Integrated power divider based on X-cut thin-film lithium niobate waveguide and preparation method thereof

Abstract

The invention belongs to the technical field of optical communication, and discloses an integrated power divider based on an X-cut thin-film lithium niobate waveguide and a preparation method thereof, wherein a buried oxide layer is placed on the substrate; a straight waveguide input region is placed on the buried oxide layer, one end of which is connected to the input end, and the other end is connected to the staggered wide waveguide region; the staggered wide waveguide region is placed on the buried oxide layer, one end of which is connected to the output end; a right-angle trapezoidal waveguide region is placed on the buried oxide layer, and a constant interval is maintained with the staggered wide waveguide region, and one end is connected to the oblique waveguide output region; the oblique waveguide output region is placed on the buried oxide layer, and one end is connected to the other output end; the straight waveguide input region, the staggered wide waveguide region, the right-angle trapezoidal waveguide region, and the oblique waveguide output region are all along the Y direction of the lithium niobate crystal axis; an insulating cladding is placed on the straight waveguide input region, the staggered wide waveguide region, the right-angle trapezoidal waveguide region, and the oblique waveguide output region; the invention has the advantages of large extinction ratio, small loss, high precision, small size, high bandwidth, large tolerance, and easy integration.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical communication, and in particular relates to an integrated power divider based on an X-cut thin-film lithium niobate waveguide and a preparation method thereof. Background Art

[0002] Integrated electronic circuits have entered the nanometer level due to the mature development of CMOS technology. However, the development of integrated circuit chips, which is limited by Moore's Law, has repeatedly faced physical bottlenecks and is difficult to meet the increasing demand for information exchange, such as ultra-high-definition video, large-scale 3D games, virtual reality, etc. Therefore, in order to meet the ultimate requirements of people for data information activities, high-performance, low-cost devices are needed to provide strong physical layer support. The explosive growth of communication capacity has promoted the development of photonic technology. Compared with the platform based on silicon materials, the thin-film lithium niobate platform has a large refractive index difference and excellent electro-optical coefficient. Based on these advantages, the thin-film lithium niobate modulators currently developed by researchers have the advantages of low driving voltage (<2V), low loss (<1dB), and high bandwidth (100Gbit-s, even 200Gbit-s). In addition to improving the modulation bandwidth of the modulator at the device level, digital coherent demodulation systems and advanced data modulation formats have also become important research directions for further improving data transmission in the current optical communication field, such as orthogonal phase shift keying and polarization multiplexing technology.

[0003] However, as the integration scale of integrated thin-film lithium niobate optical communication devices is further increased, the increase in the amount of transmitted data and the degree of integration also means that the integrated optical path is unprecedentedly complex, and it will face problems such as difficult optical path problem source tracing and difficulty in independent debugging of single devices. For example, although the integrated double-biased IQ modulator can significantly increase the transmission capacity, when ensuring the normal operation of the device, each IQ modulator needs to be in a carrier suppression working state. The total output of the reference device cannot directly reflect the working state of each modulator, which increases the difficulty of adjusting the optimal working state of each IQ modulator, making it difficult to give full play to the performance of the device. Not only that, optoelectronic hybrid is one of the important development directions of integrated photonics at present. Its working requirements are to convert a small proportion of light into electrical signals in the electrical domain for operations such as calculation and feedback control without affecting the energy requirements of the optical path. In summary, the power divider is an important component for the development of optical communication system with diversified functions, refined systems and complex development. Integrated photonic power dividers are different from traditional optical fiber power dividers. Common ones include directional coupler power dividers, multimode interference coupler power dividers, Y-branch networks, micro-ring arrays, Mach-Zehnder interferometers, etc. For example, directional coupler power dividers and their extended unbalanced directional couplers, multi-waveguide couplers, sub-wavelength directional couplers, etc., this type of power divider is heavily dependent on the phase matching conditions of the waveguide, and the small spacing between the waveguides and the characteristic size of the device lead to high requirements for process accuracy, and the small process tolerance severely limits the performance and large-scale application of the device; while the Y-branch network and multi-mode interference coupler can achieve N×N multi-way equal division through design optimization, which can significantly increase the integration scale, but both are mostly dividers, and have problems such as strong dependence on the working wavelength and severely limited working bandwidth; the microring array power divider has the advantage of high extinction ratio, but the quality factor of the microring is not only heavily dependent on the process accuracy, but also severely limited by the influence of the working environment; the Mach-Zehnder modulator combined with the electrode phase shifter has the flexible application characteristics that can be adjusted according to work requirements, but its process is complex, the device size is large, and metal absorption and other factors increase the additional loss of the device, which is not convenient for large-scale integrated application scenarios.

