Electro-optic Modulator

Abstract

An electro-optical modulator is provided, which includes: an optical splitting element; an optical coupling element; a first waveguide arm and a second waveguide arm arranged in parallel and connected between the optical splitting element and the optical coupling element; and a first ground electrode, a first signal electrode, a second ground electrode, a second signal electrode, and a third ground electrode arranged in sequence, where the first waveguide arm is located between the first ground electrode and the first signal electrode, the second waveguide arm is located between the second ground electrode and the second signal electrode, and the first signal electrode and the second signal electrode are configured to receive a differential signal. The technical solutions of the embodiments of the present disclosure can improve the operation performance of the electro-optical modulator.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Patent Application No. 202210179793.2, entitled "ELECTRO-OPTIC MODULATOR," filed February 25, 2022. The disclosure of the priority claimed by this application is incorporated herein by reference in its entirety.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to the field of optical communications, and more particularly to electro-optic modulators. [Background technology]

[0003] In recent years, the rapid development of emerging network application services such as the Internet of Things, autonomous driving, telemedicine, and distance learning has led to a growing demand for high-speed, high-capacity communication technologies. Optical communications, with its characteristics of large bandwidth, high reliability, low cost, and high anti-interference capability, has achieved rapid development in the direction of high-speed, high-capacity communication. One of the core research topics is the method for loading high-speed electrical signals onto optical carrier waves.

[0004] An electro-optic modulator is a modulator built on the electro-optic effect of electro-optic materials. The electro-optic effect means that when a voltage is applied to an electro-optic material, such as lithium niobate, gallium arsenide, or lithium tantalate crystal, the refractive index of the electro-optic material changes, thereby changing the properties of the light wave passing through the electro-optic material. The electro-optic effect can be used to modulate parameters such as the phase, amplitude, intensity, and polarization state of an optical signal.

[0005] With the ever-increasing demand for high speed and high capacity communication technologies, there are higher demands on the performance of electro-optic modulators. Summary of the Invention

[0006] An embodiment of the present disclosure provides an electro-optical modulator, the electro-optical modulator including: an optical splitting element; an optical combining element; a first waveguide arm and a second waveguide arm arranged in parallel and connected between the optical splitting element and the optical combining element; and a first ground electrode, a first signal electrode, a second ground electrode, a second signal electrode, and a third ground electrode arranged in order, the first signal electrode and the second signal electrode being configured to receive a differential signal, the first waveguide arm being located between the first ground electrode and the first signal electrode, and the second waveguide arm being located between the second ground electrode and the second signal electrode.

[0007] In some embodiments, the electro-optic modulator further includes: a first independent waveguide section and a second independent waveguide section arranged parallel to the first waveguide arm and the second waveguide arm, the first independent waveguide section being located between the first signal electrode and the second ground electrode, and the second independent waveguide section being located between the second signal electrode and the third ground electrode.

[0008] In some embodiments, the electro-optic modulator includes, in order: a substrate, an insulating layer, a waveguide layer, and an electrode layer, wherein a first waveguide arm and a second waveguide arm are located in the waveguide layer, and a first ground electrode, a first signal electrode, a second ground electrode, a second signal electrode, and a third ground electrode are located in the electrode layer.

[0009] In some embodiments, the first signal electrode and the second signal electrode each include a first main electrode having a distance of h1 from the substrate, and the first ground electrode, the second ground electrode, and the third ground electrode each include a second main electrode having a distance of h2 from the substrate, where h1≠h2.

[0010] In some embodiments, the electro-optic modulator further includes a dielectric layer located between the waveguide layer and the electrode layer, the dielectric layer having a dielectric constant smaller than that of the waveguide layer, the waveguide layer including a flat layer and a ridged layer located on a side of the flat layer away from the substrate, the first waveguide arm and the second waveguide arm being located in the ridged layer, the first main electrode being formed on a surface of the dielectric layer on a side away from the substrate, and the second main electrode being formed on a surface of the flat layer on a side away from the substrate.

