Traveling wave electrode terminal impedance matching system of silicon-based optical modulator and silicon-based optical modulator

Abstract

The utility model provides a silicon-based light modulator traveling wave electrode terminal impedance matching system and a silicon-based light modulator, the silicon-based light modulator comprises a substrate, an oxide layer, a doped polycrystalline silicon layer and a first connecting electrode arranged on the first surface of the substrate, the oxide layer is in contact with the first surface of the substrate, and the doped polycrystalline silicon layer is in contact with the first connecting electrode. The second connecting electrode is arranged on the first surface of the doped polycrystalline silicon layer, and the first surface of the doped polycrystalline silicon layer is far away from the oxide layer; the doped polycrystalline silicon layer has a target resistance value matched with the characteristic impedance of a first traveling wave electrode and a second traveling wave electrode in the silicon-based light modulator; the first connecting electrode is connected with the first traveling wave electrode, the second connecting electrode is connected with the second traveling wave electrode, and the first connecting electrode and the second connecting electrode are used for transmitting high-frequency signals transmitted on the traveling wave electrodes, impedance matching of alternating-current components in the high-frequency signals and target resistance values and transmission isolation of direct-current components in the high-frequency signals. The terminal impedance matching system provided by the utility model can realize integration with the traveling wave electrode on the basis of solving the problem of direct current power consumption in the silicon-based light modulator.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical modulators, and in particular to a silicon-based optical modulator traveling wave electrode terminal impedance matching system and a silicon-based optical modulator. Background Art

[0002] Optical modulator is an important device that converts electrical signals into optical signals for easy transmission. Therefore, it is very important to prepare electro-optical modulators with larger bandwidth, lower loss and high integration. Silicon-based optical modulator is an optical modulator that uses electric field to change the refractive index of light. It is widely used in optical communication, optical switching, optical storage, microwave optoelectronic transmission and other fields.

[0003] Typically, silicon-based optical modulators use plasma dispersion effects and traveling wave electrodes to achieve electro-optical modulation. Silicon-based optical modulators operate in a reverse biased state of the PN junction, and need to add a DC component to the high-frequency modulation signal. Therefore, the driving voltage usually includes an AC voltage and a DC bias voltage. In addition, in order to avoid reflection of the high-frequency modulation signal, an impedance matching resistor is usually added to the terminal of the traveling wave electrode for terminal impedance matching. The DC bias voltage will generate power consumption through the terminal matching resistor of the traveling wave electrode. In order to avoid this additional power consumption, an isolation DC capacitor is usually integrated at the terminal matching resistor.

[0004] In traditional solutions, metal plate capacitors (MIM) are usually used. However, since the required capacitance value is large, in order to provide sufficient capacitance value, the size of the metal plate capacitor is also large. At this time, the isolation DC capacitor cannot be well integrated with the traveling wave electrode of the silicon-based optical modulator, thereby affecting the efficacy of the silicon-based optical modulator. Utility Model Content

[0005] The embodiments of the present application provide a silicon-based optical modulator traveling wave electrode terminal impedance matching system and a silicon-based optical modulator, which are used to solve the problem in traditional solutions that the DC power consumption and traveling wave electrode integration in the silicon-based optical modulator cannot be adapted.

[0006] In a first aspect, an embodiment of the present application provides a silicon-based optical modulator traveling wave electrode terminal impedance matching system, comprising a substrate, an oxide layer, a doped polysilicon layer, a first connecting electrode arranged on a first surface of the substrate, wherein the oxide layer contacts the first surface of the substrate, and a second connecting electrode arranged on a first surface of the doped polysilicon layer, wherein the first surface of the doped polysilicon is away from the oxide layer;

[0007] Among them, the doped polysilicon layer has a target resistance value that matches the characteristic impedance of the first traveling wave electrode and the second traveling wave electrode in the silicon-based optical modulator; the first connecting electrode is connected to the first traveling wave electrode, and the second connecting electrode is connected to the second traveling wave electrode, which are used to transmit the high-frequency signal transmitted on the first traveling wave electrode and the second traveling wave electrode, and the AC component in the high-frequency signal matches the impedance of the target resistance value. The substrate, the oxide layer and the doped polysilicon layer constitute a metal-oxide-semiconductor capacitor, which is used to isolate the transmission of the DC component in the high-frequency signal.

