveguide; the width of the second single-mode waveguide is equal to the width of the output end of the third curved tapered waveguide.

[0014] Furthermore, the width of the second multimode waveguide is equal to the width of the first multimode waveguide; the width of the second multimode waveguide is greater than the width of the second single-mode waveguide.

[0015] Furthermore, the spacing between the first multimode waveguide and the third curved tapered waveguide is L1, and the spacing between the second single-mode waveguide and the second multimode waveguide is L2, with L1 and L2 being equal.

[0016] Furthermore, the dispersion compensation value is adjusted by adjusting the sizes of L1 and L2. The dispersion compensation value can be flexibly tuned by adjusting the waveguide spacing of the first coupled waveguide, the waveguide spacing of the first mode converter, and the waveguide spacing of the second mode converter during processing; the length of the first coupled waveguide is selected according to the specific dispersion compensation application.

[0017] Furthermore, the first coupled waveguide has a racetrack-shaped structure.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] This invention provides a dispersion-compensating ring reflector with high-efficiency dispersion compensation capability, low processing requirements, and strong manufacturing feasibility and mass production potential. Its coupled waveguide structure design is versatile and adaptable to various material platforms, expanding its application range in different on-chip photonic integrated systems. The device provided by this invention supports on-chip integration with other photonic devices, exhibiting excellent integrability and overcoming the limitations of traditional coupled waveguides, making it suitable for compact on-chip photonic systems. Furthermore, the device provided by this invention has flexible tuning capabilities; by adjusting the spacing of the coupled waveguides or the operating wavelength, the dispersion compensation intensity can be flexibly adjusted to adapt to different application requirements. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a dispersion-compensating ring reflector.

[0021] Figure 2 A schematic diagram of the mode converter in a dispersion-compensated ring reflector and its mode simulation analysis diagram are shown.

[0022] Figure 3 A simulation diagram of antisymmetric mode transmission in a coupled waveguide of a dispersion-compensated ring reflector;

[0023] Figure 4 Simulation data of group velocity dispersion in a coupled waveguide of a dispersion-compensated ring reflector.

[0024] Figure 5 This is a schematic diagram of the steps involved in the fabrication of a dispersion-compensating ring reflector.

[0025] In the attached figures: 1. First 1×2 multimode interferometer; 2. First curved tapered waveguide; 3. Second curved tapered waveguide; 4. First mode converter; 5. Second mode converter; 6. First coupling waveguide; 7. First single-mode waveguide; 8. First multimode waveguide; 9. Third curved tapered waveguide; 10. Second multimode waveguide; 11. Second single-mode waveguide. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0027] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0028] Example 1

[0029] This embodiment is a first embodiment of a dispersion-compensating ring reflector structure, such as... Figure 1 As shown, the waveguide includes a sapphire substrate, a silicon waveguide core layer disposed on the substrate, and a first 1×2 multimode interferometer 1, a first curved tapered waveguide 2, a second curved tapered waveguide 3, a first mode converter 4, a second mode converter 5, and a first coupling waveguide 6 disposed on the silicon waveguide core layer. The first end and the second end of the first 1×2 multimode interferometer 1 are respectively provided with one port and two ports. The port of the first end is connected to the incident and outgoing waveguide sections through the first single-mode waveguide 7. The incident and outgoing waveguide sections are the same cross section. The two ports of the second end are connected to the input ends of the first mode converter 4 and the second mode converter 5 through the first curved tapered waveguide 2 and the second curved tapered waveguide 3, respectively. The output ends of the first mode converter 4 and the second mode converter 5 are connected through the first coupling waveguide 6.

[0030] In this embodiment, both the waveguide cross-section first mode converter 4 and the waveguide cross-section second mode converter 5 include a first multimode waveguide 8 and a third curved tapered waveguide 9. The waveguide cross-section first multimode waveguide 8 and the waveguide cross-section third curved tapered waveguide 9 are spaced apart to realize mode conversion from the fundamental mode to a specific coupling mode in the first coupling waveguide 6.

[0031] In this embodiment, the first coupling waveguide 6 has a racetrack-shaped structure; the first coupling waveguide 6 includes a second single-mode waveguide 11 and a second multi-mode waveguide 10. The second single-mode waveguide 11 and the second multi-mode waveguide 10 are spaced apart. The two ends of the second multi-mode waveguide 10 are respectively connected to the output ends of two first multi-mode waveguides 8, and the two ends of the second single-mode waveguide 11 are respectively connected to the output ends of two third curved conical waveguides 9.