[0004] Through the above analysis, the problems and defects of the existing technology are as follows: the existing integrated power splitters are mostly equalizers, and their performance is generally seriously dependent on process accuracy, with a small working bandwidth and a low extinction ratio. Although some solutions can adjust the power splitting ratio, they increase the process complexity of the device and increase the device size, accompanied by additional additional losses. The existing technical solutions cannot simultaneously meet the requirements of low loss, high extinction ratio, small size, large tolerance, large bandwidth, and easy integration of integrated power splitters. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a large-tolerance, high-bandwidth, arbitrary-ratio power divider based on an X-cut thin-film lithium niobate waveguide, which has the characteristics of low loss, high extinction ratio, small size, large tolerance, high bandwidth, and easy integration.

[0006] The present invention is implemented as follows: an integrated power divider based on an X-cut thin-film lithium niobate waveguide includes a substrate, a buried oxide layer, a straight waveguide input region, a staggered wide waveguide region, a right-angle trapezoidal waveguide region, an oblique waveguide output region, and an insulating cladding; different from the idea that traditional waveguide transmission needs to avoid additional losses caused by inconsistent sizes of front and rear waveguides, the present invention cleverly controls the size of the front and rear waveguides, controls the energy ratio of the transverse electric fundamental mode and the excited transverse electric first-order mode, and avoids multi-mode interference processes such as multi-mode interferometers. Next, the present invention uses the mode evolution coupling theory and the mode evolution theory to allow the first-order transverse electric mode to couple and evolve to the transverse electric fundamental mode on another waveguide, thereby realizing the splitting function of any power division ratio.

[0007] The buried oxide layer is placed on the substrate, the straight waveguide input region, the staggered wide waveguide region, the right-angle trapezoidal waveguide region, and the oblique waveguide output region are placed on the buried oxide layer, and along the Y direction of the lithium niobate crystal axis, the staggered wide waveguide region is connected to the straight waveguide input region, the right-angle trapezoidal waveguide region maintains a constant interval with the wide waveguide region, and the other end is directly connected to the oblique waveguide output region; the insulating cladding is placed on the straight waveguide input region, the staggered wide waveguide region, the right-angle trapezoidal waveguide region, and the oblique waveguide output region.

[0008] Furthermore, the substrate is silicon.

[0009] Furthermore, the buried oxide layer is silicon dioxide with a thickness of 3 μm.

[0010] Furthermore, the straight waveguide input region is an X-cut lithium niobate film arranged along the Y-axis direction.

[0011] Furthermore, the dislocated wide waveguide region is an X-cut lithium niobate film arranged along the Y-axis direction.

[0012] Furthermore, the right-angle trapezoidal waveguide region is an X-cut lithium niobate film arranged along the Y-axis direction.

[0013] Furthermore, the oblique waveguide output region is an X-cut lithium niobate film arranged along the Y-axis direction.

[0014] Furthermore, the insulating cladding is silicon dioxide.

[0015] Another object of the present invention is to provide a method for preparing an integrated power divider based on an X-cut thin-film lithium niobate waveguide, comprising the following steps:

[0016] Step 1: Prepare input straight waveguide, staggered wide waveguide, right-angle trapezoidal waveguide and oblique waveguide on lithium niobate film by photolithography and etching technology;

[0017] Step 2: Deposit silicon dioxide as an insulating cladding layer on the substrate obtained in step 1 by chemical vapor deposition.

[0018] Furthermore, the photolithography includes stepper lithography, contact lithography, electron beam direct writing, and laser direct writing; the etching includes dry etching and wet etching.

[0019] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0020] First, the present invention uses the transverse electric fundamental mode to excite the first-order transverse electric mode due to the small deviation of the front and rear width of the waveguide, and combines the mode evolution theory to realize the excitation and separation of the first-order transverse electric mode, so as to realize the arbitrary splitting of optical transmission at the waveguide level. The first creative advantage of the scheme: Unlike the traditional method of avoiding additional losses caused by waveguide size deviations and multi-mode interferometers that excite many high-order modes, this invention only excites the first-order transverse electric mode due to the small deviation of the front and rear width of the waveguide, avoiding the dependence of the multi-mode interference process of the multi-mode interferometer on wavelength and process tolerance; The second creative advantage of the scheme: Introducing the mode evolution process to reduce the precision requirements of the process of the mode coupling device. At the same time, it reduces the strict requirements of the coupling process on phase matching. The present invention significantly improves the bandwidth and process tolerance of the device, facilitates interconnection with other functional thin-film lithium niobate devices, and has no complicated additional losses or functional damage to the device.