[0008] Optionally, the substrate comprises an N-type heavily doped SOI substrate, and the doped polysilicon layer comprises a P-type heavily doped polysilicon layer;

[0009] Alternatively, the substrate comprises a P-type heavily doped SOI substrate, and the doped polysilicon layer comprises an N-type heavily doped polysilicon layer.

[0010] Optionally, the heavily doped SOI substrate includes doped top silicon;

[0011] The oxide layer is disposed in a first region on the upper surface of the top silicon layer, and the first connecting electrode is disposed in a second region on the upper surface of the top silicon layer.

[0012] Optionally, the aspect ratio of the heavily doped polysilicon layer is adjustable.

[0013] Optionally, the oxide layer includes a gate oxide layer.

[0014] Optionally, one end of the second traveling wave electrode in contact with the second connecting electrode gradually increases in size toward an extending direction from the second traveling wave electrode to the second connecting electrode.

[0015] In the second aspect, an embodiment of the present application provides a silicon-based optical modulator, comprising a beam splitting structure, a phase shifting structure and a beam combining structure connected in sequence, the phase shifting structure comprising a first modulation arm and a second modulation arm, a first traveling wave electrode and a second traveling wave electrode, and a silicon-based optical modulator traveling wave electrode terminal impedance matching system as described in the first aspect.

[0016] Optionally, a PN junction phase shifter is provided on the first modulation arm;

[0017] The first traveling wave electrode is arranged within a preset range from the first modulation arm, and the second traveling wave electrode is arranged within a non-preset range from the first modulation arm. The first traveling wave electrode works, and the second traveling wave electrode does not work.

[0018] Optionally, a PN junction phase shifter is provided on both the first modulation arm and the second modulation arm;

[0019] The first traveling wave electrode is arranged within a preset range from the first modulation arm, the second traveling wave electrode is arranged within a preset range from the second modulation arm, and both the first traveling wave electrode and the second traveling wave electrode are in operation.

[0020] Optionally, the silicon-based optical modulator further includes an AC power supply and a DC power supply;

[0021] The AC power supply and the DC power supply are both used to supply power to the first traveling wave electrode and the second traveling wave electrode.

[0022] The terminal impedance matching system provided in this embodiment includes a substrate, an oxide layer, a doped polysilicon layer, a first connecting electrode arranged on the first surface of the substrate, the oxide layer is in contact with the first surface of the substrate, and a second connecting electrode is arranged on the first surface of the doped polysilicon layer, and the first surface of the doped polysilicon is far away from the oxide layer, wherein the doped polysilicon layer has a target resistance value that matches the characteristic impedance of the first traveling wave electrode and the second traveling wave electrode in the silicon-based optical modulator, the first connecting electrode is connected to the first traveling wave electrode, and the second connecting electrode is connected to the second traveling wave electrode, and is used to transmit the high-frequency signal transmitted on the first traveling wave electrode and the second traveling wave electrode, the AC component in the high-frequency signal is matched with the impedance of the target resistance value, and the substrate, the oxide layer and the doped polysilicon layer constitute a metal-oxide-semiconductor capacitor, which is used to block the transmission of the DC component in the high-frequency signal. Since the isolated DC capacitor in the terminal impedance matching system adopts the MOS capacitor structure of substrate-oxide layer-doped polysilicon layer, a large amount of capacitance value can be obtained per unit area, thereby greatly reducing the size of the isolated DC capacitor, which is convenient for adapting to the size of the traveling wave electrode in the silicon-based optical modulator. At the same time, the doped polysilicon layer of the MOS capacitor has a target resistance value that matches the characteristic impedance of the traveling wave electrode in the silicon-based optical modulator, and can be directly used as the terminal matching resistor of the traveling wave electrode, thereby realizing the integration of the terminal matching resistor of the traveling wave electrode of the silicon-based optical modulator with the isolated DC capacitor, and realizing integration with the traveling wave electrode on the basis of solving the DC power consumption in the silicon-based optical modulator.

[0023] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1A schematic structural diagram of an embodiment of a silicon-based optical modulator traveling wave electrode terminal impedance matching system provided by the present application is shown;

[0026] Figure 2 A schematic structural diagram of an embodiment of a silicon-based optical modulator provided by the present application is shown;

[0027] Figure 3 The circuit diagram of a silicon-based optical modulator provided by the present application is shown. Figure 1 A schematic diagram of an embodiment;

[0028] Figure 4 A schematic structural diagram of another embodiment of a silicon-based optical modulator provided in the present application is shown. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0030] In some structures described in the specification and claims of this application and the above drawings, multiple structural parts appearing in a specific order are included, and the serial numbers of these structural parts, such as 101, 102, etc., are only used to distinguish different structural parts. It should be noted that the descriptions of "first", "second", etc. in this article are used to distinguish different structural parts, etc., and do not represent the order of precedence, nor do they limit the "first" and "second" to be different types.

