Electro-optic modulator

Abstract

Provided is a first optical dividing element including a first input port configured to input an operating signal, a first output port configured to output a main path signal, and a second output port configured to output a first supervisory signal; a second optical dividing element having a 1-in 2-out configuration and an input port of the second optical dividing element connected to the first output port; two waveguide arms, one end of each of the waveguide arms correspondingly connected to two output ports of the second optical dividing element; and a bias voltage modulation module configured to apply a bias voltage to the two waveguide arms based on a bias voltage signal. a radio frequency modulation module configured to apply a radio frequency voltage to the two waveguide arms based on a radio frequency signal; a third optical splitting element having a 2-in-3-out structure and two input ports of the third optical splitting element correspondingly connected to the other ends of each of the two waveguide arms; and a fourth optical splitting element having a 1-in-2-out structure and an input port of the fourth optical splitting element connected to the first output port of the third optical splitting element, the fourth optical splitting element including a third output port configured to output a maximum optical power value and a fourth output port configured to output a second monitoring signal.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical communications, and in particular, to electro-optic modulators.

Background Art

[0002] In recent years, with the rapid development of emerging network application services such as the Internet of Things, autonomous driving, telemedicine, and distance education, higher requirements have been proposed for high-speed and high-capacity communication technologies. Due to the characteristics of optical communications such as large bandwidth, high reliability, low cost, and strong anti-interference ability, optical communications have achieved rapid development in the field of high-speed and high-capacity communications. How to load high-speed electrical signals onto an optical carrier is the core research content.

[0003] An electro-optic modulator is a type of modulator fabricated 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 fluctuates, thereby causing a change in the characteristics of the light wave propagating through the electro-optic material. The use of the electro-optic effect enables modulation of parameters such as the phase, amplitude, intensity, and polarization state of an optical signal.

[0004] Due to the increasingly urgent requirements for high-speed and high-capacity communication technologies, higher requirements have been proposed for the operating performance of electro-optic modulators.

Summary of the Invention

[0005] This disclosure includes a first optical splitting element having a first input port configured to receive an operation signal, a first output port configured to output a main path signal, and a second output port configured to output a first monitoring signal; a second optical splitting element having a 1-in, 2-out structure and an input port of the second optical splitting element connected to the first output port; two waveguide arms, each having one end connected to the two output ports of the second optical splitting element in correspondence; and a bias voltage modulation module configured to apply a bias voltage to the two waveguide arms based on a bias voltage signal. The present invention provides an electro-optic modulator comprising: a radio frequency modulation module configured to apply a radio frequency voltage to two waveguide arms based on a radio frequency signal; a third optical splitting element having a 2-in, 3-out structure and two input ports of the third optical splitting element correspondingly connected to the other end of each of the two waveguide arms; and a fourth optical splitting element having a 1-in, 2-out structure and an input port of the fourth optical splitting element connected to a first output port of the third optical splitting element, a third output port configured to output a maximum optical power value, and a fourth output port configured to output a second monitoring signal.

[0006] In some embodiments, when the electro-optic modulator is operating, the optical power input from the first input port is represented by P1, the optical power output from the first output port is represented by P2 = P1 * (100 - A)%, and the optical power output from the second output port is represented by P3 = P1 * A%, where A% is less than 50%.

[0007] In some embodiments, the electro-optic modulator further includes a fifth optical splitting element having a one-in, two-out structure and an input port of the fifth optical splitting element connected to a second output port of the third optical splitting element, a fifth output port configured to output a third monitoring signal, and a sixth output port configured to output a fourth monitoring signal.

[0008] In some embodiments, A% is a constant value, or A% is determined based on the power ratio of the third monitoring signal to the fourth monitoring signal.

[0009] In some embodiments, the electro-optic modulator further includes a sixth optical splitting element having a one-in, two-out structure and an input port of the sixth optical splitting element connected to a third output port of the third optical splitting element, a seventh output port configured to output a fifth monitoring signal, and an eighth output port configured to output a sixth monitoring signal.

