Electro-optic modulator and optical communication system

Abstract

The utility model discloses an electro -optic modulator and optical communication system. Electro -optic modulator includes lithium niobate waveguide, electrode structure and buffer structure. Lithium niobate waveguide is located between first electrode and third electrode, and is located between second electrode and fourth electrode. First electrode and second electrode are located on both sides of lithium niobate waveguide, and third electrode and fourth electrode are located on both sides of lithium niobate waveguide. The setting of above technical features can be respectively applied to the upper and lower of lithium niobate waveguide transverse electric field, and can improve the overlapping degree of light field and electric field, thereby effectively enhancing electric field intensity and improving electro -optic modulation efficiency.

Description

Technical Field

[0001] This utility model relates to the field of optical communication device technology, specifically to an electro-optic modulator and an optical communication system. Background Technology

[0002] Optical communication systems need to continuously improve their performance to meet the application transmission requirements of high capacity, high speed, and low latency. Among these, the modulator, as a core component of optical communication systems, is crucial for achieving high-speed optical communication through performance optimization.

[0003] Lithium niobate materials are widely used in electro-optic modulators due to their superior physical properties, such as wide transparency windows and high electro-optic coefficients. As the core structural component of modulators, thin-film lithium niobate materials offer significant advantages over traditional materials in terms of optical loss, modulation bandwidth, and modulation efficiency.

[0004] In related technologies, thin-film lithium niobate electro-optic modulators typically employ the method of reducing the electrode spacing to improve modulation efficiency. However, excessively narrow electrode spacing can lead to increased metal absorption losses, which in turn causes attenuation of the optical signal within the waveguide, thus affecting the modulation efficiency of the modulator. Utility Model Content

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by this utility model is how to improve the modulation efficiency of the electro-optic modulator.

[0006] To address at least one of the aforementioned technical problems, this utility model discloses an electro-optic modulator and an optical communication system.

[0007] According to one aspect of this application, an electro-optic modulator is provided, comprising:

[0008] A lithium niobate waveguide, comprising a waveguide section and a first plate section and a second plate section located on both sides of the waveguide section;

[0009] The electrode structure includes a first electrode and a third electrode stacked together, and a second electrode and a fourth electrode stacked together. The first electrode and the third electrode are electrically connected, and the second electrode and the fourth electrode are electrically connected. A lithium niobate waveguide is located between the first electrode and the third electrode, and between the second electrode and the fourth electrode. The first electrode and the second electrode are located on both sides of the lithium niobate waveguide, and the third electrode and the fourth electrode are located on both sides of the lithium niobate waveguide.

[0010] A buffer structure is located between the lithium niobate waveguide and the first, second, third, and fourth electrodes.

[0011] Optionally, the first plate portion and the first electrode and the third electrode overlap at least partially in the stacking direction, and the second plate portion and the second electrode and the fourth electrode overlap at least partially in the stacking direction.

[0012] Optionally, the distance between the first electrode and the second electrode and the waveguide portion is equal, and the distance between the third electrode and the fourth electrode and the waveguide portion is equal.

[0013] Optionally, the distance between the side of the first electrode near the waveguide and the side of the second electrode near the waveguide is the first electrode spacing, which ranges from 2μm to 7μm.

[0014] The distance between the side of the third electrode near the waveguide and the side of the fourth electrode near the waveguide is the second electrode spacing, which ranges from 1 μm to 5 μm.

[0015] Optionally, the first electrode includes a first metal conductive part and a first non-metal conductive part connected to each other, and the distance from the first non-metal conductive part to the lithium niobate waveguide is less than the distance from the first metal conductive part to the lithium niobate waveguide.

[0016] The second electrode includes a second metal conductive part and a second non-metal conductive part that are connected to each other. The distance from the second non-metal conductive part to the lithium niobate waveguide is less than the distance from the second metal conductive part to the lithium niobate waveguide.

[0017] The distance between the side of the first non-metallic conductive part near the waveguide part and the side of the second non-metallic conductive part near the waveguide part is the third electrode spacing, which is smaller than the first electrode spacing.

[0018] Optionally, the electrode structure further includes a first through-hole connection structure.

[0019] The first through-hole connection structure is located between the third electrode and the first plate portion, and between the fourth electrode and the second plate portion.

[0020] Optionally, the electro-optic modulator includes a substrate, a buffer structure, an electrode structure, and a lithium niobate waveguide disposed on the substrate.

[0021] The buffer structure includes: a first buffer layer located between the first plate portion and the first electrode, a second buffer layer located between the second plate portion and the second electrode, a third buffer layer located between the first plate portion and the third electrode, and a fourth buffer layer located between the second plate portion and the fourth electrode.

[0022] The thickness of the first buffer layer is equal to the thickness of the second buffer layer, and the thickness of the first buffer layer ranges from 50nm to 500nm; the thickness of the third buffer layer is equal to the thickness of the fourth buffer layer, and the thickness of the third buffer layer ranges from 50nm to 1500nm.

