Wavelength division multiplexing array

Abstract

The application provides a wavelength division multiplexing array, which can be applied to the technical field of optical communication and comprises a first input waveguide, a polarization rotation beam splitter, a second input waveguide, a third input waveguide and a plurality of wavelength division multiplexing units, wherein the first input waveguide is used for receiving an initial optical signal from outside, the initial optical signal containing dual polarization information; the polarization rotation beam splitter is used for converting the initial optical signal into a first optical signal and a second optical signal with the same polarization information; the second input waveguide is used for transmitting the first optical signal; the third input waveguide is used for transmitting the second optical signal; and the plurality of wavelength division multiplexing units comprise an uplink wavelength division multiplexing device and a downlink wavelength division multiplexing device, wherein the uplink wavelength division multiplexing device is used for decomposing the first optical signal into optical signals with single wavelengths; and the downlink wavelength division multiplexing device is used for decomposing the second optical signal into optical signals with single wavelengths. The structure has the advantages of polarization independence, high optical communication capacity, simple structure, friendly process and strong scalability, and can be used for providing bidirectional wavelength division multiplexing for data-intensive networks and connections.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and in particular to a wave demultiplexing array. Background Technology

[0002] With the rapid development of 5G technology, the demand for communication capacity has exploded. Optical communication technology, with its advantages of high bandwidth, low crosstalk, low loss, and resistance to electromagnetic interference, has become the mainstream technology in optical communication. Future optical communication transmission technologies will place further demands on capacity and signal rate, requiring further optimization of bandwidth, size, and power consumption. The commercialization of thin-film lithium niobate in recent years has made the processing of lithium niobate materials much easier. Although research on various optical devices based on thin-film lithium niobate has made encouraging progress in recent years, how to achieve integrated optical devices with more channels, a wider operating wavelength range, and arbitrary polarization on a single chip remains a critical technology that urgently needs breakthrough. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address at least one of the aforementioned technical problems in existing optical communication technologies, embodiments of the present invention provide a wavelength demultiplexing array. Based on a thin-film lithium niobate platform, it can achieve arbitrary polarization, number of channels, wavelength band, wavelength channel spacing, and wavelength channel bandwidth. It can be used as a receiver module in an optical communication system and has the advantages of high communication capacity, simple structure, user-friendly manufacturing process, and strong scalability.

[0005] (II) Technical Solution

[0006] To address the aforementioned technical problems, embodiments of the present invention propose a wave decomposition multiplexing array.

[0007] According to a first aspect of the present invention, a wavelength division multiplexing array is provided, comprising: a first input waveguide for receiving an initial optical signal from the outside, the initial optical signal containing dual polarization information; a polarization rotation beamsplitter for converting the initial optical signal into a first optical signal and a second optical signal, the first optical signal and the second optical signal having the same polarization information; a second input waveguide for transmitting the first optical signal; a third input waveguide for transmitting the second optical signal; and N wavelength division multiplexing units, where N is an integer greater than or equal to 2, each wavelength division multiplexing unit comprising an upper wavelength division multiplexer and a lower wavelength division multiplexer, wherein the upper wavelength division multiplexer is connected to the second input waveguide and is used to decompose the first optical signal into a single-wavelength optical signal; the lower wavelength division multiplexer is connected to the third input waveguide and is used to decompose the second optical signal into a single-wavelength optical signal; and any two wavelength division multiplexing units operate at different wavelengths.

[0008] In some exemplary embodiments, the initial optical signal includes at least two different wavelengths of optical signal; and the initial optical signal includes a first initial optical signal and a second initial optical signal, wherein the first initial optical signal includes a TMO mode optical signal; and the second initial optical signal includes a TEO mode optical signal.

[0009] In some exemplary embodiments, the polarization rotating beam splitter includes: a fourth input waveguide for inputting an initial optical signal into the polarization rotating beam splitter; an adiabatic mode conversion region for converting a first initial optical signal in TM0 mode into a first intermediate optical signal in TE1 mode; a mode demultiplexer for converting the first intermediate optical signal in TE1 mode into a first optical signal in TE0 mode; a mode filter for filtering out the TE1 mode optical signal doped in the second initial optical signal to obtain a second optical signal, wherein the second optical signal is a TE0 mode optical signal; a first output waveguide for transmitting the first optical signal to a second input waveguide; and a second output waveguide for transmitting the second optical signal to a third input waveguide.

