Lithium niobate thin film electro-optic modulator

Abstract

The application relates to a lithium niobate thin film electro-optic modulator, comprising a substrate, the substrate comprising a first substrate part and a second substrate part, the first substrate part being connected with the second substrate part, and a first plane where the first substrate part is located intersecting with a second plane where the second substrate part is located; and an optical waveguide, the optical waveguide comprising a first waveguide structure, a curved waveguide and a second waveguide structure connected in sequence, the first waveguide structure being arranged on the first substrate part, the second waveguide structure being arranged on the second substrate part, and the curved waveguide being located at the turning connection of the first substrate part and the second substrate part. The overall length of the optical waveguide can be kept unchanged to avoid affecting the half-wave voltage performance due to size change, and the length of the substrate, that is, the overall length of the lithium niobate thin film electro-optic modulator, is effectively reduced under the improvement of the three-dimensional structure, the occupied installation space is reduced, and therefore the large-scale integrated use is more favorable.

Description

Technical Field

[0001] This application relates to the field of optoelectronic device technology, and in particular to a lithium niobate thin-film electro-optic modulator. Background Technology

[0002] Lithium niobate thin-film electro-optic modulators are a novel type of optoelectronic device that modulates the properties of passing light (such as phase, amplitude, or polarization) through the electro-optic effect. Therefore, they are widely used in terrestrial systems and space-based optical communication systems. In recent years, with the expansion of backbone network technology, lithium niobate thin-film modulators have also begun to be widely used in short-range interconnection scenarios such as data centers and supercomputers. The device structure connects a directional coupler and a modulation waveguide to form an optical transmission path, and electrodes are deposited on both sides of the modulation waveguide to apply an electric field modulation. To achieve a low half-wave voltage, existing lithium niobate electro-optic modulators require sufficiently long modulation electrodes, which limits the overall length of the modulator and hinders large-scale integration. Furthermore, existing lithium niobate thin-film electro-optic modulators also require the addition of bias electrodes, which further increases the modulator's length.

[0003] To effectively reduce the length of lithium niobate thin-film electro-optic modulators, the commonly used solution is to bend the modulation waveguide by 90°. However, this approach has two drawbacks: First, to ensure that the light passing through the modulation region propagates along the y-axis of the lithium niobate, the layout needs to have two or more 90° bends. Increasing the number of 90° bends can easily lead to more light propagation loss. Second, the 90° bend is essentially to shift the bias control region to be arranged at the same lateral interval as the modulation region, similar to a series connection being converted to a parallel connection. Therefore, the length of the transition region due to the 90° bend also increases the width of the lithium niobate thin-film electro-optic modulator. Summary of the Invention

[0004] Therefore, it is necessary to provide a lithium niobate thin-film electro-optic modulator to address the problem that the length cannot be effectively reduced, which restricts the ability to integrate on a large scale.

[0005] This application provides a lithium niobate thin-film electro-optic modulator, comprising:

[0006] A substrate, the substrate comprising a first substrate portion and a second substrate portion, the first substrate portion being connected to the second substrate portion, and a first plane on which the first substrate portion is located intersecting a second plane on which the second substrate portion is located; and,

[0007] An optical waveguide includes a first waveguide structure, a bent waveguide, and a second waveguide structure connected in sequence. The first waveguide structure is disposed on a first substrate, and the second waveguide structure is disposed on a second substrate. The bent waveguide is located at the bend connection between the first substrate and the second substrate.

