Integratable device based on thin film lithium niobate platform

Abstract

The invention relates to the technical field of optical fiber communication, in particular to an integratable device based on a thin film lithium niobate platform, which comprises a z-cut thin film lithium niobate platform and an S-gate graphene electrode, the S-grid type graphene electrode is arranged at the top end of the z-cut film lithium niobate platform; the z-cut film lithium niobate platform comprises a substrate, a metal layer arranged on the substrate, a lower cladding layer arranged on the metal layer and a film lithium niobate rib type optical waveguide arranged on the lower cladding layer, and the S-gate graphene electrode is arranged at the top end of the thin-film lithium niobate rib type optical waveguide. According to the invention, the z-cut film lithium niobate platform is combined with the S-grid type graphene electrode to form the up-down structure, so that the electric field intensity is higher; in addition, the structure is easy to realize and simple in process, low in cost and small in size; and in terms of performance, the electro-optical modulation efficiency is high, the pi / 2 phase voltage is low, the optical loss is low, the pi / 2 phase voltage and the gate region length can be balanced, and the device is suitable for a new generation of integrated photon circuits.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber communication technology, and in particular to an integrable device based on a thin-film lithium niobate platform. Background Art

[0002] As the demand for high-speed, high-bandwidth communications and signal processing in areas such as telecommunications, data centers, sensing and quantum computing grows, photonic integrated circuits are continually being developed to make technological advances. Compared to traditional electronic circuits, photonic integrated circuits can provide higher bandwidth, faster data transmission, and have high-fidelity and low-noise signal processing capabilities, allowing data processing speeds to reach the terabit per second range. Photonic integrated circuits are generally very energy-efficient, especially in long-distance data transmission, and are more energy-efficient than electronic devices. In addition, the integration technology of optical components also enables the miniaturization of optical devices, which are CMOS-compatible with electronic circuits on the same chip, thereby producing a large-scale system-level hybrid optoelectronic chip that combines the advantages of both.

[0003] Currently, the following two principles are commonly used to construct integrable devices for hybrid optical chips: (1) based on the whispering gallery resonance coupling principle, such as using an optical waveguide and a resonant ring / cascade resonant ring. The disadvantage is that the resonant ring / cascade resonant ring needs to be processed additionally, which makes the process relatively complicated and increases the size of the overall device. (2) based on the grating principle, such as directly etching a grating structure on the optical waveguide. The disadvantage is that the process becomes more complicated, which significantly increases the cost. In addition, in order to accumulate to a π / 2 phase to achieve the optimal coupling efficiency, that is, a large extinction ratio, the length of the grating is fixed and relatively large, which also increases the size of the overall device. Summary of the invention

[0004] The purpose of the present invention is to provide an integrable device based on a thin film lithium niobate platform, which has the advantages of low process, low cost, small size, high electro-optical modulation efficiency and low π / 2 phase voltage.

[0005] To achieve the above object, the present invention provides an integrable device based on a thin film lithium niobate platform, the integrable device comprising:

[0006] A z-cut thin-film lithium niobate platform and an S-gate graphene electrode; the S-gate graphene electrode is arranged on the top of the z-cut thin-film lithium niobate platform;

[0007] The z-cut thin-film lithium niobate platform comprises: a substrate, a metal layer arranged on the substrate, a lower cladding arranged on the metal layer, and a thin-film lithium niobate rib-type optical waveguide arranged on the lower cladding; the S-gate graphene electrode is arranged on the top of the thin-film lithium niobate rib-type optical waveguide.

[0008] Optionally, the thin-film lithium niobate rib-type optical waveguide comprises:

[0009] A flat plate and at least one rib; the flat plate and each of the ribs are an integrally formed structure; the flat plate is formed integrally of a base and two side support members;

[0010] A groove is formed by depression downwards on the base near the supporting members on both sides; the S-gate graphene electrodes are placed on the supporting members on both sides;

[0011] When one rib is provided, the rib is provided at the middle position of the base; when multiple ribs are provided, the multiple ribs are provided at the middle position of the base with intervals therebetween;

[0012] There is a certain distance between the top of the rib and the S-gate graphene electrode.

