An electro-optic modulating device

Abstract

This invention discloses an electro-optic modulation device, which comprises, in a vertical direction, a top metal layer, an electro-optic material layer, a metal interlayer, and a silicon dioxide layer. The electro-optic material layer forms surface plasmons with the metal component on its surface and the metal interlayer on the base plate, respectively. The surface plasmons can localize the optical field in the electro-optic material and also localize the electric field and enhance the magnitude of the modulation electric field. Therefore, the overlap factor of the optical field and the electric field in the electro-optic modulation device of this invention can be greatly enhanced, thereby improving the modulation efficiency. The first metal component applies an electrical signal, and the second metal component is grounded. The two vertical surface plasmon slit waveguides formed by the two metal components on the electro-optic material layers control the refractive index of the electro-optic material in opposite ways, thereby achieving a highly efficient modulation function.

Description

Technical Field

[0001] This invention relates to the field of optical communication device technology, and in particular to an electro-optic modulation device. Background Technology

[0002] In optical communication transmission, modulators, optical amplifiers, detectors, and other devices play important roles. The modulator is the core device at the transmitting end of an optical communication system and is the key component for loading electrical signals onto optical signals.

[0003] In conventional electro-optic modulators, the overlap factor between the optical field and the modulation electric field remains relatively small due to limitations in waveguide optical field and electrode design.

[0004] Current electro-optic modulators can improve their efficiency by utilizing the localization ability of surface plasmons at the interface between metals and electro-optic materials to the optical and electric fields. However, due to the weak localization ability of the optical field in the vertical direction of the electro-optic material interface and the certain attenuation of the electric field in the horizontal direction, the ability to control the refractive index of the electro-optic material in the vertical direction is still insufficient, and the efficiency of electro-optic modulators needs to be further improved.

[0005] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0006] The main objective of this invention is to provide an electro-optic modulation device that can solve the problem of low modulation efficiency caused by the weak ability of existing modulators to adjust the refractive index of electro-optic material interfaces in the vertical direction.

[0007] To solve the above technical problems, the present invention provides an electro-optic modulation device, comprising an electro-optic material layer and a silicon dioxide layer, wherein a metal interlayer is disposed between the silicon dioxide layer and the electro-optic material layer, and the surface of the electro-optic material layer is provided with a signal input area, a modulation area and a signal output area, wherein the modulation area is located between the signal input area and the signal output area;

[0008] The modulation region includes a first metal component and a second metal component disposed opposite to each other on the surface of the electro-optic material layer. The first metal component is connected to an electrical signal, and the second metal component is grounded. The first metal component, the metal surface interlayer, and the electro-optic material layer constitute a first phase modulation arm, and the second metal component, the metal surface interlayer, and the electro-optic material layer constitute a second phase modulation arm.

[0009] The signal input area is used to receive the raw optical signal transmitted through the optical fiber;

[0010] The signal input area is also used to transmit the original optical signal to the first phase modulation arm and the second phase modulation arm respectively, so as to perform phase modulation on the original optical signal to obtain a first signal;

[0011] The signal output area is also used to cause the first signal to interfere, so as to modulate the intensity of the original optical signal to obtain a second signal, and the second signal is coupled to obtain the target optical signal.

[0012] In one embodiment, the signal input region includes a first metal grating and a first Y-shaped branch junction, and the signal output region includes a second metal grating and a second Y-shaped branch junction. The first metal grating and the second metal grating are respectively disposed on both sides of the surface of the electro-optic material layer, the first Y-shaped branch junction and the second Y-shaped branch junction are disposed opposite to each other, and the modulation region is located between the first Y-shaped branch junction and the second Y-shaped branch junction.

[0013] The first metal grating is used to receive the original optical signal, and the second metal grating is used to output the target optical signal;

[0014] The first Y-shaped branch junction is used to transmit the original optical signal to the first phase modulation arm and the second phase modulation arm respectively through the beam splitter side to generate phase modulation and obtain the first signal;

[0015] The second Y-shaped branch junction is used to interfere with the first signal through the beam-combining side to modulate the intensity of the original optical signal to obtain a second signal; the second signal is then transmitted to the second metal grating, so that the second metal grating couples the second signal to obtain the target optical signal.