[0021] Second, the process steps adopted by the present invention have the advantages of low cost, simple process, and mass production. The present invention adopts lithium niobate film to realize the power divider. The large refractive index difference of lithium niobate material makes it small in size and easy to integrate. The present invention can realize the design of power divider devices with arbitrary power division ratios, achieve the purpose of optical path monitoring and calculation at specific locations, and at the same time have the advantages of large extinction ratio, low loss, high precision, small size, high bandwidth, large tolerance, and easy integration.

[0022] Third, as auxiliary evidence of the inventiveness of the present invention, it is also reflected in the following important aspects:

[0023] (1) Expected benefits and commercial value: This technical solution can bring about breakthrough progress in the field of integrated optoelectronics. Its high bandwidth, high extinction ratio, and small size are suitable for the next generation of high-speed optical communication systems. In addition, it has the ability to achieve large process tolerances and arbitrary splitting ratios, has low requirements for process precision, and can be mass-produced, which enhances the product's scope of application and market competitiveness. The expected commercial value is not only reflected in the potential large-scale market demand, but also in its ability to significantly reduce the operator's operation and maintenance costs.

[0024] (2) Filling the technical gap: As shown in the above analysis of the defects of existing integrated splitters, there is currently no integrated splitter on the market that can simultaneously achieve small size, large bandwidth, high extinction ratio, large tolerance and arbitrary splitting ratio, and also has the characteristics of low loss. The technical solution of the present invention successfully integrates these performances and fills the technical gap in this field.

[0025] (3) Solving technical problems: For a long time, integrated splitters have often encountered problems such as small process tolerance, small bandwidth, high precision requirements, and large additional losses when trying to improve performance. The present invention provides a solution that can effectively address these problems while ensuring low loss and easy integration, meeting the industry's long-standing expectations.

[0026] (4) Overcoming technical prejudice: Previously, it was generally believed that achieving high-performance integrated splitters would inevitably be accompanied by high losses and increased design complexity. In addition, the traditional concept was that additional losses caused by small deviations in the width of the front and rear spliced ​​waveguides should be avoided as much as possible during waveguide transmission. The present invention proves that by utilizing the "shortcomings in traditional concepts" through innovative design, high performance can be achieved while maintaining low losses and simple design.

[0027] Fourthly, the invention is an integrated splitter based on an X-cut thin-film lithium niobate waveguide. Through its unique design structure, it solves many problems existing in the prior art in optical signal distribution and transmission, and achieves significant technological progress.

[0028] First, the invention uses thin-film lithium niobate as the waveguide material, which makes the waveguide have excellent optical properties, such as low loss and high refractive index, thus ensuring the high efficiency and stability of the transmission of optical signals in the waveguide. At the same time, the X-cut thin-film lithium niobate has a specific crystal orientation, which can further optimize the propagation characteristics of the optical signal.

[0029] Secondly, the invention realizes the precise distribution and efficient transmission of optical signals by designing multiple functional areas such as straight waveguide input area, staggered wide waveguide area, right-angle trapezoidal waveguide area and oblique waveguide output area. Among them, the design of the staggered wide waveguide area can reduce the reflection and scattering of optical signals and improve the transmission efficiency of optical signals; the design of the right-angle trapezoidal waveguide area and the oblique waveguide output area can realize the uniform distribution and stable output of optical signals.

[0030] In addition, the invention also uses silicon as the substrate material and silicon dioxide as the buried oxide layer material. The selection of these materials not only ensures the stability and reliability of the waveguide structure, but also enables the entire device to have good thermal stability and mechanical strength.