[0013] Optionally, the S-gate graphene electrode comprises:

[0014] At least one graphene horizontal plate and at least one graphene vertical plate; all the graphene horizontal plates and all the graphene vertical plates are integrally formed; all the graphene horizontal plates have equal widths and are parallel to each other; all the graphene vertical plates have equal lengths;

[0015] The ends of two adjacent graphene horizontal plates are connected by a graphene vertical plate; the i-th graphene vertical plate and the (i+1)-th graphene vertical plate are respectively arranged on the two supporting members of the flat plate and are parallel to each other.

[0016] Optionally, each of the graphene vertical plates is perpendicular to the adjacent graphene horizontal plates.

[0017] Optionally, the S-gate graphene electrode comprises:

[0018] At least one graphene cross plate and at least one arc-shaped graphene connecting plate; all the graphene cross plates and all the arc-shaped graphene connecting plates are integrally formed; all the graphene cross plates have equal widths and are parallel to each other; all the arc-shaped graphene connecting plates have the same structure;

[0019] The ends of two adjacent graphene transverse plates are connected by an arc-shaped graphene connecting plate; the i-th arc-shaped graphene connecting plate and the (i+1)-th arc-shaped graphene connecting plate are respectively arranged on the two supporting members of the flat plate.

[0020] Optionally, the grating length L=nΛ, wherein n is the number of grating periods and Λ is the grating period.

[0021] Optionally, the modulation center wavelength of the integrated device is λ0=Λ(N1-N2), where Λ is the grating period and N1 is the fundamental mode TM 00The effective refractive index of N2 is the high-order leaky mode TM 01 The effective refractive index.

[0022] Optionally, a distance d0 between a top end of the rib and the S-gate graphene electrode is greater than or equal to 200 nm.

[0023] Optionally, the material of the base is a silicon substrate; the material of the metal layer is Au; the material of the lower cladding layer is SiO2; and the material of the thin-film lithium niobate rib-type optical waveguide is TFLN.

[0024] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0025] The invention provides an integrable device based on a thin-film lithium niobate platform, comprising: a z-cut thin-film lithium niobate platform and an S-gate graphene electrode; the S-gate graphene electrode is arranged on the top of the z-cut thin-film lithium niobate platform; the z-cut thin-film lithium niobate platform comprises: a substrate, a metal layer arranged on the substrate, a lower cladding layer arranged on the metal layer, and a thin-film lithium niobate rib-type optical waveguide arranged on the lower cladding layer; the S-gate graphene electrode is arranged on the top of the thin-film lithium niobate rib-type optical waveguide. The present invention combines a z-cut thin-film lithium niobate platform with an S-gate graphene electrode to form an upper and lower structure to increase the electric field strength. In addition, the S-gate graphene electrode is an S-shaped periodic grating structure that spans the optical waveguide mode field, and forms two voltage poles with the metal layer to form a modulated electric field. The thin-film lithium niobate rib-type optical waveguide is a medium for optical transmission / coupling, and only the refractive index of the electrode grid strip region of the thin-film lithium niobate rib-type optical waveguide is modulated by the electric field. Therefore, the structure is easy to implement, simple, low in cost, and small in size. In terms of performance, the electro-optical modulation efficiency is high, the π / 2 phase voltage is low, the optical loss is small, and the π / 2 phase voltage and the gate region length can be balanced, which is suitable for a new generation of integrated photonic circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 paying creative labor.

[0027] Figure 1 Schematic diagram of an integrable device based on a thin-film lithium niobate platform according to an embodiment of the present invention; wherein (a) is a schematic diagram of the end surface structure and the material composition of each part, and (b) is a three-dimensional structure diagram of the integrable device;

[0028] Figure 2 Three schematic diagrams of S-gate graphene electrodes according to embodiments of the present invention; wherein (a) is a schematic diagram of intersection Figure 1 , (b) is a schematic diagram of the treatment, (c) is a schematic diagram of the intersection Figure 2 ;

[0029] Among them, 10-silicon substrate; 20-metal layer; 30-lower cladding; 40-thin-film lithium niobate rib-type optical waveguide; 41-rib; 42-plate; 43-support; 44-groove; 50-S-gate graphene electrode. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The purpose of the present invention is to provide an integrable device based on a thin film lithium niobate platform, which has the advantages of low process, low cost, small size, high electro-optical modulation efficiency and low π / 2 phase voltage.

