This application relates to an electro-optical modulator, and an optical modulation system, and an integrated optical chip that include the electro-optical modulator.
In an optical communication system, an electro-optical modulator is a core component for converting an electrical signal into an optical signal. A thin-film lithium niobate (TFLN) modulator has advantages such as good linearity, no need for cooling, low optical loss, and high bandwidth. Therefore, the thin-film lithium niobate modulator can be used in a scenario such as coherent optical communication with a baud rate higher than 130 G.
The TFLN modulator is electrically connected to an electrical chip. The electrical chip is configured to output an alternating current signal to drive the thin-film lithium niobate modulator to work, and the electrical chip needs to work under driving of a direct current signal. Therefore, the electrical chip needs to include a complex peripheral circuit (including a capacitor, an inductor, and the like) to distinguish between a transmission channel of the direct current signal and a transmission channel of the alternating current signal, to prevent the direct current signal from being transmitted to the TFLN modulator, and prevent the alternating current signal from being transmitted to a node that provides the direct current signal. The peripheral circuit causes a large overall size and high costs of the electrical chip. This is not conducive to miniaturization and cost control of the electrical chip, and is not conducive to packaging of the electrical chip and the TFLN modulator.
According to a first aspect, this application provides an electro-optical modulator, including an electrode conversion portion, including: a first input electrode and a second input electrode, where the first input electrode is configured to receive a first modulation signal output by an electrical chip, and the second input electrode is configured to receive a second modulation signal output by the electrical chip; and an optical modulation portion, including: a first modulation electrode, a second modulation electrode, a third modulation electrode, a first modulation arm, and a second modulation arm, where the first modulation electrode is between the second modulation electrode and the third modulation electrode, the first modulation arm is between the first modulation electrode and the second modulation electrode, and the second modulation arm is between the first modulation electrode and the third modulation electrode. The first modulation electrode is coupled to the first input electrode, and is configured to receive the first modulation signal. The second modulation electrode and the third modulation electrode are separately coupled to the second input electrode, and are separately configured to receive the second modulation signal. The first modulation electrode, the second modulation electrode, and the third modulation electrode are configured to modulate input light in the first modulation arm and the second modulation arm based on the first modulation signal and the second modulation signal, and modulated input light is output as modulated light from the first modulation arm and the second modulation arm.
Currently, there are mainly two driving manners in which the electrical chip drives the electro-optical modulator to work. The electrical chip has different circuit structures in the two driving manners. In Manner 1, the electrical chip has three output ends electrically connected to the electro-optical modulator. One output end outputs a modulation signal that changes with time, and two other output ends each maintain a ground voltage. In this driving manner, the electrical chip includes a peripheral circuit for separately filtering out a direct current signal and an alternating current signal. In Manner 2, the electrical chip has two output ends electrically connected to the electro-optical modulator. The two output ends respectively output the first modulation signal and the second modulation signal. The first modulation signal and the second modulation signal separately change with time, and at a same moment, the first modulation signal and the second modulation signal have a same amplitude and opposite directions. In this driving manner, the electrical chip does not include a peripheral circuit. The electro-optical modulator includes the electrode conversion portion. The first input electrode and the second input electrode are converted into the first modulation electrode, the second modulation electrode, and the third modulation electrode, so that signals transmitted on the first input electrode and the second input electrode may be separately loaded to the optical modulation portion via the first modulation electrode, the second modulation electrode, and the third modulation electrode, to modulate the input light in the first modulation arm and the second modulation arm. Therefore, the electro-optical modulator may be driven in Manner 2. In other words, the electrical chip that does not include the peripheral circuit for filtering out the direct current signal and the alternating current signal may be used to drive the electro-optical modulator. This helps reduce a size of the electrical chip driving the electro-optical modulator, helps reduce costs of the electrical chip driving the electro-optical modulator, and facilitates packaging of the electro-optical modulator and the electrical chip in an optical modulation system.
In some implementations, the electro-optical modulator further includes a substrate, and the electrode conversion portion and the optical modulation portion are on a same surface of the substrate.
In this way, the electrode conversion portion may be electrically connected to the optical modulation portion.