[0011] In some embodiments, the electro-optic modulator further includes a dielectric layer located between the waveguide layer and the electrode layer, wherein the dielectric constant of the dielectric layer is smaller than the dielectric constant of the waveguide layer, the waveguide layer is a raised pattern layer, and a first main electrode is formed on a surface of the dielectric layer on a side away from the substrate, and a second main electrode is formed on a surface of the insulating layer on a side away from the substrate.

[0012] In some embodiments, each of the first signal electrode and the second signal electrode further includes a first extension electrode connected to correspond to the respective first main electrode.

[0013] In some embodiments, each of the first ground electrode, the second ground electrode, and the third ground electrode further includes a second extended electrode connected to correspond to the respective second main electrode.

[0014] In some embodiments, each of the first signal electrode and the second signal electrode further includes a first extended electrode connected to correspond to the respective first main electrode, where the first extended electrode is a surface-shaped extended electrode having the same extension direction as the first main electrode, or the first extended electrode includes a plurality of first sub-electrodes spaced apart in the extension direction of the first main electrode; each of the first ground electrode, the second ground electrode, and the third ground electrode further includes a second extended electrode connected to correspond to the respective second main electrode, where the second extended electrode is a surface-shaped extended electrode having the same extension direction as the second main electrode, or the second extended electrode includes a plurality of second sub-electrodes spaced apart in the extension direction of the second main electrode, and at least a portion of the first extended electrode and at least a portion of the second extended electrode are located in the same plane.

[0015] In some embodiments, the waveguide layer includes a flat layer and a raised layer located on a side of the flat layer away from the substrate, the first waveguide arm and the second waveguide arm are located in the raised layer, and at least a portion of the first extended electrode and at least a portion of the second extended electrode are formed on a surface of the flat layer on a side of the flat layer away from the substrate.

[0016] In some embodiments, the waveguide layer is a raised pattern layer, and at least a portion of the first extended electrode and at least a portion of the second extended electrode are formed on a surface of the insulating layer on a side remote from the substrate.

[0017] In some embodiments, the first ground electrode includes one second extended electrode arranged on a side of the first ground electrode closer to the first signal electrode; the first signal electrode includes two first extended electrodes distributed on both sides of the first signal electrode; the second ground electrode includes two second extended electrodes distributed on both sides of the second ground electrode; the second signal electrode includes two first extended electrodes distributed on both sides of the second signal electrode; and the third ground electrode includes one second extended electrode arranged on a side of the third ground electrode closer to the second signal electrode.

[0018] In some embodiments, the waveguide layer includes a flat layer and a raised layer located on a side of the flat layer away from the substrate, the first waveguide arm and the second waveguide arm are located in the raised layer, and the first main electrode or the second main electrode penetrates the flat layer and contacts the insulating layer.

[0019] In some embodiments, the electro-optic modulator further includes a dielectric layer located between the waveguide layer and the electrode layer, the dielectric layer having a dielectric constant less than the dielectric constant of the waveguide layer, and the dielectric layer covering the first waveguide arm and the second waveguide arm.

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

[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 explanation of the drawings]

[0022] [Figure 1] 1 is a schematic structural diagram showing a conventional electro-optic modulator of the related art; [Figure 2] 1A and 1B are schematic structural diagrams of electro-optic modulators according to some exemplary embodiments of the present disclosure. [Figure 3] 10A-10C are schematic structural diagrams illustrating electro-optic modulators according to some other exemplary embodiments of the present disclosure. [Figure 4] 1A-1C are schematic structural cross-sectional views illustrating electro-optic modulators according to some exemplary embodiments of the present disclosure. [Figure 5] 1A-1C are schematic structural cross-sectional views illustrating electro-optic modulators according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0023] Only some exemplary embodiments are briefly described below. As will 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. Accordingly, the accompanying drawings and this description are to be regarded as illustrative in nature and not restrictive.

