On-chip integrated optical modulator and photonic integrated chip

Abstract

An on-chip integrated optical modulator and a photonic integrated chip. The optical modulator comprises a waveguide layer (510), a first dielectric layer (110), a second dielectric layer (120), modulation electrodes, a connection electrode (421), and conductive vias (80). The waveguide layer (510) is provided with a beam-splitting coupler, two modulator-arm waveguides (200, 300), and a beam-combining coupler. The two modulator-arm waveguides (200, 300) are each connected between the beam-splitting coupler and the beam-combining coupler. Signal electrodes (431, 432) and ground electrodes (433, 434, 435) among the modulation electrodes are provided on one side of the waveguide layer (510), and the connection electrode (421) located on the other side of the waveguide layer (510) is used to achieve interconnection between the ground electrodes (433, 434, 435). The interconnection between the ground electrodes (433, 434, 435) does not need to pass through the signal electrodes (431, 432) or transmission structures thereof. Thus, the ground electrodes (433, 434, 435) are interconnected such that the two modulator-arm waveguides (200, 300) of the optical modulator have the same bias voltage without compromising signal transmission performance, thereby improving the modulation speed and modulation bandwidth and enabling compatibility with semiconductor manufacturing processes.

Description

On-chip integrated optical modulator and photonic integrated chip

[0001] This application claims priority to Chinese Patent Application No. 202411209463.9, filed on August 30, 2024, entitled "On-chip Integrated Optical Modulator and Photonic Integrated Chip", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical communication technology, specifically to an on-chip integrated optical modulator and a photonic integrated chip. Background Technology

[0003] Silicon-based optical modulators are core components of on-chip optical logic, optical interconnects, and optical processors, used to convert radio frequency electrical signals into high-speed optical signals. They can form a complete functional network with lasers, detectors, and other wavelength division multiplexing devices.

[0004] Silicon-based optical modulators are characterized by high extinction ratios and ease of integration, and are generally fabricated using SOI (silicon-on-insulator) technology. An SOI-based silicon-based optical modulator typically consists of an optical waveguide load and traveling-wave electrodes. Electromagnetic waves propagate between the traveling-wave electrodes, while the optical carrier propagates within the load waveguide. During the propagation of the optical carrier and electromagnetic waves, the interaction between the electromagnetic waves and the optical carrier causes a phase change in the optical carrier, thus modulating the electrical signal into an optical signal.

[0005] To achieve high-quality signal transmission, reference ground electrodes (G) on different modulation arms can be interconnected. However, since the reference ground electrodes (G) that need to be connected are on the same film layer as the signal electrodes (S), and the signal transmission requires maintaining the continuity of the signal electrodes (S), it is difficult to bypass the signal electrodes in the horizontal direction. Summary of the Invention

[0006] The purpose of this invention is to provide an on-chip integrated optical modulator and a photonic integrated chip.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] According to a first aspect of the present invention, an on-chip integrated optical modulator is provided, comprising:

[0009] The waveguide layer includes a beam splitter, two modulation arm waveguides, and a beam combiner, with the two modulation arm waveguides respectively connected between the beam splitter and the beam combiner.

[0010] A first dielectric layer is stacked on the first side of the waveguide layer;

[0011] A second dielectric layer is stacked on a second side of the waveguide layer, the second side being opposite to the first side;

[0012] A modulation electrode is used to transmit electrical signals to modulate optical signals transmitted within the two modulation arm waveguides; the modulation electrode includes a signal electrode located within the second dielectric layer and at least two ground electrodes;

[0013] A connecting electrode is located within the first dielectric layer, and the at least two ground electrodes are electrically connected through the connecting electrode.

[0014] Multiple conductive vias are used to electrically connect electrodes located in different layers, and the modulation electrode and the conductive vias conductively connected to its signal electrode are all located on the same side of the connecting electrode.

[0015] According to a second aspect of the present invention, an on-chip integrated optical modulator is provided, comprising:

[0016] The waveguide layer includes a beam splitter, two modulation arm waveguides, and a beam combiner. The two modulation arm waveguides are respectively connected between the beam splitter and the beam combiner. Both modulation arm waveguides are doped waveguides and each includes an N-type electrode contact region and a P-type electrode contact region.

[0017] A first dielectric layer is stacked on the first side of the waveguide layer;

[0018] A second dielectric layer is stacked on a second side of the waveguide layer, the second side being opposite to the first side;

[0019] The modulation electrode includes two signal electrodes located within the second dielectric layer. The two signal electrodes are electrically connected to the N-type electrode contact areas of corresponding modulation arm waveguides. The two signal electrodes are used to transmit electrical signals to modulate the optical signals transmitted within the two modulation arm waveguides. The two signal electrodes are configured to have opposite polarities and together form an SS electrode.

[0020] A connecting electrode is located within the first dielectric layer, and the P-type electrode contact areas of the two modulation arm waveguides are electrically connected through the connecting electrode.

[0021] Multiple conductive vias are used to electrically connect electrodes located on different layers, and the signal electrode and the conductive vias conductively connected to it are all located on the same side of the connecting electrode.

[0022] According to a third aspect of the present invention, a photonic integrated chip is provided, comprising the on-chip integrated optical modulator described in any one of the above.

[0023] The on-chip integrated optical modulator and photonic integrated chip of this application place the modulation electrodes, such as signal electrodes and ground electrodes, on one side of the waveguide layer, and use the connecting electrodes located on the other side of the waveguide layer to interconnect the various ground electrodes, so as to ensure that the bias voltage of the first modulation arm waveguide and the second modulation arm waveguide are the same when they are working; that is, the interconnection of the various ground electrodes and the signal transmission of the signal electrodes are located on different sides of the waveguide layer. Therefore, the interconnection of the various ground electrodes does not need to pass through the signal electrodes and their transmission structures, realizing the interconnection of the various ground electrodes so that the bias voltage of the two modulation arm waveguides of the optical modulator is the same, while not destroying the signal transmission performance, thereby improving the modulation rate and modulation bandwidth, and being compatible with semiconductor manufacturing processes, which is conducive to mass production. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other implementation methods can be obtained based on these drawings without creative effort.

[0025] Figure 1A is a top view of a silicon photonic modulator used in a common technology.

[0026] Figure 1B is a schematic diagram of the cross-sectional structure of a silicon optical modulator perpendicular to the waveguide extension direction in a commonly used technology.

[0027] Figure 2A shows a schematic diagram of the cross-sectional structure of an on-chip integrated optical modulator perpendicular to the waveguide extension direction provided in the first embodiment of this application.

[0028] Figure 2B shows a schematic diagram of the cross-sectional structure of another on-chip integrated optical modulator provided in the first embodiment of this application, perpendicular to the waveguide extension direction.

[0029] Figure 3 shows a schematic diagram of the cross-sectional structure of the modulation arm waveguide in Figure 2A.