[0023] Optionally, the electrode structure may further include a fifth electrode and a sixth electrode.

[0024] The fifth electrode is electrically connected to the third electrode and stacked on top of it, and the sixth electrode is electrically connected to the fourth electrode and stacked on top of it.

[0025] Optionally, the first plate portion and the first electrode and the fifth electrode partially overlap in the stacking direction, and the second plate portion and the second electrode and the sixth electrode partially overlap in the stacking direction;

[0026] The first plate portion and the third electrode completely overlap in the stacking direction, and the second plate portion and the fourth electrode completely overlap in the stacking direction.

[0027] Optionally, the number of lithium niobate waveguides is two;

[0028] The electrode structure also includes a seventh electrode and an eighth electrode. The first electrode and the seventh electrode are respectively disposed on both sides of the first lithium niobate waveguide and the second lithium niobate waveguide, and the second electrode is located between the first lithium niobate waveguide and the second lithium niobate waveguide.

[0029] The third and eighth electrodes are respectively located on both sides of the first and second lithium niobate waveguides, and the fourth electrode is located between the first and second lithium niobate waveguides.

[0030] According to a second aspect of this application, an optical communication system is provided, the optical communication system including an electro-optic modulator as described in any of the above embodiments.

[0031] In the electro-optic modulator of this application embodiment, the stacked electrode structure and buffer structure can improve the modulation performance of the electro-optic modulator.

[0032] Specifically, a lithium niobate waveguide is positioned between the first and third electrodes, and between the second and fourth electrodes, with each electrode symmetrically positioned on both sides of the lithium niobate waveguide. This allows for the formation of a uniformly distributed transverse electric field within the region where the lithium niobate waveguide is located, reducing electric field leakage and loss, thereby increasing the electric field strength and thus improving modulation performance.

[0033] Furthermore, the electro-optic modulator also incorporates a buffer structure to isolate the lithium niobate waveguide from the first, second, third, and fourth electrodes, respectively. This prevents direct contact between the lithium niobate waveguide and the metal electrodes, thereby avoiding the impact of optical losses caused by metal absorption on the modulation efficiency and thus improving the modulation performance.

[0034] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0035] To more clearly illustrate the technical solution of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0037] Figure 1 A schematic diagram of the first structure corresponding to the electro-optic modulator provided as an exemplary embodiment of this disclosure;

[0038] Figure 2 A schematic diagram of the electric field distribution corresponding to an electro-optic modulator provided as an exemplary embodiment of this disclosure;

[0039] Figure 3 This is a schematic diagram of the electric field distribution corresponding to the electro-optic modulator in related technologies;

[0040] Figure 4 A schematic diagram of the second structure corresponding to the electro-optic modulator provided in an exemplary embodiment of this disclosure;

[0041] Figure 5 A schematic diagram of a third structure corresponding to an electro-optic modulator provided as an exemplary embodiment of this disclosure;

[0042] Figure 6 A schematic diagram of the fourth structure corresponding to the electro-optic modulator provided in an exemplary embodiment of this disclosure;

[0043] Figure 7 A schematic diagram of the fifth structure corresponding to the electro-optic modulator provided in an exemplary embodiment of this disclosure;

[0044] Figure 8 A schematic diagram of the sixth structure corresponding to the electro-optic modulator provided in an exemplary embodiment of this disclosure;

[0045] Figure 9 A schematic diagram of the seventh structure corresponding to the electro-optic modulator provided in an exemplary embodiment of this disclosure.

[0046] Explanation of reference numerals in the attached figures:

[0047] 1-Electro-optic modulator;

[0048] 10-Lithium niobate waveguide, 11-Waveguide section, 12-First planar section, 13-Second planar section, 14-First lithium niobate waveguide, 15-Second lithium niobate waveguide;

[0049] 20 - Electrode structure, 21 - First electrode, 22 - Second electrode, 23 - Third electrode, 24 - Fourth electrode, 25 - Fifth electrode, 26 - Sixth electrode, 27 - Seventh electrode, 28 - Eighth electrode, 29 - Ninth electrode;

[0050] 30 - Buffer structure, 31 - First buffer layer, 32 - Second buffer layer, 33 - Third buffer layer, 34 - Fourth buffer layer;

[0051] 40-First through-hole connection structure, 41-Second through-hole connection structure, 42-Third through-hole connection structure, 43-Fourth through-hole connection structure, 44-Fifth through-hole connection structure, 45-Sixth through-hole connection structure, 46-Seventh through-hole connection structure;

[0052] 51-First metallic conductive part, 52-First non-metallic conductive part, 53-Second metallic conductive part, 54-Second non-metallic conductive part, 55-Third non-metallic conductive part, 56-Fourth non-metallic conductive part, 57-Fifth non-metallic conductive part, 58-Sixth non-metallic conductive part;

[0053] 60-substrate. Detailed Implementation

[0054] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of them. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0055] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

[0056] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0057] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0058] In this document, the term "and / or" describes a relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0059] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0060] Figure 1 A schematic diagram of the first structure corresponding to the electro-optic modulator provided in an exemplary embodiment of this disclosure. For example... Figure 1 As shown, the electro-optic modulator 1 includes: a substrate 60, a lithium niobate waveguide 10, an electrode structure 20, and a buffer structure 30.