[0016] In one embodiment, a first side of the first metal grating is connected to an external optical fiber, a second side of the first metal grating corresponds to the bundle-combining side of the first Y-shaped branch junction, and the bundle-splitting side of the first Y-shaped branch junction is respectively opposite to the first metal component and the second metal component, for transmitting the original optical signal to the first metal component and the second metal component respectively.

[0017] The branching sides of the second Y-shaped branch junction are respectively opposite to the first metal component and the second metal component, and are used to conduct the first signal;

[0018] The beam-combining side of the second Y-shaped branch junction corresponds to the first side of the second metal grating, and is used to recouple the first signal to obtain the target optical signal.

[0019] In one embodiment, the second side of the second metal grating serves as an output end, used to output the target optical signal to an optical fiber for transmission.

[0020] In one embodiment, the electro-optic material layer is based on lithium niobate; wherein the electro-optic material layer interacts with the metal interlayer and the metal elements in the modulation region to form surface plasmons.

[0021] In one embodiment, a first air gap layer with a thickness on the nanometer scale is provided between the signal input region and the modulation region, and a second air gap layer with a thickness on the nanometer scale is provided between the signal output region and the modulation region.

[0022] In one embodiment, the thickness of the electro-optic material layer ranges from 40 nm to 200 nm; the thickness of the first metal component and the second metal component ranges from 50 nm to 300 nm; the thickness of the metal interlayer ranges from 50 nm to 200 nm; the width of the first metal component and the second metal component ranges from 200 nm to 800 nm; and the thickness of the silicon dioxide layer ranges from 2 μm to 4.7 μm.

[0023] The electro-optic modulation device provided by this invention comprises, in the vertical direction, a top metal layer, an electro-optic material layer, a metal interlayer, and a silicon dioxide layer. The top metal layer includes a modulation region formed by a metal component. The electro-optic material layer forms surface plasmons with the metal component on the surface of the electro-optic material layer and the metal interlayer of the base plate, respectively. The surface plasmons can localize the optical field in the electro-optic material and also localize the electric field and enhance the magnitude of the modulation electric field. Therefore, the overlap factor of the optical field and the electric field in the electro-optic modulation device of this invention can be greatly enhanced, thereby improving the modulation efficiency. An electrical signal is applied to the first metal component, and the second metal component is grounded. The two vertical surface plasmon slit waveguides formed by the two metal components on the left and right sides of the electro-optic material layer have opposite effects on the refractive index of the electro-optic material, thereby achieving a highly efficient modulation function. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0025] Figure 1 This is a three-dimensional structural schematic diagram of an electro-optic modulation device provided in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the cross-sectional distribution structure of the electro-optic modulation region provided in an embodiment of this application;

[0027] Figure 3This is a three-dimensional structural schematic diagram of an electro-optic modulation device provided in another embodiment of this application;

[0028] Figure 4a This is a graph showing the effect of the width and thickness of the top metal component on the modulation efficiency in one embodiment of this application;

[0029] Figure 4b This is a graph showing the effect of lithium niobate thickness on modulation efficiency in one embodiment of this application;

[0030] Figure 5 This is a comparison chart showing the modulation transmission-voltage relationship between the electro-optic modulation device of this application embodiment and the modulation transmission-voltage relationship between a conventional electro-optic modulation device.

[0031] Figure label:

[0032] 01-Electro-optic material layer;

[0033] 02-Silica layer;

[0034] 03-Metal interlayer;

[0035] 10-Signal Input Area

[0036] 11-First metal grating;

[0037] 12-First Y-shaped branch junction;

[0038] 20 - Modulation region;

[0039] 21-First metal component;

[0040] 22-Second metal part;

[0041] 30 - Output area;

[0042] 31-Second metal grating;

[0043] 32-Second Y-shaped branch junction;

[0044] 04-Substrate.