[0010] In some embodiments, the electro-optic modulator further includes a feedback module configured to adjust the bias voltage signal output to the bias voltage modulation module based on at least one of a first monitoring signal, a second monitoring signal, a third monitoring signal, a fourth monitoring signal, a fifth monitoring signal, and a sixth monitoring signal.

[0011] In some embodiments, the first optical splitting element further includes a second input port configured to receive a detection signal.

[0012] In some embodiments, when the electro-optic modulator is in a detection state, the optical power input from the second input port is represented by P0, the optical power output from the first output port is represented by P4 = P0 * A%, the optical power output from the second output port is represented by P5 = P0 * (100 - A)%, the maximum optical power value output from the third output port is represented by P6, the maximum optical power value output from the fourth output port is represented by P7 = P6 * A%, and the transmission loss of the electro-optic modulator is represented by C = P6 / P4.

[0013] In some embodiments, the first input port and the second input port of the first optical splitting element have interchangeable symmetry, and the first output port and the second output port also have interchangeable symmetry.

[0014] In some embodiments, the third output port of the fourth optical splitting element and the fourth output port of the fourth optical splitting element have exchange symmetry, and / or the fifth output port of the fifth optical splitting element and the sixth output port of the fifth optical splitting element have exchange symmetry.

[0015] In some embodiments, the seventh output port of the sixth optical splitting element and the eighth output port of the sixth optical splitting element have interchangeable symmetry.

[0016] In some embodiments, the first output port of the third optical splitting element is configured to output the maximum optical power value of the coherently augmented signal of two branched optical signals having a phase difference of 2Nπ, where N is 0 or a natural number, and the second and third output ports of the third optical splitting element are configured to output, correspondingly, a set allocation ratio of the maximum optical power value of the coherently augmented signal of two branched optical signals having a phase difference of (2N+1)π, where the set allocation ratio is greater than 0 and less than 1.

[0017] In some embodiments, the third optical splitting element has an axially symmetric structure, and the second and third output ports of the third optical splitting element are arranged symmetrically with respect to the first output port.

[0018] In some embodiments, the electro-optic modulator is configured in either an NRZ encoding scheme or a PAM4 encoding scheme.

[0019] It should be understood that the information described in this section is not intended to identify any defining or essential features of the embodiments of this disclosure, nor is it used to limit the scope of this disclosure. Other features of this disclosure will be readily apparent from the following descriptions.

[0020] Further details, features, and advantages of this disclosure are disclosed in the following description of exemplary embodiments with reference to the accompanying drawings. [Brief explanation of the drawing]

[0021] [Figure 1] This is a top view of a simplified structure of a conventional electro-optic modulator. [Figure 2] This is a schematic diagram of a simplified structure of an electro-optic modulator according to some embodiments of the present disclosure. [Figure 3] This is a curve graph illustrating the correlation between the optical power output from the first and second output ports of a third optical splitting element and the phase difference between the two branched optical signals arriving at the third optical splitting element, according to certain embodiments of the present disclosure. [Figure 4] This is a schematic diagram of a simplified structure of an electro-optic modulator according to some other embodiments of the present disclosure. [Modes for carrying out the invention]

[0022] Only a limited number of exemplary embodiments are briefly described below. As can be seen by those skilled in the art, the embodiments described can be modified in various ways without departing from the spirit or scope of this disclosure. Accordingly, the accompanying drawings and description are illustrative and not limiting.

[0023] A Mach-Zehnder modulator is a type of electro-optic modulator in which an input optical signal is split into two branched optical signals, which then enter two waveguide arms, respectively. Each of the two waveguide arms is made from an electro-optic material and has a refractive index that changes with the applied modulation voltage. Changes in the refractive index of the waveguide arms can lead to changes in the phase of the branched optical signals. Therefore, the output from the convergence of the two branched optical signals is an interference signal with an intensity that changes with the modulation voltage. In short, a Mach-Zehnder modulator can perform modulation of different sidebands 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 interconnects, optical computing, and optical communication systems.