[0061] The lithium niobate waveguide 10 includes a waveguide portion 11, and a first plate portion 12 and a second plate portion 13 located on both sides of the waveguide portion 11.

[0062] The electrode structure 20 includes a first electrode 21 and a third electrode 23 stacked together, and a second electrode 22 and a fourth electrode 24 stacked together.

[0063] The buffer structure 30 is located between the lithium niobate waveguide 10 and the first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24.

[0064] The electrode structure 20 further includes a fifth electrode 25 that is electrically connected to and stacked with the third electrode 23, and a sixth electrode 26 that is electrically connected to and stacked with the fourth electrode 24.

[0065] like Figure 1As shown, in the electro-optic modulator 1, a lithium niobate waveguide 10, an electrode structure 20, and a buffer structure 30 are disposed on a substrate 60. The lithium niobate waveguide 10 is the core of optical signal transmission and modulation, and can be fabricated from an X-cut lithium niobate thin film through an etching process. In the electro-optic modulator 1, there can be one or more lithium niobate waveguides 10; in this embodiment, there is one. For example, a lithium niobate thin film with a thickness of 350 nm can be etched to form a lithium niobate waveguide 10 with a width of 1.5 μm.

[0066] like Figure 1 As shown, the first plate portion 12 of the lithium niobate waveguide 10 is located between the first electrode 21 and the third electrode 23, and the second plate portion 13 of the lithium niobate waveguide 10 is located between the second electrode 22 and the fourth electrode 24. It can be considered that the first plate portion 12 of the lithium niobate waveguide 10 is stacked with the first electrode 21, the third electrode 23, and the fifth electrode 25, and the second plate portion 12 is stacked with the second electrode 22, the fourth electrode 24, and the sixth electrode 26. The stacking direction is perpendicular to the plane of the substrate 60.

[0067] In the lithium niobate waveguide 10, the first plate portion 12 and the first electrode 21 and the third electrode 23 partially overlap in the stacking direction, and the second plate portion 13 and the second electrode 22 and the fourth electrode 24 partially overlap in the stacking direction. The overlap between the plate portion and the electrodes in the stacking direction allows the electric field to act more effectively on the active region of the lithium niobate waveguide 10, thereby enhancing the electro-optic modulation efficiency.

[0068] The buffer structure 30 may include a first buffer layer 31, a second buffer layer 32, a third buffer layer 33, and a fourth buffer layer 34. The first buffer layer 31 is located between the first plate portion 12 and the first electrode 21, the second buffer layer 32 is located between the second plate portion 13 and the second electrode 22, the third buffer layer 33 is located between the first plate portion 12 and the third electrode 23, and the fourth buffer layer 34 is located between the second plate portion 13 and the fourth electrode 24.

[0069] The thickness of the first buffer layer 31 is equal to the thickness of the second buffer layer 32, and the thickness of the first buffer layer 31 ranges from 50nm to 500nm; the thickness of the third buffer layer 33 is equal to the thickness of the fourth buffer layer 34, and the thickness of the third buffer layer 33 ranges from 50nm to 1500nm.

[0070] In one specific embodiment, silicon dioxide can be selected as the material for forming the buffer structure 30. The thickness of the first buffer layer 31 and the second buffer layer 32 can be 100 nm, and the thickness of the third buffer layer 33 and the fourth buffer layer 34 can be 650 nm.

[0071] The buffer structure 30 avoids direct contact between the lithium niobate waveguide 10 and multiple electrodes, thereby reducing optical losses due to metal absorption. In addition, the buffer structure 30 can also increase the refractive index difference between the lithium niobate waveguide 10 and the buffer structure 30 (refractive index difference Δn > 0.7), thereby enhancing the optical field confinement capability of the lithium niobate waveguide 10.

[0072] In addition, such as Figure 1 As shown, the buffer structure 30 may also include buffer layers disposed at other locations in the electro-optic modulator 1. For example, a buffer layer may be disposed between the third electrode 23 and the fifth electrode 25, or between the first electrode 21 and the substrate 60.

[0073] In some embodiments, such as Figure 1 As shown, the electrode structure 20 can be a multi-layer structure. A multi-layer structure can form a more uniform and stronger lateral electric field distribution. Simultaneously, the design of the multi-layer electrodes can optimize the electric field distribution and enhance the overlap factor between the electric and optical fields, thereby further improving modulation efficiency. Specifically, in the electrode structure 20, the first electrode 21 and the second electrode 22 can both be located between the lithium niobate waveguide 10 and the substrate 60, or both can be located between the lithium niobate waveguide 10 and the fifth electrode 25 and the sixth electrode 26. That is, the first electrode 21 and the second electrode 22 can both be located above or below the lithium niobate waveguide 10. In this embodiment, the first electrode 21 and the second electrode 22 are located below the lithium niobate waveguide 10, and the third electrode 23 and the fourth electrode 24 are located above the lithium niobate waveguide 10.