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] As a new generation of integrated photonic circuits, the thin film lithium niobate (TFLN) platform inherits almost all the material advantages of traditional high-capacity lithium niobate devices and has become a strong competitor in recent years. Thin film lithium niobate has high electro-optical efficiency, good performance and stability, and the scalable manufacturing technology is developing rapidly, with a smaller footprint, wider bandwidth and lower power consumption, showing predictable high performance in the future. Graphene, composed of carbon atoms arranged in a two-dimensional hexagonal lattice, is the world's first true two-dimensional single-layer material. Its inherent high charge carrier mobility value and strongly confined plasmon excitation in the terahertz / infrared spectral range, two unique optoelectronic properties, indicate its potential for application in optoelectronic devices.

[0034] To maximize the electro-optic coefficient r 33=31pm / V, based on the relative position of the crystal axis z and the wafer cutting surface, the thin film lithium niobate wafer is divided into two types: x / y cut and z cut. Regardless of which one, the design problem of the electro-optical device of the thin film lithium niobate platform is mainly how to increase the applied electric field intensity in the optical mode region to make the electro-optical modulation more efficient, while taking into account other desired performance. Taking the most cutting-edge research hotspot thin film lithium niobate electro-optic modulator as an example, its focus is on the design of the thin film lithium niobate rib-type optical waveguide and the configuration of the electrode. A balanced choice between the structural form, dimensional parameters, materials, etc. of the rib-type optical waveguide, or the selection of a heterostructure with ribs made of other refractive index materials. The purpose is to better confine the optical mode field in the thin film lithium niobate to obtain a smaller π / 2 phase voltage, and then reasonably configure the electrodes to maximize the electric field intensity, thereby improving the electro-optical modulation efficiency. Compared with traditional electrode materials such as Au / Al / Pt / Pd, graphene electrodes are two-dimensional single-layer electrodes with better electrical conductivity, optical transparency, thermal conductivity and thermal stability, and it is also easy to obtain S-shaped periodic gate structures using silicon microprocessing. Therefore, the present invention combines the z-cut thin-film lithium niobate platform with the S-gate graphene electrode to form this upper and lower structure, which makes the electric field stronger and spans the optical waveguide mode field.

[0035] Example 1

[0036] The invention discloses an integrable device based on a thin-film lithium niobate platform. The integrable device comprises: a z-cut thin-film lithium niobate platform and an S-gate graphene electrode; the S-gate graphene electrode is arranged on the top of the z-cut thin-film lithium niobate platform.

[0037] As an optional implementation, the z-cut thin-film lithium niobate platform of the present invention comprises: a substrate, a metal layer disposed on the substrate, a lower cladding disposed on the metal layer, and a thin-film lithium niobate rib-type optical waveguide disposed on the lower cladding; an S-gate graphene electrode is disposed on the top of the thin-film lithium niobate rib-type optical waveguide. In this embodiment, the S-gate graphene electrode is a periodic gate structure in an S-like shape.

[0038] In this embodiment, the base is a silicon substrate processed by silicon microtechnology, and the thin-film lithium niobate rib-type optical waveguide is monolithic and is processed by silicon microtechnology based on TFLN material according to the designed structural form and size parameters; the S-shaped periodic gate structure of the S-gate graphene electrode is also processed by silicon microtechnology and placed on the thin-film lithium niobate platform, forming two poles of voltage with the metal layer to form a modulated electric field, and spanning the optical waveguide mode field.

[0039] The present invention combines a z-cut thin-film lithium niobate platform with an S-gate graphene electrode to form an upper and lower structure to increase the electric field strength. In addition, the S-gate graphene electrode is an S-shaped periodic grating structure that spans the optical waveguide mode field, and forms two voltage poles with the metal layer to form a modulated electric field. The thin-film lithium niobate rib-type optical waveguide is a medium for optical transmission / coupling, and only the refractive index of the electrode grating region of the thin-film lithium niobate rib-type optical waveguide is modulated by the electric field. Therefore, the structure is easy to implement, simple, low in cost, and small in size. In terms of performance, the electro-optical modulation efficiency is high, the π / 2 phase voltage is low, the optical loss is small, and the π / 2 phase voltage and the gate region length can be balanced, which is suitable for a new generation of integrated photonic circuits, such as optical filters based on the grating principle.