[0024] 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 identical to each other. When the Mach-Zehnder modulator 001 is not operating, neither of the two waveguide arms 02 undergoes the electro-optic effect. The input light travels through the optical splitting element 01 and is then equally split into two branched optical signals. After the two branched optical signals each travel through one waveguide arm 02, they are still in the same phase. Therefore, a coherently enhanced signal of the two branched optical signals is output from the optical combining 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. The two branched optical signals may be different in phase by an odd or even multiple of Π after each of the two branched optical signals travels through one waveguide arm 02. When the two branched optical signals are different in phase by an even multiple of Π, the optical combining element 05 outputs a coherently enhanced signal of the two branched optical signals. When the two branched optical signals are different in phase by an odd multiple of Π, the optical combining element 05 outputs a coherent cancellation signal of the two branched optical signals.

[0025] However, in practice, the two waveguide arms 02 can never be absolutely identical due to reasons such as materials and charge accumulation. When the Mach-Zehnder modulator 001 is not operating, a certain phase shift appears after the two branched optical signals each travel through one waveguide arm 02. This phase shift is inevitable and is an inherent phase difference that may vary due to changes in time and environmental conditions. The existence of this phase shift affects the accuracy of the output signal when the Mach-Zehnder modulator 001 is operating or may even make it impossible for the Mach-Zehnder modulator 001 to perform a normal output.

[0026] Therefore, in order to improve the accuracy of the operation signal output from the electro-optic modulator and thereby improve the operation performance of the electro-optic modulator, it is required to perform bias voltage modulation on two waveguide arms by a bias voltage modulation module to compensate for the phase shift caused by the inherent difference between the two waveguide arms.

[0027] Embodiments of the present disclosure provide an electro-optic modulator to improve the accuracy of the operation signal output from 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 a first optical splitting element 10, a second optical splitting element 20, two waveguide arms 70, a bias voltage modulation module 80, a radio frequency modulation module 90, a third optical splitting element 30, and a fourth optical splitting element 40.

[0029] The first optical splitting element 10 includes a first input port 101 configured to receive an operational signal, a first output port 103 configured to output a main path signal, and a second output port 104 configured to output a first monitoring signal. The second optical splitting element 20 has a 1-in, 2-out structure and an input port of the second optical splitting element 20 connected to the first output port 103, and is configured to equally split the optical signal input from the input port into two branch optical signals. Two waveguide arms 70 correspondingly provide transmission paths for the two branch optical signals, with one end of each waveguide arm correspondingly connected to the two output ports of the second optical splitting element 20. The third optical splitting element 30 has a 2-in, 3-out structure and two input ports of the third optical splitting element 30 correspondingly connected to the other end of each of the two waveguide arms 70, and is configured to correspondingly receive the branch optical signals transmitted by the two waveguide arms 70. The fourth optical splitting element 40 has a 1-in, 2-out structure and an input port of the fourth optical splitting element 40 that is connected to the first output port 301 of the third optical splitting element 30. The fourth optical splitting element 40 includes a third output port 401 configured to output a maximum optical power value, and a fourth output port 402 configured to output a second monitoring signal.

[0030] The radio frequency modulation module 90 is configured to apply a radio frequency voltage to two waveguide arms 70 based on a radio frequency signal in order to perform radio frequency modulation to the two branch optical signals transmitted in those waveguide arms 70, such that a phase difference is generated between the two branch optical signals. The bias voltage modulation module 80 is configured to apply a bias voltage to two waveguide arms 70 based on a bias voltage signal in order to perform bias voltage modulation to the two branch optical signals transmitted in those waveguide arms 70.