[0074] The thicknesses of the first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 are all less than the thicknesses of the fifth electrode 25 and the sixth electrode 26. The first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 are used to provide a transverse electric field, while the fifth electrode 25 and the sixth electrode 26 are surface electrodes used for connection with the outside world.

[0075] In some embodiments, the first electrode 21 and the second electrode 22 are located on both sides of the lithium niobate waveguide 10. The third electrode 23 and the fourth electrode 24 are located on both sides of the lithium niobate waveguide 10. The first electrode 21 and the second electrode 22 are equidistant from the waveguide portion 11, and the third electrode 23 and the fourth electrode 24 are equidistant from the waveguide portion 11. By symmetrically distributing the electrodes on both sides of the lithium niobate waveguide 10, the electric field on both sides of the lithium niobate waveguide 10 is uniformly distributed.

[0076] Please continue reading. Figure 1The distance between the side of the first electrode 21 near the waveguide portion 11 and the side of the second electrode 22 near the waveguide portion 11 is the first electrode spacing. The distance between the side of the third electrode 23 near the waveguide portion 11 and the side of the fourth electrode 24 near the waveguide portion 11 is the second electrode spacing.

[0077] The spacing between the first electrode and the second electrode is in the range of 2μm to 7μm. In a specific embodiment, the first electrode spacing can be 4.2μm and the second electrode spacing can be 1.7μm. By limiting the electrode spacing, it is possible to avoid an increase in metal absorption loss due to an excessively narrow electrode spacing, thereby reducing the impact on modulation efficiency. Alternatively, it is possible to avoid an excessively wide electrode spacing, which would lead to low modulation efficiency and affect the device's driving voltage and modulation depth.

[0078] Furthermore, the fifth electrode 25 and the sixth electrode 26 are also equidistant from the waveguide portion 11, meaning that the fifth electrode 25 and the sixth electrode 26 are symmetrically distributed relative to the center of the lithium niobate waveguide 10. This invention does not limit the electrode spacing between the side of the fifth electrode 25 closest to the waveguide portion 11 and the side of the sixth electrode 26 closest to the waveguide portion 11. In the electrode structure 20, each electrode is made of a metallic material, such as copper.

[0079] Figure 2 This is a schematic diagram of the electric field distribution corresponding to an electro-optic modulator provided as an exemplary embodiment of the present disclosure. The electro-optic modulator adopts a multilayer electrode structure. Figure 3 This is a schematic diagram of the electric field distribution corresponding to the electro-optic modulator in the related technology. The electro-optic modulator adopts a single-layer electrode structure. Figure 2 as well as Figure 3 In this system, the changes in the electric field can be represented by the color intensity and density of the lines representing the electric field distribution.

[0080] exist Figure 2 In the central region, the equipotential lines are darker and more densely distributed. Figure 2 In the edge regions, the equipotential lines are lighter in color and sparser in distribution compared to the central regions. Figure 3 In the central region, the equipotential lines are darker and more densely distributed. Figure 3 In the edge regions, the equipotential lines are lighter in color and sparser in distribution compared to the central regions. (Contrast) Figure 2 as well as Figure 3 It can be seen that, compared with the electro-optic modulator using a single-layer electrode structure, the electro-optic modulator 1 using the multi-layer electrode structure 20 provided in this application embodiment has a more uniform electric field distribution and a stronger electric field intensity.

[0081] The electro-optic modulator 1 disclosed in this embodiment achieves the same modulation depth as a traditional single-layer electrode within a shorter waveguide length through the arrangement of multiple electrode layers, thereby reducing the electrode length and minimizing the impact on modulation efficiency. Simultaneously, the first electrode 21, second electrode 22, third electrode 23, and fourth electrode 24 can apply transverse electric fields at the upper and lower positions of the lithium niobate waveguide 10, respectively. Compared to related technologies, the electro-optic modulator 1 disclosed in this embodiment can effectively enhance the electric field strength, significantly improve the overlap between the optical and electric fields, and thus enhance the efficiency of electro-optic modulation.

[0082] Electrode structure 20 also includes multiple through-hole connection structures. See [link / reference] Figure 1 In this embodiment, the electrode structure 20 includes a second through-hole connection structure 41 and a third through-hole connection structure 42.

[0083] The second through-hole connection structure 41 is located between the first electrode 21 and the third electrode 23 to achieve an electrical connection between the first electrode 21 and the third electrode 23. The second through-hole connection structure 41 is also located between the second electrode 22 and the fourth electrode 24 to achieve an electrical connection between the second electrode 22 and the fourth electrode 24. The second through-hole connection structure 41 and the lithium niobate waveguide 10 are mutually isolated by a buffer structure 30.

