Optical modulator

Abstract

An optical modulator, comprising: a first dielectric layer (10); a second dielectric layer (20), which is located on the first dielectric layer (10), wherein a waveguide structure (210) and a first metal layer (220) are provided in the second dielectric layer (20), and the waveguide structure (210) is electrically connected to the first metal layer (220); an insulating layer (30), which is located on the second dielectric layer (20); a third dielectric layer (40), which is located on the insulating layer (30), wherein a second metal layer (410) is provided in the third dielectric layer (40), and the second metal layer (410) is electrically connected to the first metal layer (220) by means of a via hole (50); and a metal gate layer (60), which comprises a plurality of metal gate structures (610) that are arranged spaced apart, wherein the metal gate structures (610) are periodically arranged in a signal transmission direction of the waveguide structure (210), and the metal gate layer (60) is configured to be respectively insulated from the first metal layer (220) and the second metal layer (410). The waveguide structure (210), the first metal layer (220) and the second metal layer (410) form a new "sandwich" modulator structure, removing a substrate from the original structure; and the metal gate layer (60) can reduce the transmission speed of an electrical signal, thereby solving the electro-optical mismatch problem, and increasing the electro-optical bandwidth of the optical modulator.

Description

optical modulator

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 18, 2023, with application number 202322529355.7 and invention name “Optical Modulator”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The utility model relates to the technical field of optical communications, in particular to an optical modulator. Background Art

[0003] In silicon-based integrated optoelectronic systems, traveling-wave electrode modulators based on SOI (silicon-on-insulator) technology typically consist of an optical waveguide load and a traveling-wave electrode. Electromagnetic waves propagate between the traveling-wave electrodes, while an optical carrier propagates through the optical waveguide of the load. During the transmission of the optical carrier and electromagnetic wave, the interaction between the electromagnetic wave and the optical carrier causes a phase shift in the optical carrier, thereby modulating the electrical signal into an optical signal. The performance metrics for evaluating traveling-wave electrode modulators primarily include electro-optical bandwidth and impedance.

[0004] In related technologies, silicon-based traveling-wave electrode modulators are primarily fabricated using the CMOS (Complementary Metal-Oxide-Semiconductor) SOI process, which boasts low cost and ease of large-scale production. The CMOS-SOI structure of a traveling-wave electrode modulator consists, from top to bottom, of a top silicon layer, an insulating layer, and a silicon substrate. Because the silicon substrate forms a parasitic capacitance with the doped contact regions on both sides of the optical waveguide through the insulating layer, this reduces the traveling-wave electrode modulator's electro-optical bandwidth and impedance, thereby degrading the modulator's modulation performance for optical signals. Utility Model Content

[0005] Based on this, it is necessary to provide an optical modulator to address the above technical problems and improve the electro-optical bandwidth of the optical modulator.

[0006] In order to achieve the above-mentioned object, the present application provides an optical modulator, comprising:

[0007] a first dielectric layer;

[0008] a second dielectric layer, located on the first dielectric layer, wherein a waveguide structure and a first metal layer are provided in the second dielectric layer, and the waveguide structure is electrically connected to the first metal layer;

[0009] an insulating layer, located on the second dielectric layer;

[0010] a third dielectric layer, located on the insulating layer, wherein a second metal layer is provided in the third dielectric layer, and the second metal layer is electrically connected to the first metal layer through a via;

[0011] The metal gate layer includes a plurality of spaced metal gate structures, each of which is periodically arranged in the signal transmission direction of the waveguide structure. The metal gate layer is insulated from the first metal layer and the second metal layer respectively.

[0012] In one embodiment, the second metal layer is electrically connected to the waveguide structure through vias and each of the first metal layers.

[0013] In one embodiment, the first dielectric layer is a silicon layer or a glass material layer.

[0014] In one embodiment, the first dielectric layer is formed on the second dielectric layer by bonding.