[0008] In the lithium niobate thin-film electro-optic modulator of this application, the substrate is designed to consist of a first substrate portion and a second substrate portion, with the first plane of the first substrate portion and the second plane of the second substrate portion intersecting. This optimizes the traditional two-dimensional planar substrate structure into a three-dimensional structure for the first time. Based on this, the first waveguide structure of the optical waveguide is disposed on the first substrate portion, the second waveguide structure is disposed on the second substrate portion, and the curved waveguide connects the first waveguide structure and the second waveguide structure and is adapted to be disposed at the turning connection of the first substrate portion and the second substrate portion. This allows optical energy to propagate sequentially along the first waveguide structure, the curved waveguide, and the second waveguide structure, always along the y-axis direction of the lithium niobate thin-film electro-optic modulator. Furthermore, the overall length of the optical waveguide can be retained to avoid affecting the half-wave voltage performance due to size changes. With this improvement in the three-dimensional structure, the length of the substrate, that is, the overall total length of the lithium niobate thin-film electro-optic modulator, is effectively reduced, reducing its installation space occupation and making it more conducive to large-scale integration.

[0009] The technical solution of this application will be further described below:

[0010] In one embodiment, one end of the first base portion is integrally connected to one end of the second base portion, and the first base portion and the second base portion are arranged at a 90° angle.

[0011] In one embodiment, the first waveguide structure includes a first Y-shaped waveguide, a second Y-shaped waveguide, and a first parallel straight waveguide. The first Y-shaped waveguide is formed from the edge of the first substrate and extends toward the center of the first substrate. The second Y-shaped waveguide is connected to the first Y-shaped waveguide, and the first parallel straight waveguide is connected to the second Y-shaped waveguide.

[0012] In one embodiment, the second waveguide structure includes a second parallel straight waveguide, a third Y-shaped waveguide, and a fourth Y-shaped waveguide. One end of the second parallel straight waveguide is connected to the other end of the first parallel straight waveguide, and together they form the curved waveguide. One end of the third Y-shaped waveguide is connected to the other end of the second parallel straight waveguide, and the other end of the third Y-shaped waveguide is connected to one end of the fourth Y-shaped waveguide. The other end of the fourth Y-shaped waveguide extends to the edge of the second substrate.

[0013] In one embodiment, the lithium niobate thin-film electro-optic modulator further includes a bias electrode structure, wherein a bias control region is provided on the surface of the first substrate, the bias control region overlaps with the first parallel straight waveguide, and the bias electrode structure is disposed within the bias control region.

[0014] In one embodiment, the bias electrode structure includes a first bias electrode, a second bias electrode, and a third bias electrode. The first bias electrode and the second bias electrode are respectively disposed on opposite sides of the first parallel straight waveguide, and the third bias electrode is disposed within the first parallel straight waveguide.

[0015] In one embodiment, the lithium niobate thin-film electro-optic modulator further includes a modulation electrode structure, wherein a modulation region is provided on the surface of the second substrate, the modulation region overlaps with the second parallel straight waveguide, and the modulation electrode structure is disposed within the modulation region.

[0016] In one embodiment, the modulation electrode structure includes a first modulation electrode, a second modulation electrode, and a third modulation electrode. The first modulation electrode and the second modulation electrode are respectively disposed on opposite sides of the second parallel straight waveguide, and the third modulation electrode is disposed within the second parallel straight waveguide.

[0017] In one embodiment, the length extension direction of the bias electrode structure and the modulation electrode structure is consistent with the length extension direction of the optical waveguide.

[0018] In one embodiment, the substrate includes a silicon layer and a silicon dioxide layer, the silicon dioxide layer being disposed on the surface of the silicon layer, and the optical waveguide, the bias electrode structure, and the modulation electrode structure being formed on the surface of the silicon dioxide layer. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a lithium niobate thin-film electro-optic modulator according to an embodiment of this application.

[0022] Explanation of reference numerals in the attached figures:

[0023] 100. Lithium niobate thin-film electro-optic modulator; 10. Substrate; 11. First substrate; 12. Second substrate; 13. Silicon dioxide layer; 14. Silicon layer; 20. Optical waveguide; 21. First waveguide structure; 211. First Y-type waveguide; 212. Second Y-type waveguide; 213. First parallel straight waveguide; 22. Bent waveguide; 23. Second waveguide structure; 231. Second parallel straight waveguide; 232. Third Y-type waveguide; 233. Fourth Y-type waveguide; 30. Bias electrode structure; 31. First bias electrode; 32. Second bias electrode; 33. Third bias electrode; 40. Modulation electrode structure; 41. First modulation electrode; 42. Second modulation electrode; 43. Third modulation electrode. Detailed Implementation

[0024] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0025] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0026] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0027] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0029] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0030] See Figure 1 The lithium niobate thin-film electro-optic modulator 100 shown in one embodiment of this application is a novel optoelectronic device that can change the properties (phase, amplitude, or polarization) of light through electro-optic effects when transmitting light.