[0045] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0046] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0047] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0048] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0049] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0050] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0051] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0052] An embodiment of the present invention discloses an electro-optic modulation device, such as... Figure 1 As shown, it includes an electro-optic material layer 01 and a silicon dioxide layer 02. A metal interlayer 03 is disposed between the silicon dioxide layer 02 and the electro-optic material layer 01. The surface of the electro-optic material layer 01 is provided with a signal input region 10, a modulation region 20 (top metal layer) and a signal output region 30. The modulation region 20 is located between the signal input region 10 and the signal output region 30.

[0053] Specifically, the modulation region 20 includes: a first metal element 21 and a second metal element 22 disposed opposite to each other on the surface of the electro-optic material layer, wherein the first metal element 21 is connected to an electrical signal and the second metal element 22 is grounded; the first metal element 21, the metal surface interlayer 03 and the electro-optic material layer 01 form a first phase modulation arm, and the second metal element 22, the metal surface interlayer 03 and the electro-optic material layer 01 form a second phase modulation arm, such that each phase modulation arm constitutes a vertical slit waveguide (perpendicular to the surface of the electro-optic material layer);

[0054] The signal input area 10 is used to receive the raw optical signal transmitted through the optical fiber;

[0055] The signal input area 10 is also used to transmit the original optical signal to the first phase modulation arm and the second phase modulation arm respectively, so as to perform phase modulation on the original optical signal to obtain a first signal;

[0056] The signal output region 30 is also used to cause the first signal to interfere, so as to achieve intensity modulation of the original optical signal to obtain a second signal, and to obtain the target optical signal after coupling processing of the second signal.

[0057] It should be noted that, in the specific implementation, the original optical signal transmitted through the optical fiber is coupled and converted into a surface plasmon mode through the signal input region 10 for on-chip transmission. Then (entering the modulation region 20), it enters the first phase modulation arm and the second phase modulation arm respectively. The first phase modulation arm is connected to the electrical signal terminal, and the second phase modulation arm is grounded. The refractive index of the electro-optic material layer is changed through the Pockels electro-optic effect. The change in refractive index causes a change in the effective refractive index of the optical modes of the two phase modulation arms, thereby generating phase modulation (obtaining the first signal). Then, the phase-modulated signal is interfered through the output region 30 to achieve intensity modulation (obtaining the second signal). Finally, the intensity-modulated second optical signal is coupled into the optical fiber for transmission.

[0058] Understandably, the electro-optic material layer 01 forms surface plasmons with the first metal component 21, the second metal component 22, and the metal interlayer 03, respectively. The surface plasmons can localize the optical field within the electro-optic material, and simultaneously localize the electric field and enhance the magnitude of the modulation electric field. Therefore, the overlap factor between the optical and electric fields in the modulation device of this embodiment can be greatly enhanced, thereby improving the modulation efficiency. When an electrical signal is applied to the first metal component 21 and the second metal component 22 is grounded, the two vertical surface plasmon slit waveguides formed on the left and right sides have opposite effects on the refractive index modulation of the electro-optic material, thus achieving a highly efficient modulation function.

[0059] In one embodiment, the electro-optic material layer of the present invention is preferably based on lithium niobate. In other embodiments of the present invention, lithium niobate is used as the material of the electro-optic material layer of the present invention for example illustration.

[0060] Understandably, lithium niobate, with its high electro-optic coefficient (30 pm / V), can achieve phase modulation by altering the effective refractive index of the modulated mode through voltage adjustment, making it one of the mainstream electro-optic modulation materials. In particular, breakthroughs in thin-film lithium niobate technology have improved the efficiency and reduced the size of bulk lithium niobate modulators, leading to widespread attention being paid to integrated thin-film lithium niobate modulator chips.

[0061] In conventional thin-film lithium niobate modulators, the overlap factor between the optical field and the modulation electric field is still small due to limitations in waveguide optical field and electrode design, resulting in a modulation efficiency of 2Vcm. This requires a size of at least mm to control the voltage below 5V, making it difficult to achieve a smaller and more efficient modulator.