[0032] In this embodiment, the waveguide cross-section first mode converter 4 and the waveguide cross-section second mode converter 5 convert the fundamental modes in the first curved tapered waveguide 2 and the second curved tapered waveguide 3 into specific coupling modes in the first coupled waveguide 6, respectively. These specific coupling modes have specific dispersion values ​​for dispersion compensation. Through the aforementioned first mode converter 4 and second mode converter 5, specific coupling modes can be excited to achieve dispersion compensation. The length of the first coupled waveguide 6 is selected based on the specific application.

[0033] The fundamental mode in the second single-mode waveguide 11 couples with the higher-order modes in the second multimode waveguide 10 to form a specific coupling mode. This specific coupling mode in the waveguide cross-section includes symmetric and antisymmetric modes, which have opposite dispersion compensation values. The first coupling waveguide 6 operates in the weak phase-matching region. The first coupling waveguide 6 can be used for coupling between the fundamental mode (e.g., TE0) and specific higher-order modes (e.g., TE1, TE2, TE3, etc.) to achieve dispersion compensation. The first mode converter 4 and the second mode converter 5 can be designed to excite the symmetric or antisymmetric modes in the first coupling waveguide 6, specifically by adjusting the width of the third tapered single-mode waveguide in the mode converter. The operating wavelength of the first coupling waveguide 6 is designed in the weak coupling region adjacent to the phase-matching region to reduce power exchange between the single-mode and multimode waveguides, thereby avoiding jumps between coupling modes and reducing the power input from the single-mode waveguide to the multimode waveguide.

[0034] In this embodiment, the width of the first multimode waveguide 8 of the waveguide cross section is greater than the width of the third curved tapered waveguide 9 of the waveguide cross section, and the width of the input end of the third curved tapered waveguide 9 of the waveguide cross section is less than the width of the output end of the third curved tapered waveguide 9; the width of the second single-mode waveguide 11 of the waveguide cross section is equal to the width of the output end of the third curved tapered waveguide 9 of the waveguide cross section.

[0035] The width of the second multimode waveguide 10 is equal to the width of the first multimode waveguide 8; the width of the second multimode waveguide 10 is greater than the width of the second single-mode waveguide 11. The spacing between the first multimode waveguide 8 and the third curved tapered waveguide 9 is L1, and the spacing between the second single-mode waveguide 11 and the second multimode waveguide 10 is L2, with L1 and L2 being equal.

[0036] In this embodiment, the dispersion compensation value of the waveguide cross-section is adjusted by adjusting the sizes of L1 and L2. The dispersion compensation value can be flexibly tuned by adjusting the waveguide spacing of the first coupled waveguide 6, the first mode converter 4, and the second mode converter 5 during manufacturing. The spacing of the first coupled waveguide 6 has a direct impact on the dispersion compensation value: the dispersion compensation value weakens when the spacing increases and strengthens when the spacing decreases. The length of the first coupled waveguide 6 is selected according to the specific dispersion compensation application.

[0037] Working principle: The first 1×2 multimode interferometer 1 is used to achieve 50:50 optical power beam splitting and combining. The light input to the first 1×2 multimode interferometer 1 is split into two beams, and then the fundamental mode is converted into a specific coupling mode by the first mode converter 4 and the second mode converter 5 of the waveguide cross section, respectively. After the two beams achieve dispersion compensation in the first coupling waveguide 6 of the waveguide cross section, the specific coupling mode is converted back to the fundamental mode by the second mode converter 5 and the first mode converter 4 of the waveguide cross section, respectively. The beams are then combined in the first 1×2 multimode interferometer 1 of the waveguide cross section, and finally output from the first port of the first 1×2 multimode interferometer of the waveguide cross section, thus completing the dispersion compensation and optical feedback functions.

[0038] This embodiment provides a dispersion-compensating ring reflector with high-efficiency dispersion compensation capability, low processing requirements, and strong manufacturing feasibility and mass production potential. Its universally applicable coupled waveguide structure design is adaptable to various material platforms (such as silicon-based, silicon nitride-based, lithium niobate, etc.), expanding the application scope of this invention in different on-chip photonic integrated systems. It exhibits good integration with other devices; the structural design supports on-chip integration with other photonic devices (such as multimode interferometers, light sources, etc.), overcoming the limitations of traditional coupled waveguides and making it suitable for compact on-chip photonic systems. Flexible tuning capability allows for flexible adjustment of dispersion compensation intensity by adjusting the spacing or operating wavelength of the coupled waveguides, thus adapting to different application requirements. The compact design results in a small overall geometric size and low chip area occupation, making it ideal for the high space efficiency requirements of on-chip photonic systems.

