Electro-optical modulator

Abstract

To provide an electro-optic modulator including a waveguide layer and an electrode layer.SOLUTION: An electrode layer includes: a plurality of first sub-electrodes and a plurality of first connecting electrodes, which are arranged in sequence; a plurality of second sub-electrodes and a plurality of second connecting electrodes, which are arranged in sequence; a plurality of third sub-electrodes and a plurality of third connecting electrodes, which are arranged in sequence; and a plurality of fourth sub-electrodes and a plurality of fourth connecting electrodes, which are arranged in sequence. The plurality of first sub-electrodes and the plurality of fourth sub-electrodes are grounded, the plurality of second sub-electrodes and the plurality of third sub-electrodes receive differential signals, the plurality of first sub-electrodes and the plurality of second sub-electrodes form a first electric field therebetween, and the plurality of third sub-electrodes and the plurality of fourth sub-electrodes form a second electric field therebetween which has an opposite direction to that of the first electric field, and the waveguide layer includes a first waveguide arm located in the first electric field and a second waveguide arm located in the second electric field.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical communications, and more particularly, to an electro-optic modulator.

Background Art

[0002] In recent years, with the rapid development of newly emerging network application services such as the Internet of Things, autonomous driving, telemedicine, and distance education, the demand for high-speed and high-capacity communication technologies has been increasing strongly. Optical communication achieves rapid development in the direction of high-speed and high-capacity communication due to its characteristics such as large bandwidth, high reliability, low cost, and high anti-interference ability. A method for loading high-speed electrical signals onto an optical carrier is one of the core research contents.

[0003] An electro-optic modulator is a modulator made based on the electro-optic effect of an electro-optic material. The electro-optic effect means that when a voltage is applied to an electro-optic material such as a lithium niobate crystal, a gallium arsenide crystal, or a lithium tantalate crystal, the refractive index of the electro-optic material changes, thereby changing the characteristics of the light wave passing through the electro-optic material. By utilizing the electro-optic effect, it is possible to modulate parameters such as the phase, amplitude, intensity, and polarization state of an optical signal.

[0004] Due to the increasingly severe requirements for high-speed and high-capacity communication technologies, there are higher requirements for the low loss and operating performance of electro-optic modulators.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Embodiments of the present disclosure provide an electro-optic modulator for reducing the transmission loss of an electro-optic modulator and for improving the operating performance of an electro-optic modulator.

Means for Solving the Problems

[0006] The electro-optical modulator provided in the embodiments of the present disclosure includes a substrate, an insulating layer, a waveguide layer, and an electrode layer arranged in sequence. Here, the electrode layer includes a plurality of first sub-electrodes arranged in sequence in a first direction and a plurality of first connection electrodes connected to the plurality of first sub-electrodes in a one-to-one corresponding and intersecting manner, a plurality of second sub-electrodes arranged in sequence in the first direction and a plurality of second connection electrodes connected to the plurality of second sub-electrodes in a one-to-one corresponding and intersecting manner, a plurality of third sub-electrodes arranged in sequence in the first direction and a plurality of third connection electrodes connected to the plurality of third sub-electrodes in a one-to-one corresponding and intersecting manner, and a plurality of fourth sub-electrodes arranged in sequence in the first direction and a plurality of fourth connection electrodes connected to the plurality of fourth sub-electrodes in a one-to-one corresponding and intersecting manner. Here, the plurality of first sub-electrodes and the plurality of fourth sub-electrodes are configured to be grounded, the plurality of second sub-electrodes and the plurality of third sub-electrodes are configured to receive differential signals, the plurality of first sub-electrodes and the plurality of second sub-electrodes are configured to form a first electric field between the plurality of first sub-electrodes and the plurality of second sub-electrodes, the plurality of third sub-electrodes and the plurality of fourth sub-electrodes are configured to form a second electric field having a direction opposite to that of the first electric field between the plurality of third sub-electrodes and the plurality of fourth sub-electrodes, and the waveguide layer includes a first waveguide arm and a second waveguide arm. Here, in a direction perpendicular to the substrate, parallel and in the first direction the first waveguide arm is located between the plurality of first sub-electrodes and the plurality of second sub-electrodes, does not intersect the plurality of first connection electrodes and the plurality of second connection electrodes, and the second waveguide arm is located between the plurality of third sub-electrodes and the plurality of fourth sub-electrodes and intersects the plurality of third connection electrodes and the plurality of fourth connection electrodes.

[0007] In some embodiments, the electrode layer includes a first ground electrode, a first signal electrode, a second signal electrode, and a second ground electrode, which are arranged in sequence. The first signal electrode and the second signal electrode are configured to receive differential signals. Here, the first ground electrode includes a first main electrode, a plurality of first connection electrodes connected to the first main electrode, and a plurality of first sub - electrodes. The first signal electrode includes a second main electrode, a plurality of second connection electrodes connected to the second main electrode, and a plurality of second sub - electrodes. The second signal electrode includes a third main electrode, a plurality of third connection electrodes connected to the third main electrode, and a plurality of third sub - electrodes. The second ground electrode includes a fourth main electrode, a plurality of fourth connection electrodes connected to the fourth main electrode, and a plurality of fourth sub - electrodes.

[0008] In some embodiments, the distance from each of the second main electrode and the third main electrode to the substrate is h1, the distance from each of the first main electrode and the fourth main electrode to the substrate is h2, and h1≠h2.

[0009] In some embodiments, the first main electrode, the second main electrode, the third main electrode, and the fourth main electrode are in a folded form as a whole and do not cross each other. The first waveguide arm and the second waveguide arm do not cross any of the first main electrode, the second main electrode, the third main electrode, and the fourth main electrode, or at least one of the first waveguide arm and the second waveguide arm crosses one or more of the first main electrode, the second main electrode, the third main electrode, and the fourth main electrode.

[0010] In some embodiments, the electrode layer further includes a third ground electrode located between the first signal electrode and the second signal electrode.