[0010] In some exemplary embodiments, the upper-path wave demultiplexer and the lower-path wave demultiplexer have the same structure, including a fifth input waveguide, a microring, and a third output waveguide connected in sequence.

[0011] In some exemplary embodiments, the adiabatic mode switching region includes a first adiabatic conical waveguide, a second adiabatic conical waveguide, and a third adiabatic conical waveguide connected in sequence, wherein the input end of the first adiabatic conical waveguide is connected to the output end of the fourth input waveguide.

[0012] In some exemplary embodiments, the mode demultiplexer includes a sixth input waveguide and a first straight waveguide, wherein the input end of the sixth input waveguide is connected to the output end of a third adiabatic tapered waveguide; and a first intermediate optical signal of TE1 mode in the third adiabatic tapered waveguide is coupled from the sixth input waveguide to the first straight waveguide, and the mode is converted from TE1 to TE0.

[0013] In some exemplary embodiments, the first output waveguide includes a first curved waveguide and a second straight waveguide connected in sequence, wherein a first optical signal is input from the first curved waveguide and output from the second straight waveguide.

[0014] In some exemplary embodiments, the mode filter includes a third straight waveguide, a subwavelength grating structure, and a fourth straight waveguide connected in sequence.

[0015] In some exemplary embodiments, the polarization rotating beamsplitter and the wave demultiplexing unit are fabricated based on a thin-film lithium niobate platform, wherein the thin-film lithium niobate platform includes an X-cut thin-film lithium niobate platform; the waveguide extension direction of the polarization rotating beamsplitter and the wave demultiplexing unit is the Y-axis direction of the thin-film lithium niobate crystal; and the waveguide extension direction of the polarization rotating beamsplitter and the wave demultiplexing unit is perpendicular to the Z-axis direction of the lithium niobate crystal.

[0016] In some exemplary embodiments, the thin-film lithium niobate platform includes: a substrate; a buried oxide substrate located on the substrate; and a thin-film lithium niobate structural layer bonded to the upper surface of the buried oxide substrate, wherein the thin-film lithium niobate structural layer includes a first thin-film lithium niobate layer and a second thin-film lithium niobate layer, wherein the first thin-film lithium niobate layer is located on the side of the buried oxide substrate away from the substrate; the second thin-film lithium niobate layer is located on the side of the first thin-film lithium niobate layer away from the substrate; and the first thin-film lithium niobate layer and the second thin-film lithium niobate layer form a ridge structure.

[0017] (III) Beneficial Effects

[0018] As can be seen from the above technical solutions, the wave decomposition multiplexing array provided by the embodiments of the present invention has at least the following beneficial effects:

[0019] (1) Wave demultiplexer arrays with arbitrary polarization, number of channels, bands, channel spacing and channel width can be obtained on the lithium niobate platform.

[0020] (2) This structure has the advantages of being polarization independent, having high optical communication capacity, simple structure, user-friendly process and strong scalability.

[0021] (3) Cool the detector before testing to reduce the impact of thermal background on the detector. Attached Figure Description

[0022] The above-described features, other objects, and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0023] Figure 1 The schematic diagram illustrates a structural schematic of a wave decomposition multiplexing array according to an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of a polarization rotating beam splitter according to an embodiment of the present invention is shown.

[0025] Figure 3 A schematic diagram of the structure of a mode demultiplexer according to an embodiment of the present invention is shown, wherein, Figure 3 (a) schematically illustrates a pattern demultiplexer according to an embodiment of the present invention, which is a structure of asymmetric directional coupling. Figure 3 (b) schematically illustrates a pattern demultiplexer according to an embodiment of the present invention, which is a thermal evolution coupling structure; and Figure 3 (c) schematically illustrates a subwavelength grating waveguide structure as the mode demultiplexer according to an embodiment of the present invention;

[0026] Figure 4 A schematic diagram of the structure of a mode filter according to an embodiment of the present invention is shown.