[0062] The existing surface plasmon lithium niobate technology utilizes the localization ability of surface plasmons at the metal-lithium niobate interface to the optical and electric fields, which can improve the efficiency of thin-film lithium niobate modulators (0.23 Vcm) while maintaining a bandwidth greater than 10 GHz. However, due to the weak localization ability of the optical field in the vertical direction and the certain attenuation of the electric field in the horizontal direction, the ability to control the refractive index of lithium niobate in the vertical direction is still insufficient.

[0063] In this embodiment, reference Figure 2 , Figure 2 This is a schematic diagram of the cross-sectional distribution structure of the modulation region in this embodiment. The two metal strips at the top of the lithium niobate thin film (i.e., the first metal element 21 and the second metal element 22) and the metal interlayer 03 at the bottom, together with the lithium niobate material in the middle, respectively construct two vertical surface plasmon slit waveguides (i.e., a gold-lithium niobate-gold vertical slit structure), constituting the two phase modulation arms of the modulation device. This embodiment mainly enhances the optical field confinement in the lithium niobate material through surface plasmon resonances at the two metal / lithium niobate interfaces. Furthermore, the electro-optic modulation device also includes a semiconductor substrate 04, with the silicon dioxide layer 02 covering the substrate 04. The substrate 04 is preferably made of silicon.

[0064] Understandably, the lithium niobate thin film forms surface plasmons with the (first / second) metal components and the metal surface interlayer, respectively. These surface plasmons can localize the optical field within the lithium niobate material, and simultaneously localize the electric field and enhance the magnitude of the modulation electric field. Therefore, the overlap factor between the optical and electric fields in the modulation device of this embodiment can be greatly enhanced, thereby improving the modulation efficiency. When an electrical signal is applied to the first metal component and the second metal component is grounded, the two vertical surface plasmon slit waveguides on the left and right sides exert opposite effects on the refractive index of lithium niobate, thus achieving a highly efficient modulation function.

[0065] Furthermore, in some embodiments, other electro-optic materials can be selected. These other electro-optic materials require a higher electro-optic coefficient compared to lithium niobate, and the light loss generated by passing through them must be within an acceptable range. Additionally, if the fabrication process of other electro-optic materials is compatible with CMOS processes, they can replace lithium niobate as the material for the electro-optic material layer 01 in one embodiment of this invention. Then, based on structural simulations of the electro-optic material layer 01, the first metal component 21, the second metal component 22, and the metal interlayer 03, the modulation efficiency under different structures and sizes is obtained, the optimal structural dimensions are found, and finally, fabrication, testing, and application are carried out.

[0066] refer to Figure 3 , Figure 3 This is a schematic diagram of another embodiment of the electro-optic modulation device of the present invention;

[0067] In this embodiment, the signal input region 10 includes a first metal grating 11 and a first Y-shaped branch junction 12, and the signal output region 30 includes a second metal grating 31 and a second Y-shaped branch junction 32; wherein, the first metal grating 11 and the second metal grating 31 are respectively disposed on both sides of the surface of the electro-optic material layer 01; the first Y-shaped branch junction 12 and the second Y-shaped branch junction 32 are disposed opposite to each other; and the modulation region 20 is located between the first Y-shaped branch junction 12 and the second Y-shaped branch junction 32;

[0068] Specifically, the first metal grating 11 is used to receive the original optical signal transmitted through the optical fiber, and the second metal grating 31 is used to output the modulated target optical signal.

[0069] In a specific implementation, the first Y-shaped branch junction 12 is used to transmit the original optical signal to the first phase modulation arm and the second phase modulation arm respectively through the beam splitting side to generate phase modulation and obtain the first signal;

[0070] The second Y-shaped branch junction 32 is used to interfere with the first signal through the beam-combining side to modulate the intensity of the original optical signal to obtain a second signal; the second signal is then transmitted to the second metal grating 31, so that the second metal grating 31 couples the second signal to obtain the target optical signal.