In some implementations, the electrode conversion portion further includes a bridging portion. The bridging portion is embedded in the substrate, and a part of the bridging portion is exposed relative to the surface that is of the substrate and on which the electrode conversion portion is located. The part of the bridging portion exposed relative to the substrate is separately coupled to the first modulation electrode and the first input electrode.
In this way, an electrical connection is established between the first input electrode and the first modulation electrode, and the electrical connection is implemented via the bridging portion embedded in the substrate, so that the first input electrode and the second input electrode may be flush with an end face of the electro-optical modulator, and a packaging process of the electro-optical modulator is facilitated.
In some implementations, two ends of the second input electrode are respectively coupled to the second modulation electrode and the third modulation electrode, and the second modulation electrode, the second input electrode, and the third modulation electrode are enclosed to form an accommodation area having an opening. The first input electrode is in the accommodation area, and the first modulation electrode extends from outside of the accommodation area through the opening to the accommodation area and is coupled to the first input electrode.
In this way, an electrical connection is established between the first input electrode and the first modulation electrode.
In some implementations, the electrode conversion portion is an axi symmetric structure as a whole.
In some implementations, the first modulation electrode, the second modulation electrode, and the third modulation electrode are made of metal. The optical modulation portion further includes a transparent conduction layer on the substrate. The first modulation electrode, the second modulation electrode, and the third modulation electrode are on a surface that is of the transparent conduction layer and that is away from the substrate, and are in electrical contact with the transparent conduction layer.
Because the first modulation electrode, the second modulation electrode, and the third modulation electrode that are made of metal materials easily absorb the input light in the first modulation arm and the second modulation arm, to reduce an absorption amount of the input light by the first modulation electrode, the second modulation electrode, and the third modulation electrode, a preset distance should be kept between the first modulation electrode, the second modulation electrode, and the third modulation electrode and the first modulation arm and the second modulation arm that are adjacently arranged. Compared with a metal material, a transparent conducting material has a small absorption function on light. If the first modulation electrode, the second modulation electrode, and the third modulation electrode are set to be made of transparent conducting materials, absorption functions of the first modulation electrode, the second modulation electrode, and the third modulation electrode on the light can be reduced, and the preset distance between the first modulation electrode, the second modulation electrode, and the third modulation electrode, and the first modulation arm and the second modulation arm can be reduced. However, compared with the metal material, the transparent conducting material has a weak conductivity. This is not conducive to conduction of electrical signals (including the first modulation signal and the second modulation signal). Therefore, in some embodiments, the first modulation electrode, the second modulation electrode, and the third modulation electrode are set to be made of the metal materials, and the transparent conduction layer in direct electrical contact with the first modulation electrode, the second modulation electrode, and the third modulation electrode is added, to enable the transparent conduction layer and the first modulation electrode, the second modulation electrode, and the third modulation electrode to jointly transmit the electrical signals. In an aspect, a good conductivity may be implemented via the first modulation electrode, the second modulation electrode, and the third modulation electrode that are made of the metal materials. In another aspect, because the transparent conduction layer has a small absorption function on the light, a distance between the transparent conduction layer and the first modulation arm and a distance between the transparent conduction layer and the second modulation arm can be reduced. When the distance between the transparent conduction layer and the first modulation arm and the distance between the transparent conduction layer and the second modulation arm are reduced, impact of a first electric field and a second electric field that is generated by the first modulation electrode, the second modulation electrode, and the third modulation electrode on the first modulation arm and the second modulation arm is improved. Therefore, modulation efficiency of the electro-optical modulator is improved.
In some implementations, the transparent conduction layer is in direct contact with the first modulation arm and the second modulation arm.
In this way, the distance between the transparent conduction layer and the first modulation arm and the distance between the transparent conduction layer and the second modulation arm are 0, the impact of the first electric field and the second electric field that is generated by the first modulation electrode, the second modulation electrode, and the third modulation electrode on the first modulation arm and the second modulation arm is greater, and the modulation efficiency of the electro-optical modulator is higher.
In some implementations, the electro-optical modulator further includes a first impedance sheet, a second impedance sheet, and a third impedance sheet. The first impedance sheet and the second impedance sheet are connected in series to each other and then are coupled between the second modulation electrode and the third modulation electrode. The first modulation electrode is coupled to a node between the first impedance sheet and the second impedance sheet. The third impedance sheet is coupled between the first modulation electrode and the node.