[0030] Figures 4A-4E are schematic diagrams of the relevant manufacturing processes of the on-chip integrated optical modulator provided according to the first embodiment of this application.

[0031] Figure 5 shows a schematic diagram of the cross-sectional structure of the on-chip integrated optical modulator provided in the second embodiment of this application, perpendicular to the waveguide extension direction.

[0032] Figure 6A shows a schematic diagram of the cross-sectional structure of the first on-chip integrated optical modulator provided in the third embodiment of this application, perpendicular to the waveguide extension direction.

[0033] Figure 6B shows a schematic diagram of the cross-sectional structure of the second type of on-chip integrated optical modulator provided in the third embodiment of this application, perpendicular to the waveguide extension direction.

[0034] Figure 7A shows a schematic diagram of the cross-sectional structure of the third type of on-chip integrated optical modulator provided in the third embodiment of this application, perpendicular to the waveguide extension direction.

[0035] Figure 7B shows a schematic diagram of the cross-sectional structure of the fourth type of on-chip integrated optical modulator provided in the third embodiment of this application, perpendicular to the waveguide extension direction.

[0036] The meanings of the reference numerals in the attached figures are as follows:

[0037] 100, Support substrate; 110, First dielectric layer; 120, Second dielectric layer; 510, Waveguide layer; 200, First modulation arm waveguide; 300, Second modulation arm waveguide; 210, Waveguide region; 220, P-type electrode contact region; 230, N-type electrode contact region; 410, First metal layer; 420, Second metal layer; 430, Third metal layer; 421, Connecting electrode; 411, First electrode; 412, Second electrode; 413, Third electrode; 414, Fourth electrode; 415, Fifth electrode; 431, First signal electrode; 432, Second signal electrode; 433, First ground electrode; 434, Second ground electrode; 435, Third ground electrode; 80, Conductive via.

[0038] 601, Substrate layer; 602, Buried oxide layer; 603, Semiconductor layer; 10, Ridge; 21, First plate portion; 22, Second plate portion. Detailed Implementation

[0039] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. The term "chip" in this document can include a bare die. When referring to method steps, the sequence of steps illustrated herein represents an exemplary scheme but does not imply a limitation on the order. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] To make the objectives, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Figure 1A is a top view of a silicon optical modulator in a commonly used technology, and Figure 1B is a cross-sectional view of a silicon optical modulator in a commonly used technology perpendicular to the waveguide extension direction.

[0043] Please refer to Figures 1A-1B. In this commonly used technology, the electrode structure of the silicon photonic modulator is a GSSG structure adapted for differential signals. Light enters from one end and, after passing through a beam splitting structure (such as a Y-branch or a multimode interference (MMI) coupler), is split into two beams of equal proportion. These beams enter the first modulation arm waveguide 200' and the second modulation arm waveguide 300', respectively. The two beams are modulated within their respective modulation arm waveguides and then combined by the beam combining structure at the output end to form a single modulated optical signal. In each modulation arm waveguide, the PN junction is typically a gradient doping structure with decreasing doping concentrations of P++, P+, P and N++, N+, N. The P++ doped region is connected to the outer ground electrode (G) via a conductive via, and the N++ doped region is connected to the signal electrode (S) via a conductive via. The modulation electrode is positioned along the modulation arm waveguide, and the electrical signal is modulated and loaded into the optical signal via the modulation electrode.

[0044] In the electrode structure of silicon photonic modulators, the interconnection of different electrodes is crucial for achieving high-quality signal transmission. For example, the ground electrodes (G) or reference ground electrodes can be interconnected to ensure that the bias voltage of the two modulation arm waveguides is the same during operation, so that the reference ground of the differential signal always maintains the same potential during transmission, thereby effectively mitigating signal distortion. However, since the ground electrodes (G) that need to be connected are located on the same film layer as the signal electrodes (S), and the signal transmission requires maintaining the continuity of the signal electrodes (S), it is difficult to bypass the signal electrodes in the horizontal direction.

[0045] Therefore, there are currently two solutions:

[0046] The first method involves making an "air bridge" connection from above the outer ground electrode (G) that needs to be connected. However, in the manufacturing process of silicon photonic modulators, it is necessary to be compatible with CMOS manufacturing processes, which the "air bridge" method cannot be used with.

[0047] The second approach uses a multilayer electrode structure for the silicon photonic modulator. The signal is primarily transmitted through a thicker metal layer at the top. At least one thinner metal layer is placed between the top electrode and the silicon substrate. Connections between metal layers and between metal layers and the silicon substrate are made vias. These vias are elongated conductive trenches that are electrically connected to the modulation electrode throughout its extension direction, with a length approximately equal to the length of the modulation electrode. Taking the GSGSG structure as an example, to maintain the continuity of the top metal layer, a technique is used to periodically cut the thin metal layer below the signal electrode to create gaps, allowing the ground electrodes (G) on both sides to be electrically interconnected through these gaps. However, in these gaps, a certain electrostatic capacitance is formed between the top metal layer of the signal electrode (S) and the thin metal layer below it, as well as between the thin metal layers containing the ground electrodes (G) passing through the gaps. This significantly affects the microwave signal transmission performance, thus impacting the bandwidth. Furthermore, the signal electrode at the gap still has some defects, affecting the electric field in the corresponding modulation arm waveguide PN junction, thereby reducing modulation efficiency.

[0048] In view of this, this application provides an on-chip integrated optical modulator to interconnect the various ground electrodes (G) that need to be connected, without having to pass through the signal electrodes and their transmission structures, thus maintaining the continuity of the signal electrodes (S).

[0049] The on-chip integrated optical modulator provided in this application places the signal electrode and ground electrode, among other modulation electrodes, on one side of the waveguide layer. Interconnection between the ground electrodes is achieved using connecting electrodes located on the other side of the waveguide layer, ensuring that the bias voltages of the first and second modulation arm waveguides are the same during operation. That is, the interconnection of the ground electrodes and the signal transmission of the signal electrodes are located on different sides of the waveguide layer. Therefore, the interconnection of the ground electrodes does not need to pass through the signal electrode and its transmission structure, achieving interconnection of the ground electrodes to ensure that the bias voltages of the two modulation arms of the modulator are the same, without compromising signal transmission performance. Furthermore, it is compatible with semiconductor manufacturing processes, facilitating mass production.

[0050] The specific structure will be described in detail in the following embodiments. Example

[0051] As shown in Figures 2A and 2B, the electrode structure of the on-chip integrated optical modulator provided in the first embodiment of this application is an SS electrode structure adapted to differential signals, omitting the ground electrode (G). Specifically, the on-chip integrated optical modulator of this embodiment includes a waveguide layer 510, a first dielectric layer 110, a second dielectric layer 120, a modulation electrode, a connection electrode 421, and a plurality of conductive vias 80.