[0039] Example 2

[0040] This embodiment is a second embodiment of the structure of a dispersion-compensating ring reflector. This embodiment is similar to the first embodiment, except that the device structure provided in the first embodiment is simulated.

[0041] like Figure 2As shown in Figure 'a', this is a schematic diagram of the two mode converters. The first mode converter 4 and the second mode converter 5 have identical structures, both including a first multimode waveguide 8 of a specific width and a third curved conical waveguide 9, with a fixed spacing between them. Detailed numerical simulations of the mode evolution of the two mode converters under varying widths of the third curved conical waveguide 9 were performed using the Lumerical FDE waveguide mode solver. Figure 2 Figure b shows the effect of the effective refractive index of the mode converter on the width of the third curved conical waveguide 9, and the mode field distribution of the antisymmetric mode at a specific width. When the width of the third curved conical waveguide 9 at the input of the mode converter is I, its mode field is mainly concentrated in the third curved conical waveguide 9, which is the fundamental mode. As the width of the third curved conical waveguide 9 gradually increases to II, the effective refractive index of the fundamental mode in the third curved conical waveguide 9 gradually approaches the effective refractive index of a certain higher-order mode in the first multimode waveguide 8, and the two tend to be phase matched, thereby enhancing the coupling effect. At this time, the input fundamental mode gradually transforms into an antisymmetric mode, and a small part of the optical power is distributed in the first multimode waveguide 8. When the width of the third curved conical waveguide 9 is further increased to III, the mode converter enters the strong phase-matching region. At this time, the effective refractive indices of the antisymmetric mode and the symmetric mode are closest, which easily leads to mode switching phenomena. Under this width condition, mode coupling between coupled modes is unavoidable. Therefore, to achieve efficient mode switching, the width of the third curved conical waveguide 9 in this embodiment is designed to gradually increase from I to II, thereby effectively exciting antisymmetric modes and minimizing mode transitions between coupled modes. It should be noted that the length of the mode converter needs to be set to ensure adiabatic mode transmission.

[0042] It should be noted that the width of the second multimode waveguide 10 in the first coupled waveguide 6 is equal to the width of the first multimode waveguide 8 at position II of the two mode converters, and the width of the second single-mode waveguide 11 in the first coupled waveguide 6 is equal to the width of the third curved tapered waveguide 9 at position II of the mode converter. The waveguide spacing of the first coupled waveguide 6 is equal to the waveguide spacing of the mode converters. The numerical simulation results of the optical field transmission of the antisymmetric mode excited by the mode converter in the first coupled waveguide 6 are as follows: Figure 3 As shown, the antisymmetric mode maintains stable propagation in the coupled waveguide.

[0043] Based on theoretical derivation (Applied Physics Letters, vol. 67, no. 15, pp. 2111-2113, 1995), the group velocity dispersion of the coupled modes in the first coupled waveguide 6 is:

[0044]

[0045] Where D0 is the fundamental mode group velocity dispersion in the second single-mode waveguide 11; κ is the inter-waveguide coupling coefficient; v1 is the fundamental mode group velocity in the second single-mode waveguide 11; v2 is the higher-order mode group velocity in the second multimode waveguide 10; ω is the optical wave angular frequency; ω0 represents the phase-matched optical wave angular frequency; and δω represents the coupling mode dispersion bandwidth. For the antisymmetric mode in the first coupling waveguide 6, its group velocity dispersion value is smaller than that of the fundamental mode in the second single-mode waveguide 11, and the antisymmetric mode exhibits anomalous dispersion. The generation of optical frequency combs based on nonlinear effects usually requires anomalous dispersion conditions within the cavity. Therefore, in this embodiment, a dispersion-compensated circulator with anomalous dispersion is constructed by exciting the antisymmetric mode.

[0046] like Figure 4 The figure shows the numerical simulation results of the group velocity dispersion of the antisymmetric mode in the first coupled waveguide 6. The group velocity dispersion value of the fundamental mode in the second single-mode waveguide 11 is (0-10000 fs). 2 The dispersion ( / mm) is normal, while the antisymmetric mode in the first coupled waveguide 6 exhibits significant anomalous dispersion characteristics. As the waveguide spacing increases, the coupling effect between waveguides gradually weakens, leading to a reduction in the negative range of the anomalous dispersion value. By adjusting the spacing of the first coupled waveguide 6, the dispersion compensation capability can be flexibly tuned to meet the needs of different dispersion compensation applications.