In this way, the first modulation signal and the second modulation signal may be terminated via the first impedance sheet, the second impedance sheet, and the third impedance sheet, to avoid a case in which the first modulation signal and the second modulation signal are reflected, and consequently a modulation process of the input light is affected.
In some implementations, the first modulation signal and the second modulation signal are radio frequency signals.
In some implementations, the first modulation arm and the second modulation arm are made of lithium niobate.
According to a second aspect, this application further provides an optical modulation system, including: the electro-optical modulator according to any one of the implementations of the first aspect; and an electrical chip, separately coupled to a first input electrode and a second input electrode, and configured to output a first modulation signal to the first input electrode and output a second modulation signal to the second input electrode.
The optical modulation system includes the electrical chip and an optical chip that are electrically connected to each other. An electrode conversion portion in the optical chip is used, so that a peripheral circuit is not needed to distinguish between a transmission channel of a direct current signal and a transmission channel of an alternating current signal. This helps reduce a size of the optical modulation system and reduce costs of the optical modulation system.
Currently, there are mainly two driving manners in which the electrical chip drives the electro-optical modulator to work. The electrical chip has different circuit structures in the two driving manners. In Manner 1, the electrical chip has three output ends electrically connected to the electro-optical modulator. One output end outputs a modulation signal that changes with time, and two other output ends each maintain a ground voltage. In this driving manner, the electrical chip includes the peripheral circuit for separately filtering out the direct current signal and the alternating current signal. In Manner 2, the electrical chip has two output ends electrically connected to the electro-optical modulator. The two output ends respectively output the first modulation signal and the second modulation signal. The first modulation signal and the second modulation signal separately change with time, and at a same moment, the first modulation signal and the second modulation signal have a same amplitude and opposite directions. In this driving manner, the electrical chip does not include a peripheral circuit. The electro-optical modulator includes the electrode conversion portion. The first input electrode and the second input electrode are converted into a first modulation electrode, a second modulation electrode, and a third modulation electrode, so that signals transmitted on the first input electrode and the second input electrode may be separately loaded to an optical modulation portion via the first modulation electrode, the second modulation electrode, and the third modulation electrode, to modulate input light in a first modulation arm and a second modulation arm. Therefore, the electro-optical modulator may be driven in Manner 2. In other words, the electrical chip that does not include the peripheral circuit for filtering out the direct current signal and the alternating current signal may be used to drive the electro-optical modulator. This enables the overall size of the optical modulation system to be small, and helps reduce the costs of the optical modulation system.
According to a third aspect, this application further provides an integrated optical chip, including: a laser, configured to emit input light; and the electro-optical modulator according to any one of the foregoing implementations, coupled to the laser, and configured to receive the input light, modulate the input light, and output modulated light.
The integrated optical chip integrates the electro-optical modulator, and can implement all beneficial effects of the electro-optical modulator.
The following describes embodiments of this application with reference to the accompanying drawings in embodiments of this application.
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The electrode conversion portion 11 includes a first input electrode 111 and a second input electrode 112 that are disposed at intervals. The first input electrode 111 and the second input electrode 112 are separately coupled to the electrical chip 20. The first input electrode 111 is configured to receive the first modulation signal S+ output by the electrical chip 20, and the second input electrode 112 is configured to receive the second modulation signal S− output by the electrical chip 20.
The optical modulation portion 12 includes a first modulation electrode 121, a second modulation electrode 122, a third modulation electrode 123, a first modulation arm 124, and a second modulation arm 125. The first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 are disposed at intervals and parallel to each other, and the first modulation electrode 121 is between the second modulation electrode 122 and the third modulation electrode 123. When an electrical signal is separately applied to the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123, the first modulation electrode 121 and the second modulation electrode 122 form a first capacitor to generate a first electric field; and the first modulation electrode 121 and the third modulation electrode 123 form a second capacitor to generate a second electric field.