[0052] Referring to Figures 2A and 2B, waveguide layer 510 includes a splitter coupler, two modulation arm waveguides, and a combining coupler. The two modulation arm waveguides are connected between the splitter coupler and the combining coupler, respectively, for transmitting two optical signals. In this embodiment, both modulation arm waveguides are doped waveguides and each includes an N-type electrode contact region 230 and a P-type electrode contact region 220. A first dielectric layer 110 is stacked on the first side of waveguide layer 510. A second dielectric layer 120 is stacked on the second side of waveguide layer 510, opposite to the first side. The modulation electrodes include two signal electrodes located within the second dielectric layer 120. The two signal electrodes are electrically connected to the corresponding N-type electrode contact regions 230 of the modulation arm waveguides, respectively. The two signal electrodes are used to transmit electrical signals to modulate the optical signals transmitted within the two modulation arm waveguides. In this embodiment, the two signal electrodes are configured with opposite polarities to jointly form an SS electrode. The connecting electrode 421 is located within the first dielectric layer 110, and the P-type electrode contact areas 220 of the two modulation arm waveguides are electrically connected through the connecting electrode 421. Multiple conductive vias 80 are used to electrically connect electrodes located in different layers, and the signal electrode and the conductive via 80 conductively connected to it are all located on the same side of the connecting electrode 421.

[0053] The two modulation arm waveguides are designated as first modulation arm waveguide 200 and second modulation arm waveguide 300, respectively. The two signal electrodes are designated as first signal electrode 431 and second signal electrode 432, respectively, with opposite polarities. First signal electrode 431 is connected to the N-type doped region of first modulation arm waveguide 200, and second signal electrode 432 is connected to the N-type doped region of second modulation arm waveguide 300, thereby transmitting two electrical signals with opposite polarities. The P-type doped regions of first modulation arm waveguide 200 and second modulation arm waveguide 300 are interconnected via connecting electrode 421 to lock the potential of the P-type doped regions of both waveguides, ensuring that the bias voltages of first and second modulation arm waveguides are the same during operation, thus mitigating signal distortion.

[0054] For example, the aforementioned optical splitter is a one-to-two splitter coupler, and the optical combiner is a two-to-one coupler. Two modulation arm waveguides are arranged side-by-side and connected between the optical splitter and the optical combiner, respectively. A first dielectric layer 110 is stacked on the first side of the waveguide layer 510, covering one side of the first modulation arm waveguide 200 and the second modulation arm waveguide 300. A second dielectric layer 120 is stacked on the second side of the waveguide layer 510, opposite to the first side.

[0055] For example, the optical modulator can be a silicon-based optical modulator, wherein the first dielectric layer 110 is silicon dioxide or silicon oxynitride, the second dielectric layer 120 is silicon dioxide or silicon oxynitride, and the waveguide layer 510 is a silicon layer, that is, both the first modulation arm waveguide 200 and the second modulation arm waveguide 300 are doped silicon waveguides.

[0056] Specifically, as shown in Figure 3, taking a silicon waveguide optical modulator as an example, both the first modulation arm waveguide 200 and the second modulation arm waveguide 300 include a waveguide region 210 and P-type electrode contact regions 220 and N-type electrode contact regions 230 located on both sides of the waveguide region 210. The waveguide region 210 includes a ridge 10 and a first plate portion 21 and a second plate portion 22 located on opposite sides of the ridge 10. The P-type electrode contact region 220 is connected to the side of the first plate portion 21 that is relatively far from the ridge 10, and the N-type electrode contact region 230 is connected to the side of the second plate portion 22 that is relatively far from the ridge 10.

[0057] In the modulation section of the optical modulator, the ridge 10 includes a P-type doped region (P) and an N-type doped region (N), which are connected to form a depletion region located in the ridge 10. In some embodiments, the first plate portion 21 includes P-doped regions, P+ doped regions, and P++ doped regions with increasing doping concentrations. The second plate portion 22 includes N-doped regions, N+ doped regions, and N++ doped regions with increasing doping concentrations.

[0058] It should be understood that in other embodiments, the doping type of the waveguide region 210 described above may also be other gradient doping types such as P+, P, N, N+, or simply P and N doping.

[0059] It should be noted that in other embodiments of this application, the same doped structure as the modulation arm waveguide in Figure 3 will be used for description, and will not be repeated hereafter.

[0060] Referring to Figures 2A, 2B, and 3, in this embodiment, a first metal layer 410 and a second metal layer 420 are disposed within the first dielectric layer 110, and a third metal layer 430 is disposed within the second dielectric layer 120. The first metal layer 410 is located between the second metal layer 420 and the waveguide layer 510. In the stacking direction, the stacking relationship of each layer is, in sequence, the third metal layer 430, the waveguide layer 510, the first metal layer 410, and the second metal layer 420, wherein the waveguide layer 510, the first metal layer 410, and the second metal layer 420 are located within the first dielectric layer 110, and the third metal layer 430 is located within the second dielectric layer 120. It should be noted that the conductive via 80 is used to electrically connect electrodes located in different layers. Electrodes located in different layers refer to electrodes located in different metal layers such as the first metal layer 410, the second metal layer 420, and the third metal layer 430, as well as the P-type electrode contact area and the N-type electrode contact area of ​​the modulation arm waveguide. An example of this connection relationship will be provided below.

[0061] The first metal layer 410 is provided with a first electrode 411, a second electrode 412, a third electrode 413, and a fourth electrode 414. The first electrode 411 is electrically connected to the P-type electrode contact area 220 of the first modulation arm waveguide 200 via a conductive via 80; the third electrode 413 is electrically connected to the P-type electrode contact area 220 of the second modulation arm waveguide 300 via a conductive via 80; the second electrode 412 is electrically connected to the N-type electrode contact area 230 of the first modulation arm waveguide 200 via a conductive via 80; and the fourth electrode 414 is electrically connected to the N-type electrode contact area 230 of the second modulation arm waveguide 300 via a conductive via 80. Exemplarily, the first electrode 411 and the second electrode 412 both extend along the extension direction of the first modulation arm waveguide 200, and the third electrode 413 and the fourth electrode 414 both extend along the extension direction of the second modulation arm waveguide 300.

[0062] The aforementioned connecting electrode 421 is located in the second metal layer 420. The connecting electrode 421 is electrically connected to the first electrode 411 and the third electrode 413 through the conductive via 80, so that the first electrode 411 is electrically connected to the P-type electrode contact area 220 of the first modulation arm waveguide 200, and the third electrode 413 is electrically connected to the P-type electrode contact area 220 of the second modulation arm waveguide 300.