[0040] As an optional implementation, the thin-film lithium niobate rib-type optical waveguide of the present invention includes: a flat plate and at least one rib; the flat plate and each rib are an integrally formed structure; the flat plate is integrally formed by a base and two side supports; a groove is formed by a downward depression on the base close to the two side supports; and S-gate graphene electrodes are placed on the two side supports.

[0041] When one rib is provided, the rib is provided at the middle position of the base; when multiple ribs are provided (not shown), the multiple ribs are provided at the middle position of the base with intervals therebetween. There is a certain distance between the top of the rib and the S-gate graphene electrode.

[0042] In order to better limit the electric field and to improve the electric field strength at the overlap with the optical mode to a certain extent, the present invention forms a groove on the base near the two side supports, and the size and shape of the two grooves are the same. The size of the groove can be set according to actual needs. In addition, according to actual engineering needs, multiple ribs can be selected. The present invention does not limit the specific setting. It only needs to extend the width of the plate to ensure that the sum of the width of the bottom ends of the multiple ribs and the spacing between the multiple ribs is less than the length of the base after the depression, or the multiple ribs can be arranged at intervals so that they can be completely placed on the base after the depression.

[0043] As an optional implementation mode, the S-gate graphene electrode of the present invention is provided with three technical solutions, which are as follows:

[0044] The first solution: at least one graphene horizontal plate and at least one graphene vertical plate; all graphene horizontal plates and all graphene vertical plates are integrally formed structures; all graphene horizontal plates have equal widths and are parallel to each other; all graphene vertical plates have equal lengths; the ends of two adjacent graphene horizontal plates are connected by a graphene vertical plate; the i-th graphene vertical plate and the i+1-th graphene vertical plate are respectively set on two supporting members of the flat plate and are parallel to each other. In other words, the two adjacent graphene horizontal plates intersect with the graphene vertical plates, but are not perpendicular to each other. You only need to place the graphene vertical plates on the supporting members. Figure 2 As shown in Figure (a).

[0045] Second option:

[0046] On the same basis as the first solution, the following features are added: each graphene vertical plate is perpendicular to the adjacent graphene horizontal plate, such as Figure 2 As shown in Figure (b) in the figure. When K1=K2, the duty cycle is 1:1, indicating that the effect is best at this time.

[0047] The third option:

[0048] At least one graphene cross plate and at least one arc-shaped graphene connecting plate; all graphene cross plates and all arc-shaped graphene connecting plates are integrally formed structures; all graphene cross plates have equal widths and are parallel to each other; all arc-shaped graphene connecting plates have the same structure; the ends of two adjacent graphene cross plates are connected by an arc-shaped graphene connecting plate; the i-th arc-shaped graphene connecting plate and the i+1-th arc-shaped graphene connecting plate are respectively arranged on two supporting members of the flat plate, as shown in FIG. Figure 2 As shown in Figure (c).

[0049] As an optional implementation, the grating length L of the present invention is L=nΛ, wherein n is the number of grating periods and Λ is the grating period.

[0050] As an optional implementation, the modulation center wavelength of the integrated device of the present invention is λ0=Λ(N1-N2), where Λ is the grating period and N1 is the fundamental mode TM 00 The effective refractive index of N2 is the high-order leaky mode TM 01 The effective refractive index.

[0051] As an optional implementation manner, the distance d0 between the top of the rib of the present invention and the S-gate graphene electrode is greater than or equal to 200 nm.