[0024] Electro-optic modulation-related technologies have been widely developed and applied in fields such as optical communications, microwave photonics, laser beam deflection, and wavefront modulation. The Mach-Zehnder modulator is a type of electro-optic modulator in which an input optical signal is equally split into two branch optical signals, each of which enters two waveguide arms. The two waveguide arms are made of electro-optic materials and have refractive indices that change with the applied modulation voltage. The change in refractive index of the waveguide arms can cause a change in the phase of the branch optical signals. Therefore, the output from the convergence of the two branch optical signals is an interference signal whose intensity changes with the modulation voltage. In short, a Mach-Zehnder modulator can implement various sideband modulations by controlling the modulation voltage applied to the two waveguide arms. As a device for converting electrical signals to optical signals, the Mach-Zehnder modulator is one of the common core devices in optical interconnection, optical computing, and optical communication systems.

[0025] As shown in Figure 1, a schematic diagram of a conventional Mach-Zehnder modulator is shown. Ideally, the Mach-Zehnder modulator 001 has two waveguide arms 02 that are exactly equal to each other. When the Mach-Zehnder modulator 001 is not operating, neither of the two waveguide arms 02 is subject to the electro-optic effect. The input light passes through the optical splitter 01 and is then equally split into two branch optical signals. The two branch optical signals are in phase with each other after passing through the corresponding waveguide arms 02, and therefore, coherently amplified signals for the two branch optical signals are output from the optical combiner 05. When the Mach-Zehnder modulator 001 is operating, the modulation electrodes 04 (e.g., including a signal electrode 040, a first ground electrode 041, and a second ground electrode 042) apply modulation voltages to the two waveguide arms 02, such that the phases of the two branch optical signals can differ by odd or even multiples of Π after each of the two branch optical signals passes through one waveguide arm 02. When the phases of the two branch optical signals differ by even multiples of Π, the optical coupler 05 outputs coherently amplified signals for the two branch optical signals. When the phases of the two branch optical signals differ by odd multiples of Π, the optical coupler 05 outputs coherently canceled signals for the two branch optical signals.

[0026] In electro-optical modulators, the transmission speed of electrical signals is mainly affected by the dielectric constant and the structure of the material, and the transmission speed of optical signals is mainly affected by the refractive index and the structure of the material. Electro-optical modulators in the related art are made of electro-optical materials with a relatively small refractive index and a relatively large dielectric constant, which increases the transmission speed of optical signals and decreases the transmission speed of electrical signals, making it difficult to achieve a better match between these two transmission speeds, which results in a relatively large transmission loss in the electro-optical modulator and suboptimal device performance.

[0027] In view of this, the embodiments of the present disclosure provide an electro-optic modulator to reduce the transmission loss of the electro-optic modulator, thus improving the operating performance of the electro-optic modulator.

[0028] As shown in FIG. 2 , an electro-optic modulator 100 provided according to some embodiments of the present disclosure includes an optical splitter element 110; an optical combiner element 120; a first waveguide arm 131 and a second waveguide arm 132 arranged in parallel; and a first ground electrode 151, a first signal electrode 152, a second ground electrode 153, a second signal electrode 154, and a third ground electrode 155 arranged in sequence. The first signal electrode 152 and the second signal electrode 154 are configured to receive a differential signal. The first waveguide arm 131 and the second waveguide arm 132 are connected between the optical splitter element 110 and the optical combiner element 120. Furthermore, the first waveguide arm 131 is located between the first ground electrode 151 and the first signal electrode 152, and the second waveguide arm 132 is located between the second ground electrode 153 and the second signal electrode 154.

[0029] The optical dividing element 110 is not particularly limited in type and includes at least one input port and two output ports, for example, an optical dividing element having one input section and two output sections. The optical combining element 120 is not particularly limited in type and includes at least two input ports and one output port, for example, an optical combining element having two input sections and one output section, or an optical combining element having two input sections and three output sections. A first waveguide arm 131 is connected between one output port of the optical dividing element 110 and one input port of the optical combining element 120, and a second waveguide arm 132 is connected between the other output port of the optical dividing element 110 and the other input port of the optical combining element 120.