[0084] The third through-hole connection structure 42 is located between the third electrode 23 and the fifth electrode 25 to achieve an electrical connection between the third electrode 23 and the fifth electrode 25. The third through-hole connection structure 42 is also located between the fourth electrode 24 and the sixth electrode 26 to achieve an electrical connection between the fourth electrode 24 and the sixth electrode 26.

[0085] The through-hole connection structure is also made of metal. Since the through-hole connection structure and the electrode are manufactured separately, the material of the through-hole connection structure can be the same as or different from that of the electrode. For example, the material of the second through-hole connection structure 41 and the third through-hole connection structure 42 can be aluminum, while the material of the first electrode 21, the second electrode 22, the third electrode 23, etc., can be copper.

[0086] Please see Figure 1 There are two of each of the second through-hole connection structure 41 and the third through-hole connection structure 42, and they are symmetrically distributed with respect to the center of the lithium niobate waveguide 10. The symmetrical arrangement of each structure in the electrode structure 20 ensures a uniform electric field distribution. Furthermore, the through-hole connection structure increases the relative area of ​​the metal on both sides of the lithium niobate waveguide 10, thus further enhancing the electric field.

[0087] Another electro-optic modulator in this application embodiment is as follows: Figure 4 As shown. In this electro-optic modulator 1, the electrode structure 20 also includes a first through-hole connection structure 40.

[0088] This embodiment is compared to Figure 1 The embodiment shown adds a first through-hole connection structure 40. The arrangement of the lithium niobate waveguide 10, electrode structure 20, and buffer structure 30, such as their quantity, connection method, materials, and functions, are all the same as... Figure 1 The embodiments shown are the same and will not be repeated here. The first through hole connection structure 40 will be described below.

[0089] In one specific embodiment, the first through-hole connection structure 40 is located between the third electrode 23 and the first plate portion 12, and between the fourth electrode 24 and the second plate portion 13, to achieve the connection between the third electrode 23, the fourth electrode 24 and the lithium niobate waveguide 10. A buffer layer is also provided between the first through-hole connection structure 40 and the second through-hole connection structure 41. The material of the first through-hole connection structure 40 can be the same as or a different metal material as the electrode.

[0090] In this embodiment, the first through-hole connection structure 40 is configured compared to... Figure 1 The illustrated embodiment can further increase the relative area of ​​the metal on both sides of the lithium niobate waveguide 10 and achieve electrical connection between the third electrode 23 and the fourth electrode 24 and the lithium niobate waveguide 10. Therefore, this embodiment achieves... Figure 1 While achieving the technical effects of the illustrated embodiments, it is also possible to Figure 1 The electric field strength is further enhanced based on the embodiment shown.

[0091] Another electro-optic modulator in this application embodiment is as follows: Figure 5 As shown. This embodiment is compared to... Figure 1 The illustrated embodiments and Figure 4 The embodiment shown modifies the materials of the first electrode 21 and the second electrode 22. The arrangement of the remaining structures of the lithium niobate waveguide 10, buffer structure 30, and electrode structure 20, excluding the first electrode 21 and the second electrode 22, such as their quantity, materials, connection methods, and functions, are all the same as described above. Figure 1 The illustrated embodiments and Figure 4 The embodiments shown are the same and will not be repeated here. The changes of the first electrode 21 and the second electrode 22 will be explained below.

[0092] In this electro-optic modulator 1, the materials of the first electrode 21 and the second electrode include a first metallic conductive portion 51 and a first non-metallic conductive portion 52 that are interconnected. The distance from the first non-metallic conductive portion 52 to the lithium niobate waveguide 10 is less than the distance from the first metallic conductive portion 51 to the lithium niobate waveguide 10.

[0093] The second electrode 22 includes a second metallic conductive portion 53 and a second non-metallic conductive portion 54 that are interconnected. The distance from the second non-metallic conductive portion 54 to the lithium niobate waveguide 10 is less than the distance from the second metallic conductive portion 53 to the lithium niobate waveguide 10.

[0094] The distance between the side of the first non-metallic conductive portion 52 near the waveguide portion 11 and the side of the second non-metallic conductive portion 54 near the waveguide portion 11 is the third electrode spacing. The third electrode spacing is smaller than the first electrode spacing. Since a smaller electrode spacing results in a stronger electric field, this embodiment can provide a stronger electric field compared to... Figure 1 The illustrated embodiments and Figure 4 The embodiment shown has a stronger electric field.

[0095] Simultaneously, the materials of the first electrode 21 near the lithium niobate waveguide 10 and the second electrode 22 near the lithium niobate waveguide 10 are both replaced with non-metallic conductive materials. This avoids the impact of excessively close spacing between metal electrodes on modulation efficiency while increasing the electric field strength. The materials of the first non-metallic conductive part 52 and the second non-metallic conductive part 54 are both non-metallic materials capable of conducting electricity, such as titanium nitride, doped silicon, graphene, indium tin oxide, and group III-V materials.