[0052] Example 2

[0053] like Figure 1 As shown, the present invention takes a rib, where each graphene vertical plate is perpendicular to the adjacent graphene horizontal plate as an example for discussion:

[0054] In this embodiment, Figure 1 As shown in Figure (a), the z-cut thin-film lithium niobate platform includes a silicon substrate 10, a metal layer 20, a lower cladding layer 30 and a thin-film lithium niobate rib-type optical waveguide 40 from bottom to top. The silicon substrate 10 is preferably a silicon substrate for silicon microprocessing, with a thickness of 300μm; the metal layer 20, as an electrode, is preferably Au, with a thickness of 0.15μm; the lower cladding layer 30 is preferably SiO2, with a thickness of 1μm, and the above dimensions are in line with the current silicon microprocessing technology level. Alternatively, the most advanced commercially mature z-cut thin-film lithium niobate platform is preferred, and the technology level is equivalent.

[0055] The thin film lithium niobate rib type optical waveguide 40 comprises a rib 41 and a plate 42; the plate 42 is composed of a base (not shown) and a support 43; the thin film lithium niobate layer raw material is processed by plasma etching to form a rib 41 with a width w and a height d, and a base with a remaining height ds, which is a thin film lithium niobate rib type optical waveguide commonly seen in optical devices; preferably w = 1.5 μm, d = 0.7 μm, ds = 0.3 μm; because the rib 41 processed by plasma etching naturally forms a trapezoid, the lower angle of the trapezoid is usually α = 55° to 75°; or further, in order to better limit the electric field to improve the electric field strength at the overlap with the optical mode to a certain extent, a width w is processed on each base on both sides close to the support 43. t and high d t The groove 44. There is a certain size of spacing d0 between the upper surface of the rib 41 and the S-gate graphene electrode 50 (usually d0 is not less than 200nm, and its absorption loss of light can be ignored. Because the graphene of a single layer of carbon atoms does not allow any current to flow in the normal direction, it will not dissipate the normal electric field component of the propagating wave, that is, the graphene plane is perpendicular to the vibration direction of the TM mode electric field, so the metal absorption loss is small), so as to significantly reduce the absorption loss of light generated by the graphene electrode; and the air medium located above the rib 41 and the plate 42 is essentially its upper cladding for the optical transmission mode of the thin-film lithium niobate rib-type optical waveguide 40. Or further, the material of the upper cladding is replaced with SiO2. The electro-optical modulation based on the z-cut thin-film lithium niobate platform is consistent with the direction of the applied electric field, that is, it corresponds to the TM mode of the thin-film lithium niobate rib-type optical waveguide, and one of the two coupling modes is the fundamental mode TM 00 , and the other is usually a high-order TM 0n Leakage mold, preferably TM 01 When the electrical modulation reaches the π / 2 phase, the fundamental mode TM 00 Theoretically fully coupled to TM 01 The light intensity of the central wavelength λ0 is zero, that is, extinction; empirical experimental results show that the extinction ratio is usually not less than 25dB when the phase is π / 2.

[0056] like Figure 1As shown in Figure (b), the S-gate graphene electrode 50 uses silicon microprocessing to realize an S-shaped periodic gate structure, and is placed on a thin-film lithium niobate platform to form two poles of voltage with the metal layer 20. After the voltage V is applied, a modulated electric field is formed. The lateral width of the graphene electrode only needs to span the optical waveguide, and as one end of the applied electric field, it can satisfy the electric field modulation of the waveguide refractive index; its length is the length of the entire grating. In the thin-film lithium niobate rib-type optical waveguide 40, only the area corresponding to the graphene electrode 50 is modulated by the electric field. Based on the grating principle, the central wavelength of the modulation is λ0=Λ(N1-N2), where Λ is the grating period, the duty cycle can be selected as 1:1, and N1 is the fundamental mode TM 00 The effective refractive index of N2 is the high-order leaky mode TM 01 The effective refractive index of the fundamental mode TM 00 Light is coupled into the TM through the grating 01 The transmission scattering loss after the mode is eliminated, and optical filtering is achieved. For example, the N1=2.055 and N2=1.712 of the thin film lithium niobate rib-type optical waveguide are modulated to λ0=1550nm, and Λ=4.519μm is calculated by the formula Λ=λ0 / (N1-N2). According to the π / 2 phase accumulation of the grating mode coupling principle, the coupling efficiency of the two modes is directly related to the applied voltage and the grating length L; usually L requires more than 10 grating periods to obtain a large extinction ratio, that is, when n grating periods are selected, L=nΛ. At the same time, or by applying a larger voltage modulation to obtain a large extinction ratio, a grating period length of 3 to 4 can be selected. In other words, as the voltage increases or the grating length increases, the phase gradually increases to the π / 2 phase, thereby achieving a balance between the π / 2 phase voltage and the gate length. Therefore, when designing an optical integrated circuit, if it is to be compatible with the electronic circuit CMOS and use this voltage value (≤1V), a larger gate length can be selected, but this will result in a larger device size; conversely, a smaller gate length can be selected and a larger voltage can be applied.