[0030] The first ground electrode 151, the first signal electrode 152, the second ground electrode 153, the second signal electrode 154, and the third ground electrode 155 are arranged in juxtaposition, for example, in parallel. The first signal electrode 152 and the second signal electrode 154 are configured to receive differential signals. That is, the first signal electrode 152 and the second signal electrode 154 receive radio frequency voltage signals S1 and S2, respectively, of equal amplitude and opposite phase, and the radio frequency voltage signals S1 and S2 are differential signals.

[0031] The material of the first waveguide arm 131 and the second waveguide arm 132 may include an electro-optic material, such as lithium niobate, lithium tantalate, or potassium titanyl phosphate. When a differential signal (such as the radio frequency voltage signals S1 and S2 described above) is input to the first signal electrode 152 and the second signal electrode 154, and the first ground electrode 151, the second ground electrode 153, and the third ground electrode 155 are grounded, the first waveguide arm 131 is located in an electric field E1 between the first signal electrode 152 and the first ground electrode 151, and the second waveguide arm 132 is located in an electric field E2 between the second signal electrode 154 and the second ground electrode 153. The direction of the electric field E1 is opposite to the direction of the electric field E2. The refractive index of the first waveguide arm 131 and the refractive index of the second waveguide arm 132 vary with the differential signals S1 and S2 received by the first signal electrode 152 and the second signal electrode 154, thereby enabling the phase of the branched optical signals transmitted therein to be modulated so as to achieve a target phase difference when the two branched optical signals reach the optical coupling element 120. The target phase difference may be, for example, an odd or even multiple of Π.

[0032] In the embodiment of the present disclosure, the second ground electrode 153 is disposed between the first signal electrode 152 and the second signal electrode 154 so that crosstalk that may occur between the two signal electrodes can be blocked or reduced. In contrast to conventional electro-optical modulators, the first signal electrode 152 and the second signal electrode 154 are independent of each other and relatively far from each other, which is also beneficial for reducing crosstalk that may occur between the two signal electrodes. The first signal electrode 152 is disposed between the first ground electrode 151 and the second ground electrode 153, and the second signal electrode 154 is disposed between the second ground electrode 153 and the third ground electrode 155, thereby blocking or reducing crosstalk that may occur to the signal electrodes due to factors unrelated to this group of electrodes. After crosstalk is reduced, the stability of electrical signal transmission is improved, resulting in reduced transmission loss of the device, thereby improving the accuracy and stability of the modulation output of the electro-optical modulator 100 and improving operational performance.

[0033] As shown in FIG. 3 , in some embodiments of the present disclosure, the electro-optical modulator 100 further includes a first independent waveguide section 133 and a second independent waveguide section 134 arranged parallel to the first waveguide arm 131 and the second waveguide arm 132, where the first independent waveguide section 133 is located between the first signal electrode 152 and the second ground electrode 153, and the second independent waveguide section 134 is located between the second signal electrode 154 and the third ground electrode 155.

[0034] First and second independent waveguide sections 133 and 134 differ from first and second waveguide arms 131 and 132 primarily in that first and second independent waveguide sections 133 and 134 are not connected to other elements and are not configured to transmit optical signals. First and second independent waveguide sections 133 and 134 are located within electric field E3 between first signal electrode 152 and second ground electrode 153, respectively, and second and third independent waveguide sections 134 and 134 are located within electric field E4 between second signal electrode 154 and third ground electrode 155. This arrangement of the independent waveguide sections allows the effects of the electric fields on both sides of the signal electrodes to be balanced. For example, electric field E1 acts on first waveguide arm 131, and electric field E3, which is opposite in direction to electric field E1, acts on first independent waveguide section 133. Although the first independent waveguide section 133 is not configured to transmit optical signals, the first independent waveguide section can symmetrically change the effects of the electric fields E1 and E3, thereby making the transmission of electrical signals of the two signal electrodes more stable, which is beneficial for further reducing the transmission loss of the device.