[0031] Optical modulator is an important device that converts electrical signals into optical signals for easy transmission. Therefore, it is very important to prepare electro-optical modulators with larger bandwidth, lower loss and high integration. Silicon-based optical modulator is an optical modulator that uses electric field to change the refractive index of light. It is widely used in optical communication, optical switching, optical storage, microwave optoelectronic transmission and other fields.

[0032] Typically, silicon-based optical modulators use plasma dispersion effects and traveling wave electrodes to achieve electro-optical modulation. Silicon-based optical modulators operate in a reverse biased state of the PN junction, and need to add a DC component to the high-frequency modulation signal. Therefore, the driving voltage usually includes an AC voltage and a DC bias voltage. In addition, in order to avoid reflection of the high-frequency modulation signal, an impedance matching resistor is usually added to the terminal of the traveling wave electrode for terminal impedance matching. The DC bias voltage will generate power consumption through the terminal matching resistor of the traveling wave electrode. In order to avoid this additional power consumption, an isolation DC capacitor is usually integrated at the terminal matching resistor.

[0033] In traditional solutions, metal plate capacitors (MIM) are usually used. However, since the required capacitance value is large, in order to provide sufficient capacitance value, the size of the metal plate capacitor is also large. At this time, the isolation DC capacitor cannot be well integrated with the traveling wave electrode of the silicon-based optical modulator, thereby affecting the efficacy of the silicon-based optical modulator.

[0034] Therefore, in order to solve the above technical problems, the inventors have proposed the technical solution of the present application, namely, providing a silicon-based optical modulator traveling wave electrode terminal impedance matching system, comprising a substrate, an oxide layer, a doped polysilicon layer, a first connecting electrode arranged on the first surface of the substrate in sequence from bottom to top, wherein the oxide layer is in contact with the first surface of the substrate, and a second connecting electrode arranged on the first surface of the doped polysilicon layer, wherein the first surface of the doped polysilicon is away from the oxide layer; wherein the doped polysilicon layer has a target resistance value that matches the characteristic impedance of the first traveling wave electrode and the second traveling wave electrode in the silicon-based optical modulator; the first connecting electrode is connected to the first traveling wave electrode, and the second connecting electrode is connected to the second traveling wave electrode, and is used to transmit the high-frequency signal transmitted on the first traveling wave electrode and the second traveling wave electrode, the AC component in the high-frequency signal is matched with the impedance of the target resistance value, and the substrate, the oxide layer and the doped polysilicon layer constitute a metal-oxide-semiconductor capacitor, which is used to block the transmission of the DC component in the high-frequency signal.

[0035] Since the isolated DC capacitor in the terminal impedance matching system adopts the MOS capacitor structure of substrate-oxide layer-doped polysilicon layer, a large amount of capacitance value can be obtained per unit area, thereby greatly reducing the size of the isolated DC capacitor, which is convenient for adapting to the size of the traveling wave electrode in the silicon-based optical modulator. At the same time, the doped polysilicon layer of the MOS capacitor has a target resistance value that matches the characteristic impedance of the traveling wave electrode in the silicon-based optical modulator, and can be directly used as the terminal matching resistor of the traveling wave electrode, thereby realizing the integration of the terminal matching resistor of the traveling wave electrode of the silicon-based optical modulator with the isolated DC capacitor, and realizing integration with the traveling wave electrode on the basis of solving the DC power consumption in the silicon-based optical modulator.

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0037] like Figure 1, shows a schematic structural diagram of a traveling wave electrode terminal impedance matching system of a silicon-based optical modulator in an embodiment, including a substrate 101, an oxide layer 102, a doped polysilicon layer 103, a first connecting electrode 104 arranged on a first surface of the substrate 101, wherein the first surface of the substrate 101 is in contact with the oxide layer 102, and a second connecting electrode 105 arranged on a first surface of the doped polysilicon layer 103, wherein the first surface of the doped polysilicon layer 103 is away from the oxide layer 102.

[0038] The doped polysilicon layer 103 has a target resistance value that matches the characteristic impedance of the first traveling wave electrode and the second traveling wave electrode in the silicon-based optical modulator (not shown).