[0031] Specifically, an electro-optic modulator (EOM) is a modulator made using the electro-optic effect of certain electro-optic crystals. The electro-optic effect refers to the change in the refractive index of an electro-optic crystal when it is subjected to an external electric field, which in turn changes the optical wave characteristics passing through the crystal, thereby modulating parameters such as the amplitude, phase, and polarization state of the optical signal.

[0032] Lithium niobate (LiNbO3) is a compound of niobium, lithium, and oxygen. It exhibits high spontaneous polarization (0.70°C / m at room temperature). 2Lithium niobate crystals are negative crystals. Lithium niobate crystals have the characteristics of multiple photoelectric effects, strong performance controllability, stable physical and chemical properties, and wide light transmission range. (1) Lithium niobate crystals have multiple photoelectric effects, including piezoelectric effect, electro-optic effect, nonlinear optical effect, photorefractive effect, photovoltaic effect, photoelastic effect, acousto-optic effect and other photoelectric properties; (2) The performance of lithium niobate crystals is highly controllable, which is caused by the crystal lattice structure and rich defect structure of lithium niobate crystals. Many properties of lithium niobate crystals can be greatly controlled by crystal composition, element doping, valence state control, etc.; (3) The physical and chemical properties of lithium niobate crystals are quite stable and easy to process; (4) The light transmission range is wide, with large birefringence, and it is easy to prepare high-quality optical waveguides20. Therefore, optoelectronic devices such as surface acoustic wave filters, optical modulators, phase modulators, optical isolators, and electro-optic Q-switches based on lithium niobate crystals have been widely studied and applied in the fields of electronic technology, optical communication technology, and laser technology.

[0033] The lithium niobate electro-optic modulator works by utilizing the linear electro-optic effect of lithium niobate crystals.

[0034] For example, the lithium niobate thin-film electro-optic modulator 100 includes a substrate 10 and an optical waveguide 20. The substrate 10 is the main structure of the entire lithium niobate thin-film electro-optic modulator 100 and is used to support the optical waveguide 20.

[0035] Please continue reading. Figure 1 In this embodiment, the substrate 10 includes a first substrate portion 11 and a second substrate portion 12. The first substrate portion 11 is connected to the second substrate portion 12, and the first plane where the first substrate portion 11 is located intersects the second plane where the second substrate portion 12 is located. The optical waveguide 20 includes a first waveguide structure 21, a bent waveguide 22 and a second waveguide structure 23 connected in sequence. The first waveguide structure 21 is disposed on the first substrate portion 11, and the second waveguide structure 23 is disposed on the second substrate portion 12. The bent waveguide 22 is located at the turning connection between the first substrate portion 11 and the second substrate portion 12.

[0036] In summary, implementing the technical solution of this embodiment will have the following beneficial effects: In the lithium niobate thin-film electro-optic modulator 100 of this application, by designing the substrate 10 to be composed of a first substrate portion 11 and a second substrate portion 12, and with the first plane where the first substrate portion 11 is located and the second plane where the second substrate portion 12 is located intersecting, the traditional two-dimensional planar structure of the substrate 10 is optimized into a three-dimensional structure for the first time. On this basis, the first waveguide structure 21 of the optical waveguide 20 is disposed on the first substrate portion 11, the second waveguide structure 23 is disposed on the second substrate portion 12, and the curved waveguide 22 connects the first waveguide structure 21 and the second waveguide structure 22. The second waveguide structure 23 is connected to and adapted to the bend connection between the first substrate 11 and the second substrate 12, so that when in use, optical energy propagates sequentially along the first waveguide structure 21, the bend waveguide 22 and the second waveguide structure, always along the y-axis direction of the lithium niobate thin film electro-optic modulator 100. The overall length of the optical waveguide 20 can be retained to avoid the impact of size changes on the half-wave voltage performance. With this improvement of the three-dimensional structure, the length of the substrate 10, that is, the overall length of the lithium niobate thin film electro-optic modulator 100, is effectively reduced, reducing its installation space occupation, which is more conducive to large-scale integrated use.