[0035] 4 , in some embodiments, electro-optic modulator 100 includes, in order, substrate 210, insulating layer 220, waveguide layer 230, and electrode layer 250, where first waveguide arm 131 and second waveguide arm 132 are located in waveguide layer 230, and first ground electrode 151, first signal electrode 152, second ground electrode 153, second signal electrode 154, and third ground electrode 155 are located in electrode layer 250. In embodiments including first and second independent waveguide sections 133 and 134 mentioned above, first and second independent waveguide sections 133 and 134 may alternatively be located in waveguide layer 230 (not shown in this figure).

[0036] In an embodiment of the present disclosure, the waveguide layer 230 may be a ridge waveguide layer as shown in Figure 4. The ridge waveguide layer includes a flat layer 2300 and a ridge layer 2310 located on the side of the flat layer 2300 away from the substrate 210. The flat layer 2300 and the ridge layer 2310 are an integrated structure formed by etching, with the first waveguide arm 131 and the second waveguide arm 132 located within the ridge layer 2310. The first independent waveguide section 133 and the second independent waveguide section 134 mentioned above may alternatively be located within the ridge layer 2310 (not shown in this figure). The first ground electrode 151, the first signal electrode 152, the second ground electrode 153, the second signal electrode 154, and the third ground electrode 155 are formed on the surface of the flat layer 2300 away from the substrate 210 and are located in the same plane.

[0037] In some embodiments of the present disclosure, the waveguide layer may alternatively be a raised pattern layer, i.e., the waveguide layer does not include a flat layer, and the above-mentioned first waveguide arm, second waveguide arm, first independent waveguide section, and second independent waveguide section may be formed directly on the surface of the insulating layer away from the substrate.

[0038] As shown in FIG. 5 , in the electro-optic modulator 100 according to some embodiments of the present disclosure, the first signal electrode 152 and the second signal electrode 154 each include a first main electrode 5101 having a distance of h1 from the substrate 210, and the first ground electrode 151, the second ground electrode 153, and the third ground electrode 155 each include a second main electrode 5102 having a distance of h2 from the substrate 210, where h1≠h2, and where h1>h2 or h1 <h2である。

[0039] In this embodiment, the electro-optic modulator 100 further includes a dielectric layer 240 located between the waveguide layer 230 and the electrode layer 250, and the dielectric constant of the dielectric layer 240 is smaller than that of the waveguide layer 230. The dielectric layer 240 can cover the first waveguide arm 131 and the second waveguide arm 132, as shown in the figure. In addition, the height difference between the first main electrode 5101 and the second main electrode 5102 can be formed by the pattern design of the dielectric layer 240. For example, in this embodiment, the waveguide layer 230 includes a flat layer 2300 and a raised layer 2310 located on the side of the flat layer 2300 away from the substrate 210, and the first main electrode 5101 is formed on the surface of the dielectric layer 240 away from the substrate 210, and the second main electrode 5102 is formed on the surface of the flat layer 2300 away from the substrate 210. In some other embodiments, when the waveguide layer is a raised pattern layer, the first main electrode is formed on the surface of the dielectric layer facing away from the substrate, and the second main electrode is formed on the surface of the insulating layer facing away from the substrate.

[0040] In some embodiments of the present disclosure, the height difference between the first and second main electrodes may alternatively be formed by a difference in the thickness of the planar layers of the waveguide layer in different regions. In this design, the electro-optic modulator may or may not include a dielectric layer.

[0041] In some embodiments, the waveguide layer includes a flat layer and a raised layer located on a side of the flat layer away from the substrate, where the first and second waveguide arms are located in the raised layer, and the first or second main electrode penetrates the flat layer to contact the insulating layer. A height difference between the first and second main electrodes can also be implemented by this design.