[0027] Figure 5 A schematic diagram of the microring structure of a wave decomposition and multiplexing unit according to an embodiment of the present invention is shown, wherein, Figure 5 (a) schematically illustrates that the structure of the microring of the wave decomposition and multiplexing unit according to an embodiment of the present invention is a perfect circle; Figure 5 (b) schematically illustrates that the structure of the microring of the wave decomposition and multiplexing unit according to an embodiment of the present invention is elliptical; Figure 5 (c) schematically illustrates a structure of an insulating microring in the wave decomposition and multiplexing unit according to an embodiment of the present invention; Figure 5 (d) schematically illustrates a runway microring structure for the wave decomposition and multiplexing unit according to an embodiment of the present invention; and Figure 5 (e) schematically illustrates a triangular microring structure of the wave decomposition and multiplexing unit according to an embodiment of the present invention; and

[0028] Figure 6 A schematic diagram of a thin-film lithium niobate platform structure according to an embodiment of the present invention is shown.

[0029] Figure label:

[0030] 1-First input waveguide; 2-Polarization rotating beam splitter; 21-Fourth input waveguide; 22-Adiabatic mode conversion region; 221-First adiabatic tapered waveguide; 222-Second adiabatic tapered waveguide; 223-Third adiabatic tapered waveguide; 23-Mode demultiplexer; 231-Sixth input waveguide; 232-First straight waveguide; 24-Mode filter; 241-Third straight waveguide; 242-Subwavelength grating structure; 243-Fourth straight waveguide; 25-First output waveguide; 251-The 1-Bent waveguide; 252-Second straight waveguide; 26-Second output waveguide; 3-Second input waveguide; 4-Third input waveguide; 5-Wave demultiplexing unit; 51-Upper wave demultiplexer; 511-Fifth input waveguide; 512-Microring; 513-Third output waveguide; 514-Photodetector; 52-Lower wave demultiplexer; 6-Substrate; 7-Buried oxide substrate; 8-Thin film lithium niobate structural layer; 81-First thin film lithium niobate layer; 82-Second thin film lithium niobate layer. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] Figure 1 The schematic diagram illustrates the structure of a wave decomposition multiplexing array according to an embodiment of the present invention.

[0033] like Figure 1 As shown, the structure of a wave demultiplexing array according to an embodiment of the present invention includes: a first input waveguide 1 for receiving an initial optical signal from the outside, the initial optical signal containing dual polarization information; a polarization rotating beam splitter 2 for converting the initial optical signal into a first optical signal and a second optical signal, the first optical signal and the second optical signal having the same polarization information; a second input waveguide 3 for transmitting the first optical signal; a third input waveguide 4 for transmitting the second optical signal; and N wave demultiplexing units 5 (DeMux), where N is an integer greater than or equal to 2. Each wave demultiplexing unit 5 includes an upper wave demultiplexer 51 and a lower wave demultiplexer 52, wherein the upper wave demultiplexer 51 is connected to the second input waveguide 3 and is used to decompose the first optical signal into a single-wavelength optical signal; the lower wave demultiplexer 52 is connected to the third input waveguide 4 and is used to decompose the second optical signal into a single-wavelength optical signal; and any two wave demultiplexing units 5 have different operating wavelengths.

[0034] In this embodiment of the invention, the initial optical signal includes at least two different wavelengths of optical signal, for example, the initial optical signal includes wavelengths λ1, λ2, ..., λ. n There are n different wavelength optical signals, where n is an integer greater than or equal to 2. The initial optical signal includes a first initial optical signal and a second initial optical signal, wherein the first initial optical signal includes a TM0 mode optical signal (the fundamental mode of the transverse magnetic mode in which the magnetic field direction of the optical signal is perpendicular to the propagation direction); and the second initial optical signal includes a TE0 mode optical signal (the fundamental mode of the transverse electric mode in which the electric field direction of the input optical signal is perpendicular to the propagation direction, and its polarization state is not changed during transmission).