[0037] It is necessary to explain that the reduction in length of the lithium niobate thin-film electro-optic modulator 100 in this solution can be understood as follows: In the existing two-dimensional lithium niobate thin-film electro-optic modulator 100, the substrate 10 is a single flat plate structure, that is, the first substrate portion 11 and the second substrate portion 12 are in the same plane, and the length of the substrate 10 is the sum of the length of the first substrate portion 11 and the length of the second substrate portion 12. In the improved solution, since the first substrate portion 11 and the second substrate portion 12 are intersecting, the length of the substrate 10 is the sum of the thickness of the first substrate portion 11 and the length of the second substrate portion 12. Since the thickness of the first substrate portion 11 is less than its own length, the total length of the substrate 10 must be reduced, thereby achieving the goal of reducing the length of the lithium niobate thin-film electro-optic modulator 100.

[0038] Please continue reading. Figure 1 Based on the above embodiments, it is preferable that one end of the first base portion 11 is integrally connected to one end of the second base portion 12, and the first base portion 11 and the second base portion 12 are arranged at a 90° angle.

[0039] The first substrate 11 and the second substrate 12 are perpendicularly connected to each other, resulting in better structural stability. At this time, the length of the substrate 10 is strictly equal to the sum of the thickness of the first substrate 11 and the length of the second substrate 12, which can reduce the length of the lithium niobate thin film electro-optic modulator 100 to a minimum, thereby further improving the large-scale integration capability of the lithium niobate thin film electro-optic modulator 100.

[0040] Please continue reading. Figure 1 In addition, in some embodiments, the first waveguide structure 21 includes a first Y-shaped waveguide 211, a second Y-shaped waveguide 212 and a first parallel straight waveguide 213. The first Y-shaped waveguide 211 is formed from the edge of the first substrate 11 and extends toward the center of the first substrate 11. The second Y-shaped waveguide 212 is connected to the first Y-shaped waveguide 211 and the first parallel straight waveguide 213 is connected to the second Y-shaped waveguide 212.

[0041] Furthermore, the second waveguide structure 23 includes a second parallel straight waveguide 231, a third Y-shaped waveguide 232, and a fourth Y-shaped waveguide 233. One end of the second parallel straight waveguide 231 is connected to the other end of the first parallel straight waveguide 213 and they cooperate to form a curved waveguide 22. One end of the third Y-shaped waveguide 232 is connected to the other end of the second parallel straight waveguide 231, and the other end of the third Y-shaped waveguide 232 is connected to one end of the fourth Y-shaped waveguide 233. The other end of the fourth Y-shaped waveguide 233 extends to the edge of the second substrate 12.

[0042] On the one hand, designing the first waveguide structure 21 and the second waveguide structure 23 as a composite structure of Y-type waveguide and parallel straight waveguide is more conducive to obtaining a lower half-wave voltage. On the other hand, by sequentially connecting the first Y-type waveguide 211, the second Y-type waveguide 212, the first parallel straight waveguide 213, the second parallel straight waveguide 231, the third Y-type waveguide 232 and the fourth Y-type waveguide 233, multiple beam splitting and beam combining effects can be formed on the light, optimizing the light interference effect and improving the stability of light propagation.