[0011] In some embodiments, the first main electrode, the second main electrode, the third ground electrode, the third main electrode, and the fourth main electrode are in a folded form as a whole, do not cross each other, and the first waveguide arm and the second waveguide arm do not cross any of the first main electrode, the second main electrode, the third ground electrode, the third main electrode, and the fourth main electrode, or at least one of the first waveguide arm and the second waveguide arm crosses one or more of the first main electrode, the second main electrode, the third ground electrode, the third main electrode, and the fourth main electrode.

[0012] In some embodiments, the electrode layer includes a first ground electrode, a first signal electrode, a second ground electrode, a second signal electrode, and a third ground electrode that are arranged in sequence. The first signal electrode and the second signal electrode are configured to receive differential signals. Here, the second ground electrode includes a plurality of first connection electrodes located on one side of the first main electrode and connected to the first main electrode, a plurality of first sub - electrodes, a plurality of fourth connection electrodes located on the other side of the first main electrode and connected to the first main electrode, and a plurality of fourth sub - electrodes. The first signal electrode includes the second main electrode, a plurality of second connection electrodes connected to the second main electrode, and a plurality of second sub - electrodes. The second signal electrode includes the third main electrode, a plurality of third connection electrodes connected to the third main electrode, and a plurality of third sub - electrodes.

[0013] In some embodiments, the distance from each of the second main electrode and the third main electrode to the substrate is h3, the distance from each of the first ground electrode, the third ground electrode, and the first main electrode to the substrate is h4, and h3≠h4.

[0014] In some embodiments, the first ground electrode, the second main electrode, the first main electrode, the third main electrode, and the third ground electrode are in a folded form as a whole, do not cross each other, and the first waveguide arm and the second waveguide arm do not cross any of the first ground electrode, the second main electrode, the first main electrode, the third main electrode, and the third ground electrode, or at least one of the first waveguide arm and the second waveguide arm crosses one or more of the first ground electrode, the second main electrode, the first main electrode, the third main electrode, and the third ground electrode.

[0015] In some embodiments, each of the first sub - electrodes is in a T - shaped or L - shaped connection state with a corresponding one of the first connection electrodes among the first connection electrodes, each of the second sub - electrodes is in a T - shaped or L - shaped connection state with a corresponding one of the second connection electrodes among the second connection electrodes, each of the third sub - electrodes is in a T - shaped or L - shaped connection state with a corresponding one of the third connection electrodes among the third connection electrodes, and each of the fourth sub - electrodes is in a T - shaped or L - shaped connection state with a corresponding one of the fourth connection electrodes among the fourth connection electrodes.

[0016] In some embodiments, in the first direction, a plurality of the first sub - electrodes are arranged opposite to a plurality of the second sub - electrodes in a one - to - one correspondence, and a plurality of the third sub - electrodes are arranged alternately with a plurality of the fourth sub - electrodes.

[0017] In some embodiments, the waveguide layer further includes a slab waveguide, and the first waveguide arm and the second waveguide arm are located on one side of the slab waveguide away from the substrate.

[0018] In some embodiments, the electro - optical modulator is an optical branching element including a signal input end portion, a first optical branching output end portion, and a second optical branching output end portion, where one end portion of the first waveguide arm and one end portion of the second waveguide arm are connected to the first optical branching output end portion and the second optical branching output end portion in a one - to - one correspondence, and an optical coupling element including a first optical branching input end portion, a second optical branching input end portion, and a signal output end portion, where the other end portion of the first waveguide arm and the other end portion of the second waveguide arm are connected to the first optical branching input end portion and the second optical branching input end portion in a one - to - one correspondence.

[0019] According to one or more embodiments of the present disclosure, by using this structural design of the electrode layer, in addition to being able to design the electric fields acting on the two waveguide arms to have opposite directions, the distance between the signal electrode and the ground electrode can be shortened. As a result, the strength of the electric field can be increased, and the transmission loss of the electrical signal can be reduced.

[0020] These and other aspects of the present disclosure will become apparent from the embodiments described below and will be clarified with reference to the embodiments described below.

[0021] Further details, features, and advantages of the present disclosure are disclosed in the following description of exemplary embodiments with reference to the accompanying drawings.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Embodiments for Carrying Out the Invention

[0023] List of Reference Numerals Related Technical Field 001 - Mach-Zehnder modulator; 02 - Waveguide arm; 01 - Optical branching element; 04 - Modulating electrode 040 - Signal electrode; 041 - First ground electrode; 042 - Second ground electrode; and 05 - Optical coupling element Comparative Examples of the Present Disclosure 002 - Electro-optical modulator; 241 - First ground electrode; 242 - First signal electrode; 243 - Second ground electrode 244 - Second signal electrode; 245 - Third ground electrode; 231 - First waveguide arm; and 232 - Second waveguide arm Embodiments of the Present Disclosure 100 - Electro-optical modulator; 110 - Substrate; 120 - Insulating layer; 130 - Waveguide layer; 131 - First waveguide arm 132 - Second waveguide arm; 133 - Slab waveguide; 140 - Electrode layer; 141 - First ground electrode; 11 - First main electrode 12 - First connection electrode; 13 - First sub - electrode; 142 - First signal electrode; 21 - Second main electrode 22 - Second connection electrode; 23 - Second sub - electrode; 143 - Second signal electrode; 31 - Third main electrode 32 - Third connection electrode; 33 - Third sub - electrode; 144 - Second ground electrode; 41 - Fourth main electrode 42 - Fourth connection electrode; 43 - Fourth sub - electrode; 145 - Third ground electrode; 150 - Patterned dielectric layer 741 - First ground electrode; 742 - First signal electrode; 743 - Second ground electrode; 744 - Second signal electrode 745 - Third ground electrode; 7430 - First main electrode; 7420 - Second main electrode; and 7440 - Third main electrode

[0024] Hereinafter, only some exemplary embodiments will be briefly described. As can be recognized by those skilled in the art, the described embodiments can be modified in various ways without departing from the spirit or scope of the present disclosure. Therefore, the accompanying drawings and this description are to be regarded as illustrative in nature and not restrictive.