[0035] For example, the wavelengths carrying dual polarization information are λ1…λ nAn initial optical signal of n wavelengths enters the polarization rotating beamsplitter 2 from the first input waveguide 1 and is converted into a first optical signal and a second optical signal of the same polarization, respectively, which are then input into the wave demultiplexing unit 5 from the second input waveguide 3 and the third input waveguide 4. Each wavelength of light passes through its corresponding wave demultiplexer and is output from the third output waveguide 513 of the wave demultiplexer to the corresponding photodetector 514 for information processing. Before testing, the photodetector 514 is cooled to reduce the influence of thermal background on the detector. By optimizing the structural parameters of the polarization rotating beamsplitter 2 and the wave demultiplexing unit 5, wave demultiplexers with arbitrary polarization, operating band, operating bandwidth, and number of channels can be demultiplexed, achieving a highly integrated, channel-expandable wave demultiplexer array on thin-film lithium niobate.

[0036] Figure 2 A schematic diagram of the structure of a polarization rotating beam splitter 2 according to an embodiment of the present invention is shown.

[0037] like Figure 2 As shown, the polarization rotating beamsplitter 2 according to an embodiment of the present invention includes: a fourth input waveguide 21 for inputting an initial optical signal into the polarization rotating beamsplitter 2; an adiabatic mode conversion region 22 for converting the first initial optical signal in TM0 mode into a first intermediate optical signal in TE1 mode (a first-order transverse electric mode with the electric field direction perpendicular to the propagation direction); a mode demultiplexer 23 for converting the first intermediate optical signal in TE1 mode into a first optical signal in TE0 mode; a mode filter 24 for filtering out the TE1 mode optical signal doped in the second initial optical signal to obtain a second optical signal, wherein the second optical signal is a TE0 mode optical signal; a first output waveguide 25 for transmitting the first optical signal to a second input waveguide 3; and a second output waveguide 26 for transmitting the second optical signal to a third input waveguide 4. Different input stages can have different wavelength bandwidths, bands, wavelength spacings, and polarizations. The structural parameters of the polarization rotating beamsplitter 2 vary depending on the application scenario.

[0038] In some exemplary embodiments, the adiabatic mode conversion region 22 includes a first adiabatic conical waveguide 221, a second adiabatic conical waveguide 222 and a third adiabatic conical waveguide 223 connected in sequence, wherein the input end of the first adiabatic conical waveguide 221 is connected to the output end of the fourth input waveguide 21.

[0039] In some exemplary embodiments, the mode demultiplexer 23 includes a sixth input waveguide 231 and a first straight waveguide 232, wherein the input end of the sixth input waveguide 231 is connected to the output end of the third adiabatic tapered waveguide 223; and a first intermediate optical signal in TE1 mode in the third adiabatic tapered waveguide 223 is coupled from the sixth input waveguide 231 to the first straight waveguide 232, and the mode is converted from TE1 to TE0. During this process, the second initial optical signal in TE0 mode in the third adiabatic tapered waveguide 223 does not couple. See the structural diagram of the mode demultiplexer 23. Figure 3 ,in, Figure 3 (a) shows that the structure of the mode demultiplexer 23 according to an embodiment of the present invention is an asymmetric directional coupling structure; Figure 3 (b) shows that the structure of the mode demultiplexer 23 according to an embodiment of the present invention is an adiabatic evolution coupling structure; and Figure 3 (c) shows that the structure of the mode demultiplexer 23 according to an embodiment of the present invention is a subwavelength grating waveguide structure.

[0040] In some exemplary embodiments, the first output waveguide 25 includes a first curved waveguide 251 and a second straight waveguide 252 connected in sequence, wherein a first optical signal is input from the first curved waveguide 251 and output from the second straight waveguide 252.

[0041] In some exemplary embodiments, the mode filter 24 includes a third straight waveguide 241, a subwavelength grating structure 242, and a fourth straight waveguide 243 connected in sequence. See [link to documentation] for the structure of the mode filter 24. Figure 4 ,Depend on Figure 4 It can be seen that in the subwavelength grating structure 242 units, W is the waveguide width, a is the unetched part of the grating, and A is the grating period. By optimizing the structural parameters of the subwavelength grating, the corresponding appropriate working bandwidth, band, etc. can be obtained, and the optical signals of different demultiplexing units can be transmitted to the second input waveguide 3 and the third input waveguide 4.