[0043] Specifically, in this embodiment, the bifurcation end of the first Y-shaped waveguide 211 is connected to the edge of the first substrate 11, and the convergence end of the first Y-shaped waveguide 211 is connected to the convergence end of the second Y-shaped waveguide 212; the bifurcation end of the second Y-shaped waveguide 212 is connected to one end of the first parallel straight waveguide 213, and the other end of the first parallel straight waveguide 213 is connected to one end of the second parallel straight waveguide 231; the other end of the second parallel straight waveguide 231 is connected to the bifurcation end of the third Y-shaped waveguide 232, the convergence end of the third Y-shaped waveguide 232 is connected to the convergence end of the fourth Y-shaped waveguide 233, and the bifurcation end of the fourth Y-shaped waveguide 233 is connected to the edge of the second substrate 12.

[0044] In addition, based on any of the above embodiments, the lithium niobate thin film electro-optic modulator 100 further includes a bias electrode structure 30, a bias control region is provided on the surface of the first substrate 11, the bias control region overlaps with the first parallel straight waveguide 213, and the bias electrode structure 30 is disposed within the bias control region.

[0045] By setting a bias electrode structure 30 in the bias control region, the bias electrode structure 30 enables the first parallel straight waveguide 213 to operate in the linear region.

[0046] For example, in an optional embodiment, the bias electrode structure 30 includes a first bias electrode 31, a second bias electrode 32, and a third bias electrode 33. The first bias electrode 31 and the second bias electrode 32 are respectively disposed on opposite sides of the first parallel straight waveguide 213, and the third bias electrode 33 is disposed within the first parallel straight waveguide 213. During operation, the first bias electrode 31, the second bias electrode 32, and the third bias electrode 33 can simultaneously apply a balanced force to the first parallel straight waveguide 213, thereby ensuring that the first parallel straight waveguide 213 operates more reliably within the linear region.

[0047] Please continue reading. Figure 1 Furthermore, in some embodiments, the lithium niobate thin-film electro-optic modulator 100 further includes a modulation electrode structure 40. A modulation region is provided on the surface of the second substrate 12, overlapping with the second parallel straight waveguide 231. The modulation electrode structure 40 is disposed within the modulation region. The modulation electrode structure 40 can apply an electric field modulation to the second parallel straight waveguide 231, causing a change in the refractive index of the lithium niobate crystal and a corresponding change in the optical wave characteristics of the lithium niobate crystal, thereby achieving modulation of parameters such as the amplitude, phase, and polarization state of the optical signal.

[0048] Specifically, based on the above embodiments, the modulation electrode structure 40 includes a first modulation electrode 41, a second modulation electrode 42 and a third modulation electrode 43. The first modulation electrode 41 and the second modulation electrode 42 are respectively disposed on opposite sides of the second parallel straight waveguide 231, and the third modulation electrode 43 is disposed inside the second parallel straight waveguide 231.

[0049] Therefore, during operation, the first modulation electrode 41, the second modulation electrode 42 and the third modulation electrode 43 can simultaneously apply a uniform electric field modulation to the second parallel straight waveguide 231 to ensure more accurate and stable modulation of parameters such as amplitude, phase and polarization of the optical signal.

[0050] Based on any of the above embodiments, the length extension directions of the bias electrode structure 30 and the modulation electrode structure 40 are consistent with the length extension direction of the optical waveguide 20. This allows the bias electrode structure 30, the modulation electrode structure 40, and the optical waveguide 20 to fully utilize the width space of the substrate 10, thereby minimizing their length while avoiding increasing the width of the lithium niobate thin-film electro-optic modulator 100, which is beneficial for improving the large-scale integration capability of the lithium niobate thin-film electro-optic modulator 100.

[0051] In this application, the substrate 10 includes a silicon layer 14 and a silicon dioxide layer 13. The silicon dioxide layer 13 is disposed on the surface of the silicon layer 14, and the optical waveguide 20, the bias electrode structure 30, and the modulation electrode structure 40 are respectively formed on the surface of the silicon dioxide layer 13. The silicon layer 14 and the silicon dioxide layer 13 have high strength and good stability, and strong adhesion to the bias electrode structure 30 and the modulation electrode structure 40, which helps to improve the overall structure and performance of the lithium niobate thin-film electro-optic modulator 100.