[0042] In the embodiment of the present disclosure, the main electrodes of the first signal electrode 152 and the second signal electrode 154 (i.e., the first main electrode 5101) are arranged at the same height, and the main electrodes of the first ground electrode 151, the second ground electrode 153, and the third ground electrode 155 (i.e., the second main electrode 5102) are arranged at another height, which is beneficial to the adjustment of the signal electrode and the ground electrode respectively, making the adjustment of the electrical signal transmission more flexible and accurate, thereby more easily reducing the difference in transmission speed between the optical signal and the electrical signal, and achieving a good match between them. When the first main electrode 5101 is appropriately separated from the waveguide layer 230 having a large dielectric constant by the dielectric layer 240 having a small dielectric constant, the constraint of the electro-optical material on the transmission speed of the electrical signal can be significantly reduced, and as a result, the effect of increasing the transmission speed of the electrical signal can be achieved.

[0043] In some embodiments, each of the first signal electrode 152 and the second signal electrode 154 of the electro-optical modulator 100 further includes a first extended electrode 5201 connected to correspond to the respective first main electrode 5101; and / or each of the first ground electrode 151, the second ground electrode 153, and the third ground electrode 155 further includes a second extended electrode 5202 connected to correspond to the respective second main electrode 5102.

[0044] 5 , in some embodiments, each of the first signal electrode 152 and the second signal electrode 154 further includes a first extended electrode 5201 connected to correspond to the respective first main electrode 5101, where the first extended electrode 5201 includes a plurality of first sub-electrodes 5211 (e.g., T-shaped or L-shaped first sub-electrodes 5211) spaced apart in the extension direction of the first main electrode 5101. Each of the first ground electrode 151, the second ground electrode 153, and the third ground electrode 155 further includes a second extended electrode 5202 connected to correspond to the respective second main electrode 5102, where the second extended electrode 5202 includes a plurality of second sub-electrodes 5212 (e.g., T-shaped or L-shaped second sub-electrodes 5212) spaced apart in the extension direction of the second main electrode 5102. In this embodiment, at least a portion of the first extended electrode 5201 and at least a portion of the second extended electrode 5202 lie in the same plane.

[0045] The shapes of the first extended electrode 5201 and the second extended electrode 5202 are not limited to those shown in the drawings. For example, each of the first extended electrode 5201 and the second extended electrode 5202 may alternatively be an extended electrode whose surface is shaped in the same extension direction as the respective main electrodes.

[0046] 5 , the first waveguide arm 131 and the second waveguide arm 132 are located in the raised layer 2310, and at least a portion of the first extended electrode 5201 and at least a portion of the second extended electrode 5202 are formed on the surface of the flat layer 2300 on the side remote from the substrate 210. Because the first main electrode 5101 is separated from the flat layer 2300 by the dielectric layer 240, the first main electrode 5101 is raised, and therefore the first extended electrode 5201 further includes a high portion along the etched cross section of the dielectric layer 240.

[0047] In some embodiments, when the waveguide layer is a raised pattern layer, at least a portion of the first extended electrode and at least a portion of the second extended electrode are formed on a surface of the insulating layer on a side away from the substrate, and since the first main electrode is separated from the insulating layer by the dielectric layer, the first extended electrode is raised, and therefore the first extended electrode further includes a high portion along the etched cross section of the dielectric layer.

[0048] In this embodiment, the first ground electrode 151 includes one second extended electrode 5202 (including a plurality of second sub-electrodes 5212) disposed on a side of the first ground electrode 151 closer to the first signal electrode 152, and the first signal electrode 152 includes two first extended electrodes 5201 (each including a plurality of first sub-electrodes 5211) distributed on both sides of the first signal electrode 512. The second ground electrode 153 includes two second extended electrodes 5202 (each including a plurality of second sub-electrodes 5212) distributed on both sides of the second ground electrode 153, and the second signal electrode 154 includes two first extended electrodes 5201 (each including a plurality of first sub-electrodes 5211) distributed on both sides of the second signal electrode 154. The third ground electrode 155 includes one second extended electrode 5202 (including multiple second sub-electrodes 5212) disposed on a side of the third ground electrode 155 closer to the second signal electrode 154. Only some of the sub-electrodes are indicated by reference numerals.