[0025] Electro-optical modulation-related technologies have been widely developed and applied in fields such as optical communication, microwave photonics, laser beam deflection, and wavefront modulation. The Mach-Zehnder modulator is a type of electro-optical modulator, where an input optical signal is split into two branched optical signals, and the branched optical signals enter two waveguide arms respectively. Each of the two waveguide arms is made of an electro-optical material having a refractive index that changes with the applied modulation voltage. The change in the refractive index of the waveguide arm can cause a change in the phase of the branched optical signal. Therefore, the output from the convergence of the two branched optical signals is an interference signal having an intensity that changes with the modulation voltage. Briefly speaking, the Mach-Zehnder modulator can perform various sideband modulations by controlling the modulation voltage applied to the two waveguide arms. As a device for converting an electrical signal into an optical signal, the Mach-Zehnder modulator is one of the common core devices in optical interconnection, optical computing, and optical communication systems.

[0026] FIG. 1 shows a schematic structural diagram of a conventional Mach-Zehnder modulator. Ideally, the Mach-Zehnder modulator 001 has two waveguide arms 02 that are equal to each other. When the Mach-Zehnder modulator 001 is not operating, neither of the two waveguide arms 02 undergoes the electro-optic effect. After the input light passes through the optical branching element 01, it is equally divided into two branched optical signals. The two branched optical signals are in the same phase even after each of the two branched optical signals passes through one waveguide arm 02. Therefore, a coherently enhanced signal for the two branched optical signals is output from the optical coupling element 05. When the Mach-Zehnder modulator 001 is operating, the modulation electrode 04 (for example, including the signal electrode 040, the first ground electrode 041, and the second ground electrode 042) applies a modulation voltage to the two waveguide arms 02, so that the phases of the two branched optical signals can be different by an odd or even multiple of π after each of the two branched optical signals passes through one waveguide arm 02. When the phases of the two branched optical signals are different by an even multiple of π, the optical coupling element 05 outputs a coherently enhanced signal for the two branched optical signals. When the phases of the two branched optical signals are different by an odd multiple of π, the optical coupling element 05 outputs a coherently suppressed signal for the two branched optical signals.

[0027] In an electro-optic modulator, the transmission speed of an electrical signal is mainly affected by the permittivity and the structure of the material, and the transmission speed of an optical signal is mainly affected by the refractive index and the structure of the material. Electro-optic modulators in the related art are made of electro-optic materials having a relatively small refractive index and a relatively large permittivity, thereby increasing the transmission speed of the optical signal and decreasing the transmission speed of the electrical signal, making it difficult to achieve a better match between these two transmission speeds, thereby increasing the relative transmission loss of the electro-optic modulator and making the operating performance of the device sub-optimal.

[0028] In view of this, embodiments of the present disclosure provide an electro-optic modulator that can reduce the transmission loss of the electro-optic modulator and improve the operating performance of the electro-optic modulator.

[0029] As shown in FIGS. 2 and 3, an electro-optical modulator 100 provided in some embodiments of the present disclosure includes a substrate 110, an insulating layer 120, a waveguide layer 130, and an electrode layer 140, which are arranged in sequence.

[0030] In an embodiment of the present disclosure, the electrode layer 140 includes a plurality of first sub-electrodes 13 arranged in sequence in a first direction, and a plurality of first connection electrodes 12 connected to the plurality of first sub-electrodes 13 in a one-to-one corresponding and intersecting manner, a plurality of second sub-electrodes 23 arranged in sequence in the first direction, and a plurality of second connection electrodes 22 connected to the plurality of second sub-electrodes 23 in a one-to-one corresponding and intersecting manner, a plurality of third sub-electrodes 33 arranged in sequence in the first direction, and a plurality of third connection electrodes 32 connected to the plurality of third sub-electrodes 33 in a one-to-one corresponding and intersecting manner, and a plurality of fourth sub-electrodes 43 arranged in sequence in the first direction, and a plurality of fourth connection electrodes 42 connected to the plurality of fourth sub-electrodes 43 in a one-to-one corresponding and intersecting manner.

[0031] The plurality of first sub-electrodes 13 and the plurality of fourth sub-electrodes 43 are configured to be grounded, the plurality of second sub-electrodes 23 and the plurality of third sub-electrodes 33 are configured to receive differential signals (represented by S1 and S2 respectively), the plurality of first sub-electrodes 13 and the plurality of second sub-electrodes 23 are configured to form a first electric field E1 between the plurality of first sub-electrodes and the plurality of second sub-electrodes, and the plurality of third sub-electrodes 33 and the plurality of fourth sub-electrodes 43 are configured to form a second electric field E2 having a direction opposite to the direction of the first electric field between the plurality of third sub-electrodes and the plurality of fourth sub-electrodes.

[0032] The waveguide layer 130 includes a first waveguide arm 131 and a second waveguide arm 132. Here, with respect to the substrate 110 parallel and in the first directionIn the vertical direction, the first waveguide arm 131 is located between the plurality of first sub - electrodes 13 and the plurality of second sub - electrodes 23 (i.e., located within the first electric field E1), does not intersect the plurality of first connection electrodes 12 and the plurality of second connection electrodes 22, and the second waveguide arm 132 is located between the plurality of third sub - electrodes 33 and the plurality of fourth sub - electrodes 43 (i.e., located within the second electric field E2) and intersects the plurality of third connection electrodes 32 and the plurality of fourth connection electrodes 42.