[0015] In one embodiment, the insulating layer and the third dielectric layer are made of the same material.

[0016] In one embodiment, the metal gate layer is disposed in the third dielectric layer and spaced apart from the second metal layer, or the metal gate layer is disposed in the second dielectric layer and spaced apart from the first metal layer.

[0017] In one embodiment, the metal gate layer is provided in the second dielectric layer and the third dielectric layer, and the metal gate layer is spaced apart from the first metal layer and the second metal layer respectively.

[0018] In one embodiment, the metal gate layer includes a first sub-gate layer and a second sub-gate layer; wherein, the first sub-gate layer and the second sub-gate layer are symmetrically located on both sides of the second metal layer, and the first sub-gate layer and the second sub-gate layer respectively include multiple gate structures periodically arranged along the signal transmission direction of the waveguide structure.

[0019] In one embodiment, the optical modulator includes at least two second metal layers, wherein the at least two second metal layers are electrically connected through vias, and the metal gate layer includes a plurality of first sub-gate structures periodically arranged along the signal transmission direction of the waveguide structure, and each of the first sub-gate structures is located in the gap between two adjacent vias above the same second metal layer.

[0020] In one embodiment, the metal gate layer also includes a plurality of second sub-gate structures periodically arranged along the signal transmission direction of the waveguide structure; wherein each of the first sub-gate structures is arranged on the insulating layer and is staggered with each of the second sub-gate structures in the signal transmission direction of the waveguide structure.

[0021] The optical modulator comprises a metal gate layer and a first dielectric layer, a second dielectric layer, an insulating layer and a third dielectric layer stacked in sequence from bottom to top, wherein the second dielectric layer is provided with a waveguide structure and a first metal layer, and the third dielectric layer is provided with a second metal layer, wherein the first metal layer is electrically connected to the waveguide structure and the second metal layer through vias, respectively, to form a novel "sandwich" structure, and the first dielectric layer replaces the substrate layer in the CMOS-SOI process in the related art, and the first dielectric layer does not form parasitic capacitance with the waveguide structure, and compared with the substrate layer and the waveguide structure, the first dielectric layer does not form parasitic capacitance with the waveguide structure. Compared with the old optical modulator (substrate layer, waveguide structure layer and oxide layer) in which parasitic capacitance exists between the structures, the optical modulator provided by the present application improves the electro-optical bandwidth of the optical modulator, thereby improving the modulation performance of the optical modulator for optical signals; in addition, the metal gate layer includes a metal gate structure periodically arranged along the signal transmission direction of the waveguide structure, which can effectively reduce the transmission speed of the electromagnetic wave, that is, slow down the transmission speed of the electromagnetic wave, so that the transmission speed of the electromagnetic wave matches the transmission speed of light, solves the problem of electro-optical mismatch in the electro-optical modulator, and improves the electro-optical bandwidth of the modulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a schematic diagram of a cross-sectional structure of a light modulator provided by one embodiment;

[0023] FIG2 is a schematic diagram of a three-dimensional structure of a light modulator provided by one embodiment;

[0024] FIG3 is a second schematic diagram of a cross-sectional structure of an optical modulator provided by an embodiment;

[0025] FIG4 is a second schematic diagram of a three-dimensional structure of an optical modulator provided by an embodiment;

[0026] FIG5 is a third schematic diagram of a three-dimensional structure of an optical modulator provided by an embodiment;

[0027] FIG6 is a third schematic diagram of a cross-sectional structure of an optical modulator provided by an embodiment;

[0028] FIG7 is a schematic diagram of a three-dimensional structure of the light modulator shown in FIG6 according to an embodiment;

[0029] FIG8 is a fourth schematic diagram of a three-dimensional structure of an optical modulator provided by an embodiment;

[0030] FIG9 is a fourth schematic diagram of a cross-sectional structure of an optical modulator provided by an embodiment;

[0031] FIG10 is a schematic diagram of a three-dimensional structure of the light modulator shown in FIG9 according to an embodiment;

[0032] FIG11 is a fifth schematic diagram of a cross-sectional structure of an optical modulator provided by an embodiment;

[0033] FIG12 is a schematic diagram of a three-dimensional structure of the light modulator shown in FIG11 according to an embodiment;

[0034] FIG13 is a fifth schematic diagram of the cross-sectional structure of an optical modulator provided by an embodiment.