[0052] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A lithium niobate thin-film electro-optic modulator, characterized in that, include: A substrate, the substrate comprising a first substrate portion and a second substrate portion, the first substrate portion being connected to the second substrate portion, and a first plane on which the first substrate portion is located intersecting a second plane on which the second substrate portion is located; and, An optical waveguide includes a first waveguide structure, a bent waveguide, and a second waveguide structure connected in sequence. The first waveguide structure is disposed on a first substrate, and the second waveguide structure is disposed on a second substrate. The bent waveguide is located at the bend connection between the first substrate and the second substrate.

2. The lithium niobate thin-film electro-optic modulator according to claim 1, characterized in that, One end of the first base portion is integrally connected to one end of the second base portion, and the first base portion and the second base portion are arranged at a 90° angle.

3. The lithium niobate thin-film electro-optic modulator according to claim 1, characterized in that, The first waveguide structure includes a first Y-shaped waveguide, a second Y-shaped waveguide, and a first parallel straight waveguide. The first Y-shaped waveguide is formed from the edge of the first substrate and extends toward the center of the first substrate. The second Y-shaped waveguide is connected to the first Y-shaped waveguide, and the first parallel straight waveguide is connected to the second Y-shaped waveguide.

4. The lithium niobate thin-film electro-optic modulator according to claim 3, characterized in that, The second waveguide structure includes a second parallel straight waveguide, a third Y-shaped waveguide, and a fourth Y-shaped waveguide. One end of the second parallel straight waveguide is connected to the other end of the first parallel straight waveguide, and they cooperate to form the curved waveguide. One end of the third Y-shaped waveguide is connected to the other end of the second parallel straight waveguide, and the other end of the third Y-shaped waveguide is connected to one end of the fourth Y-shaped waveguide. The other end of the fourth Y-shaped waveguide extends to the edge of the second substrate.

5. The lithium niobate thin-film electro-optic modulator according to claim 4, characterized in that, The lithium niobate thin-film electro-optic modulator further includes a bias electrode structure. A bias control region is provided on the surface of the first substrate. The bias control region overlaps with the first parallel straight waveguide. The bias electrode structure is disposed within the bias control region.

6. The lithium niobate thin-film electro-optic modulator according to claim 5, characterized in that, The bias electrode structure includes a first bias electrode, a second bias electrode, and a third bias electrode. The first bias electrode and the second bias electrode are respectively disposed on opposite sides of the first parallel straight waveguide, and the third bias electrode is disposed inside the first parallel straight waveguide.

7. The lithium niobate thin-film electro-optic modulator according to claim 6, characterized in that, The lithium niobate thin-film electro-optic modulator further includes a modulation electrode structure. A modulation region is provided on the surface of the second substrate. The modulation region overlaps with the second parallel straight waveguide. The modulation electrode structure is disposed within the modulation region.

8. The lithium niobate thin-film electro-optic modulator according to claim 7, characterized in that, The modulation electrode structure includes a first modulation electrode, a second modulation electrode, and a third modulation electrode. The first modulation electrode and the second modulation electrode are respectively disposed on opposite sides of the second parallel straight waveguide, and the third modulation electrode is disposed inside the second parallel straight waveguide.

9. The lithium niobate thin-film electro-optic modulator according to claim 8, characterized in that, The length extension direction of the bias electrode structure and the modulation electrode structure is consistent with the length extension direction of the optical waveguide.

10. The lithium niobate thin-film electro-optic modulator according to any one of claims 1 to 9, characterized in that, The substrate includes a silicon layer and a silicon dioxide layer, the silicon dioxide layer being disposed on the surface of the silicon layer, and the optical waveguide, the bias electrode structure, and the modulation electrode structure being formed on the surface of the silicon dioxide layer.

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