[0033] In the embodiments shown in FIGS. 2 and 3, the electrode layer adopts the design of the electrode arrangement structure of GSSG (G represents the ground electrode and S represents the signal electrode). The electrode layer 140 includes a first ground electrode 141, a first signal electrode 142, a second signal electrode 143, and a second ground electrode 144 arranged in sequence. The first signal electrode 142 and the second signal electrode 143 are configured to receive differential signals. The first ground electrode 141 includes the first main electrode 11, the plurality of first connection electrodes 12 connected to the first main electrode 11, and the plurality of first sub - electrodes 13. The first signal electrode 142 includes the second main electrode 21, the plurality of second connection electrodes 22 connected to the second main electrode 21, and the plurality of second sub - electrodes 23. The second signal electrode 143 includes the third main electrode 31, the plurality of third connection electrodes 32 connected to the third main electrode 31, and the plurality of third sub - electrodes 33. The second ground electrode 144 includes the fourth main electrode 41, the plurality of fourth connection electrodes 42 connected to the fourth main electrode 41, and the plurality of fourth sub - electrodes 43.

[0034] The basic structure of the electro-optical modulator 100 generally further includes an optical branching element and an optical coupling element (these are not shown in the figure, and the connection of the optical branching element and the optical coupling element to the first waveguide arm 131 and the second waveguide arm 132 can be as shown with reference to FIG. 1). The optical branching element includes at least a signal input end, a first optical branching output end, and a second optical branching output end. The optical coupling element includes at least a first optical branching input end, a second optical branching input end, and a signal output end. One end of the first waveguide arm 131 and one end of the second waveguide arm 132 are connected to the first optical branching output end and the second optical branching output end in a one-to-one correspondence, and the other end of the first waveguide arm 131 and the other end of the second waveguide arm 132 are connected to the first optical branching input end and the second optical branching input end in a one-to-one correspondence.

[0035] In an embodiment of the present disclosure, the first ground electrode 141, the first signal electrode 142, the second signal electrode 143, and the second ground electrode 144 extend in the first direction as a whole, and their respective main electrodes can be arranged parallel to each other. The first signal electrode 142 and the second signal electrode 143 are used to receive differential signals. Specifically, the first signal electrode 142 and the second signal electrode 143 each receive radio frequency voltage signals S1 and S2 of equal amplitude and opposite phases (indicated by the symbols "-" and "+"), and thus the radio frequency voltage signals S1 and S2 are differential signals.

[0036] The material of the waveguide layer 130 can include an electro-optic material such as lithium niobate, lithium tantalate, or potassium titanyl phosphate. When differential signals (such as the radio frequency voltage signals S1 and S2 described above) are input to the first signal electrode 142 and the second signal electrode 143, and the first ground electrode 141 and the second ground electrode 144 are grounded (indicated by "G" in the figure), the first waveguide arm 131 is located within a first electric field E1 formed by the first signal electrode 142 and the first ground electrode 141, and the second waveguide arm 132 is located within a second electric field E2 formed by the second signal electrode 143 and the second ground electrode 144. As shown in the figure, the sub-electrode structure design of the first ground electrode 141, the first signal electrode 142, the second signal electrode 143, and the second ground electrode 144 enables the direction of the first electric field E1 to be exactly opposite to the direction of the second electric field E2. The refractive index of the first waveguide arm 131 and the refractive index of the second waveguide arm 132 change together with the differential signals S1 and S2 received by the first signal electrode 142 and the second signal electrode 143 respectively, thereby enabling modulation of the phase of the branched optical signal transmitted therein. As a result, when the two branched optical signals reach the optical coupling element, a target phase difference is achieved. Here, the target phase difference is, for example, an odd multiple or an even multiple of π.

[0037] In an embodiment of the present disclosure, by using the sub-electrode structure design of the first ground electrode 141, the first signal electrode 142, the second signal electrode 143, and the second ground electrode 144, in addition to enabling the first electric field E1 and the second electric field E2 to be designed to have opposite directions, the distance between the signal electrode and the ground electrode can also be shortened, and the two electrodes can be brought as close to each other as possible. As a result, the strength of the electric field can be increased, and the transmission loss of the electrical signal can be reduced.

[0038] In addition, some characteristics of the electrode structure (such as impedance and transmission speed) are closely related to specific design parameters of the sub - electrodes (such as shape, size, and number) that can be flexibly adjusted according to actual design requirements. As a result, the electro - optical modulator 100 comes to have an impedance that is equal to or similar to the impedance at the input end of the electro - optical modulator as much as possible, thereby compensating to a certain extent for the difference in the transmission speeds of the optical signal and the electrical signal, and thereby achieving the best possible matching between these two transmissions.

[0039] As shown in FIG. 4, in the electro - optical modulator 002 of some comparative embodiments of the present disclosure, the electrode layer adopts an electrode arrangement configuration of GSGSG. Specifically, the first ground electrode 241, the first signal electrode 242, the second ground electrode 243, the second signal electrode 244, and the third ground electrode 245 are arranged in order. The first ground electrode 241 and the first signal electrode 242 form a first electric field E111 therebetween, the second ground electrode 243 and the second signal electrode 244 form a second electric field E22 having a direction opposite to that of the first electric field E11 therebetween, the first waveguide arm 231 is located between the first ground electrode 241 and the first signal electrode 242, and the second waveguide arm 233 is located between the second ground electrode 243 and the second signal electrode 244. In such a structure of the electro - optical modulator 002, in order to block or reduce crosstalk that may be generated by external factors in relation to the second signal electrode 244, the third ground electrode 245 is also necessarily provided. Therefore, three ground electrodes are included in the structural design of the electro - optical modulator 002, thereby making the overall size of the electro - optical modulator 002 relatively large in the extending direction perpendicular to the waveguide arm.

[0040] However, by using the design of the electro - optical modulator 100 in the embodiment of the present disclosure with reference to FIG. 2, it is possible to include a minimum of two ground electrodes, thereby making it possible to design the electro - optical modulator 100 to have an overall smaller size compared to the above - mentioned comparative example.