[0035] Description of reference numerals:

[0036] 10-first dielectric layer, 20-second dielectric layer, 210-waveguide structure, 211-optical waveguide, 212-slab structure, 213-contact structure, 220-first metal layer, 30-insulating layer, 40-third dielectric layer, 410-second metal layer, 50-via, 60-metal gate layer, 610-metal gate structure, 620-first sub-gate layer, 630-second sub-gate layer, 640-first sub-gate structure, 650-second sub-gate structure. DETAILED DESCRIPTION

[0037] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of this invention are for the purpose of describing specific embodiments only and are not intended to limit this invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] In the description of the present invention, it should be understood that the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the method or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0040] As mentioned in the background technology, the silicon-based traveling wave electrode modulator based on the COMS-SOI process has a film layer where the waveguide is located separated from the substrate layer by only an insulating layer, and the substrate itself has a certain resistivity, and the substrate can be regarded as a conductor with low electrical conductivity. In addition, the waveguide, the slab layer, and the contact layer are generally silicon with a certain doping concentration, and their electrical characteristics are close to those of a conductor. This results in the film layer where the waveguide, the slab layer, and the contact layer are located forming a flat capacitor structure with the substrate layer, which has a large parasitic capacitance. This large parasitic capacitance will lead to a significant reduction in the bandwidth and impedance of the traveling wave electrode modulator, degrading the modulation performance of the traveling wave electrode modulator. In response to this, the present application provides a modulator that forms a new "sandwich" modulator structure without a substrate, eliminates the parasitic capacitance between the second dielectric layer and the substrate layer, improves the electro-optical bandwidth of the modulator, and thereby improves the modulation performance of the modulator for optical signals.

[0041] In one embodiment, as shown in FIG1 and FIG2 , a light modulator is provided, which includes a first dielectric layer 10 , a second dielectric layer 20 , an insulating layer 30 , a third dielectric layer 40 , and a metal gate layer 60 , which are stacked sequentially from bottom to top.

[0042] A waveguide structure 210 and a first metal layer 220 are provided in the second dielectric layer 20, and the waveguide structure 210 is electrically connected to the first metal layer 220. The waveguide structure 210 may include an optical waveguide 211, a slab structure 212, and a contact structure 213. The slab structure 212 and the contact structure 213 are respectively located on both sides of the optical waveguide 211 and are symmetrically arranged. The optical waveguide 211 is electrically connected to the contact structure 213 through the slab structure 212. The optical waveguide 211 is used to transmit optical signals, and the slab structure 212 and the contact structure 213 can be used to transmit electrical signals. The waveguide structure 210 is electrically connected to the first metal layer 220 through a via 50. A second metal layer 410 is provided in the third dielectric layer 40, and the second metal layer 410 is electrically connected to the first metal layer 220 through a via 50. The via 50 may be a continuous conductive panel structure, or a conductive structure with multiple gaps. The material and structure of the via 50 are not specifically limited herein.

[0043] The metal gate layer 60 includes a plurality of spaced-apart metal gate structures 610, each of which is periodically arranged in the signal transmission direction of the waveguide structure. The metal gate layer 60 is insulated from the first metal layer 220 and the second metal layer 410. The period and duty cycle of the metal gate structure 610 can be designed through simulation to align the transmission speed of the electromagnetic wave with the transmission speed of light, thereby resolving the electro-optical mismatch problem in the electro-optical modulator. Optionally, the period of the metal gate structure 610 can be set to 4 to 15 microns, and the duty cycle can be set to 10% to 25%, thereby matching the group velocity of the electrical signal with the group velocity of the optical carrier.