[0049] This arrangement of the extended electrodes can shorten the distance between the signal electrode and the ground electrode, thereby improving the strength of the electric field and reducing the transmission loss of the electrical signal. In addition, some characteristics of the electrode structure (such as impedance and transmission speed) are closely related to the specific design parameters (such as the shape, size, and number) of the extended electrodes. The design parameters of the extended electrodes can be flexibly adjusted according to actual design requirements, so that the impedance of the electro-optical modulator 100 is as close to or equal to the impedance at the input end of the electro-optical modulator as possible, and the difference in transmission speed between the optical signal and the electrical signal can be compensated to a certain extent, so that the transmission of the optical signal and the electrical signal can be matched as much as possible, thereby further improving the performance of the electro-optical modulator 100.

[0050] In the present description, the orientations, positional relationships, or dimensions indicated by 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" are orientations, positional relationships, or dimensions shown based on the accompanying drawings, and it should be understood that these terms do not indicate or imply that the referred devices or elements must have a particular orientation or be constructed and operated in this particular orientation, but are used merely for ease of description, and therefore should not be construed as limiting the protective scope of the present disclosure.

[0051] Additionally, terms such as "first," "second," and "third" are merely for descriptive purposes and should not be construed as indicating or implying relative importance or the number of technical features shown. Thus, features defined with "first," "second," and "third" can include one or more features, whether explicitly or implicitly. In the description of this disclosure, the term "plurality" means two or more, unless expressly or specifically defined otherwise.

[0052] In the present disclosure, unless expressly stated or otherwise defined, terms such as "install," "connect," "connected," and "fix" should be interpreted broadly, for example, these terms may refer to a fixed connection, a detachable connection, or an integral connection, a mechanical connection or an electrical connection, or a communication, and may be a direct connection or an indirect connection through an intermediate medium, or an internal communication between two elements or an interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in the present disclosure according to a specific environment.

[0053] In this disclosure, unless otherwise specified or defined, a first feature being "above" or "below" a second feature can include cases where the first feature is in direct contact with the second feature, or cases where the first and second features are not in direct contact but are connected via another feature between them. Furthermore, a first feature being "above," "above," or "in contact with" a second feature includes cases where the first feature is directly above or diagonally above the second feature, i.e., simply indicates that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "just below" a second feature includes cases where the first feature is directly below or diagonally below the second feature, i.e., simply indicates that the first feature is at a lower level than the second feature.

[0054] This description provides many different implementations or examples that can be used to implement the present disclosure. It should be understood that these various implementations or examples are merely illustrative and are not intended to limit the scope of protection of the present disclosure. Based on the disclosure of the description of the present disclosure, a person skilled in the art may come up with various modifications or substitutions. All these modifications or substitutions shall fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure shall be governed by the scope of protection of the claims.

Claims

1. a light dividing element; an optical coupling element; a first waveguide arm and a second waveguide arm arranged in parallel and connected between the optical splitter element and the optical combiner element; a first ground electrode, a first signal electrode, a second ground electrode, a second signal electrode, and a third ground electrode arranged in order, the first signal electrode and the second signal electrode being configured to receive a differential signal, the first waveguide arm being located between the first ground electrode and the first signal electrode, and the second waveguide arm being located between the second ground electrode and the second signal electrode; a first independent waveguide section and a second independent waveguide section disposed parallel to the first waveguide arm and the second waveguide arm, respectively; the first independent waveguide section is located between the first signal electrode and the second ground electrode, and the second independent waveguide section is located between the second signal electrode and the third ground electrode; Electro-optic modulator.

2. a substrate, an insulating layer, a waveguide layer, and an electrode layer, arranged in that order; the first waveguide arm and the second waveguide arm are located within the waveguide layer; the first ground electrode, the first signal electrode, the second ground electrode, the second signal electrode, and the third ground electrode are located in the electrode layer; 10. The electro-optic modulator of claim 1.