[0063] The first signal electrode 431 and the second signal electrode 432 are located in the third metal layer 430. The first signal electrode 431 is electrically connected to the second electrode 412 through a conductive via 80, thereby enabling the first signal electrode 431 to be electrically connected to the N-type electrode contact area 230 of the first modulation arm waveguide 200 through the second electrode 412, thus achieving modulation of the optical signal transmitted within the first modulation arm waveguide 200. The second signal electrode 432 is connected to the fourth electrode 414 through a conductive via 80, thereby enabling the second signal electrode 432 to be electrically connected to the N-type electrode contact area 230 of the second modulation arm waveguide 300 through the fourth electrode 414, thus achieving modulation of the optical signal transmitted within the second modulation arm waveguide 300.

[0064] In this embodiment, the first signal electrode 431 and the second signal electrode 432 are constructed as traveling wave electrodes of the SS electrode structure of the optical modulator, having opposite polarities, for transmitting differential electrical signals of opposite polarities. The first electrode 411 and the third electrode 413 are constructed as reference ground electrodes. At this time, the two reference ground electrodes are electrically connected to the P-type electrode contact areas of the two modulation arm waveguides, and these two reference ground electrodes are electrically interconnected through the connecting electrode 421 located in the second metal layer 420, thereby electrically connecting the P-type electrode contact areas of the two modulation arm waveguides. From the equivalent circuit perspective, it is equivalent to connecting two PN junction capacitors in series from the first signal electrode 431 (e.g., S+) to the second signal electrode 432 (e.g., S-). If these two PN junction capacitances are equal, then the capacitance value of the equivalent capacitor after connecting these two PN junction capacitors in series is half the capacitance value of the original single PN junction capacitor. Since the bandwidth of the optical modulator is closely related to the PN junction capacitance, the larger the PN junction capacitance, the smaller the bandwidth of the optical modulator. Therefore, this electrode structure can effectively reduce the transmission loss of microwave signals and significantly improve the bandwidth of the modulator.

[0065] In this embodiment, the N-type electrode contact area 230 of the first modulation arm waveguide 200 is connected to the positive signal via the first signal electrode 431 located in the third metal layer 430, and the N-type electrode contact area 230 of the second modulation arm waveguide 300 is connected to the negative signal via the second signal electrode 432 located in the third metal layer 430. The P-type electrode contact areas 220 of the first and second modulation arm waveguides 200 are electrically interconnected via the connecting electrode 421 located in the second metal layer 420. This ensures that the bias voltages of the first and second modulation arm waveguides 200 are the same during operation, allowing the reference ground of the differential signal to maintain the same potential during transmission, thereby effectively mitigating signal distortion. In other words, the interconnection of the reference ground electrode and the signal transmission of the signal electrode are located on different sides of the waveguide layer 510. The interconnection of the reference ground electrode does not need to pass through the signal electrode and its transmission structure, maintaining the continuity of the signal electrode and thus not compromising signal transmission performance, thereby further improving the modulation rate and modulation bandwidth. Moreover, this electrode structure is compatible with semiconductor manufacturing processes, which is conducive to mass production.

[0066] In this embodiment, as shown in FIG2A, the waveguide regions 210 of the first modulation arm waveguide 200 and the second modulation arm waveguide 300 are doped with PN junctions of the same orientation, forming a PNPN doped structure. In some embodiments, the doped structures of the waveguide regions 210 of the first modulation arm waveguide 200 and the second modulation arm waveguide 300 can also be NP junctions of the same orientation, forming an NPNP doped structure. Correspondingly, the positions of the electrodes connected thereto also need to be adjusted accordingly.

[0067] In some embodiments, as shown in FIG2B, the doping structure of the waveguide region 210 of the first modulation arm waveguide 200 and the second modulation arm waveguide 300 can also be a PN junction or an NP junction with opposite directions, constituting a PNNP doping structure or an NPPN doping structure. Correspondingly, the position of the electrode connected thereto also needs to be adjusted accordingly.

[0068] It should be noted that in the embodiments of this application, the above-mentioned optical modulator can also be provided with more layers of electrode structure, for example, not limited to three metal layers, but can also include three or more electrode layers. The electrodes connected to the P-type electrode contact area 220 of each modulation arm waveguide can be located on any metal layer, while the electrodes connected to the N-type electrode contact area 230 of each modulation waveguide are all located on the same side of the connecting electrode 421, that is, on the side of the connecting electrode 421 close to the waveguide layer 510.

[0069] This application also provides a method for manufacturing an optical modulator based on a back-facing process, which can be used to fabricate the aforementioned optical modulator. For details, please refer to Figures 4A-4E.

[0070] Exemplarily, in the first step, a modulator waveguide is fabricated to form a waveguide layer 510. As shown in Figure 4A, two modulation arm waveguides in an optical modulator can be fabricated based on semiconductor-on-insulator (SOI). In this embodiment, the SOI structure is a silicon-on-insulator (SOI) structure. A silicon waveguide is formed by etching on the silicon layer, and the silicon waveguide is doped to form a doped silicon waveguide, which serves as the modulation arm waveguide.

[0071] Taking a silicon-based optical modulator as an example, the semiconductor-on-insulator may include a substrate layer 601, a buried oxide layer 602, and a semiconductor layer 603 stacked together. The substrate layer 601 is substrate silicon (substrate silicon layer), and the semiconductor layer 603 can be silicon, also known as the top silicon layer. The semiconductor layer 603 can be patterned, etched, deposited, and doped using semiconductor processes to fabricate the waveguide layer 510 of the silicon optical modulator, including the first modulation arm waveguide 200 and the second modulation arm waveguide 300 in the above embodiment.

[0072] The second step involves covering the waveguide layer 510 with a first dielectric layer 110 and fabricating electrodes within the first dielectric layer 110. As shown in Figure 4B, the first dielectric layer 110 is fabricated on the waveguide layer 510 using a complementary metal-oxide-semiconductor (CMOS) process. A first electrode 411, a second electrode 412, a third electrode 413, and a fourth electrode 414 are fabricated on a first metal layer 410 within the first dielectric layer 110. A connecting electrode 421 is fabricated on a second metal layer 420 within the first dielectric layer 110, and conductive vias 80 are fabricated to electrically connect the corresponding electrodes and electrode contact areas.

[0073] The third step involves bonding a support substrate 100 onto the first dielectric layer, as shown in FIG4C. The support substrate 100 is bonded to the surface of the first dielectric layer 110 on the side away from the substrate layer 601 to serve as support for subsequent processes. The support substrate 100 can be a silicon substrate.

[0074] The fourth step involves removing the substrate 601 and thinning the buried oxide layer 602. After bonding the support substrate 100, the entire structure, which includes both the substrate 601 and the support substrate 100, is flipped vertically so that the support substrate 100 is below and the substrate 601 is above, facilitating the removal of the substrate 601. As shown in Figure 4D, the substrate 601 is removed to expose the buried oxide layer 602. Next, the buried oxide layer 602 is thinned, as shown in Figure 4E, by reducing its thickness in the thickness direction to remove most of the buried oxide layer 602, forming a thinned buried oxide layer 602 to protect the structure of the semiconductor layer 603 (waveguide layer 510).