The first modulation arm 124 is between the first modulation electrode 121 and the second modulation electrode 122, and the second modulation arm 125 is between the first modulation electrode 121 and the third modulation electrode 123. The first modulation arm 124 and the second modulation arm 125 converge at an input end P1 and an output end P2. In other words, the first modulation arm 124 and the second modulation arm 125 have the common input end P1 and the common output end P2. The input end P1 is configured to receive the input light L1. A part of the input light L1 enters the first modulation arm 124 for transmission and modulation, and the other part enters the second modulation arm 125 for transmission and modulation. When the electrical signal is separately applied to the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123, the first modulation arm 124 is in the first electric field, the part of the input light L1 transmitted in the first modulation arm 124 is modulated by the first electric field, and the other part of the input light L1 transmitted in the second modulation arm 125 is modulated by the second electric field. The input light L1 modulated by the first modulation arm 124 and the second modulation arm 125 converges at the output end P2, and then is output as the modulated light L2.
The first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 are disposed at intervals and approximately parallel to each other, and the first modulation electrode 121 is between the second modulation electrode 122 and the third modulation electrode 123. The first modulation electrode 121 is coupled to the first input electrode 111, and is configured to receive the first modulation signal S+. The second modulation electrode 122 and the third modulation electrode 123 are separately coupled to the second input electrode 112, and are separately configured to receive the second modulation signal S—. The first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 are configured to modulate the input light L1 based on the first modulation signal S+ and the second modulation signal S—.
Refer to
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Because the first input electrode 111, the second input electrode 112, the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 are all disposed on the surface that is of the dielectric layer 132 and that is away from the substrate layer 131, if the electrical connection between the first input electrode 111 and the first modulation electrode 121 is established directly via a conduction structure disposed on the surface that is of the dielectric layer 132 and that is away from the substrate layer 131, the first input electrode 111 and the second input electrode 112 are easily short-circuited. If a manner of adding an insulation layer is used to avoid short-circuiting, it is not conducive to reduction of overall thickness of the electro-optical modulator 10. In this way, the bridging portion 116 is embedded in the dielectric layer 132 to establish the electrical connection between the first input electrode 111 and the first modulation electrode 121. This helps avoid short-circuiting between the first input electrode 111 and the second input electrode 112, and further helps reduce the overall thickness of the electro-optical modulator 10.
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In this embodiment, the first input electrode 111, the second input electrode 112, the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 are all made of conducting metal, for example, gold, aluminum, copper, titanium, and platinum.
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In this embodiment, the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 are made of metal materials, and the metal materials easily absorb the input light L1 in the first modulation arm 124 and the second modulation arm 125. To reduce an absorption amount of the input light L1 by the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123, a preset distance should be kept between the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 and the first modulation arm 124 and the second modulation arm 125 that are adjacently arranged, as shown in
Compared with a metal material, a transparent conducting material has a small absorption function on light. If the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 are set to be made of transparent conducting materials, absorption functions of the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 on the light can be reduced, and the preset distance between the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123, and the first modulation arm 124 and the second modulation arm 125 can be reduced. However, compared with the metal material, the transparent conducting material has a weak conductivity. This is not conducive to conduction of electrical signals (including the first modulation signal S+ and the second modulation signal S−).
Therefore, in the foregoing changed embodiment, the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 are set to be made of the metal materials, and the transparent conduction layer 127 is added, to enable the transparent conduction layer 127 and the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 to jointly transmit the electrical signals. In an aspect, a good conductivity may be implemented via the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 that are made of the metal materials. In another aspect, because the transparent conduction layer 127 has a small absorption function on the light, a distance between the transparent conduction layer 127 and the first modulation arm 124 and a distance between the transparent conduction layer 127 and the second modulation arm 125 can be reduced. In this changed embodiment (
When the distance between the transparent conduction layer 127 and the first modulation arm 124 and the distance between the transparent conduction layer 127 and the second modulation arm 125 are reduced, impact of the first electric field and the second electric field that is generated by the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 on the first modulation arm 124 and the second modulation arm 125 is greater, and modulation efficiency of the electro-optical modulator 10 is higher.
Therefore, in this changed embodiment, the transparent conduction layer 127 is added, to help improve the modulation efficiency of the electro-optical modulator 10 while ensuring the good conductivity.
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The following describes a working process of the optical modulation system 1 with reference to an equivalent circuit diagram of the electro-optical modulator 10 and the electrical chip 20.