[0096] Another electro-optic modulator in this application embodiment is as follows: Figure 6 As shown. In this embodiment, the materials of the first electrode 21 and the second electrode 22 can be completely replaced with non-metallic conductive materials. This embodiment is different from... Figure 1 , Figure 4 as well as Figure 5 The embodiment shown modifies the materials of the first electrode 21 and the second electrode 22. The arrangement of the remaining structures of the lithium niobate waveguide 10, buffer structure 30, and electrode structure 20, excluding the first electrode 21 and the second electrode 22, such as their quantity, materials, connection methods, and functions, are all the same as described above. Figure 1 , Figure 4 as well as Figure 5 The embodiments shown are the same and will not be described again here.

[0097] In some embodiments, both the first electrode 21 and the second electrode 22 can be selected from a variety of different non-metallic conductive materials. For example... Figure 6 As shown, the first electrode 21 may include a first non-metallic conductive portion 52, a third non-metallic conductive portion 55, and a fourth non-metallic conductive portion 56. The second electrode 22 may include a second non-metallic conductive portion 54, a fifth non-metallic conductive portion 57, and a sixth non-metallic conductive portion 58.

[0098] Alternatively, the materials of the third electrode 23 and the fourth electrode 24 can be replaced from metallic conductive materials to metallic conductive materials and non-metallic conductive materials, or completely replaced with non-metallic conductive materials. Using non-metallic conductive materials to fabricate the modulation electrodes can significantly reduce light absorption near the lithium niobate waveguide 10, thereby improving the transmission performance and modulation depth of the electro-optic modulator 1.

[0099] Another electro-optic modulator in this application embodiment is as follows: Figure 7 As shown. In this embodiment, the length of the electrodes in the electrode structure changes, and the connection relationship also changes accordingly. This embodiment is different from... Figure 1 , Figures 4 to 6 In the illustrated embodiment, the quantity, material selection, function, and electrode spacing range of the lithium niobate waveguide 10, buffer structure 30, and electrode structure 20 are all similar to those of the previous embodiment. Figure 1 , Figures 4 to 6 The embodiments shown are the same and will not be described again here. The changes in the electrodes will be explained below.

[0100] The electrode structure 20 also includes a fourth through hole connection structure 43, through which the first electrode 21 and the fifth electrode 25 are electrically connected, and through the third through hole connection structure 42, the fifth electrode 25 and the third electrode 23 are electrically connected.

[0101] In addition, the electrical connection between the second electrode 22 and the sixth electrode 26 is achieved through the fourth through-hole connection structure 43, and the electrical connection between the sixth electrode 26 and the fourth electrode 24 is achieved through the third through-hole connection structure 42.

[0102] In this embodiment, the first electrode spacing can be 3.25 μm, and the second electrode spacing can be 4 μm. The distance between the side of the fifth electrode 25 near the lithium niobate waveguide 10 and the side of the sixth electrode 26 near the lithium niobate waveguide 10 can be 3 μm.

[0103] With the above connection method, the modulation voltage can be mainly applied to the electric field region between the third electrode 23 and the fifth electrode 25, and the electric field region between the fourth electrode 24 and the sixth electrode 26, thereby more accurately controlling the electric field distribution position and improving the electro-optic modulation efficiency.

[0104] like Figure 7 As shown, the first plate portion 12 and the first electrode 21 and the fifth electrode 25 partially overlap in the stacking direction, and the second plate portion 13 and the second electrode 22 and the sixth electrode 26 partially overlap in the stacking direction.

[0105] The first plate portion 12 and the third electrode 23 completely overlap in the stacking direction, and the second plate portion 13 and the fourth electrode 24 completely overlap in the stacking direction.

[0106] Compared to this application Figure 1 , Figures 4 to 6 In the illustrated embodiment, by reducing the lengths of the third electrode 23 and the fourth electrode 24, the overall capacitive load of the electrode structure 20 can be reduced, thereby increasing the modulation bandwidth and operating speed of the electro-optic modulator 1. Simultaneously, the third electrode 23 and the fourth electrode 24 completely overlap with the lithium niobate waveguide 10 in the stacking direction, causing the electric field distribution to concentrate in the core region of the lithium niobate waveguide 10, effectively improving the overlap efficiency of the electric and optical fields, thereby enhancing the electro-optic modulation efficiency.

[0107] In the electro-optic modulator 1, the number of lithium niobate waveguides 10 can be one or more. Another electro-optic modulator according to an embodiment of this application is as follows: Figure 8 As shown. In this embodiment, there are two lithium niobate waveguides 10.

[0108] like Figure 8 As shown, the electro-optic modulator 1 includes a first lithium niobate waveguide 14 and a second lithium niobate waveguide 15. This embodiment, compared to... Figure 1 , Figures 4 to 7 In the corresponding embodiment, the electrode structure 20 changes. Other structures will not be described in detail in this embodiment; the electrode structure 20 will be described below.

[0109] The electrode structure 20 includes a first electrode 21, a second electrode 22, a third electrode 23, a fourth electrode 24, a fifth electrode 25, a sixth electrode 26, a seventh electrode 27, an eighth electrode 28, a second through-hole connection structure 41, and a third through-hole connection structure 42.