[0031] In this disclosure, each optical splitting element refers to an optical power allocation element, for example, a multimode interference element having an optical power allocation function. The designer may design the actual structure of the optical splitting elements according to the designed allocation ratio of optical power. When the electro-optic modulator 100 is operating, the optical power input from the first input port 101 is represented by P1, the optical power output from the first output port 103 is represented by P2 = P1 * (100 - A)%, and the optical power output from the second output port 104 is represented by P3 = P1 * A%.

[0032] In embodiments of this disclosure, a first monitoring signal output from the second output port 104 of the first optical splitting element 10 can be used to monitor whether the operating signal input from the first input port 101 is normal, for example, whether the power for coupling the operating signal into the electro-optic modulator 100 can reach a target power. A second monitoring signal output from the fourth output port 402 of the fourth optical splitting element 40, and a signal output from the second output port 302 or the third output port 303 of the third optical splitting element 30 can be used to monitor whether the operating state of the electro-optic modulator 100 is normal, for example, whether the two split optical signals reach a target phase difference.

[0033] Referring to Figure 3, Figure 3 is a curve graph showing the correlation between the optical power output from the first output port 301 and the second output port 302 (and possibly the third output port 303) of the third optical splitting element 30 and the phase difference between the two split optical signals.

[0034] When the optical power ratio K of the second monitoring signal output from the fourth output port 402 (which is a set ratio of the optical power output from the first output port 301) with respect to the signal output from the second output port 302 or the third output port 303 of the third optical splitting element 30 reaches its maximum value, it can be obtained that the phase difference between the two branched optical signals is 0 or an even multiple of π, and when the ratio K reaches its minimum value, it can be obtained that the phase difference between the two branched optical signals is an odd multiple of π.

[0035] Therefore, the design of the embodiments of the present disclosure allows for effective monitoring of the operating signals and operating conditions input into the electro-optic modulator 100, and based on this monitoring information, the bias voltage signal output to the bias voltage modulation module 80 can be adjusted to compensate for the phase shift caused by the inherent difference between the two waveguide arms 70, thereby improving the accuracy of the operating signals output from the electro-optic modulator 100 in the operating state.

[0036] Based on the encoding scheme and target output of the electro-optic modulator 100, at least one target phase difference to be achieved by the two branched optical signals can be predetermined. The encoding scheme of the electro-optic modulator 100 includes, but is not limited to, the NRZ encoding scheme and the PAM4 encoding scheme. The encoding scheme of the electro-optic modulator 100 can vary, and the specific setting value of the target phase difference can also vary.

[0037] In some embodiments, the electro-optic modulator 100 uses an NRZ (Non-Zero Reset Code) coding scheme, thereby enabling the two branched optical signals to generate a first target phase difference φ1 and a second target phase difference φ2, where the first target phase difference φ1 and the second target phase difference φ2 satisfy |φ1-(2NΠ+Π / 2)|=|φ2-(2NΠ+Π / 2)|. For example, the first target phase difference φ1 may be represented by 2Nπ and the second target phase difference φ2 by (2N+1)π, or the first target phase difference φ1 may be represented by 2Nπ+3π / 10 and the second target phase difference φ2 by 2Nπ+7π / 10, or the first target phase difference φ1 may be represented by 2Nπ+π / 10 and the second target phase difference φ2 by 2Nπ+9π / 10, and so on, but these are not listed herein. The control chip of the electro-optic modulator 100 outputs a radio frequency modulated signal to the radio frequency modulation module 90 based on the first target phase difference φ1 and the second target phase difference φ2.