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When starting to work, the electrical chip 20 receives the initial modulation signal S0, outputs the first modulation signal S+ through the first output end 211, and outputs the second modulation signal S− through the second output end 212. The first modulation signal S+ is transmitted by the first input electrode 111 to the first modulation electrode 121, and the second modulation signal S− is separately transmitted by the second input electrode 112 to the second modulation electrode 122 and the third modulation electrode 123. At the same time, the input end P1 of the optical modulation portion 12 receives the input light L1 input by the external light source.
In this embodiment, the first modulation signal S+ and the second modulation signal S− are sinusoidal signals. In another embodiment, the first modulation signal S+ and the second modulation signal S− may alternatively be alternating current signals in other forms, for example, square wave signals. Specific forms of the first modulation signal S+ and the second modulation signal S− are not limited in this application. In a working process of the optical modulation portion 12, at a same moment, the first modulation signal S+ and the second modulation signal S− have a same amplitude and opposite directions. By changing the first modulation signal S+ and the second modulation signal S− at the same time, the first electric field and the second electric field may be changed respectively, to respectively control the first modulation arm 124 and the second modulation arm 125 in the first electric field and the second electric field to modulate the input light L1, to output the modulated light L2. In other words, in the foregoing process, changes of the first modulation signal S+ and the second modulation signal S− are reflected in a change of a parameter (for example, a phase, an intensity, or a polarization state) of light, so that modulated light, namely, the modulated light L2, carries modulation information.
In this embodiment, the optical modulation portion 12 further includes a first impedance sheet R1, a second impedance sheet R2, and a third impedance sheet R3 that are on the surface of the substrate 13. The first impedance sheet R1, the second impedance sheet R2, and the third impedance sheet R3 each are a material layer having a specific impedance value, for example, a material layer made of titanium. The first impedance sheet R1 and the second impedance sheet R2 are coupled between one end of the second modulation electrode 122 and one end of the third modulation electrode 123, and the first impedance sheet R1 and the second impedance sheet R2 are coupled to the ends that are of the second modulation electrode 122 and the third modulation electrode 123 and that are close to the output end P2. A node between the first impedance sheet R1 and the second impedance sheet R2 is coupled to the drive end 128 and one end of the first modulation electrode 121, and the third impedance sheet R3 is coupled between the first modulation electrode 121 and the node. The first impedance sheet R1, the second impedance sheet R2, and the third impedance sheet R3 are separately configured to terminate the first modulation signal S+ and the second modulation signal S− that are high-frequency signals and that are transmitted on the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123, to avoid a case in which the first modulation signal S+ and the second modulation signal S− are reflected, and consequently a modulation process of the input light L1 is affected.
As described above, the electro-optical modulator 10 in this embodiment is configured to receive the first modulation signal S+ and the second modulation signal S− output by the electrical chip 20. The electro-optical modulator 10 is further configured to receive the input light L1, and is configured to modulate the input light L1 based on the first modulation signal S+ and the second modulation signal S−, to output the modulated light L2. The first modulation signal S+ and the second modulation signal S− are the alternating current signals, the electrical chip 20 needs to work under driving of the direct current drive signal D.
Currently, there are mainly two driving manners in which the electrical chip drives the electro-optical modulator to work. The electrical chip has different circuit structures in the two driving manners.
In Manner 1, the electrical chip has three output ends coupled to the electro-optical modulator. One output end outputs a modulation signal that changes with time, and two other output ends each maintain a ground voltage. In this driving manner, the electrical chip includes a peripheral circuit for separately filtering out a direct current signal and an alternating current signal. This manner is also referred to as a signal transmission manner of a coplanar waveguide-based (CPW) electrode structure.
In Manner 2, the electrical chip has two output ends coupled to the electro-optical modulator. The two output ends respectively output the first modulation signal and the second modulation signal. The first modulation signal and the second modulation signal separately change with time, and at a same moment, the first modulation signal and the second modulation signal have a same amplitude and opposite directions. In this driving manner, the electrical chip does not include a peripheral circuit. This manner is also referred to as a signal transmission manner of a coplanar strip-based (CPS) electrode structure.