[0041] In some embodiments of the present disclosure as shown in FIG. 5, the electrode layer 140 may further include a third ground electrode 145 located between the first signal electrode 142 and the second signal electrode 143, that is, a GSGSG electrode arrangement configuration may be adopted. By doing so, the third ground electrode 145 is located between the first signal electrode 142 and the second signal electrode 143. As a result, crosstalk that may occur between the first signal electrode and the second signal electrode can be blocked or reduced, thereby improving the stability of differential signal transmission and promoting further reduction of transmission loss. To minimize the overall size of the electro-optic modulator 100, the third ground electrode 145 may be designed to have a relatively small width.

[0042] As shown in FIG. 2, in some embodiments of the present disclosure, each first sub-electrode 13 is in a T-shaped connection state with the corresponding first connection electrode 12, each second sub-electrode 23 is in a T-shaped connection state with the corresponding second connection electrode 22, each third sub-electrode 33 is in a T-shaped connection state with the corresponding third connection electrode 32, and each fourth sub-electrode 43 is in a T-shaped connection state with the corresponding fourth connection electrode 42.

[0043] In some other embodiments of the present disclosure, each first sub-electrode may also be in an L-shaped connection state with the corresponding first connection electrode. Similarly, each second sub-electrode may be in an L-shaped connection state with the corresponding second connection electrode, each third sub-electrode may be in an L-shaped connection state with the corresponding third connection electrode, and each fourth sub-electrode may be in an L-shaped connection state with the corresponding fourth connection electrode.

[0044] The shape of the sub-electrode is flexibly designed, and the design parameters of the sub-electrode can be adjusted according to actual design requirements. As a result, the electro-optic modulator 100 has an impedance equal to or similar to the impedance at the input end of the electro-optic modulator as much as possible, thereby compensating for the difference in the transmission speeds of the optical signal and the electrical signal, and thereby achieving the best possible compatibility between these two transmissions.

[0045] As shown in FIG. 2, in some embodiments, in the extending direction of the first waveguide arm 131 and the second waveguide arm 132 (i.e., in the first direction), a plurality of first sub - electrodes 13 are arranged opposite to a plurality of second sub - electrodes 23 in a one - to - one correspondence, and a plurality of third sub - electrodes 33 are arranged alternately with a plurality of fourth sub - electrodes 43. With this design, it is possible to make the effective overlapping area between the plurality of first sub - electrodes 13 and the plurality of second sub - electrodes 23 and between the plurality of third sub - electrodes 33 and the plurality of fourth sub - electrodes 43 relatively large. As a result, the strengths of the formed first electric field E1 and second electric field E2 can be increased, and the transmission loss of the electrical signal can be minimized.

[0046] In some embodiments of the present disclosure with reference to FIG. 6, the distance from each of the second main electrode 21 and the third main electrode 31 to the substrate 110 is h1, the distance from each of the first main electrode 11 and the fourth main electrode 41 to the substrate 110 is h2, and h1≠h2.

[0047] The main electrodes of the signal electrodes are arranged at various heights from the main electrodes of the ground electrode. Thereby, by utilizing this height difference through this structural design, it supports flexible adjustment and design of electrical signal transmission, thereby making it possible to reduce the difference in transmission speeds between optical signals and electrical signals, and thereby enabling optical signals and electrical signals to achieve good compatibility between them.

[0048] As shown in FIG. 6, in some embodiments of the present disclosure, the electro - optical modulator 100 further includes a patterned dielectric layer 150 located between the waveguide layer 130 and the electrode layer 140, and the patterned dielectric layer 150 has a lower dielectric constant than the waveguide layer 130. With respect to the substrate 110 parallel and in the first directionIn the vertical direction, the patterned dielectric layer 150 has no overlapping portions with the first main electrode 11 and the fourth main electrode 41, and at least a part of the patterned dielectric layer 150 overlaps with the second main electrode 21 and the third main electrode 31. In this embodiment, by utilizing the difference in the thickness of the patterned dielectric layer 150 in various regions, the second main electrode 21 and the third main electrode 31 are made higher so that they are arranged at various heights from the first main electrode 11 and the fourth main electrode 41.

[0049] In some other embodiments of the present disclosure, the patterned dielectric layer can also be designed so as not to have overlapping portions with the second main electrode and the third main electrode, and also so that at least a part of the patterned dielectric layer overlaps with the first main electrode and the fourth main electrode. In this embodiment, by utilizing the difference in the thickness of the patterned dielectric layer 150 in various regions, the first main electrode 11 and the fourth main electrode 41 are made higher so that they are arranged at various heights from the second main electrode 21 and the third main electrode 31.

[0050] When the electrode layer of the electro - optical modulator 100 adopts the design scheme shown in FIG. 5, it can be designed such that the distance from the third ground electrode 145 of the electrode layer to the substrate 110 becomes h1. That is, the third ground electrode is arranged at the same height as the first main electrode 11 and the fourth main electrode 41, and thus is arranged at a different height from the second main electrode 21 and the third main electrode 31. It should be noted.

[0051] As shown in FIG. 7, in some embodiments of the present disclosure, the electrode layer of the electro-optical modulator 100 adopts a design of a GSGSG electrode arrangement configuration. The electrode layer includes a first ground electrode 741, a first signal electrode 742, a second ground electrode 743, a second signal electrode 744, and a third ground electrode 745, which are arranged in sequence. The first signal electrode 742 and the second signal electrode 744 are configured to receive differential signals (represented by S1 and S2 respectively). The second ground electrode 743 includes a first main electrode 7430, a plurality of first connection electrodes 12 located on one side of the first main electrode 7430 and connected to the first main electrode 7430, a plurality of first sub-electrodes 13, a plurality of fourth connection electrodes 42 located on the other side of the first main electrode 7430 and connected to the first main electrode 7430, and a plurality of fourth sub-electrodes 43. The first signal electrode 742 includes a second main electrode 7420, a plurality of second connection electrodes 22 connected to the second main electrode 7420, and a plurality of second sub-electrodes 23. The second signal electrode 744 includes a third main electrode 7440, a plurality of third connection electrodes 32 connected to the third main electrode 7440, and a plurality of third sub-electrodes 33.