[0075] The fifth step involves covering the thinned buried oxide layer 602 with a second dielectric layer 120 and fabricating electrodes within the second dielectric layer 120. The second dielectric layer 120 is fabricated on the side of the thinned buried oxide layer 602 facing away from the support substrate 100, and a first signal electrode 431 and a second signal electrode 432 are fabricated on the third metal layer 430 within the second dielectric layer 120. At this time, the first metal layer 410 and the second metal layer 420 are located on the front side of the waveguide layer 510 (semiconductor layer 603), and the third metal layer 430 is located on the back side of the waveguide layer 510. The first signal electrode 431 and the second signal electrode 432 of the third metal layer 430 are electrically connected to the corresponding electrodes in the first metal layer 410 from the side of the first metal layer 410 facing away from the second metal layer 420 through conductive vias 80. The first signal electrode 431 and the second signal electrode 432, as signal electrodes, constitute a traveling wave electrode of the SS structure for transmitting differential electrical signals.

[0076] For example, the first dielectric layer 110 and the second dielectric layer 120 are made of silicon dioxide.

[0077] For ease of explanation, the buried oxide layer 602 in the remaining part of the structure of the silicon-based optical modulator is omitted in the accompanying drawings of the various embodiments of this application. Example

[0078] As shown in Figure 5, unlike Embodiment 1, the on-chip integrated optical modulator provided in the second embodiment of this application is a GSSG electrode structure adapted to differential signals.

[0079] The on-chip integrated optical modulator of this embodiment includes a waveguide layer 510, a first dielectric layer 110, a second dielectric layer 120, a modulation electrode 43, a connection electrode 421, and a plurality of conductive vias 80.

[0080] Referring to Figure 5, waveguide layer 510 includes a splitter coupler, two modulation arm waveguides, and a combiner coupler. The two modulation arm waveguides are connected between the splitter coupler and the combiner coupler, respectively, for transmitting two optical signals. A first dielectric layer 110 is stacked on the first side of waveguide layer 510. A second dielectric layer 120 is stacked on the second side of waveguide layer 510, opposite to the first side. Modulation electrode 43 is used to transmit electrical signals to modulate the optical signals transmitted in the two modulation arm waveguides; the modulation electrode includes a signal electrode located in the second dielectric layer 120 and at least two ground electrodes. Connecting electrode 421 is located in the first dielectric layer 110, and each of the at least two ground electrodes is electrically connected through connecting electrode 421. Conductive via 80 is used to electrically connect electrodes located in different layers, and the modulation electrode and the conductive via 80 conductively connected to its signal electrode are both located on the same side of connecting electrode 421.

[0081] The optical splitter is a one-to-two splitter coupler, and the optical combiner is a two-to-one coupler. The two modulation arm waveguides include a first modulation arm waveguide 200 and a second modulation arm waveguide 300, which are arranged side-by-side and connected to the optical splitter and the optical combiner, respectively. A first dielectric layer 110 covers one side of the first modulation arm waveguide 200 and the second modulation arm waveguide 300.

[0082] In this embodiment, a first metal layer 410 and a second metal layer 420 are disposed within the first dielectric layer 110, and a third metal layer 430 is disposed within the second dielectric layer 120. In the stacking direction, the stacking relationship of each layer is, in sequence, the third metal layer 430, the waveguide layer 510, the first metal layer 410, and the second metal layer 420. It should be noted that the conductive via 80 is used to electrically connect electrodes located in different layers. Here, electrodes located in different layers refer to electrodes located in different metal layers such as the first metal layer 410, the second metal layer 420, and the third metal layer 430, as well as the P-type electrode contact area and the N-type electrode contact area of ​​the modulation arm waveguide. An example of this connection relationship will be provided below.

[0083] The aforementioned connection electrode 421 is located in the second metal layer 420, and the signal electrode and at least two ground electrodes are located in the third metal layer 430. In this embodiment, the at least two ground electrodes include a first ground electrode 433 and a second ground electrode 434, and the signal electrodes include a first signal electrode 431 and a second signal electrode 432. In addition to the signal electrode and at least two ground electrodes, the modulation electrode also includes a first electrode 411, a second electrode 412, a third electrode 413, and a fourth electrode 414, all of which are located in the first metal layer 410.

[0084] The first signal electrode 431 is electrically connected to the second electrode 412 through a conductive via 80, and the second signal electrode 432 is electrically connected to the fourth electrode 414 through a conductive via 80; the first ground electrode 433 is electrically connected to the first electrode 411 through a conductive via 80, and the second ground electrode 434 is electrically connected to the third electrode 413 through a conductive via 80.

[0085] In this embodiment, the signal electrodes (S) corresponding to the two modulation arm waveguides of the optical modulator can be applied with the same polarity. In this case, the first ground electrode 433, the first signal electrode 431, the second signal electrode 432, and the second ground electrode 434 together form a traveling wave electrode of the GSSG electrode structure. Two electrical signals are transmitted from the first signal electrode 431 of the first modulation arm waveguide 200 to the corresponding first ground electrode 433, and from the second signal electrode 432 of the second modulation arm waveguide 300 to the corresponding second ground electrode 434, respectively, to modulate the optical signals transmitted within the first and second modulation arm waveguides 200 and 300, respectively.

[0086] Similarly, referring to Figures 3 and 5, a silicon-based optical modulator is used as an example. Both the first modulation arm waveguide 200 and the second modulation arm waveguide 300 are doped silicon waveguides, and both include an N-type electrode contact area 230 and a P-type electrode contact area 220. In this embodiment, the first ground electrode 433 located in the third metal layer 430 is electrically connected to the first electrode 411 located in the first metal layer 410 through a conductive via 80. The first signal electrode 431 is electrically connected to the second electrode 412 through a conductive via 80. The first electrode 411 is then electrically connected to the P-type electrode contact area 220 of the first modulation arm waveguide 200 through a conductive via 80, and the second electrode 412 is then electrically connected to the N-type electrode contact area 230 of the first modulation arm waveguide 200 through a conductive via 80, thereby modulating the optical signal transmitted within the first modulation arm waveguide 200. The second ground electrode 434 located in the third metal layer 430 is electrically connected to the third electrode 413 located in the first metal layer 410 through a conductive via 80. The second signal electrode 432 is electrically connected to the fourth electrode 414 through a conductive via 80. The third electrode 413 is then electrically connected to the P-type electrode contact area 220 of the second modulation arm waveguide 300 through a conductive via 80. The fourth electrode 414 is then electrically connected to the N-type electrode contact area 230 of the second modulation arm waveguide 300 through a conductive via 80, so as to realize the modulation of the optical signal transmitted in the second modulation arm waveguide 300.