[0039] The first connecting electrode 104 is connected to the first traveling wave electrode, and the second connecting electrode 105 is connected to the second traveling wave electrode, and is used to transmit the high-frequency signal transmitted on the first traveling wave electrode and the second traveling wave electrode. The AC component in the high-frequency signal is matched with the impedance of the target resistance value of the above-mentioned doped polysilicon layer 103, and the transmission of the DC component in the high-frequency signal is blocked.

[0040] In this embodiment, the silicon-based optical modulator traveling wave electrode terminal impedance matching system can be composed of a MOS capacitor. Specifically, the MOS capacitor can include a lower substrate 101, an upper doped polysilicon layer 103, and an oxide layer 102 located in the middle. Specifically, the MOS capacitor can be used to block the transmission of the DC component in the high-frequency signal.

[0041] In an optional embodiment, the oxide layer 102 can be implemented as a gate oxide layer. Compared with the conventional solution, the oxide thickness in the metal planar capacitor (MIM) reaches hundreds of nm, while the oxide thickness of the gate oxide layer in the MOS capacitor is smaller, only 2-5 nm, so that a large capacitance value can be obtained per unit area, which greatly reduces the size of the isolation DC capacitor and facilitates integration with the traveling wave electrode of the silicon-based optical modulator.

[0042] In addition, the oxide layer 102 may also be made of a high dielectric constant (High-K) dielectric material, which is not limited in the present application.

[0043] Furthermore, the doped polysilicon layer 103 can have a target resistance value that matches the characteristic impedance of the traveling wave electrode, thereby integrating the terminal matching resistor and the isolation DC capacitor of the traveling wave electrode of the silicon-based optical modulator.

[0044] At this time, the first connecting electrode 104 in the terminal impedance matching system is connected to the first traveling wave electrode, and the second connecting electrode 105 is connected to the second traveling wave electrode, so that the high-frequency signals on the first traveling wave electrode and the second traveling wave electrode are transmitted. Through the terminal impedance matching structure of the above structure, the AC component in the high-frequency signal can be impedance matched with the target resistance value of the above-mentioned doped polysilicon layer 103, and the transmission of the DC component in the high-frequency signal can be blocked.

[0045] The terminal impedance matching system provided in this embodiment includes a substrate, an oxide layer, a doped polysilicon layer, a first connecting electrode arranged on the first surface of the substrate, the oxide layer is in contact with the first surface of the substrate, and a second connecting electrode is arranged on the first surface of the doped polysilicon layer, and the first surface of the doped polysilicon is far away from the oxide layer, wherein the doped polysilicon layer has a target resistance value that matches the characteristic impedance of the first traveling wave electrode and the second traveling wave electrode in the silicon-based optical modulator, the first connecting electrode is connected to the first traveling wave electrode, and the second connecting electrode is connected to the second traveling wave electrode, and is used to transmit the high-frequency signal transmitted on the first traveling wave electrode and the second traveling wave electrode, the AC component in the high-frequency signal is matched with the impedance of the target resistance value, and the substrate, the oxide layer and the doped polysilicon layer constitute a metal-oxide-semiconductor capacitor, which is used to block the transmission of the DC component in the high-frequency signal. Since the isolated DC capacitor in the terminal impedance matching system adopts the MOS capacitor structure of substrate-oxide layer-doped polysilicon layer, a large amount of capacitance value can be obtained per unit area, thereby greatly reducing the size of the isolated DC capacitor, which is convenient for adapting to the size of the traveling wave electrode in the silicon-based optical modulator. At the same time, the doped polysilicon layer of the MOS capacitor has a target resistance value that matches the characteristic impedance of the traveling wave electrode in the silicon-based optical modulator, and can be directly used as the terminal matching resistor of the traveling wave electrode, thereby realizing the integration of the terminal matching resistor of the traveling wave electrode of the silicon-based optical modulator with the isolated DC capacitor, and realizing integration with the traveling wave electrode on the basis of solving the DC power consumption in the silicon-based optical modulator.

[0046] In an optional embodiment, the substrate 101 can be implemented as an N-type heavily doped SOI substrate, and the doped polysilicon layer 103 can be implemented as a P-type heavily doped polysilicon layer (Poly-Si); or, the substrate 101 can be implemented as a P-type heavily doped SOI substrate, and the doped polysilicon layer 103 can be implemented as an N-type heavily doped polysilicon layer.