[0052] As shown in FIG. 7, a plurality of first sub-electrodes 13 and a plurality of second sub-electrodes 23 are configured to form a first electric field E1 between the plurality of first sub-electrodes and the plurality of second sub-electrodes, and a plurality of third sub-electrodes 33 and a plurality of fourth sub-electrodes 43 are configured to form a second electric field E2 having a direction opposite to that of the first electric field between the plurality of third sub-electrodes and the plurality of fourth sub-electrodes. The first waveguide arm 131 is located between the plurality of first sub-electrodes 13 and the plurality of second sub-electrodes 23, and thus is located within the first electric field E1. The second waveguide arm 132 is located between the plurality of third sub-electrodes 33 and the plurality of fourth sub-electrodes 43, and thus is located within the second electric field E2.

[0053] In these embodiments, in addition to being able to design the first electric field E1 and the second electric field E2 to have opposite directions by this structural design of the electrode layer, the distance between the signal electrode and the ground electrode can be shortened, and these two electrodes can be made to approach each other as closely as possible. As a result, the strength of the electric field can be increased, and the transmission loss of the electrical signal can be reduced.

[0054] In some embodiments, the distance from each of the second main electrode 7420 and the third electrode 7440 to the substrate is h3, the distance from each of the first ground electrode 741, the third ground electrode 745, and the first main electrode 7430 to the substrate is h4, and h3≠h4. Specifically, the main electrodes of the first ground electrode, the third ground electrode, and the second ground electrode are arranged and configured at different heights from the main electrodes of the two signal electrodes. Thereby, by utilizing this height difference through this structural design, it is possible to assist in the flexible adjustment and design of electrical signal transmission, thereby reducing the difference in transmission speeds between optical signals and electrical signals, and thereby enabling the optical signal and the electrical signal to achieve good compatibility between them.

[0055] In the embodiments of the present disclosure, the specific product form of the electro-optical modulator 100 is not limited. For example, it can be designed as a stripe electro-optical modulator or a folded type electro-optical modulator based on the above concept. Here, the folded type electro-optical modulator can include one or more curved portions.

[0056] In some embodiments, the electrode layer of this folded type electro-optical modulator adopts the design of the GSSG electrode arrangement configuration, and various sub-electrodes and connection electrodes can be designed with reference to the embodiments shown in FIG. 2. Here, the first main electrode 11, the second main electrode 21, the third main electrode 31, and the fourth main electrode 41 are in a folded form as a whole (this folding form is not shown in the figure) and do not cross each other.

[0057] Based on the design of the electrode arrangement configuration of the GSSG, in some embodiments, the first waveguide arm 131, the second waveguide arm 132, the first main electrode 11, the second main electrode 21, the third main electrode 31, and the fourth main electrode 41 are designed so as not to cross each other and to have substantially synchronized bends.

[0058] Based on the design of the electrode arrangement configuration of the GSSG, in some other embodiments, the first waveguide arm 131 and / or the second waveguide arm 132 can cross one or more of the first main electrode 11, the second main electrode 21, the third main electrode 31, and the fourth main electrode 41 in order to form a bending delay. In this way, the transmission speed of the waveguide and the transmission speed of the electrodes can be flexibly adjusted to achieve the best possible matching between them, thereby reducing transmission loss.

[0059] As shown in FIG. 8A, in some embodiments of the present disclosure, the electro-optic modulator 100 is a folded type electro-optic modulator. The electrode layer of this folded type electro-optic modulator adopts the design of the electrode arrangement configuration of GSGSG, and each of the sub-electrodes and each of the connection electrodes are designed in a manner similar to the method of the embodiment shown in FIG. 5, where the first main electrode 11, the second main electrode 21, the third ground electrode 145, the third main electrode 31, and the fourth main electrode 41 are in a folded form as a whole and do not cross each other.

[0060] In this embodiment, the first waveguide arm 131, the second waveguide arm 132, the first main electrode 11, the second main electrode 21, the third main electrode 31, and the fourth main electrode 41 are designed so as not to cross each other and to have substantially synchronized bends.

[0061] As shown in FIG. 8B, in some other embodiments of the present disclosure, the electro-optic modulator 100 is a folded type electro-optic modulator. The electrode layer of this folded type electro-optic modulator adopts the design of the GSGSG electrode arrangement configuration, and each of the sub-electrodes and each of the connection electrodes are designed in the same manner as the method of the embodiment shown in FIG. 5. Here, the first main electrode 11, the second main electrode 21, the third ground electrode 145, the third main electrode 31, and the fourth main electrode 41 are in a folded form as a whole, do not cross each other, and the first waveguide arm 131 and the second waveguide arm 132 (alternatively, the first waveguide arm 131 or the second waveguide arm 132) cross one or more of the first main electrode 11, the second main electrode 21, the third ground electrode 145, the third main electrode 31, and the fourth main electrode 41 in order to form a bending delay. In this way, the transmission speed of the waveguide and the transmission speed of the electrode can be flexibly adjusted to achieve the best possible matching between them, thereby reducing the transmission loss.

[0062] As shown in FIG. 9A, in some other embodiments of the present disclosure, the electro-optic modulator 100 is a folded type electro-optic modulator. The electrode layer of this folded type electro-optic modulator adopts the design of the GSGSG electrode arrangement configuration, and various sub-electrodes and connection electrodes are designed in the same manner as the method of the embodiment shown in FIG. 7. Here, the first ground electrode 741, the second main electrode 7420, the first main electrode 7430, the third main electrode 7440, and the third ground electrode 745 are in a folded form as a whole and do not cross each other. In this embodiment, the first waveguide arm 131, the second waveguide arm 132, the first ground electrode 741, the second main electrode 7420, the first main electrode 7430, the third main electrode 7440, and the third ground electrode 745 are designed so as not to cross each other and to have substantially synchronized curvatures.