[0087] In this embodiment, the first ground electrode 433 and the second ground electrode 434 are electrically interconnected through a connecting electrode 421 located in the second metal layer 420. Specifically, the connecting electrode 421 is electrically connected to the first electrode 411 and the third electrode 413 through a conductive via 80, thereby connecting the first ground electrode 433 and the second ground electrode 434. At this time, the first ground electrode 433 and the second ground electrode 434 have the same potential, ensuring that the bias voltage of the two modulation arm waveguides is the same during operation, thus effectively mitigating signal distortion. Simultaneously, the first ground electrode 433, the first signal electrode 431, the second signal electrode 432, and the second ground electrode 434 are located on one side of the waveguide layer 510, while the connecting electrode 421 is located on the other side of the waveguide layer 510. Furthermore, the conductive vias electrically connected to the two signal electrodes, as well as the first and second electrodes, are all located on the same side of the ground electrode. Therefore, the interconnection of the ground electrodes does not need to pass through the signal electrodes and their transmission structure, maintaining the continuity of the signal electrodes and thus not compromising signal transmission performance, thereby further improving the modulation rate and modulation bandwidth.

[0088] For example, in this embodiment, the waveguide region 210 doping structure of the first modulation arm waveguide 200 and the second modulation arm waveguide 300 is a PN junction with opposite directions, forming a PNNP doping structure, which is connected to the traveling wave electrode structure of the GSSG.

[0089] It should be understood that in other embodiments, the above-described GSSG electrode structure can also be applied to optical modulators made of other semiconductor materials, such as silicon nitride, lithium niobate, etc. For example, in the case of a lithium niobate optical modulator, both modulation arm waveguides are lithium niobate waveguides, which are undoped. The first electrode 411 and the second electrode 412 are respectively close to the first modulation arm waveguide 200, so that the first modulation arm waveguide 200 is in the electric field between the first electrode 411 and the second electrode 412. By changing the electric field strength between the first electrode 411 and the second electrode 412, the refractive index of the first modulation arm waveguide 200 is changed, thereby modulating the optical signal transmitted in the first modulation arm waveguide 200. Similarly, the third electrode 413 and the fourth electrode 414 are respectively close to the second modulation arm waveguide 300. By changing the electric field strength between the third electrode 413 and the fourth electrode 414, the refractive index of the second modulation arm waveguide 300 is changed, thereby modulating the optical signal transmitted in the second modulation arm waveguide 300. Example

[0090] As shown in Figures 6A-7B, the on-chip integrated optical modulator provided in the third embodiment of this application is a GGSSG electrode structure adapted to differential signals. In this GGSSG electrode structure, a signal electrode (S) is loaded with a doped PN junction between itself and a ground electrode (G) on one side, while it is either unloaded or loaded with an undoped silicon plate between itself and the ground electrode (G) on the other side, forming an asymmetric structure. In order to ensure high-quality signal transmission, all ground electrodes (G) in the optical modulator still need to be interconnected.

[0091] This embodiment is structurally similar to the second embodiment, the only difference being that the electrode structure in this embodiment is a GSGSG traveling wave electrode. Therefore, compared to the second embodiment, the modulation electrodes of the optical modulator in this embodiment further include a third ground electrode 435 and a fifth electrode 415, wherein the third ground electrode 435 is located in the third metal layer 430, and the fifth electrode 415 is located in the first metal layer 410. The first signal electrode 431 is electrically connected to the second electrode 412 through a conductive via 80, and the second signal electrode 432 is electrically connected to the fourth electrode 414 through a conductive via 80; the first ground electrode 433 is electrically connected to the first electrode 411 through a conductive via 80, the second ground electrode 434 is electrically connected to the third electrode 413 through a conductive via 80, and the third ground electrode 435 is electrically connected to the fifth electrode 415 through a conductive via 80. The third ground electrode 435 is electrically connected to the first ground electrode 433 and the second ground electrode 434 through a connecting electrode 421.

[0092] In this embodiment, the signal electrodes (S) corresponding to the two modulation arm waveguides of the optical modulator can be applied with the same polarity. At this time, the first signal electrode 431, the first ground electrode 433, the second signal electrode 432, the second ground electrode 434, and the third ground electrode 435 together form a GGSSG electrode structure. Electrical signals are transmitted from the first signal electrode 431 of the first modulation arm waveguide 200 of the optical modulator to the corresponding first ground electrode 433, and from the second signal electrode 432 of the second modulation arm waveguide 300 of the optical modulator to the corresponding second ground electrode 434. The third ground electrode 435 is unloaded and electrically connected to the first ground electrode 433 and the second ground electrode 434 via a connecting electrode 421.

[0093] Similar to Embodiment 2, a silicon-based optical modulator is used as an example for illustration. Both the first modulation arm waveguide 200 and the second modulation arm waveguide 300 are silicon-doped waveguides, and both include an N-type electrode contact area 230 and a P-type electrode contact area 220. In this embodiment, the first ground electrode 433 located in the third metal layer 430 is electrically connected to the first electrode 411 located in the first metal layer 410 through a conductive via 80. The first signal electrode 431 is electrically connected to the second electrode 412 through a conductive via 80. The first electrode 411 is then electrically connected to the P-type electrode contact area 220 of the first modulation arm waveguide 200 through a conductive via 80, and the second electrode 412 is then electrically connected to the N-type electrode contact area 230 of the first modulation arm waveguide 200 through a conductive via 80, thereby modulating the optical signal transmitted within the first modulation arm waveguide 200. The second ground electrode 434, located in the third metal layer 430, is electrically connected to the third electrode 413, located in the first metal layer 410, through a conductive via 80. The second signal electrode 432 is electrically connected to the fourth electrode 414, located in the first metal layer 410, through a conductive via 80. The third electrode 413 is then electrically connected to the P-type electrode contact area 220 of the second modulation arm waveguide 300 through a conductive via 80. The fourth electrode 414 is then electrically connected to the N-type electrode contact area 230 of the second modulation arm waveguide 300 through a conductive via 80, thereby modulating the optical signal transmitted within the second modulation arm waveguide 300. The third ground electrode 435, located in the third metal layer 430, is electrically connected to the fifth electrode 415, located in the first metal layer 410, through a conductive via 80.

[0094] The fifth electrode 415 located in the first metal layer 410 does not contact the modulation arm waveguide, so the third ground electrode 435 is suspended and unloaded.

[0095] In this embodiment, the first ground electrode 433, the second ground electrode 434, and the third ground electrode 435 are electrically interconnected through a connecting electrode 421 located in the second metal layer 420. Specifically, the connecting electrode 421 is electrically connected to the first electrode 411, the third electrode 413, and the fifth electrode 415 through a conductive via 80, so that the first ground electrode 433, the second ground electrode 434, and the third ground electrode 435 are electrically connected. At this time, the first ground electrode 433, the second ground electrode 434, and the third ground electrode 435 have the same potential, ensuring that the bias voltage of the two modulation arm waveguides is the same when they are working, thereby effectively mitigating signal distortion. At the same time, the first ground electrode 433, the first signal electrode 431, the second signal electrode 432, the second ground electrode 434, and the third ground electrode 435 are located on one side of the waveguide layer 510, while the connecting electrode 421 is located on the other side of the waveguide layer 510. The interconnection of the ground electrodes does not need to pass through the signal electrodes and their transmission structure, maintaining the continuity of the signal electrodes. Therefore, it does not damage the signal transmission performance, thereby further improving the modulation rate and modulation bandwidth.