[0031] This invention solves the problem of optical signal distribution and transmission in the prior art by optimizing waveguide materials, designing a reasonable waveguide structure, and selecting an appropriate material combination, improves the transmission efficiency and stability of optical signals, and achieves significant technological progress. This integrated power divider based on X-cut thin-film lithium niobate waveguide has broad application prospects in the fields of optical communications, optical sensing, etc., and is of great significance for promoting the development of related industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 1 is a schematic diagram of the structure of an integrated splitter based on an X-cut thin-film lithium niobate waveguide provided in an embodiment of the present invention; in order to clearly show the optical waveguide structure, the insulating cladding is omitted;

[0034] Figure 2 1 is a top view schematic diagram of a large tolerance and high bandwidth arbitrary ratio power divider based on an X-cut thin film lithium niobate waveguide provided by an embodiment of the present invention; in order to clearly show the optical waveguide structure, the insulating cladding is omitted;

[0035] Figure 3 It is a flow chart of a method for preparing an integrated power divider based on an X-cut thin-film lithium niobate waveguide provided by an embodiment of the present invention;

[0036] Figure 4 is a schematic cross-sectional view of the optical mode field of TE00 and TE01 provided in an embodiment of the present invention;

[0037] Figure 5 It is the proportion of the output energy of the transverse electric fundamental mode and the first-order transverse electric mode generated by the transverse electric fundamental mode input after the width, wavelength, and manufacturing tolerance of the input straight waveguide and the offset wide waveguide provided in the embodiment of the present invention change;

[0038] Figure 6 It is a propagation electric field distribution diagram of TE00 and TE01 in a staggered wide waveguide, a right-angle trapezoidal waveguide, and an output oblique waveguide provided by an embodiment of the present invention;

[0039] Figure 7 It is a wavelength response diagram of the wide waveguide output port and the oblique waveguide output port of TE00 and TE01 provided by the embodiment of the present invention after passing through the staggered wide waveguide, the right-angle trapezoidal waveguide, and the output oblique waveguide. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] like Figure 1 and Figure 2 As shown, an integrated power divider based on an X-cut thin-film lithium niobate waveguide provided by an embodiment of the present invention includes a silicon substrate 1, a buried oxide layer 2, a lithium niobate ridge input straight waveguide 3, a lithium niobate ridge dislocation wide waveguide 4, a lithium niobate ridge right-angle trapezoidal waveguide 5, and a lithium niobate ridge output oblique waveguide 6;

[0042] The buried oxide layer 2 is placed on the substrate 1; the lithium niobate ridge input straight waveguide 3, the lithium niobate ridge dislocation wide waveguide 4, the lithium niobate ridge right-angle trapezoidal waveguide 5, and the lithium niobate ridge output oblique waveguide 6 are placed on the buried oxide layer 2; in order to clearly show the optical waveguide structure, Figure 1 and Figure 2 The insulating sheath is omitted and is located at the top layer of the device.

[0043] The silicon substrate has a thickness of 500 μm, the buried oxide layer has a thickness of 3 μm, the input straight waveguide has a width of 1.8 μm, and a lithium niobate film with a thickness of 360 μm is etched by an electron beam exposure method and inductively coupled plasma to obtain a ridge waveguide with a thickness of 180 μm, including a lithium niobate ridge input straight waveguide 3, a lithium niobate ridge dislocation wide waveguide 4, a lithium niobate ridge right-angle trapezoidal waveguide 5, and a lithium niobate ridge output oblique waveguide 6. Furthermore, the widths of the lithium niobate ridge input straight waveguide and the dislocation wide waveguide are 1.8 μm and 2.2 μm respectively, with a total length of 5 μm. The widths of the two ends of the lithium niobate ridge right-angle trapezoidal waveguide are 0.6 μm and 1.2 μm respectively, with a length of 80 μm. The width of the oblique waveguide is 1.2 μm, with a length of 60 μm. Next, a chemical vapor deposition method is used to obtain an insulating cladding with a thickness greater than 400 nm.

[0044] like Figure 3 As shown, a method for preparing an integrated power divider based on an X-cut thin-film lithium niobate waveguide provided in an embodiment of the present invention comprises the following steps:

[0045] S101, using photolithography and etching technology to prepare input straight waveguides, offset wide waveguides, right-angle trapezoidal waveguides, and oblique waveguides on lithium niobate films;

[0046] S102, depositing silicon dioxide as an insulating cladding layer on the substrate obtained in S101 by using a chemical vapor deposition method.

[0047] Furthermore, the photolithography includes stepper lithography, contact lithography, electron beam direct writing, and laser direct writing; the etching includes dry etching and wet etching.