[0042] In some exemplary embodiments, the upper-path demultiplexer 51 and the lower-path demultiplexer 52 have the same structure, including a fifth input waveguide 511, a micro-ring 512, and a third output waveguide 513 connected in sequence. The structure of the micro-ring 512 is described below. Figure 5 ,Depend on Figure 5 It can be seen that the structure of microring 512 includes a perfect circle, an ellipse, an adiabatic microring, a racetrack microring, and a triangular microring. Optionally, the upper wave demultiplexer 51 and the lower wave demultiplexer 52 also include a photodetector 514, which is used to convert the input optical signal into an electrical signal. Adjacent wave demultiplexing units 5 are connected by straight waveguides.

[0043] For example, the input end of the fifth input waveguide 511 is connected to an output waveguide of the polarization separation rotator. The optical signal enters the micro-ring 512 through the fifth input waveguide 511. After a period of transmission, the optical signal is coupled out of the micro-ring 512 through the straight waveguide of the third output waveguide 513, and then connected to the photodetector 514 of the local wave decomposition and multiplexing unit 5 through the curved waveguide.

[0044] The input signals of the upper-path demultiplexer 51 and the lower-path demultiplexer 52 can be of different wavelength ranges, wavelength intervals, and band ranges. Different demultiplexer units 5 have different parameters to achieve operation at different wavelengths and bands.

[0045] In this embodiment of the invention, the polarization rotating beamsplitter 2 and the wave demultiplexing unit 5 are fabricated based on a thin-film lithium niobate platform, wherein the thin-film lithium niobate platform includes an X-cut thin-film lithium niobate platform; the waveguide extension direction of the polarization rotating beamsplitter 2 and the wave demultiplexing unit 5 is along the Y-axis direction of the thin-film lithium niobate crystal; and the waveguide extension direction of the polarization rotating beamsplitter 2 and the wave demultiplexing unit 5 is perpendicular to the Z-axis direction of the lithium niobate crystal. This configuration achieves a highly integrated filter array setup.

[0046] In some exemplary embodiments, the thin-film lithium niobate platform includes: a substrate 6; a buried oxide substrate 7 located on the substrate 6; and a thin-film lithium niobate structural layer 8 bonded to the upper surface of the buried oxide substrate 7, wherein the thin-film lithium niobate structural layer 8 includes a first thin-film lithium niobate layer 81 and a second thin-film lithium niobate layer 82, wherein the first thin-film lithium niobate layer 81 is located on the side of the buried oxide substrate 7 away from the substrate 6; the second thin-film lithium niobate layer 82 is located on the side of the first thin-film lithium niobate layer 81 away from the substrate 6; and the first thin-film lithium niobate layer 81 and the second thin-film lithium niobate layer 82 form a ridge structure.

[0047] Optionally, the first thin film lithium niobate layer 81 and the second thin film lithium niobate layer 82 have the same thickness, both being 300 nm, and the etching tilt angle of the top thin film lithium niobate layer is designed to be 65°.

[0048] For example, a nanowire waveguide based on lithium niobate on an insulator can be selected, wherein the core layer is lithium niobate, the thickness of the thin-film lithium niobate is 600 nm, the waveguide structure etching depth is 300 nm, and the refractive index is n at a wavelength of 1550 nm. o =2.21, n e =2.14, the waveguide sidewall tilt angle caused by the etching process is 65°; the lower cladding material is silicon dioxide with a thickness of 4.7μm and a refractive index of 1.44; the upper cladding is air.

[0049] The embodiments of this invention can realize the demultiplexing of optical filters with different structures, and can be fabricated using standard optical waveguide processes, requiring only one etching operation. The fabrication process is simple, with good performance, low cost, and high production potential. Through multi-port demultiplexing units, demultiplexers with arbitrary number of channels and arbitrary operating wavelength bands can be realized. A highly integrated, high-performance, and scalable wavelength demultiplexer array has been achieved on a thin-film lithium niobate platform.