[0047] Example 3

[0048] This embodiment provides a method for fabricating a dispersion-compensating ring reflector, used to prepare the dispersion-compensating ring reflector provided in Embodiment 1; as follows: Figure 5 As shown, it includes the following steps:

[0049] S0. Clean the wafer surface;

[0050] S1. Spin-coating electronic adhesive onto the surface of the silicon core layer;

[0051] S3. The pattern of the designed dispersion-compensating ring reflector is transferred onto the electron adhesive by electron beam exposure, and the unwanted parts of the electron adhesive are removed by development to obtain the electron adhesive mask;

[0052] S4. The mask structure is transferred to the silicon waveguide core layer by plasma etching;

[0053] S5. Remove the electronic adhesive;

[0054] S6. Optionally, a silicon dioxide thin film is deposited as a cladding layer.

[0055] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0056] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A dispersion-compensating ring reflector, characterized in that, The system includes a substrate, a silicon waveguide core layer disposed on the substrate, and a first 1×2 multimode interferometer (1), a first curved conical waveguide (2), a second curved conical waveguide (3), a first mode converter (4), a second mode converter (5), and a first coupling waveguide (6) disposed on the silicon waveguide core layer. The first 1×2 multimode interferometer (1) has one port at its first end and two ports at its second end. The port at the first end is connected to the incident and exit waveguide cross-sections via a first single-mode waveguide (7), and the incident and exit waveguide cross-sections are the same. The two ports at the second end are connected to the input ends of the first mode converter (4) and the second mode converter (5) via the first curved conical waveguide (2) and the second curved conical waveguide (3), respectively. The output ends of the first mode converter (4) and the second mode converter (5) are connected via the first coupling waveguide (6). The first mode converter (4) and the second mode converter (5) are connected to each other via the first coupling waveguide (6). 5) The fundamental modes in the first curved conical waveguide (2) and the second curved conical waveguide (3) are respectively converted into specific coupling modes in the first coupling waveguide (6), and the specific coupling modes have specific dispersion values ​​for dispersion compensation; the first mode converter (4) and the second mode converter (5) both include a first multimode waveguide (8) and a third curved conical waveguide (9), the first multimode waveguide (8) and the third curved conical waveguide (9) are spaced apart, and are used to realize the mode conversion from the fundamental mode to the specific coupling mode in the first coupling waveguide (6); the first coupling waveguide (6) includes a second single-mode waveguide (11) and a second multimode waveguide (10), the second single-mode waveguide (11) and the second multimode waveguide (10) are spaced apart, the two ends of the second multimode waveguide (10) are respectively connected to the output ends of the two first multimode waveguides (8), and the two ends of the second single-mode waveguide (11) are respectively connected to the output ends of the two third curved conical waveguides (9).

2. The dispersion-compensating annular reflector according to claim 1, characterized in that, The fundamental mode in the second single-mode waveguide (11) is coupled with the higher-order mode in the second multimode waveguide (10) to form a specific coupling mode, which includes a symmetric mode and an antisymmetric mode, both of which have opposite dispersion compensation values; the first coupling waveguide (6) operates in the weak phase matching region.

3. The dispersion-compensating annular reflector according to claim 2, characterized in that, The width of the first multimode waveguide (8) is greater than the width of the third curved conical waveguide (9), and the width of the input end of the third curved conical waveguide (9) is less than the width of the output end of the third curved conical waveguide (9).

4. The dispersion-compensating annular reflector according to claim 2, characterized in that, The width of the second single-mode waveguide (11) is equal to the width of the output end of the third curved conical waveguide (9); the width of the second multimode waveguide (10) is equal to the width of the first multimode waveguide (8); the width of the second multimode waveguide (10) is greater than the width of the second single-mode waveguide (11).

5. The dispersion-compensating annular reflector according to claim 2, characterized in that, The spacing between the first multimode waveguide (8) and the third curved conical waveguide (9) is L1, and the spacing between the second single-mode waveguide (11) and the second multimode waveguide (10) is L2, with L1 and L2 being equal.

6. The dispersion-compensating annular reflector according to claim 5, characterized in that, The dispersion compensation value is adjusted by adjusting the values ​​of L1 and L2.

7. The dispersion-compensating annular reflector according to any one of claims 1 to 6, characterized in that, The first coupling waveguide (6) is a racetrack-shaped structure.

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