[0048] Figure 4 a is the TE00 mode field distribution of the optical waveguide cross section in this example, Figure 4 b is the TE01 mode field distribution. The two modes are orthogonal to each other and the energy is concentrated inside the waveguide. Figure 5 a is the output energy change curve of TE00 mode and TE01 mode obtained with the change of input straight waveguide width under TE00 mode input, and the width of the offset wide waveguide is 2.2μm. Different from the requirement of avoiding additional loss caused by the front and back splicing misalignment and width inconsistency of the same waveguide in waveguide preparation, this case actively introduces the inconsistency of the front and back waveguide widths in a waveguide. The different width differences correspond to different first-order transverse electric mode energies, so as to achieve the conversion of part of the original input light energy into the first-order transverse electric mode of the waveguide. Figure 5 As shown by the star mark in a, the input straight waveguide width is 1.8 μm, and the corresponding output TE00 mode energy and TE01 mode energy accounts for 0.948 and 0.5 respectively. Figure 5 b is the output TE00 mode energy and TE01 mode energy ratio in the [1.5-1.6]μm wavelength range under the parameters of the input straight waveguide and the offset wide waveguide with a design power split of 95:5. In this wavelength range, the energy distribution caused by the inconsistent splicing width of a waveguide is almost the same, showing the characteristics of high bandwidth. Figure 5 c is the energy ratio of the output TE00 mode and TE01 mode under the design of 95:5 power division performance within the process manufacturing tolerance range of [-0.3-0.3]μm. Figure 5 c shows that within the waveguide width tolerance range, the energy share of the TE01 mode changes from 0.47 to 0.54, with a change value of only 0.007, showing a large tolerance characteristic. High bandwidth and large tolerance are important performance indicators in the preparation process of integrated photonic devices. Unlike traditional power dividers based on directional couplers and multimode interference couplers, these power dividers often rely on high-precision preparation processes and have very limited working bandwidths. The power divider solution proposed in this example clearly shows the performance advantages of high bandwidth and large tolerance.

[0049] Figure 6 a is the propagation electric field distribution of TE00 mode in wide waveguide, right-angle trapezoidal waveguide and inclined waveguide. Figure 6b is the propagation electric field distribution of TE01 mode in the offset wide waveguide, right-angle trapezoidal waveguide and slanted waveguide. When part of the input TE00 energy is excited to the TE01 mode, there are TE00 mode and a small part of TE01 mode in the offset wide waveguide, and the right-angle trapezoidal waveguide and output slanted waveguide that maintain a constant interval with the offset wide waveguide separate the two modes based on mode coupling and mode evolution theory. In the integrated optical waveguide, there is a direct coupling process between adjacent waveguides. The mode that meets the phase matching condition in the waveguide can couple energy to a specific mode in another waveguide. The mode energy of the two waveguides changes periodically with the transmission distance. In order to prevent the coupled energy from being coupled back with the increase of the transmission distance, the waveguide width is generally gradually increased. Correspondingly, the effective refractive index of the optical mode increases with the increase of the propagation distance, and the mode evolution process occurs. In this case, the input TE00 mode in the offset wide waveguide does not meet the mode coupling condition within the width range of the right-angle trapezoidal waveguide, so the TE00 mode can pass through the structure without loss and remain output in the offset wide waveguide. As the transmission distance increases, the TE01 mode meets the coupling condition and couples to the TE00 mode of the right-angle trapezoidal waveguide. At the same time, the width of the right-angle trapezoidal waveguide also increases with the change of transmission distance, evolving into the TE00 mode with a larger effective refractive index, breaking the coupling condition with the TE01 mode of the offset wide waveguide. Therefore, the input light of the TE01 mode of the offset wide waveguide is completely converted into the output TE00 mode of the oblique waveguide. Based on this principle, the purpose of mode separation is achieved.

[0050] Figure 7 a is the interpolation loss wavelength response of the TE00 mode from the output end of the staggered wide waveguide and the output end of the slanted waveguide after passing through the staggered wide waveguide, the right-angle trapezoidal waveguide and the slanted waveguide. Figure 7 b is the wavelength response of the interpolation loss of the TE01 mode from the output end of the staggered wide waveguide, the right-angle trapezoidal waveguide, and the slanted waveguide. In the range of [1.5-1.6] μm, both TE00 and TE01 modes pass losslessly and achieve the purpose of mode separation, and the extinction ratio is greater than 24 dB. In general, this example presents a new integrated platform power divider solution, which exhibits excellent properties of large bandwidth, large tolerance, easy integration, and small size.