[0063] As shown in FIG. 9B, in some embodiments of the present disclosure, the electro-optic modulator 100 is a folded type electro-optic modulator. The electrode layer of this folded type electro-optic modulator adopts the design of the GSGSG electrode arrangement configuration. Some sub-electrodes and connection electrodes are designed in the same manner as the method of the embodiment shown in FIG. 5, while some sub-electrodes and connection electrodes are designed in the same manner as the method of the embodiment shown in FIG. 7, that is, the combined design of the embodiments shown in FIGS. 5 and 7 is adopted. The fourth main electrode 41 is in a curved connection state with the third ground electrode 745, the third main electrode 31 is in a curved connection state with the third main electrode 7440, the third ground electrode 145 is in a curved connection state with the first main electrode 7430, the second main electrode 21 is in a curved connection state with the second main electrode 7420, and the first main electrode 11 is in a curved connection state with the first ground electrode 741. The first waveguide arm 131 and the second waveguide arm 132 (alternatively, the first waveguide arm 131 or the second waveguide arm 132) intersect one or more of the above ground electrodes or main electrodes to form a bending delay. In this way, the transmission speed of the waveguide and the transmission speed of the electrode can be flexibly adjusted to achieve the best possible matching between them, thereby reducing the transmission loss.

[0064] The folded type electro-optic modulator has an S-shaped bending portion, thereby making it possible to reduce the size of the device in the longitudinal direction. To achieve better device performance, the length of the waveguide can be designed to increase as needed. However, due to the folded type design, the length of the device is less affected, thereby making it possible to implement a device with a miniaturized design.

[0065] As shown in FIG. 3, in some embodiments of the present disclosure, the waveguide layer 130 adopts the design of a ridge waveguide and further includes a slab waveguide 133. The first waveguide arm 131 and the second waveguide arm 132 are located on one side of the slab waveguide 133 away from the substrate 110 and are integrally connected to the slab waveguide 133, so that they can be integrally formed. Since the waveguide layer 130 adopts the design of a ridge waveguide, it has a series of excellent characteristics of a ridge waveguide, such as a low cut-off frequency of the fundamental mode, a wide bandwidth, and a low impedance.

[0066] In conclusion, due to the design of the electro-optic modulator 100 of the above embodiments of the present disclosure, in addition to being designed such that the electric fields acting on the two waveguide arms have opposite directions, the distance between the signal electrode and the ground electrode can be shortened. As a result, the strength of the electric field can be increased, and the transmission loss of the electrical signal can be reduced.

[0067] In this description, terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" indicate the orientation or positional relationship or dimensions shown based on the accompanying drawings. These terms are not used to indicate or imply that the device or element being referred to must have a specific orientation and must be constructed and operated in this specific orientation. Instead, they are used for the sake of ease of explanation and should not be construed as limiting the protection scope of the present disclosure.

[0068] In addition, terms such as "first", "second", and "third" are for illustrative purposes only and should not be construed as indicating relative importance or implicitly meaning, or implicitly indicating the number of technical features shown. Thus, features defined using "first", "second", and "third" can include one or more features, whether explicit or implicit. In the description of the present disclosure, the term "a plurality of" means two or more unless explicitly or specifically defined otherwise.

[0069] In the present disclosure, terms such as "install", "connect", "connected", and "fix" should be construed in a broad sense unless explicitly stated or otherwise defined. For example, these terms can be a fixed connection, a detachable connection, or an integral connection, or a mechanical connection or an electrical connection, or communication, and can be a direct connection or an indirect connection through an intermediate medium, or internal communication between two elements or interaction between two elements. A person skilled in the art can understand the specific meaning of the above terms of the present disclosure according to a specific environment.

[0070] In the present disclosure, unless explicitly stated or otherwise defined, the expression that a first feature is "above" or "below" a second feature can include cases where the first feature directly contacts the second feature, or cases where the first feature and the second feature are not in direct contact but are connected through another feature therebetween. Further, the fact that a first feature is "on", "above", or "in contact and above" a second feature includes cases where the first feature is directly above or obliquely above the second feature, that is, simply indicates that the first feature is at a higher level than the second feature. The fact that a first feature is "under", "below", or "right below" a second feature includes cases where the first feature is directly below or obliquely below the second feature, that is, simply indicates that the first feature is at a lower level than the second feature.

[0071] This description provides many different implementation forms or examples that can be used to implement the present disclosure. It should be understood that these various implementation forms or examples are merely illustrative and are not intended to limit the protection scope of the present disclosure. Based on the disclosure of this description of the present disclosure, those skilled in the art will be able to come up with various modification forms or replacement forms. All of these modification forms or replacement forms shall be within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be under the control of the protection scope of the claims.

Claims

1. An electro-optical modulator comprising a substrate, an insulating layer, a waveguide layer, and an electrode layer arranged in sequence, wherein the electrode layer includes a plurality of first sub-electrodes arranged in sequence in a first direction and a plurality of first connection electrodes connected to the plurality of first sub-electrodes in a manner that intersects one-to-one; a plurality of second sub-electrodes arranged in sequence in the first direction and a plurality of second connection electrodes connected to the plurality of second sub-electrodes in a manner that intersects one-to-one; a plurality of third sub-electrodes arranged in sequence in the first direction and a plurality of third connection electrodes connected to the plurality of third sub-electrodes in a manner that intersects one-to-one; and a plurality of fourth sub-electrodes arranged in sequence in the first direction and a plurality of fourth connection electrodes connected to the plurality of fourth sub-electrodes in a manner that intersects one-to-one. The plurality of first sub-electrodes and the plurality of fourth sub-electrodes are configured to be grounded, the plurality of second sub-electrodes and the plurality of third sub-electrodes are configured to receive differential signals, the plurality of first sub-electrodes and the plurality of second sub-electrodes are configured to form a first electric field between the plurality of first sub-electrodes and the plurality of second sub-electrodes, and the plurality of third sub-electrodes and the plurality of fourth sub-electrodes are configured to form a second electric field having a direction opposite to that of the first electric field between the plurality of third sub-electrodes and the plurality of fourth sub-electrodes, wherein the waveguide layer includes a first waveguide arm and a second waveguide arm, the first waveguide arm is located between the plurality of first sub-electrodes and the plurality of second sub-electrodes in a direction parallel to the substrate and perpendicular to the first direction, and does not intersect the plurality of first connection electrodes and the plurality of second connection electrodes, and the second waveguide arm is located between the plurality of third sub-electrodes and the plurality of fourth sub-electrodes and intersects the plurality of third connection electrodes and the plurality of fourth connection electrodes. An electro-optical modulator.