[0038] In some other embodiments, the electro-optic modulator 100 uses a PAM4 (4-level pulse amplitude modulation) coding scheme, thereby enabling the two branched optical signals to produce a first target phase difference φ1, a second target phase difference φ2, a third target phase difference φ3, and a fourth target phase difference φ4. The first target phase difference φ1, the second target phase difference φ2, the third target phase difference φ3, and the fourth target phase difference φ4 satisfy |φ1-Π / 2|=3|φ2-Π / 2|=3|φ3-Π / 2|=|φ4-Π / 2|. The control chip of the electro-optic modulator 100 outputs a radio frequency modulated signal to the radio frequency modulation module 90 based on the first target phase difference φ1, the second target phase difference φ2, the third target phase difference φ3, and the fourth target phase difference φ4.

[0039] In some embodiments of the present disclosure, the first output port 301 of the third optical splitting element 30 is configured to output the maximum optical power value (corresponding to the maximum energy value or maximum intensity value of the coherently augmented signal) of two branched optical signals having a phase difference of 2Nπ, where N is 0 or a natural number, and the second output port 302 and the third output port 303 of the third optical splitting element 30 are configured to output, respectively, a set allocation ratio of the maximum optical power value (corresponding to the maximum energy value or maximum intensity value of the coherently augmented signal) of two branched optical signals having a phase difference of (2N+1)π, where the set allocation ratio is greater than 0 and less than 1.

[0040] The specific values ​​of the set allocation ratios described above are not limited. For example, the signals output from the second output port 302 and the third output port 303 of the third optical splitting element 30 can both reach 50% of the maximum optical power value of the coherently augmented signal of two branched optical signals with a phase difference of (2N+1)π. As another example, the signal output from the second output port 302 of the third optical splitting element 30 can reach 40% of the maximum optical power value of the coherently augmented signal of two branched optical signals with a phase difference of (2N+1)π, and the signal output from the third output port 303 of the third optical splitting element 30 can reach 60% of the maximum optical power value of the coherently augmented signal of two branched optical signals with a phase difference of (2N+1)π. After the set allocation ratios are determined, the specific structural dimensions of the third optical splitting element 30 can be designed based on the set allocation ratios.

[0041] When the phase difference between the two branched optical signals is (2N+1)Π, the two branched optical signals still produce coherent enhancement by utilizing the multimode interference effect of the third optical splitting element 30. The coherently enhanced signals are either equally divided or proportionally allocated between the second output port 302 and the third output port 303 of the third optical splitting element 30, and are output as monitoring signals, capable of reaching the maximum optical power value of those coherently enhanced signals. Therefore, according to the technical solution of the embodiments of this disclosure, a relatively strong monitoring signal can be obtained without significantly reducing the intensity of the operating signal output from the electro-optic modulator 100, thereby ensuring the effectiveness of monitoring.

[0042] In some embodiments, the third optical splitting element 30 has an axially symmetric structure, and the second output port 302 and the third output port 303 of the third optical splitting element 30 are arranged symmetrically with respect to the first output port 301. Such a design allows the overall structure to be symmetric, thereby reducing the element's dependence on wavelength, and thereby the electro-optic modulator 100 is applicable to a wider signal wave band and has a greater range of application.

[0043] As shown in Figure 4, in some embodiments of the present disclosure, the electro-optic modulator 100 further includes a fifth optical splitting element 50 having a one-in, two-out structure and an input port of the fifth optical splitting element 50 connected to a second output port 302 of the third optical splitting element 30, and including a fifth output port 501 configured to output a third monitoring signal and a sixth output port 502 configured to output a fourth monitoring signal; and a sixth optical splitting element 60 having a one-in, two-out structure and an input port of the sixth optical splitting element 60 connected to a third output port 303 of the third optical splitting element 30, and including a seventh output port 601 configured to output a fifth monitoring signal and an eighth output port 602 configured to output a sixth monitoring signal. The structures of the fifth optical splitting element 50 and the sixth optical splitting element 60 may be completely identical. In addition, it is also possible that only one of the fifth light-dividing element 50 and the sixth light-dividing element 60 is provided.