[0071] refer to Figure 3 The specific structure includes: the first side of the first metal grating 11 is connected to an external optical fiber, the second side of the first metal grating 11 corresponds to the bundle-combining side of the first Y-shaped branch junction 12, and the bundle-splitting side of the first Y-shaped branch junction 12 is respectively opposite to the first metal component 21 and the second metal component 22, for transmitting the original optical signal to the first metal component 21 and the second metal component 22 respectively.

[0072] The splitting side of the second Y-shaped branch junction 32 is opposite to the first metal component 21 and the second metal component 22, respectively, and is used to conduct the first signal; the combining side of the second Y-shaped branch junction 32 corresponds to the first side of the second metal grating 31, and is used to recouple the first signal to obtain the target optical signal. The second side of the second metal grating 31 serves as the output end, used to output the target optical signal to the optical fiber for transmission.

[0073] Understandably, in this embodiment, the original optical signal transmitted through the optical fiber can be converted into a surface plasmon mode through coupling with the first metal grating for on-chip transmission. Then, it is split by the first Y-shaped branch junction and enters two (first and second) phase modulation arms respectively. The two phase modulation arms are respectively connected to a signal terminal and grounded. The refractive index of lithium niobate is changed by the Pockels electro-optic effect. The change in refractive index causes a change in the effective refractive index of the optical mode of the two phase modulation arms, thereby generating phase modulation. Then, the signal is combined by the second Y-shaped branch junction to cause interference and achieve intensity modulation. Finally, it is recoupled into the optical fiber for transmission through the second metal grating.

[0074] In this embodiment, an air gap layer with a thickness on the nanometer scale can be provided between the signal input region 10 (signal output region 30) and the modulation region 20. That is, an air gap layer with a thickness on the nanometer scale is provided between the branching side of each Y-shaped branch junction and the metal part of the modulation region (the input region 10 corresponds to the first air gap layer, and the output region 30 corresponds to the second air gap layer) so that the electrical signal will not be short-circuited.

[0075] In this embodiment, simulating the electric and optical fields of the electro-optic modulation device of the present invention can achieve the following technical effects:

[0076] Since lithium niobate is an anisotropic material, the main modulation axis in this embodiment is in the vertical direction (i.e., the z-axis). Therefore, increasing the electric field confinement in the z-direction can change the refractive index of the material to a greater extent, thereby achieving more effective mode refractive index control. The change in the effective mode refractive index is reflected in the phase change. Intensity modulation is achieved through the structure of the electro-optic modulation device in this embodiment.

[0077] The specific simulation method is as follows: In this embodiment, a 25V electrical signal is applied to the first metal component of the electro-optic modulation device, and the second metal component is grounded. The double-layer metal structure of the surface plasmon slit in this embodiment has a stronger light field confinement capability than that of conventional modulators, with a larger field distribution ratio in the z-direction. In addition, the double-layer metal structure of the surface plasmon slit on the lithium niobate film surface in this embodiment makes the electric field more localized in the vertical direction, achieving stronger modulation electric field localization at the same voltage compared to conventional modulators. The double-layer metal structure of the surface plasmon slit on the lithium niobate film surface in this embodiment makes the electric field components more distributed in the vertical direction, thereby achieving a 3-fold enhancement of the z-component of the electric field.

[0078] In some other embodiments, the thickness of the electro-optic material layer ranges from 40 nm to 200 nm; the thickness of the first metal part and the second metal part ranges from 50 nm to 300 nm; the thickness of the metal interlayer ranges from 50 nm to 200 nm; the width of the first metal part and the second metal part ranges from 200 nm to 800 nm; and the thickness of the silicon dioxide layer ranges from 2 μm to 4.7 μm.