[0047] Further, in an optional embodiment, the heavily doped SOI substrate may include doped top silicon, the oxide layer may be disposed in a first region of a first surface on the top silicon, the first connection electrode 104 may be disposed in a second region of the first surface on the top silicon, and connected to the first traveling wave electrode. Also, the heavily doped polysilicon layer may be disposed on a surface of the oxide layer, the second connection electrode 105 may be disposed on a first surface of the heavily doped polysilicon layer, and connected to the second traveling wave electrode.

[0048] In an optional embodiment, the aspect ratio of the heavily doped polysilicon layer is adjustable. In this case, by adjusting the aspect ratio, the target resistance value matching the characteristic impedance of the traveling wave electrode in the silicon-based optical modulator can be achieved. The implementation method of changing the resistance value by adjusting the aspect ratio can refer to the specific implementation method in the traditional solution, which will not be described in detail here.

[0049] In an optional embodiment, the doped polysilicon layer is implemented as a P+ heavily doped polysilicon layer. Since the resistance of the P+ heavily doped polysilicon layer is relatively large, in order to reduce the resistance of the contact resistance between the second connection electrode 105 and the P+ heavily doped polysilicon layer, the contact area between the two can be increased. Considering that the width of the contact portion between the second connection electrode 105 and the P+ heavily doped polysilicon layer needs to remain stable, the cross-section of the second traveling wave electrode cannot change suddenly, and the width of the second traveling wave electrode is usually small. Therefore, before contacting the P+ heavily doped polysilicon layer, the second traveling wave electrode can be set to have a slowly thickening gradient structure. In other words, the end of the second traveling wave electrode in contact with the second connection electrode 105 can gradually increase in the extension direction from the second traveling wave electrode to the second connection electrode 105.

[0050] One or more of the above embodiments provide an implementation structure of a terminal impedance matching system for a silicon-based optical modulator traveling wave electrode. The terminal impedance matching system can be applied to a silicon-based optical modulator.

[0051] In one embodiment, the silicon-based optical modulator may include a beam splitting structure, a phase shifting structure, and a beam combining structure connected in sequence, wherein the phase shifting structure includes a first modulation arm and a second modulation arm, a first traveling wave electrode and a second traveling wave electrode, and Figure 1 The silicon-based optical modulator traveling wave electrode terminal impedance matching system described in the embodiment.

[0052] In this embodiment, the silicon-based optical modulator can be implemented as a Mach-Zehnder electro-optic modulator. The connection method between the traveling wave electrode and the terminal impedance matching system in the silicon-based optical modulator can be referred to Figure 1 The description in the embodiments will not be repeated here.

[0053] In an optional embodiment, the silicon-based optical modulator may further include an AC power supply and a DC power supply;

[0054] Both the AC power supply and the DC power supply can be used to supply power to the first traveling-wave electrode and the second traveling-wave electrode.

[0055] Specifically, the phase shift structure 30 may be implemented in a variety of ways.

[0056] As an optional implementation, it can be implemented as a single phase shift arm solution, that is, a PN junction phase shifter is provided on one modulation arm in the phase shift structure 30. Figure 2 , shows a schematic structural diagram of a silicon-based optical modulator in an embodiment, including a beam splitting structure 20, a phase shifting structure and a beam combining structure 40 connected in sequence, the phase shifting structure including a first modulation arm 301 and a second modulation arm 302, a first traveling wave electrode 303 and a second traveling wave electrode 304, and Figure 1 The silicon-based optical modulator traveling wave electrode terminal impedance matching system 10 described in the embodiment.

[0057] A PN junction phase shifter is disposed on the first modulation arm 301 .

[0058] At this time, the first traveling wave electrode 303 can be set within a preset range from the first modulation arm 301, and the second traveling wave electrode 304 is set within a non-preset range from the first modulation arm 301. The first traveling wave electrode 303 works, and the second traveling wave electrode 304 does not work. The preset range can be set according to actual needs.

[0059] Further, such as Figure 3 , shows a schematic diagram of a circuit diagram of a silicon-based optical modulator in an embodiment, wherein V ac Can represent AC voltage, V bias Can represent the DC bias voltage, Z t Can represent the terminal matching resistance, C DC_block Can represent DC blocking capacitor, this circuit diagram is applicable to Figure 2 The single-phase arm shifting solution described in the embodiment.