[0051] The working principle of the integrated splitter based on X-cut thin-film lithium niobate waveguide is summarized as follows:

[0052] 1. Basic structure composition: The integrated splitter is based on an X-cut thin-film lithium niobate waveguide, which is selected for its excellent electro-optical properties. The substrate is usually made of silicon material, covered with a layer of silicon dioxide as a buried oxide layer, which is separated from the substrate and waveguide layer to ensure that the loss of light waves when propagating in the waveguide is minimized.

[0053] 2. Straight waveguide input area: The optical signal is first input into the straight waveguide area, which is made of X-cut lithium niobate film and arranged along the Y-axis direction to guide the incident light wave to propagate along a predetermined path.

[0054] 3. Dislocation wide waveguide area: After the straight waveguide input area is the dislocation wide waveguide area, which is also composed of X-cut lithium niobate film. The design of this area enables the light waves of different modes to be effectively separated, providing conditions for subsequent waveguide decomposition.

[0055] 4. Right-angle trapezoidal waveguide area: This area connects the staggered wide waveguide area and the oblique waveguide output area. The right-angle trapezoidal structural design enables the light waves to be distributed at a specific angle between different output waveguides, thereby realizing the decomposition and distribution of the light waves.

[0056] 5. Slanted waveguide output area: Finally, the decomposed light waves enter the slanted waveguide output area. These waveguides are arranged at specific angles to output light signals of different modes or wavelengths.

[0057] 6. Insulating cladding: The entire waveguide structure is covered by an insulating cladding, usually made of silicon dioxide, which protects the waveguide structure from external influences while ensuring the stability and efficiency of light waves propagating inside the waveguide.

[0058] Through the above-mentioned specially designed waveguide regions, the integrated splitter can realize high-precision optical signal decomposition and distribution functions, which is suitable for complex optical communication systems and optical integrated circuits, and improves the performance and reliability of the system.

[0059] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. An integrated power divider based on an X-cut thin-film lithium niobate waveguide, characterized in that: It includes a substrate, a buried oxide layer, a straight waveguide input region, a staggered wide waveguide region, a right-angle trapezoidal waveguide region, an oblique waveguide output region, and an insulating cladding; The buried oxide layer is placed on the substrate, the straight waveguide input region, the dislocated wide waveguide region, the right-angle trapezoidal waveguide region, and the oblique waveguide output region are placed on the buried oxide layer, and along the Y direction of the lithium niobate crystal axis, the dislocated wide waveguide region is connected to the straight waveguide input region, the right-angle trapezoidal waveguide region is kept at a constant interval with the wide waveguide region, and the other end is directly connected to the oblique waveguide output region; the insulating cladding is placed on the straight waveguide input region, the dislocated wide waveguide region, the right-angle trapezoidal waveguide region, and the oblique waveguide output region; The silicon substrate has a thickness of 500 μm, the buried oxide layer has a thickness of 3 μm, and the lithium niobate film has a thickness of 360 μm. After electron beam exposure and inductively coupled plasma etching, a ridge waveguide with a thickness of 180 μm is obtained, including a lithium niobate ridge input straight waveguide, a lithium niobate ridge dislocation wide waveguide, a lithium niobate ridge right-angle trapezoidal waveguide, and a lithium niobate ridge output oblique waveguide. The widths of the lithium niobate ridge input straight waveguide and the dislocation wide waveguide are 1.8 μm and 2.2 μm respectively, and the total length is 5 μm. The widths of the two ends of the lithium niobate ridge right-angle trapezoidal waveguide are 0.6 μm and 1.2 μm respectively, and the length is 80 μm. The width of the oblique waveguide is 1.2 μm, and the length is 60 μm. The insulating cladding with a thickness greater than 400 nm is obtained by chemical vapor deposition.

2. The integrated power divider based on the X-cut thin film lithium niobate waveguide according to claim 1, characterized in that: The insulating cladding is silicon dioxide.

3. A method for preparing an integrated power divider based on an X-cut thin-film lithium niobate waveguide as claimed in any one of claims 1 to 2, characterized in that: The steps include: Step 1: Prepare input straight waveguide, staggered wide waveguide, right-angle trapezoidal waveguide and oblique waveguide on lithium niobate film by photolithography and etching technology; Step 2: Deposit silicon dioxide as an insulating cladding layer on the substrate obtained in step 1 by chemical vapor deposition.

4. The method for preparing an integrated power divider based on an X-cut thin-film lithium niobate waveguide according to claim 3, characterized in that: The photolithography includes stepper lithography, contact lithography, electron beam direct writing, and laser direct writing; the etching includes dry etching and wet etching.

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