[0044] In some embodiments of this disclosure, the first input port 101 and the second input port 102 of the first optical splitting element 10 have exchange symmetry, the first output port 103 and the second output port 104 have exchange symmetry, and / or the third output port 401 and the fourth output port 402 of the fourth optical splitting element 40 have exchange symmetry, and / or the fifth output port 501 and the sixth output port 502 of the fifth optical splitting element 50 have exchange symmetry, and / or the seventh output port 601 and the eighth output port 602 of the sixth optical splitting element 60 have exchange symmetry.

[0045] In this disclosure, A% may be a constant value determined empirically, or a constant value determined based on the power ratio of the third monitoring signal to the fourth monitoring signal. In some embodiments of this disclosure, the A% described above is less than 50%, for example, A% may be set to a value of 3% or 5%. By branching off a small portion of the optical power and coupling the optical power to the second output port 104, the operating signal input from the first input port 101 can be monitored, thereby ensuring the effectiveness of monitoring and the modulation efficiency of the electro-optic modulator 100.

[0046] As shown in Figure 4, in some embodiments of the present disclosure, the first optical splitting element 10 further includes a second input port 102 configured to receive a detection signal. The second input port 102 may be used as a debugging and detection input port for the electro-optic modulator 100 during product development or testing. When the electro-optic modulator 100 is in a detection state, the optical power input from the second input port 102 is represented by P0, the optical power output from the first output port 103 is represented by P4 = P0 * A%, the optical power output from the second output port 104 is represented by P5 = P0 * (100 - A)%, the maximum optical power value output from the third output port 401 is represented by P6, the maximum optical power value output from the fourth output port 402 is represented by P7 = P6 * A%, and the transmission loss of the electro-optic modulator 100 is represented by C = P6 / P4. A% is less than 50%, for example, A% can be set to a value of 3% or 5%, which may allow the majority of the optical power to be output from the second output port 104, thus leading to improved detection accuracy.

[0047] Based on the monitored values ​​of at least some parameters such as P0, P4, P5, P6, P7, and others, the transmission loss of an electro-optic modulator 100 using a particular design can be calculated. If the transmission loss is controlled within the target range, the product meets the ex-factory design requirements; if the transmission loss is greater and outside the target range, the specific structural details of the product may be revised in the design to reduce the transmission loss.

[0048] In some embodiments of the present disclosure, the electro-optic modulator 100 further includes a feedback module configured to adjust the bias voltage signal output to the bias voltage modulation module 80 based on at least one of a first monitoring signal, a second monitoring signal, a third monitoring signal, a fourth monitoring signal, a fifth monitoring signal, and a sixth monitoring signal. The feedback module may include a signal intensity monitoring sensor located at the corresponding monitoring output port, and provided that the output operating signal of the electro-optic modulator 100 meets accuracy requirements, the signal intensity monitoring sensor may detect the monitoring signal output from the output port in real time or at a specific frequency.

[0049] In some embodiments, the electro-optic modulator 100 itself has the function of monitoring operating signals and operating states, and can automatically and dynamically adjust the bias voltage signal output to the bias voltage modulation module 80 based on this monitoring information to compensate for phase shifts caused by the inherent difference between the two waveguide arms 70, so that the accuracy and reliability of the operating signals output from the electro-optic modulator 100 can be improved. In some embodiments, when the intensity of some monitoring signals does not reach a target intensity value (for example, when a first monitoring signal disappears or becomes extremely weak), the feedback module may further activate the alarm unit of the electro-optic modulator 100 to provide an alarm prompt.

[0050] In this description, any orientation, positional relationship, or dimension indicated by terms such as “center,” “vertical,” “horizontal,” “length,” “width,” “thickness,” “top,” “bottom,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “upper,” “lower,” “inside,” “outside,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” is the orientation, positional relationship, or dimension shown in the attached drawings, and these terms are used solely for ease of explanation and should not be interpreted as limiting the scope of protection of this disclosure.