[0096] In this embodiment, as shown in FIG6A, the waveguide region 210 of the first modulation arm waveguide 200 and the second modulation arm waveguide 300 has a PNPN structure. Correspondingly, the third ground electrode 435 is located on the side of the second modulation arm waveguide 300 away from the first modulation arm waveguide 200. That is, the electrode arrangement order is the first ground electrode 433, the first signal electrode 431, the second ground electrode 434, the second signal electrode 432, and the third ground electrode 435. The first modulation arm waveguide 200 is located between the first ground electrode 433 and the first signal electrode 431, and the second modulation arm waveguide 300 is located between the second ground electrode 434 and the second signal electrode 432.

[0097] For example, as shown in FIG6B, in this embodiment, the doped structure of the waveguide region 210 of the first modulation arm waveguide 200 and the second modulation arm waveguide 300 can also be an NPNP structure. Correspondingly, the third ground electrode 435 is located on the side of the first modulation arm waveguide 200 away from the second modulation arm waveguide 300. That is, the electrode arrangement order is the third ground electrode 435, the first signal electrode 431, the first ground electrode 433, the second signal electrode 432, and the second ground electrode 434. The first modulation arm waveguide 200 is located between the first ground electrode 433 and the first signal electrode 431, and the second modulation arm waveguide 300 is located between the second ground electrode 434 and the second signal electrode 432.

[0098] For example, as shown in FIG7A, in this embodiment, the doped structure of the waveguide region 210 of the first modulation arm waveguide 200 and the second modulation arm waveguide 300 can also be a PNNP structure. Correspondingly, the third ground electrode 435 is located between the first modulation arm waveguide 200 and the second modulation arm waveguide 300. That is, the electrode arrangement order is the first ground electrode 433, the first signal electrode 431, the third ground electrode 435, the second signal electrode 432, and the second ground electrode 434. The first modulation arm waveguide 200 is located between the first ground electrode 433 and the first signal electrode 431, and the second modulation arm waveguide 300 is located between the second ground electrode 434 and the second signal electrode 432.

[0099] For example, as shown in FIG7B, the doping structure of the waveguide region 210 of the first modulation arm waveguide 200 and the second modulation arm waveguide 300 in this embodiment can also be an NPPN structure.

[0100] Accordingly, the first ground electrode 433 is configured as a shared ground electrode for the two modulation arm waveguides, located between the two modulation arm waveguides. The second ground electrode 434 and the third ground electrode 435 are configured as unloaded. The third ground electrode 435 and the first signal electrode 431 are located on the side of the first modulation arm waveguide 200 away from the first ground electrode 433, and the second ground electrode 434 and the second signal electrode 432 are located on the side of the second modulation arm waveguide 300 away from the first ground electrode 433. That is, the electrode arrangement order is as follows: third ground electrode 435, first signal electrode 431, first ground electrode 433, second signal electrode 432, and second ground electrode 434. The first modulation arm waveguide 200 is located between the first signal electrode 431 and the first ground electrode 433, and the second modulation arm waveguide 300 is located between the first ground electrode 433 and the second signal electrode 432.

[0101] Specifically, the first ground electrode 433 and the first signal electrode 431 are electrically connected to the first electrode 411 and the second electrode 412 respectively through conductive vias, and act on the first modulation arm waveguide 200 through the first electrode 411 and the second electrode 412 to modulate the optical signal transmitted in the first modulation arm waveguide 200. The first ground electrode 433 and the second signal electrode 432 are electrically connected to the first electrode 411 and the fourth electrode 414 respectively through conductive vias, and act on the second modulation arm waveguide 300 through the first electrode 411 and the fourth electrode 414 to modulate the optical signal transmitted in the second modulation arm waveguide 300. The second ground electrode 434 is electrically connected to the third electrode 413 through a conductive via, the third ground electrode 435 is electrically connected to the fifth electrode 415 through a conductive via, and the connecting electrode 421 is electrically connected to the first electrode 411, the third electrode 413, and the fifth electrode 415 through a conductive via 80, so that the first ground electrode 433, the second ground electrode 434, and the third ground electrode 435 are electrically connected.

[0102] In this embodiment, the second ground electrode 434 and the third electrode 413 overlap in projection along each layer stacking direction, and the third ground electrode 435 and the fifth electrode 415 overlap in projection to save wiring space.

[0103] For example, similar to Embodiment 2, the waveguide layer 510 of the optical modulator can be a silicon layer, a lithium niobate layer, or a silicon nitride layer, etc. Please refer to Embodiment 2 for details, which will not be repeated here.

[0104] According to another aspect of the present invention, a photonic integrated chip is proposed, including an on-chip integrated optical modulator according to any embodiment of the present application.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent variations and modifications made in accordance with the shape, structure, features and spirit described in the claims of the present invention should be included within the scope of the claims of the present invention.

Claims

1. An on-chip integrated optical modulator, characterized in that, include: The waveguide layer includes a beam splitter, two modulation arm waveguides, and a beam combiner, with the two modulation arm waveguides respectively connected between the beam splitter and the beam combiner. A first dielectric layer is stacked on the first side of the waveguide layer; A second dielectric layer is stacked on a second side of the waveguide layer, the second side being opposite to the first side; Modulation electrodes are used to transmit electrical signals to modulate optical signals transmitted within the two modulation arm waveguides; The modulation electrode includes a signal electrode located within the second dielectric layer and at least two ground electrodes; A connecting electrode is located within the first dielectric layer, and the at least two ground electrodes are electrically connected through the connecting electrode. Multiple conductive vias are used to electrically connect electrodes located in different layers, and the modulation electrode and the conductive vias conductively connected to its signal electrode are all located on the same side of the connecting electrode.

2. The on-chip integrated optical modulator as described in claim 1, characterized in that, The first dielectric layer contains a first metal layer and a second metal layer, the second dielectric layer contains a third metal layer, and the first metal layer is located between the second metal layer and the waveguide layer. The connection electrode is located in the second metal layer, and the signal electrode and the at least two ground electrodes are located in the third metal layer; The modulation electrode further includes a first electrode, a second electrode, a third electrode, and a fourth electrode located in the first metal layer; the signal electrode includes a first signal electrode and a second signal electrode; and the at least two ground electrodes include a first ground electrode and a second ground electrode. The first ground electrode is electrically connected to the first electrode through the conductive via, the first signal electrode is electrically connected to the second electrode through the conductive via, the second ground electrode is electrically connected to the third electrode through the conductive via, and the second signal electrode is electrically connected to the fourth electrode through the conductive via.