The electro-optical modulator 10 in this embodiment includes the electrode conversion portion 11. The first input electrode 111 and the second input electrode 112 are converted into the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123, so that signals transmitted on the first input electrode 111 and the second input electrode 112 may be separately loaded to the first modulation electrode 121, the second modulation electrode 122, and the third modulation electrode 123 that are of the optical modulation portion 12, to modulate the input light L1 in the first modulation arm 124 and the second modulation arm 125. In other words, in this embodiment, the electro-optical modulator 10 converts the CPS-based electrode structure into the CPW-based electrode structure, so that when the electro-optical modulator 10 is coupled to the electrical chip 20 for working, the electro-optical modulator 10 may be driven in Manner 2. In other words, the electrical chip 20 that does not include the peripheral circuit for filtering out the direct current signal and the alternating current signal may be used to drive the electro-optical modulator 10. This enables an overall size of the optical modulation system 1 to be small, helps reduce costs of the optical modulation system 1, and facilitates packaging of the electro-optical modulator 10 and the electrical chip 20 in the optical modulation system 1.
On this basis, because the second modulation electrode 122 and the third modulation electrode 123 form a capacitor, the drive signal D input at the drive end 128 of the electro-optical modulator 10 is filtered out by the capacitor, and is not transmitted on the second modulation electrode 122 and the third modulation electrode 123. The drive signal D is loaded to the electrical chip 20 only along a path of the first modulation electrode 121.
Refer to
In some changed embodiments, a specific structure of the integrated optical chip 100 may alternatively be shown in
Compared with the integrated optical chip in
Compared with the integrated optical chip in
Compared with the integrated optical chip in
The integrated optical chips 100 shown in
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In this embodiment, the electrode conversion portion 31 includes a first input electrode 311 and a second input electrode 312 that are disposed at intervals. The first input electrode 311 and the second input electrode 312 are separately coupled to an electrical chip. The first input electrode 311 is configured to receive a first modulation signal S+, and the second input electrode 312 is configured to receive a second modulation signal S− output by the electrical chip 20.
Two ends of the second input electrode 312 are respectively coupled to a second modulation electrode 122 and a third modulation electrode 123. In other words, the second modulation electrode 122, the second input electrode 312, and the third modulation electrode 123 are sequentially coupled in a head-to-tail manner. The second modulation electrode 122, the second input electrode 312, and the third modulation electrode 123 are enclosed to form an accommodation area 317 having an opening 316. The first input electrode 311 is in the accommodation area 317. A first modulation electrode 121 extends from outside of the accommodation area 317 through the opening 316 to the accommodation area 317, and is coupled to the first input electrode 311. In this embodiment, the electrode conversion portion 31 is an axisymmetric structure as a whole. Specifically, the electrode conversion portion 31 is axisymmetric relative to the first modulation electrode 121. The electrode conversion portion 31 is set to be axisymmetric. This helps ensure symmetry between the first modulation signal S+ and the second modulation signal S—.
The first modulation electrode 121 is coupled to the first input electrode 311, and is configured to receive the first modulation signal S+. The second modulation electrode 122 and the third modulation electrode 123 are separately coupled to the second input electrode 312, and are separately configured to receive the second modulation signal S—.
In this embodiment, the electro-optical modulator further includes a substrate 33. The electrode conversion portion 31 and an optical modulation portion are on a same surface of the substrate 33. The substrate 33 includes a substrate layer 331 and a dielectric layer 332 that are stacked, and the substrate layer 331 is on a surface that is of the dielectric layer 332 and that is away from the electrode conversion portion 31. In this embodiment, a material of the substrate 33 is the same as the material of the substrate 13 in Embodiment 1. Details are not described again.
The electro-optical modulator in this embodiment can implement all beneficial effects of the electro-optical modulator 10 in Embodiment 1.
It should be noted that the foregoing descriptions are merely specific implementations of this application, but are not intended to limit the protection scope of this application. Any variation or replacement easily figured out by a person skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. In a case that no conflict occurs, the implementations of this application and the features in the implementations may be mutually combined. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.
This application is a continuation of International Application No. PCT/CN2021/106805, filed on Jul. 16, 2021, the disclosure of which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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Parent | PCT/CN2021/106805 | Jul 2021 | US |
Child | 18408214 | US |