[0057] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0058] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An integrable device based on a thin film lithium niobate platform, characterized in that: The integrable device comprises: A z-cut thin-film lithium niobate platform and an S-gate graphene electrode; the S-gate graphene electrode is arranged on the top of the z-cut thin-film lithium niobate platform; The z-cut thin-film lithium niobate platform comprises: a substrate, a metal layer arranged on the substrate, a lower cladding arranged on the metal layer, and a thin-film lithium niobate rib-type optical waveguide arranged on the lower cladding; the S-gate graphene electrode is arranged on the top of the thin-film lithium niobate rib-type optical waveguide.

2. The integrable device based on the thin film lithium niobate platform according to claim 1, characterized in that: The thin film lithium niobate rib type optical waveguide comprises: A flat plate and at least one rib; the flat plate and each of the ribs are an integrally formed structure; the flat plate is formed integrally of a base and two side support members; A groove is formed by depression downwards on the base near the supporting members on both sides; the S-gate graphene electrodes are placed on the supporting members on both sides; When one rib is provided, the rib is provided at the middle position of the base; when multiple ribs are provided, the multiple ribs are provided at the middle position of the base with intervals therebetween; There is a certain distance between the top of the rib and the S-gate graphene electrode.

3. The integrable device based on the thin film lithium niobate platform according to claim 2, characterized in that: The S-gate graphene electrode comprises: At least one graphene horizontal plate and at least one graphene vertical plate; all the graphene horizontal plates and all the graphene vertical plates are integrally formed; all the graphene horizontal plates have equal widths and are parallel to each other; all the graphene vertical plates have equal lengths; The ends of two adjacent graphene horizontal plates are connected by a graphene vertical plate; the i-th graphene vertical plate and the (i+1)-th graphene vertical plate are respectively arranged on the two supporting members of the flat plate and are parallel to each other.

4. The integrable device based on the thin film lithium niobate platform according to claim 3, characterized in that: Each of the graphene vertical plates is perpendicular to the adjacent graphene horizontal plates.

5. The integrable device based on the thin film lithium niobate platform according to claim 2, characterized in that: The S-gate graphene electrode comprises: At least one graphene cross plate and at least one arc-shaped graphene connecting plate; all the graphene cross plates and all the arc-shaped graphene connecting plates are integrally formed; all the graphene cross plates have equal widths and are parallel to each other; all the arc-shaped graphene connecting plates have the same structure; The ends of two adjacent graphene transverse plates are connected by an arc-shaped graphene connecting plate; the i-th arc-shaped graphene connecting plate and the (i+1)-th arc-shaped graphene connecting plate are respectively arranged on the two supporting members of the flat plate.

6. The integrable device based on the thin film lithium niobate platform according to claim 5, characterized in that: The grating length L=nΛ, where n is the number of grating periods and Λ is the grating period.

7. The integrable device based on the thin film lithium niobate platform according to claim 6, characterized in that: The central wavelength of the modulation of the integrated device is λ0=Λ(N1-N2), where Λ is the grating period and N1 is the fundamental mode TM. 00 The effective refractive index of N2 is the high-order leaky mode TM 01 The effective refractive index.

8. The integrable device based on the thin film lithium niobate platform according to claim 2, characterized in that: A distance d0 between the top of the rib and the S-gate graphene electrode is greater than or equal to 200 nm.

9. The integrable device based on the thin film lithium niobate platform according to claim 1, characterized in that: The material of the base is a silicon substrate; the material of the metal layer is Au; the material of the lower cladding is SiO2; and the material of the thin-film lithium niobate rib-type optical waveguide is TFLN.

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