[0079] In a specific implementation, the electro-optic material is preferably lithium niobate. The relationship between the modulator efficiency and the top metal structure parameters and the thickness of the lithium niobate in this scheme is as follows: Figure 4a and Figure 4b As shown. Figure 4a This is a graph showing the effect of the width and thickness of the top-layer (first / second) metal components on the modulation efficiency. Figure 4b The two graphs above show the effect of lithium niobate thickness on modulation efficiency. From these two graphs, we can see that:

[0080] The thickness of lithium niobate has a significant impact on the modulation efficiency of the device. The modulation efficiency gradually increases as the thickness decreases, fully demonstrating the advantage of surface plasmon slit waveguides in improving modulation efficiency. The smaller the lithium niobate thickness, i.e., the narrower the slit width of the vertical slit structure, the stronger the localization of the optical field and the modulation electric field in the surface plasmon slit waveguide. Based on actual process conditions, the lithium niobate thickness of the surface plasmon slit waveguide in this embodiment is designed to be 100 nm; the thickness of the two top metal components is 80 nm and the width is 375 nm; the thickness of the bottom metal interlayer is 100 nm. Under these device parameters, a modulation efficiency of 0.045 Vcm (push-pull mode) can be achieved, which is about 4 to 5 times higher than that of conventional surface plasmon lithium niobate modulators.

[0081] In one embodiment, the electro-optic modulation device of the present invention is fabricated using the following materials and equipment: a custom-designed lithium niobate-on-insulator substrate is used, wherein the top layer of lithium niobate has a thickness of 100 nm, the silicon dioxide has a thickness of 4.7 μm, the intermediate gold layer between lithium niobate and silicon dioxide has a thickness of 100 nm, and the bottom layer of substrate silicon has a thickness of 525 μm. Electron beam lithography is performed using a Vistec EBPG5000plus electron beam lithography machine with a minimum linewidth of 7 nm. Furthermore, during electron beam lithography, conductive polymer AR-PC 5090 is used as the top layer on the insulating substrate to dissipate electron beam charge, and high-resolution positive resist AR-P is used.

[0082] 6200 (CSAR62) was used as the electron beam adhesive. The Ohmiker-50B electron beam evaporation coating system was used for the evaporation coating of Au materials.

[0083] The embodiments of the present invention exhibit higher modulation efficiency (0.045 Vcm, a 4-5 times improvement) compared to conventional modulation devices, while also possessing the characteristics of small size (15 μm) and large bandwidth (theoretical bandwidth > 1.4 THz). The present invention primarily introduces a surface plasmonic slit waveguide structure with better localization capabilities for optical and electric fields (two metal layers achieve localization of optical and electric fields), enhancing the overlap factor between the optical and electric fields, thereby improving modulation efficiency. Furthermore, due to the high modulation efficiency of the slit waveguide structure and a device size of only 15 μm, the top metal structure of the vertical surface plasmonic slit waveguide can serve as an electrode, resulting in a small overall device capacitance. Combined with the electro-optic effect of lithium niobate, it achieves a modulation bandwidth on the order of THz.

[0084] Furthermore, in some embodiments, the modulation efficiency of the modulator of the present invention was experimentally calculated, and the modulation efficiency of a single metal / lithium niobate interface (a conventional modulator scheme in the prior art) and a bimetallic / lithium niobate interface (the present invention adds a bottom metal interlayer) were compared; with the operating wavelength of 1550nm selected for both schemes and the length of the lithium niobate modulation region of 15μm for both schemes, the comparison results of the modulation efficiency obtained by the two schemes are as follows: Figure 5 As shown, Figure 5 This is a comparison chart showing the modulation transmission-voltage relationship between the electro-optic modulation device of this application and a conventional electro-optic modulation device:

[0085] The change in transmission efficiency with voltage as observed from the transmission curve shows that before adding the bottom metal interlayer, the modulation efficiency of the single-metal / lithium niobate interface structure was approximately 0.23 Vcm. However, after adding the bottom metal interlayer to the modulation device of this invention, the modulation efficiency at the bimetal / lithium niobate interface was approximately 0.045 Vcm. This demonstrates that adding the bottom metal interlayer improved the modulation efficiency by approximately five times. This enhanced modulation efficiency reduces the requirements for the input RF signal and device size, thereby reducing device power consumption and overall device size.