[0050] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wave decomposition and multiplexing array, characterized in that, include: A first input waveguide is used to receive an initial optical signal from the outside, the initial optical signal containing dual polarization information; A polarization rotating beam splitter is used to convert an initial optical signal into a first optical signal and a second optical signal, wherein the first optical signal and the second optical signal have the same polarization information. The second input waveguide is used to transmit the first optical signal; The third input waveguide is used to transmit the second optical signal; as well as There are N wave demultiplexing and multiplexing units, where N is an integer greater than or equal to 2. Each wave demultiplexing and multiplexing unit includes an upper wave demultiplexer and a lower wave demultiplexer. The upper-path wave demultiplexer is connected to the second input waveguide and is used to decompose the first optical signal into optical signals of a single wavelength. The lower-path wave demultiplexer is connected to the third input waveguide and is used to decompose the second optical signal into single-wavelength optical signals; and The operating wavelengths of any two of the aforementioned wave decomposition and multiplexing units are different; The initial optical signal includes at least two optical signals of different wavelengths; and The initial optical signal includes a first initial optical signal and a second initial optical signal. Wherein, the first initial optical signal includes an optical signal in TM0 mode; and The second initial optical signal includes an optical signal in TEO mode; The polarization rotating beam splitter includes: The fourth input waveguide is used to input the initial optical signal into the polarization rotating beam splitter; The adiabatic mode conversion zone is used to convert the first initial optical signal in TM0 mode into the first intermediate optical signal in TE1 mode. A mode demultiplexer is used to convert the first intermediate optical signal of TE1 mode into the first optical signal of TE0 mode. A mode filter is used to filter out the TE1 mode optical signal doped in the second initial optical signal to obtain the second optical signal, wherein the second optical signal is a TE0 mode optical signal; A first output waveguide is used to transmit the first optical signal to the second input waveguide; and The second output waveguide is used to transmit the second optical signal to the third input waveguide.

2. The wave decomposition and multiplexing array according to claim 1, characterized in that, The upper-path wave demultiplexer and the lower-path wave demultiplexer have the same structure, including a fifth input waveguide, a micro-ring, and a third output waveguide connected in sequence.

3. The wave decomposition and multiplexing array according to claim 1, characterized in that, The adiabatic mode conversion region includes a first adiabatic conical waveguide, a second adiabatic conical waveguide, and a third adiabatic conical waveguide connected in sequence, wherein the input end of the first adiabatic conical waveguide is connected to the output end of the fourth input waveguide.

4. The wave decomposition and multiplexing array according to claim 3, characterized in that, The mode demultiplexer includes a sixth input waveguide and a first straight waveguide. Wherein, the input end of the sixth input waveguide is connected to the output end of the third adiabatic tapered waveguide; and The first intermediate optical signal in the TE1 mode in the third adiabatic conical waveguide is coupled from the sixth input waveguide to the first straight waveguide, and the mode is converted from TE1 to TE0.

5. The wave decomposition and multiplexing array according to claim 4, characterized in that, The first output waveguide includes a first curved waveguide and a second straight waveguide connected in sequence. The first optical signal is input from the first curved waveguide and output from the second straight waveguide.

6. The wave decomposition and multiplexing array according to claim 5, characterized in that, The mode filter includes a third straight waveguide, a subwavelength grating structure, and a fourth straight waveguide connected in sequence.

7. The wave decomposition and multiplexing array according to claim 1, characterized in that, The polarization rotating beam splitter and the wave decomposition and multiplexing unit are fabricated based on a thin-film lithium niobate platform. The thin-film lithium niobate platform includes an X-cut thin-film lithium niobate platform; The waveguide extension direction of the polarization rotating beam splitter and the wave demultiplexing unit is along the Y-axis direction of the thin-film lithium niobate crystal; and The waveguide extension direction of the polarization rotating beam splitter and the wave demultiplexing unit is perpendicular to the Z-axis direction of the lithium niobate crystal.

8. The wave decomposition and multiplexing array according to claim 7, characterized in that, The thin-film lithium niobate platform includes: Substrate; Buried oxide substrate, located on the substrate; and A thin-film lithium niobate structural layer is bonded to the upper surface of the buried oxide substrate. The thin-film lithium niobate structural layer includes a first thin-film lithium niobate layer and a second thin-film lithium niobate layer, wherein the first thin-film lithium niobate layer is located on the side of the buried oxide layer substrate away from the substrate; the second thin-film lithium niobate layer is located on the side of the first thin-film lithium niobate layer away from the substrate; and the first thin-film lithium niobate layer and the second thin-film lithium niobate layer form a ridge structure.

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