[0044] In the above-mentioned optical modulator, the first dielectric layer 10 replaces the substrate layer in the CMOS-SOI process in the related art. The first dielectric layer 10 does not form parasitic capacitance with the waveguide structure 210. Compared with the old optical modulator (substrate layer, waveguide structure layer and oxide layer) in which parasitic capacitance exists between the substrate layer and the waveguide structure 210, the optical modulator provided by the present application improves the electro-optical bandwidth of the optical modulator, thereby improving the modulation performance of the optical modulator for optical signals; in addition, the metal gate layer 60 includes a metal gate structure 610 periodically arranged along the signal transmission direction of the waveguide structure, which can effectively reduce the transmission speed of the electromagnetic wave, that is, slow down the transmission speed of the electromagnetic wave, so that the transmission speed of the electromagnetic wave matches the transmission speed of light, solves the problem of electro-optical mismatch in the electro-optical modulator, and improves the electro-optical bandwidth of the modulator.

[0045] For example, the first metal layer 220 may be one or more layers. In the embodiment of the present application, the number of layers of the first metal layer 220 is not limited. When the optical modulator includes multiple first metal layers 220, one of the metal layers 220 is electrically connected to the contact structure 213 through a via 50. The first metal layers 220 are stacked in a direction from the second dielectric layer 20 to the first dielectric layer 10, and two adjacent first metal layers 220 are electrically connected through the via 50. For example, the first metal layers 220 are symmetrically arranged on both sides of the optical waveguide 211.

[0046] Exemplarily, the second metal layer 410 may be one or more layers. In the embodiment of the present application, the number of layers of the second metal layer 410 is not limited. When the optical modulator includes multiple second metal layers 410, one of the second metal layers 410 is adjacent to the insulating layer 30 and electrically connected to the first metal layer 220 through the via 50. The second metal layers 410 are stacked along the direction from the first dielectric layer 10 to the insulating layer 30, and two adjacent second metal layers 410 are electrically connected through the via 50. Exemplarily, the second metal layers 410 are symmetrically arranged on both sides of the optical waveguide 211.

[0047] For example, the total number of the first metal layer 220 and the second metal layer 410 is 6 to 8. In practical applications, the number of the first metal layer 220 and the second metal layer 410 can be set according to application requirements and is not limited here.

[0048] Exemplarily, the first dielectric layer 10 may be a silicon layer or a glass material layer. Glass materials include, but are not limited to, silicon oxide, boron oxide, and the like. The first dielectric layer 10 acts as a supporting silicon substrate. Exemplarily, the second dielectric layer 20 and the third dielectric layer 40 may be any one or more of any suitable dielectric layers, such as a silicon nitride layer and a silicon dioxide layer. Exemplarily, the second dielectric layer 20 and the third dielectric layer 40 may be formed by a multilayer deposition of silicon dioxide and silicon nitride. Exemplarily, the insulating layer 30 may be an oxide layer, such as a silicon dioxide layer. Exemplarily, the insulating layer 30 and the third dielectric layer 40 may be formed from the same material, for example, both the insulating layer 30 and the third dielectric layer 40 may be silicon dioxide layers. Exemplarily, the waveguide structure 210 may be a silicon structure. The shielding structure 50 may be a metal structure, such as copper or aluminum. The materials of the various layers and structures are not limited herein.