[0086] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. An electro-optic modulating device, characterized by, The application relates to an optical signal modulation device, which comprises an electro-optical material layer and a silicon dioxide layer, a metal interlayer is arranged between the electro-optical material layer and the silicon dioxide layer, a surface of the electro-optical material layer is provided with a signal input area, a modulation area and a signal output area, and the modulation area is located between the signal input area and the signal output area. The modulation area comprises a first metal piece and a second metal piece which are oppositely arranged on the surface of the electro-optical material layer, the first metal piece is connected to an electrical signal, the second metal piece is grounded, the first metal piece, the metal interlayer and the electro-optical material layer form a first phase modulation arm, and the second metal piece, the metal interlayer and the electro-optical material layer form a second phase modulation arm. The signal input area is used for receiving an original optical signal transmitted by an optical fiber. The signal input area is also used for conducting the original optical signal to the first phase modulation arm and the second phase modulation arm respectively, so that the original optical signal is phase-modulated to obtain a first signal. The signal output area is also used for making the first signal interfere to intensity-modulate the original optical signal, so as to obtain a second signal, and the second signal is coupled to obtain a target optical signal.

2. The electro-optic modulating device of claim 1, wherein, The signal input area comprises a first metal grating and a first Y-shaped branch junction, the signal output area comprises a second metal grating and a second Y-shaped branch junction, the first metal grating and the second metal grating are arranged on two sides of the surface of the electro-optical material layer respectively, the first Y-shaped branch junction and the second Y-shaped branch junction are oppositely arranged, and the modulation area is located between the first Y-shaped branch junction and the second Y-shaped branch junction. The first metal grating is used for receiving the original optical signal, and the second metal grating is used for outputting the target optical signal. The first Y-shaped branch junction is used for conducting the original optical signal to the first phase modulation arm and the second phase modulation arm through a beam splitting side to generate phase modulation, so as to obtain a first signal. The second Y-shaped branch junction is used for making the first signal interfere through a beam combining side to intensity-modulate the original optical signal, so as to obtain a second signal, and the second signal is conducted to the second metal grating to make the second metal grating couple the second signal to obtain a target optical signal.

3. The electro-optic modulating device of claim 2, wherein, A first side of the first metal grating is connected to an external optical fiber, a second side of the first metal grating corresponds to a beam combining side of the first Y-shaped branch junction, a beam splitting side of the first Y-shaped branch junction is opposite to the first metal piece and the second metal piece respectively, and the beam splitting side is used for conducting the original optical signal to the first metal piece and the second metal piece respectively. A beam splitting side of the second Y-shaped branch junction is opposite to the first metal piece and the second metal piece respectively, and the beam splitting side is used for conducting the first signal. A beam combining side of the second Y-shaped branch junction corresponds to a first side of the second metal grating, and the beam combining side is used for recoupling the first signal to obtain a target optical signal.

4. The electro-optic modulating device of claim 3, wherein, A second side of the second metal grating is used as an output end for outputting the target optical signal to an optical fiber for transmission.

5. The electro-optic modulating device of any one of claims 1-4, wherein, The electro-optical material layer is realized based on a lithium niobate material; and the electro-optical material layer interacts with the metal surface interlayer and the metal piece in the modulation region to form surface plasmons.

6. The electro-optic modulating device of any one of claims 1-4, wherein, The signal input region and the modulation region are provided with a first air spacing layer with a thickness of nanometer order, and the signal output region and the modulation region are provided with a second air spacing layer with a thickness of nanometer order.

7. The electro-optic modulating device of any one of claims 1-4, wherein, The thickness of the electro-optical material layer ranges from 40 nm to 200 nm; the thickness of the first metal piece and the second metal piece ranges from 50 nm to 300 nm; and the thickness of the metal surface interlayer ranges from 50 nm to 200 nm.

8. The electro-optic modulating device of claim 7, wherein, The width of the first metal piece and the second metal piece ranges from 200 nm to 800 nm.

9. The electro-optic modulating device of claim 7, wherein, The thickness of the silicon dioxide layer ranges from 2 μm to 4.7 μm.

10. The electro-optic modulating device of any one of claims 1-4, wherein, The electro-optical modulation device further comprises a substrate of semiconductor material, and the silicon dioxide layer is covered on the substrate.

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