3. the first signal electrode and the second signal electrode each comprise a first main electrode having a distance h1 from the substrate, and the first ground electrode, the second ground electrode, and the third ground electrode each comprise a second main electrode having a distance h2 from the substrate, where h1≠h2; 3. The electro-optic modulator of claim 2.

4. a dielectric layer positioned between the waveguide layer and the electrode layer, the dielectric constant of the dielectric layer being smaller than the dielectric constant of the waveguide layer; the waveguide layer comprises a flat layer and a raised layer located on a side of the flat layer away from the substrate, the first waveguide arm and the second waveguide arm are located in the raised layer, the first main electrode is formed on a surface of the dielectric layer on a side away from the substrate, and the second main electrode is formed on a surface of the flat layer on the side away from the substrate; 4. The electro-optic modulator of claim 3.

5. a dielectric layer positioned between the waveguide layer and the electrode layer, the dielectric constant of the dielectric layer being smaller than the dielectric constant of the waveguide layer; the waveguide layer is a raised pattern layer, the first main electrode is formed on a surface of the dielectric layer away from the substrate, and the second main electrode is formed on a surface of the insulating layer away from the substrate; 4. The electro-optic modulator of claim 3.

6. each of the first signal electrode and the second signal electrode further includes a first extension electrode connected to a corresponding one of the first main electrodes; 4. The electro-optic modulator of claim 3.

7. each of the first ground electrode, the second ground electrode, and the third ground electrode further includes a second extension electrode connected to correspond to the second main electrode; 4. The electro-optic modulator of claim 3.

8. Each of the first signal electrode and the second signal electrode further includes a first extension electrode connected to the respective first main electrode, and the first extension electrode is an extension electrode formed on a surface having the same extension direction as the first main electrode, or the first extension electrode includes a plurality of first sub-electrodes spaced apart in the extension direction of the first main electrode; Each of the first ground electrode, the second ground electrode, and the third ground electrode further includes a second extension electrode connected to correspond to the respective second main electrode, and the second extension electrode is an extension electrode formed with a surface having the same extension direction as the second main electrode, or the second extension electrode includes a plurality of second sub-electrodes spaced apart in the extension direction of the second main electrode; at least a portion of the first extended electrode and at least a portion of the second extended electrode lie in the same plane; 4. The electro-optic modulator of claim 3.

9. the waveguide layer comprises a flat layer and a raised layer located on a side of the flat layer remote from the substrate, the first waveguide arm and the second waveguide arm being located in the raised layer, and at least a portion of the first extended electrode and at least a portion of the second extended electrode being formed on a surface of the side of the flat layer remote from the substrate; 9. The electro-optic modulator of claim 8.

10. the waveguide layer is a raised pattern layer, and at least a portion of the first extended electrode and at least a portion of the second extended electrode are formed on a surface of the insulating layer away from the substrate; 9. The electro-optic modulator of claim 8.

11. the first ground electrode includes one second extension electrode disposed on a side of the first ground electrode closer to the first signal electrode; the first signal electrode comprises two first extension electrodes distributed on both sides of the first signal electrode; the second ground electrode includes two second extended electrodes distributed on both sides of the second ground electrode; the second signal electrode includes two first extension electrodes distributed on both sides of the second signal electrode; the third ground electrode includes one second extension electrode disposed on a side of the third ground electrode closer to the second signal electrode; 9. The electro-optic modulator of claim 8.

12. the waveguide layer comprises a flat layer and a raised layer located on a side of the flat layer away from the substrate, the first waveguide arm and the second waveguide arm are located in the raised layer, and the first main electrode or the second main electrode passes through the flat layer and contacts the insulating layer; 4. The electro-optic modulator of claim 3.

13. 13. The electro-optic modulator of claim 2, further comprising a dielectric layer located between the waveguide layer and the electrode layer, the dielectric layer having a dielectric constant smaller than that of the waveguide layer, and the dielectric layer covering the first waveguide arm and the second waveguide arm.

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