[0110] like Figure 8 As shown, the first electrode 21 and the seventh electrode 27 are respectively disposed on both sides of the first lithium niobate waveguide 14 and the second lithium niobate waveguide 15, and the second electrode 22 is located between the first lithium niobate waveguide 14 and the second lithium niobate waveguide 15.

[0111] The third electrode 23 and the eighth electrode 28 are respectively disposed on both sides of the first lithium niobate waveguide 14 and the second lithium niobate waveguide 15, and the fourth electrode 24 is located between the first lithium niobate waveguide 14 and the second lithium niobate waveguide 15.

[0112] In one specific embodiment, a waveguide spacing exists between the first lithium niobate waveguide 14 and the second lithium niobate waveguide 15, and they are symmetrically distributed with respect to the center of the waveguide spacing. The first electrode 21 and part of the second electrode 22 are located below the first lithium niobate waveguide 14, and part of the second electrode 22 and the seventh electrode 27 are located below the second lithium niobate waveguide 15. The third electrode 23 and part of the fourth electrode 24 are located above the first lithium niobate waveguide 14, and part of the fourth electrode 24 and the eighth electrode 28 are located above the second lithium niobate waveguide 15. The first electrode 21 and the seventh electrode 27 are symmetrically distributed with respect to the center of the waveguide spacing, and the center of the second electrode 22 is the center of the waveguide spacing. Similarly, the third electrode 23 and the eighth electrode 28 are also symmetrically distributed with respect to the center of the waveguide spacing, and the center of the fourth electrode 24 is the center of the waveguide spacing.

[0113] Please continue reading. Figure 8 The first electrode 21 and the third electrode 23, the second electrode 22 and the fourth electrode 24, and the seventh electrode 27 and the eighth electrode 28 are all connected through the second through-hole connection structure 41. The fifth electrode 25 and the third electrode 23, the sixth electrode 26 and the fourth electrode 24, and the sixth electrode 26 and the eighth electrode 28 are all connected through the third through-hole connection structure 42.

[0114] In this embodiment, both the fifth electrode 25 and the sixth electrode 26 can be interdigitated structures, with the fifth electrode 25 being a negative signal electrode and the sixth electrode 26 being a positive signal electrode. The fifth electrode 25 and the sixth electrode 26 are shown by dashed boxes, their fingers arranged alternately and spaced apart in a direction parallel to the substrate 60. Specifically, the sixth electrode 26 is electrically connected to both the third electrode 23 and the eighth electrode 28 through the third through-hole connection structure 42. The fifth electrode 25 is electrically connected to the fourth electrode 24 through the fourth through-hole connection structure 43. To achieve this connection, the fifth electrode 25 and the sixth electrode 26 form an interdigitated but non-overlapping interdigitated structure on a surface parallel to the substrate 60. That is, the fifth electrode 25 extends above the fourth electrode 24, and the sixth electrode 26 extends above both the fourth electrode 24 and the third electrode 23. In the region above the fourth electrode 24 and the third electrode 23, the fifth electrode 25 and the sixth electrode 26 form an interdigitated structure.

[0115] In this embodiment, by setting the first lithium niobate waveguide 14 and the second lithium niobate waveguide 15, and setting the fifth electrode 25 and the sixth electrode 26 as the positive signal electrode and the negative signal electrode respectively, differential modulation can be achieved on the basis of achieving the technical effects of the previous embodiment.

[0116] Another electro-optic modulator in this application embodiment is as follows: Figure 9 As shown. This embodiment is compared to... Figure 1 , Figures 4 to 8In the corresponding embodiment, the electrode structure 20 changes. Other structures will not be described in detail in this embodiment; the electrode structure 20 will be described below.

[0117] When the fifth electrode 25 and the sixth electrode 26 are not interdigitated, the electrode structure 20 in this embodiment may also include a ninth electrode 29. For example... Figure 9 As shown, the fifth electrode 25 and the sixth electrode 26 are respectively disposed on both sides of the first lithium niobate waveguide 14 and the second lithium niobate waveguide 15, and the ninth electrode 29 is located between the first lithium niobate waveguide 14 and the second lithium niobate waveguide 15. The fifth electrode 25 and the ninth electrode 29 can be negative signal electrodes, and the sixth electrode 26 can be a positive signal electrode.

[0118] In one specific embodiment, a portion of the fifth electrode 25 is located above the third electrode 23, a portion of the sixth electrode 26 is located above the eighth electrode 28, and the ninth electrode 29 is located above the fourth electrode 24. The fifth electrode 25 and the sixth electrode 26 are symmetrically distributed with respect to the center of the ninth electrode 29. The center of the ninth electrode 29 is the center of the waveguide spacing.

[0119] Please continue reading. Figure 9 The fifth electrode 25 and the third electrode 23 are connected through the fifth through-hole connection structure 44. The ninth electrode 29 and the fourth electrode 24 are connected through the sixth through-hole connection structure 45. The sixth electrode 26 and the eighth electrode 28 are connected through the seventh through-hole connection structure 46.