2. The electrode layer includes a first ground electrode, a first signal electrode, a second signal electrode, and a second ground electrode arranged in sequence, and the first signal electrode and the second signal electrode are configured to receive differential signals. The first ground electrode includes a first main electrode, the plurality of first connection electrodes connected to the first main electrode, and the plurality of first sub - electrodes. The first signal electrode includes a second main electrode, the plurality of second connection electrodes connected to the second main electrode, and the plurality of second sub - electrodes. The second signal electrode includes a third main electrode, the plurality of third connection electrodes connected to the third main electrode, and the plurality of third sub - electrodes. The electro - optical modulator according to claim 1, wherein the second ground electrode includes a fourth main electrode, the plurality of fourth connection electrodes connected to the fourth main electrode, and the plurality of fourth sub - electrodes.

3. The electro - optical modulator according to claim 2, wherein the distance from each of the second main electrode and the third main electrode to the substrate is h1, the distance from each of the first main electrode and the fourth main electrode to the substrate is h2, and h1≠h2.

4. The first main electrode, the second main electrode, the third main electrode, and the fourth main electrode are in a folded form as a whole and do not intersect with each other. The electro - optical modulator according to claim 2, wherein the first waveguide arm and the second waveguide arm do not intersect with any of the first main electrode, the second main electrode, the third main electrode, and the fourth main electrode, or at least one of the first waveguide arm and the second waveguide arm intersects with one or more of the first main electrode, the second main electrode, the third main electrode, and the fourth main electrode.

5. The electro - optical modulator according to claim 2, wherein the electrode layer further includes a third ground electrode located between the first signal electrode and the second signal electrode.

6. The first main electrode, the second main electrode, the third ground electrode, the third main electrode, and the fourth main electrode are in a folded form as a whole and do not intersect with each other. The first waveguide arm and the second waveguide arm do not intersect any of the first main electrode, the second main electrode, the third ground electrode, the third main electrode, and the fourth main electrode, or at least one of the first waveguide arm and the second waveguide arm intersects one or more of the first main electrode, the second main electrode, the third ground electrode, the third main electrode, and the fourth main electrode. The electro-optic modulator according to claim 5.

7. The electrode layer includes a first ground electrode, a first signal electrode, a second ground electrode, a second signal electrode, and a third ground electrode arranged in sequence. The first signal electrode and the second signal electrode are configured to receive differential signals. The second ground electrode includes a first main electrode, a plurality of first connection electrodes located on one side of the first main electrode and connected to the first main electrode, the plurality of first sub-electrodes, a plurality of fourth connection electrodes located on the other side of the first main electrode and connected to the first main electrode, and the plurality of fourth sub-electrodes. The first signal electrode includes a second main electrode, a plurality of second connection electrodes connected to the second main electrode, and the plurality of second sub-electrodes. The second signal electrode includes a third main electrode, a plurality of third connection electrodes connected to the third main electrode, and the plurality of third sub-electrodes. The electro-optic modulator according to claim 1.

8. The distance from each of the second main electrode and the third main electrode to the substrate is h3, the distance from each of the first ground electrode, the third ground electrode, and the first main electrode to the substrate is h4, and h3 ≠ h4. The electro-optic modulator according to claim 7.

9. The first ground electrode, the second main electrode, the first main electrode, the third main electrode, and the third ground electrode are in a folded form as a whole and do not intersect each other. The first waveguide arm and the second waveguide arm do not intersect any of the first ground electrode, the second main electrode, the first main electrode, the third main electrode, and the third ground electrode, or at least one of the first waveguide arm and the second waveguide arm intersects one or more of the first ground electrode, the second main electrode, the first main electrode, the third main electrode, and the third ground electrode. The electro-optic modulator according to claim 7.

10. Each of the first sub-electrodes is in a T-shaped or L-shaped connection state with a corresponding one of the first connection electrodes among the first connection electrodes. Each of the second sub-electrodes is in a T-shaped or L-shaped connection state with a corresponding one of the second connection electrodes among the second connection electrodes. Each of the third sub-electrodes is in a T-shaped or L-shaped connection state with a corresponding one of the third connection electrodes among the third connection electrodes. Each of the fourth sub-electrodes is in a T-shaped or L-shaped connection state with a corresponding one of the fourth connection electrodes among the fourth connection electrodes. The electro-optic modulator according to claim 1.

11. In the first direction, the plurality of first sub-electrodes are arranged opposite to the plurality of second sub-electrodes in a one-to-one correspondence, and the plurality of third sub-electrodes are arranged alternately with the plurality of fourth sub-electrodes. The electro-optic modulator according to claim 1.

12. The waveguide layer further includes a slab waveguide. The first waveguide arm and the second waveguide arm are located on one side of the slab waveguide away from the substrate. The electro-optic modulator according to claim 1.

13. The electro-optic modulator is An optical branching element including a signal input end portion, a first optical branching output end portion, and a second optical branching output end portion, wherein one end portion of the first waveguide arm and one end portion of the second waveguide arm are connected to the first optical branching output end portion and the second optical branching output end portion in a one-to-one correspondence. An optical branching element, An optical coupling element including a first optical branching input end portion, a second optical branching input end portion, and a signal output end portion, wherein the other end portion of the first waveguide arm and the other end portion of the second waveguide arm are connected to the first optical branching input end portion and the second optical branching input end portion in a one-to-one correspondence. An optical coupling element, The electro-optic modulator according to claim 1 further comprising.

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