3. The on-chip integrated optical modulator as described in claim 2, characterized in that, The connecting electrode is electrically connected to the first electrode and the third electrode through the conductive via, thereby electrically connecting the first ground electrode and the second ground electrode.

4. The on-chip integrated optical modulator as described in claim 2, characterized in that, The first signal electrode and the second signal electrode are configured to have the same polarity, and the first signal electrode, the first ground electrode, the second signal electrode and the second ground electrode together constitute a GSSG electrode structure.

5. The on-chip integrated optical modulator as described in claim 2, characterized in that, The modulation electrode further includes a third ground electrode and a fifth electrode. The third ground electrode is located in the third metal layer, and the fifth electrode is located in the first metal layer. The third ground electrode is electrically connected to the fifth electrode through the conductive via. The third grounding electrode is electrically connected to the first grounding electrode and the second grounding electrode through the connecting electrode.

6. The on-chip integrated optical modulator as described in claim 5, characterized in that, The connecting electrode is electrically connected to the first electrode, the third electrode, and the fifth electrode through the conductive via, thereby electrically connecting to the first ground electrode, the second ground electrode, and the third ground electrode.

7. The on-chip integrated optical modulator as described in claim 5, characterized in that, The first signal electrode and the second signal electrode are configured to have the same polarity, and the first signal electrode, the first ground electrode, the second signal electrode, the second ground electrode and the third ground electrode together constitute a GGSSG electrode.

8. The on-chip integrated optical modulator as described in claim 7, characterized in that, The two modulation arm waveguides include a first modulation arm waveguide and a second modulation arm waveguide; The first ground electrode and the first signal electrode are located on both sides of the first modulation arm waveguide, the second signal electrode and the second ground electrode are located on both sides of the second modulation arm waveguide, and the third ground electrode is configured to be unloaded and located between the first signal electrode and the second signal electrode.

9. The on-chip integrated optical modulator as described in claim 7, characterized in that, The two modulation arm waveguides include a first modulation arm waveguide and a second modulation arm waveguide; The first ground electrode is configured as a common ground electrode for the two modulation arm waveguides and is located between the two modulation arm waveguides. The second ground electrode and the third ground electrode are configured to be unloaded. The third ground electrode and the first signal electrode are located on the side of the first modulation arm waveguide away from the first ground electrode, and the second ground electrode and the second signal electrode are located on the side of the second modulation arm waveguide away from the first ground electrode.

10. The on-chip integrated optical modulator as described in claim 1, characterized in that, The waveguide layer is a silicon layer or a lithium niobate layer.

11. The on-chip integrated optical modulator as described in claim 1, characterized in that, The waveguide layer is a silicon layer, and the two modulation arm waveguides include a first modulation arm waveguide and a second modulation arm waveguide. Both the first modulation arm waveguide and the second modulation arm waveguide are silicon-doped waveguides and both include an N-type electrode contact area and a P-type electrode contact area. The number of signal electrodes is two, one of which is electrically connected to the N-type electrode contact area of ​​the first modulation arm waveguide, and the other is electrically connected to the N-type electrode contact area of ​​the second modulation arm waveguide. One of the at least two grounding electrodes is electrically connected to the P-type electrode contact area of ​​the first modulation arm waveguide, and the other grounding electrode is electrically connected to the P-type electrode contact area of ​​the second modulation arm waveguide; or, one of the at least two grounding electrodes is electrically connected to the P-type electrode contact areas of both the first and second modulation arm waveguides, and the other grounding electrode is configured to be unloaded.

12. The on-chip integrated optical modulator as described in claim 11, characterized in that, The waveguide regions of the first modulation arm waveguide and the second modulation arm waveguide are doped with PN junctions or NP junctions in the same direction; or, The waveguide regions of the first modulation arm waveguide and the second modulation arm waveguide are doped with PN junctions or NP junctions in opposite directions.

13. An on-chip integrated optical modulator, characterized in that, include: The waveguide layer includes a beam splitter, two modulation arm waveguides, and a beam combiner. The two modulation arm waveguides are respectively connected between the beam splitter and the beam combiner. Both modulation arm waveguides are doped waveguides and each includes an N-type electrode contact region and a P-type electrode contact region. A first dielectric layer is stacked on the first side of the waveguide layer; A second dielectric layer is stacked on a second side of the waveguide layer, the second side being opposite to the first side; The modulation electrode includes two signal electrodes located within the second dielectric layer. The two signal electrodes are respectively electrically connected to the N-type electrode contact areas of the corresponding modulation arm waveguides. The two signal electrodes are used to transmit electrical signals to modulate the optical signals transmitted in the two modulation arm waveguides. The two signal electrodes are configured to have opposite polarities and together form an SS electrode; A connecting electrode is located within the first dielectric layer, and the P-type electrode contact areas of the two modulation arm waveguides are electrically connected through the connecting electrode. Multiple conductive vias are used to electrically connect electrodes located on different layers, and the signal electrode and the conductive vias conductively connected to it are all located on the same side of the connecting electrode.

14. The on-chip integrated optical modulator as described in claim 13, characterized in that, The two modulation arm waveguides include a first modulation arm waveguide and a second modulation arm waveguide; The first dielectric layer contains a first metal layer and a second metal layer, the second dielectric layer contains a third metal layer, and the first metal layer is located between the second metal layer and the waveguide layer. The connection electrode is located in the second metal layer, and the two signal electrodes are located in the third metal layer; The first metal layer is provided with a first electrode, a second electrode, a third electrode and a fourth electrode. The first electrode and the third electrode are electrically connected to the P-type electrode contact areas of the first modulation arm waveguide and the second modulation arm waveguide respectively through conductive vias. The second electrode and the fourth electrode are electrically connected to the N-type electrode contact areas of the first modulation arm waveguide and the second modulation arm waveguide respectively through conductive vias. The two signal electrodes are electrically connected to the second electrode and the fourth electrode respectively through the conductive via, so as to electrically connect the N-type electrode contact areas of the first modulation arm waveguide and the second modulation arm waveguide respectively through the second electrode and the fourth electrode. The connecting electrodes are electrically connected to the first electrode and the third electrode respectively through conductive vias, so as to electrically connect the P-type electrode contact areas of the first modulation arm waveguide and the second modulation arm waveguide through the first electrode and the third electrode.

15. The on-chip integrated optical modulator as described in claim 13, characterized in that, The waveguide regions of the two modulation arm waveguides are doped with PN or NP junctions in the same orientation; or, The waveguide regions of the two modulation arm waveguides are doped with PN junctions or NP junctions in opposite directions.

16. A photonic integrated chip, characterized in that, The photonic integrated chip includes an on-chip integrated optical modulator as described in any one of claims 1-12 or 13-15.

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