[0120] Accordingly, this application also discloses an optical communication system, which includes the electro-optic modulator as described in any of the above embodiments.

[0121] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0122] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0123] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0124] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent variations, or alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application. The terminology used herein is chosen to best explain the principles, practical applications, or technical improvements to the market of the various embodiments, or to enable other persons skilled in the art to understand the various embodiments disclosed herein.

Claims

1. An electro-optic modulator, characterized in that, include: A lithium niobate waveguide includes a waveguide section and a first plate section and a second plate section located on both sides of the waveguide section; An electrode structure includes a first electrode and a third electrode stacked together, and a second electrode and a fourth electrode stacked together. The first electrode and the third electrode are electrically connected, and the second electrode and the fourth electrode are electrically connected. A lithium niobate waveguide is located between the first electrode and the third electrode, and between the second electrode and the fourth electrode. The first electrode and the second electrode are located on both sides of the lithium niobate waveguide, and the third electrode and the fourth electrode are located on both sides of the lithium niobate waveguide. A buffer structure is located between the lithium niobate waveguide and the first electrode, the second electrode, the third electrode, and the fourth electrode.

2. The electro-optic modulator according to claim 1, characterized in that, The first plate portion and the first electrode, and the third electrode overlap at least partially in the stacking direction, and the second plate portion and the second electrode, and the fourth electrode overlap at least partially in the stacking direction.

3. The electro-optic modulator according to claim 1, characterized in that, The first electrode and the second electrode are spaced equally from the waveguide portion, and the third electrode and the fourth electrode are spaced equally from the waveguide portion.

4. The electro-optic modulator according to claim 3, characterized in that, The distance between the side of the first electrode near the waveguide portion and the side of the second electrode near the waveguide portion is the first electrode spacing, which ranges from 2μm to 7μm. The distance between the side of the third electrode near the waveguide and the side of the fourth electrode near the waveguide is the second electrode spacing, which ranges from 1 μm to 5 μm.

5. The electro-optic modulator according to claim 1, characterized in that, The first electrode includes a first metal conductive part and a first non-metal conductive part connected to each other, and the distance from the first non-metal conductive part to the lithium niobate waveguide is less than the distance from the first metal conductive part to the lithium niobate waveguide. The second electrode includes a second metal conductive part and a second non-metal conductive part that are connected to each other, and the distance from the second non-metal conductive part to the lithium niobate waveguide is less than the distance from the second metal conductive part to the lithium niobate waveguide; The distance between the side of the first non-metallic conductive part near the waveguide part and the side of the second non-metallic conductive part near the waveguide part is the third electrode spacing, which is smaller than the first electrode spacing.

6. The electro-optic modulator according to claim 1, characterized in that, The electrode structure also includes a first through-hole connection structure. The first through-hole connection structure is located between the third electrode and the first plate portion, and between the fourth electrode and the second plate portion.

7. The electro-optic modulator according to claim 1, characterized in that, The electro-optic modulator includes a substrate, and the buffer structure, the electrode structure, and the lithium niobate waveguide are disposed on the substrate. The buffer structure includes: a first buffer layer located between the first plate portion and the first electrode, a second buffer layer located between the second plate portion and the second electrode, a third buffer layer located between the first plate portion and the third electrode, and a fourth buffer layer located between the second plate portion and the fourth electrode. The thickness of the first buffer layer is equal to the thickness of the second buffer layer, and the thickness of the first buffer layer ranges from 50 nm to 500 nm; the thickness of the third buffer layer is equal to the thickness of the fourth buffer layer, and the thickness of the third buffer layer ranges from 50 nm to 1500 nm.

8. The electro-optic modulator according to claim 1, characterized in that, The electrode structure also includes a fifth electrode and a sixth electrode. The fifth electrode is electrically connected to the third electrode and stacked on top of each other, and the sixth electrode is electrically connected to the fourth electrode and stacked on top of each other.

9. The electro-optic modulator according to claim 8, characterized in that, The first plate portion and the first electrode and the fifth electrode partially overlap in the stacking direction, and the second plate portion and the second electrode and the sixth electrode partially overlap in the stacking direction; The first plate portion and the third electrode completely overlap in the stacking direction, and the second plate portion and the fourth electrode completely overlap in the stacking direction.

10. The electro-optic modulator according to claim 1, characterized in that, The number of lithium niobate waveguides is two; The electrode structure further includes a seventh electrode and an eighth electrode. The first electrode and the seventh electrode are respectively disposed on both sides of the first lithium niobate waveguide and the second lithium niobate waveguide, and the second electrode is located between the first lithium niobate waveguide and the second lithium niobate waveguide. The third electrode and the eighth electrode are respectively disposed on both sides of the first lithium niobate waveguide and the second lithium niobate waveguide, and the fourth electrode is located between the first lithium niobate waveguide and the second lithium niobate waveguide.

11. An optical communication system, characterized in that, The optical communication system includes an electro-optic modulator as described in any one of claims 1-10.

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