[0060] As another optional implementation, it can be implemented as a differential signal solution, that is, a PN junction phase shifter is provided on both modulation arms in the phase shift structure 30. Figure 4 , shows a schematic structural diagram of a silicon-based optical modulator in another embodiment, including a beam splitting structure 20, a phase shifting structure 30 and a beam combining structure 40 connected in sequence, the phase shifting structure 30 includes a first modulation arm 301 and a second modulation arm 302, a first traveling wave electrode 303 and a second traveling wave electrode 304, and Figure 1 The silicon-based optical modulator traveling wave electrode terminal impedance matching system 10 described in the embodiment.

[0061] Wherein, PN junction phase shifters are disposed on both the first modulation arm 301 and the second modulation arm 302 .

[0062] At this time, the first traveling wave electrode 303 can be set within a preset range from the first modulation arm 301, and the second traveling wave electrode 304 can be set within a preset range from the second modulation arm 302, and both the first traveling wave electrode 303 and the second traveling wave electrode 304 work. The preset range can also be set according to actual needs.

[0063] It is clear to those skilled in the art that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative labor.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A silicon-based optical modulator traveling wave electrode terminal impedance matching system, characterized in that: The invention comprises a substrate, an oxide layer, a doped polysilicon layer, a first connecting electrode arranged on a first surface of the substrate, wherein the oxide layer contacts the first surface of the substrate, and a second connecting electrode arranged on a first surface of the doped polysilicon layer, wherein the first surface of the doped polysilicon is away from the oxide layer; Among them, the doped polysilicon layer has a target resistance value that matches the characteristic impedance of the first traveling wave electrode and the second traveling wave electrode in the silicon-based optical modulator; the first connecting electrode is connected to the first traveling wave electrode, and the second connecting electrode is connected to the second traveling wave electrode, which are used to transmit the high-frequency signal transmitted on the first traveling wave electrode and the second traveling wave electrode, and the AC component in the high-frequency signal matches the impedance of the target resistance value. The substrate, the oxide layer and the doped polysilicon layer constitute a metal-oxide-semiconductor capacitor, which is used to isolate the transmission of the DC component in the high-frequency signal.

2. The system according to claim 1, characterized in that The substrate comprises an N-type heavily doped SOI substrate, and the doped polysilicon layer comprises a P-type heavily doped polysilicon layer; Alternatively, the substrate comprises a P-type heavily doped SOI substrate, and the doped polysilicon layer comprises an N-type heavily doped polysilicon layer.

3. The system according to claim 2, characterized in that The heavily doped SOI substrate includes a doped top layer of silicon; The oxide layer is disposed in a first region on the upper surface of the top silicon layer, and the first connecting electrode is disposed in a second region on the upper surface of the top silicon layer.

4. The system according to claim 2, characterized in that The aspect ratio of the heavily doped polysilicon layer is adjustable.

5. The system according to claim 1, characterized in that The oxide layer includes a gate oxide layer.

6. The system according to claim 1, characterized in that One end of the second traveling wave electrode in contact with the second connecting electrode gradually increases in size toward an extending direction from the second traveling wave electrode to the second connecting electrode.

7. A silicon-based optical modulator, characterized in that: It comprises a beam splitting structure, a phase shifting structure and a beam combining structure connected in sequence, wherein the phase shifting structure comprises a first modulation arm and a second modulation arm, a first traveling wave electrode and a second traveling wave electrode, and a silicon-based optical modulator traveling wave electrode terminal impedance matching system as claimed in any one of claims 1 to 6.

8. The silicon-based optical modulator according to claim 7, characterized in that: A PN junction phase shifter is provided on the first modulation arm; The first traveling wave electrode is arranged within a preset range from the first modulation arm, and the second traveling wave electrode is arranged within a non-preset range from the first modulation arm. The first traveling wave electrode works, and the second traveling wave electrode does not work.

9. The silicon-based optical modulator according to claim 7, characterized in that: The first modulation arm and the second modulation arm are both provided with a PN junction phase shifter; The first traveling wave electrode is arranged within a preset range from the first modulation arm, the second traveling wave electrode is arranged within a preset range from the second modulation arm, and both the first traveling wave electrode and the second traveling wave electrode are in operation.

10. The silicon-based optical modulator according to claim 7, characterized in that: The silicon-based optical modulator also includes an AC power supply and a DC power supply; The AC power supply and the DC power supply are both used to supply power to the first traveling wave electrode and the second traveling wave electrode.

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