[0049] In practical applications, an optical modulator can be obtained by etching and depositing an SOI wafer based on CMOS-SOI technology. The SOI wafer includes a substrate layer, an insulating layer 30, and a crystalline silicon layer stacked in sequence. First, the crystalline silicon layer is etched to form a waveguide structure 210 on the insulating layer 30, comprising a waveguide 211, a contact structure 213, and a slab structure 212. Then, through a doping process, the waveguide structure 210 is doped with carriers to form an electrical connection with the metal layer above. A metal deposition process is then used to form a first metal layer 220 electrically connected to the waveguide structure 210, and a second dielectric layer 20 is deposited on the insulating layer 30, with the first metal layer 220 located within the second dielectric layer 20. In this manner, the waveguide structure 210 and the first metal layer 220 form a conventional optical modulator in the related art.

[0050] Based on the above process, the present application can form a first dielectric layer 10 on the second dielectric layer 20 by bonding, and remove the original substrate layer. After inverting the structure, the insulating layer 30 is etched to form vias, and a second metal layer 410 and a metal gate layer 60 are formed on the insulating layer 30 by a metal deposition process. The third dielectric layer 40 is then deposited on the insulating layer 30, with the second metal layer 410 located within the third dielectric layer 40. The first metal layer 220 is electrically connected to the second metal layer 410 through the via 50. Based on this, the waveguide structure 210, the first metal layer 220, and the second metal layer 220 form a novel optical modulator with a "sandwich" structure.

[0051] The optical modulator comprises a first dielectric layer 10, a second dielectric layer 20, an insulating layer 30, and a third dielectric layer 40 stacked from bottom to top. The waveguide structure 210, the first metal layer 220, and the second metal layer 410 in the third dielectric layer 40 form a novel optical modulator with a "sandwich" structure. In conventional optical modulators with a substrate layer, the silicon layer where the waveguide structure 210 resides is separated from the substrate layer by only the thickness of the insulating layer 30, which is typically less than 3 μm thick. Furthermore, the substrate layer itself has a certain resistivity (1-3000 ohm-cm), making it a conductor with low electrical conductivity. Furthermore, because the waveguide structure 210 is made of doped silicon, its electrical properties are similar to those of a conductor. This results in the formation of a planar capacitor between the silicon layer where the waveguide structure 210 resides and the substrate layer. This planar capacitor has a large parasitic capacitance, which significantly reduces the bandwidth and impedance of the optical modulator, degrading the performance of the traveling wave electrode modulator. To this end, the novel optical modulation layer provided in the embodiment of the present application removes the original substrate layer, so that the silicon layer where the waveguide structure 210 is located can no longer form a flat plate with the substrate layer. In other words, the parasitic capacitance between the waveguide structure 210 and the substrate is eliminated, avoiding the problem of parasitic capacitance causing the bandwidth and impedance of the optical modulator to be reduced, thereby improving the modulation performance of the optical modulator. In addition, the optical modulator provided in the embodiment of the present application also includes a metal gate layer 60. The metal gate layer 60 includes a metal gate structure 610 arranged periodically along the signal transmission direction of the waveguide structure. This can effectively reduce the transmission speed of the electromagnetic wave. In other words, by slowing down the transmission speed of the electromagnetic wave, the transmission speed of the electromagnetic wave is matched with the transmission speed of light, thereby solving the problem of electro-optical mismatch in the electro-optical modulator and improving the electro-optical bandwidth of the modulator.

[0052] For example, as shown in Figures 3 to 8 , the metal gate layer 60 can be disposed within the second dielectric layer 20 and spaced apart from the first metal layer 220, with the metal gate layer 60 not electrically connected to the first metal layer 60 or the waveguide structure 210. For example, as shown in Figures 9 to 12 , the metal gate layer 60 can also be disposed within the third dielectric layer 40 and spaced apart from the second metal layer 410, that is, the metal gate layer 60 is not electrically connected to the second metal layer 410. For example, as shown in Figure 13 , the metal gate layer 60 can be disposed within the second dielectric layer 20 and the third dielectric layer 40, with the metal gate layer 60 spaced apart from the waveguide structure 210, the first metal layer 220, and the second metal layer 410, respectively. When the metal gate layer 60 is disposed within the second dielectric layer 20 and the third dielectric layer 40, the metal gate layer 60 can have the metal gate layer 60 structure shown in Figures 3 to 12 . It should be noted that Figures 3 to 13 are for illustrative purposes only and are not intended to limit the present application.

[0053] Taking the metal gate layer 60 disposed on the third dielectric layer 40 as an example, as shown in Figures 3 and 4 , the metal gate layer 60 includes a first sub-gate layer 620 and a second sub-gate layer 630. The first sub-gate layer 620 and the second sub-gate layer 630 are symmetrically located on either side of the second metal layer 410, and each includes a plurality of gate structures periodically arranged along the signal transmission direction of the waveguide structure 210. In the embodiment of the present application, the period and duty cycle of the first sub-gate layer 620 and the second sub-gate layer 630 can be designed through simulation to ensure that the transmission speed of the electrical signal is consistent with the transmission speed of the optical signal, without any limitation herein.

[0054] For example, as shown in FIG5 , the second metal layer 410 may include two first sub-metal layers 401 and a second sub-metal layer 402 spaced apart and arranged in parallel, and the first sub-metal layer 401 includes a plurality of first sub-metal layers 401a spaced apart along the signal transmission direction of the waveguide structure 210, and the second sub-metal layer 402 includes a plurality of second sub-metal layers 402a spaced apart along the signal transmission direction of the waveguide structure 210. Each metal gate structure 610 is located in the gap between two adjacent first sub-metal layers 401a and two adjacent second sub-metal layers 402a. It should be noted that the metal gate layer structure 610 may also be provided at any position on either side of the first sub-metal layer 401a and the second sub-metal layer 402a, or between the first sub-metal layer 401a and the second sub-metal layer 402a. The specific arrangement of the metal gate structure 610 is not limited herein, and FIG11 is merely an exemplary illustration.

[0055] For example, as shown in Figures 6 and 7 , when the optical modulator includes at least two second metal layers 410, the at least two second metal layers 410 are electrically connected through vias 50. The metal gate layer 60 may include multiple first sub-gate structures 640 periodically arranged along the signal transmission direction of the waveguide structure 210. Each first sub-gate structure 640 is located in the gap between two adjacent vias 50 above the same second metal layer 410. Each first sub-gate structure 640 is insulated from the vias 50 and each second metal layer 410. For example, the gap period of the vias 50 may be N times the period of the first sub-gate structures 640, where N is a positive integer greater than or equal to 1. For clarity, Figure 13 does not show the third dielectric layer 40.

[0056] Based on the above embodiments and the optical modulator provided in Figures 6 and 7 , illustratively, as shown in Figure 8 , the metal gate layer 60 may further include a plurality of second sub-gate structures 650 periodically arranged along the signal transmission direction of the waveguide structure 210. The first sub-gate structures 640 are disposed on the insulating layer 30, and the first sub-gate structures 640 and the second sub-gate structures 650 are staggered in the signal transmission direction of the waveguide structure 210. This further aligns the electromagnetic wave transmission speed with the optical wave transmission speed, thereby increasing the electro-optical bandwidth of the optical modulator.

[0057] In the optical modulator provided in the above embodiment, the metal gate layer 60 is located within the third dielectric layer 40. Since the metal gate layer 60 has a metal structure periodically arranged along the signal transmission direction of the waveguide structure 210, and the metal gate layer 60 is insulated from the second metal layer 410 within the third dielectric layer 40, the transmission speed of the electromagnetic wave can be effectively slowed down, so that the transmission speed of the electromagnetic wave matches the transmission speed of the light wave, thereby solving the problem of electro-optical mismatch and improving the electro-optical bandwidth of the optical modulator.

[0058] Taking the metal gate layer 60 as an example, as shown in Figures 9 and 10, the metal gate layer 60 may include two symmetrically arranged sub-gate layers, and each sub-gate layer is located on both sides of the first metal layer 220. Optionally, the thickness of each sub-gate layer may be the same as the thickness of the second dielectric layer 20 to reduce the process difficulty and improve the product yield. For a clearer illustration, the third dielectric layer 40 and the first dielectric layer 10 are not shown in Figure 16. For example, as shown in Figures 11 and 12, the metal gate layer 60 may also be located in the lower area of ​​the bottommost first metal layer 210. In particular, for a clearer illustration, the third dielectric layer 40 and the first dielectric layer 10 are not shown in Figure 12.

[0059] In the optical modulator provided in the above embodiment, the metal gate layer 60 is located within the second dielectric layer 20. Since the metal gate layer 60 has a metal structure periodically arranged along the signal transmission direction of the waveguide structure 210, and the metal gate layer 60 is insulated from the second metal layer 410 within the second dielectric layer 20, the transmission speed of the electromagnetic wave can be effectively reduced, that is, the transmission speed of the electromagnetic wave is slowed down, so that the transmission speed of the electrical signal matches the transmission speed of the optical carrier, thereby solving the problem of electro-optical mismatch in the optical modulator and improving the electro-optical bandwidth of the optical modulator.

[0060] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0061] The above-described embodiments merely represent several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be determined by the appended claims.

Claims

1. An optical modulator, characterized in that: include: a first dielectric layer; a second dielectric layer, located on the first dielectric layer, wherein a waveguide structure and a first metal layer are provided in the second dielectric layer, and the waveguide structure is electrically connected to the first metal layer; an insulating layer, located on the second dielectric layer; a third dielectric layer, located on the insulating layer, wherein a second metal layer is provided in the third dielectric layer, and the second metal layer is electrically connected to the first metal layer through a via hole; The metal gate layer includes a plurality of metal gate structures arranged at intervals, each of the metal gate structures is periodically arranged in the signal transmission direction of the waveguide structure, and the metal gate layer is insulated from the first metal layer and the second metal layer respectively.

2. The optical modulator according to claim 1, characterized in that The second metal layer is electrically connected to the waveguide structure through vias and the first metal layer.

3. The optical modulator according to claim 1, wherein: The first dielectric layer is a silicon layer or a glass material layer.

4. The optical modulator according to claim 1, wherein: The first dielectric layer is formed on the second dielectric layer by bonding.

5. The optical modulator according to claim 1, characterized in that The insulating layer and the third dielectric layer are made of the same material.

6. The optical modulator according to claim 1, characterized in that The metal gate layer is disposed in the third dielectric layer and spaced apart from the second metal layer, or the metal gate layer is disposed in the second dielectric layer and spaced apart from the first metal layer.

7. The optical modulator according to claim 1, characterized in that The metal gate layer is disposed on the second dielectric layer and the third dielectric layer, and the metal gate layer is spaced apart from the first metal layer and the second metal layer respectively.

8. The optical modulator according to claim 6 or 7, characterized in that: The metal gate layer includes a first sub-gate layer and a second sub-gate layer; wherein the first sub-gate layer and the second sub-gate layer are symmetrically located on both sides of the second metal layer, and the first sub-gate layer and the second sub-gate layer respectively include multiple gate structures periodically arranged along the signal transmission direction of the waveguide structure.

9. The optical modulator according to claim 6 or 7, characterized in that: The optical modulator includes at least two second metal layers, wherein the at least two second metal layers are electrically connected through vias, and the metal gate layer includes a plurality of first sub-gate structures periodically arranged along the signal transmission direction of the waveguide structure, and each of the first sub-gate structures is located in a gap between two adjacent vias above the same second metal layer.

10. The optical modulator according to claim 9, characterized in that The metal gate layer also includes a plurality of second sub-gate structures periodically arranged along the signal transmission direction of the waveguide structure; wherein each of the first sub-gate structures is disposed on the insulating layer and is staggered with each of the second sub-gate structures in the signal transmission direction of the waveguide structure.

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