[0051] In addition, terms such as “first,” “second,” and “third” are for descriptive purposes only and should not be interpreted as indicating or suggesting relative importance, or implicitly indicating the number of technical features being referred to. Therefore, features defined by “first,” “second,” and “third” may explicitly or implicitly include one or more features. In this disclosure, the term “multiple” means two or more unless otherwise explicitly and specifically defined.

[0052] Unless otherwise explicitly stated or defined in this disclosure, terms such as “attach,” “connect,” “connected,” and “fix” should be interpreted broadly, for example, and could refer to a fixed connection, a detachable connection, or an integrated connection; a mechanical connection, an electrical connection, or a communication; a direct connection, or an indirect connection via an intermediate medium; or internal communication between two elements, or interaction between two elements. A person skilled in the art will understand the specific meaning of the above terms in this disclosure in accordance with the specific circumstances.

[0053] Unless otherwise expressly stated or defined in this disclosure, the expression that the first feature is “above” or “below” the second feature may 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 brought into contact through another feature between them. Furthermore, “above,” “above,” or “up” the first feature of the second feature may include cases where the first feature is directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher altitude than the second feature. “Above,” “below,” or “below” the second feature may include cases where the first feature is directly below or diagonally below the second feature, or simply indicate that the first feature is at a lower altitude than the second feature.

[0054] This description provides many different implementations or examples that may be used to realize the disclosure. It should be understood that these different implementations or examples are purely illustrative and are not intended in any way to limit the scope of protection of the disclosure. Based on the disclosures in this description, a person skilled in the art may conceive of various modifications or substitutions. All such modifications or substitutions shall fall within the scope of protection of the disclosure. Therefore, the scope of protection of the disclosure shall be subject to the scope of protection of the claims.

Claims

1. A first optical splitting element including a first input port configured to receive an operation signal, a first output port configured to output a main path signal, and a second output port configured to output a first monitoring signal, A second optical splitting element having a 1-in, 2-out structure and an input port of the second optical splitting element connected to the first output port, Two waveguide arms, each having one end connected to the two output ports of the second optical splitting element, A bias voltage modulation module configured to apply a bias voltage to the two waveguide arms based on a bias voltage signal, A radio frequency modulation module configured to apply a radio frequency voltage to the two waveguide arms based on a radio frequency signal, A third optical splitting element having a 2-in, 3-out structure and two input ports of the third optical splitting element, which are connected to the other end of each of the two waveguide arms in correspondence. A fourth optical splitting element having a one-in, two-out structure, and an input port of the fourth optical splitting element connected to the first output port of the third optical splitting element, including a third output port configured to output a maximum optical power value, and a fourth output port configured to output a second monitoring signal. An electro-optic modulator, including one.

2. When the electro-optic modulator is in operation, the optical power input from the first input port is represented by P1, the optical power output from the first output port is represented by P2 = P1 * (100 - A)%, and the optical power output from the second output port is represented by P3 = P1 * A%, where A% is less than 50%. The electro-optic modulator according to claim 1.

3. A fifth optical splitting element having a one-in, two-out structure, and an input port of the fifth optical splitting element connected to the second output port of the third optical splitting element, a fifth output port configured to output a third monitoring signal, and a sixth output port configured to output a fourth monitoring signal. The electro-optic modulator according to claim 2, further comprising:

4. A% is a constant value, or A% is determined based on the power ratio of the third monitoring signal to the fourth monitoring signal. The electro-optic modulator according to claim 3.

5. A sixth optical splitting element having a one-in, two-out structure, and an input port of the sixth optical splitting element connected to the third output port of the third optical splitting element, including a seventh output port configured to output a fifth monitoring signal, and an eighth output port configured to output a sixth monitoring signal. The electro-optic modulator according to claim 3, further comprising:

6. A feedback module configured to adjust the bias voltage signal output to the bias voltage modulation module based on at least one of the first monitoring signal, the second monitoring signal, the third monitoring signal, the fourth monitoring signal, the fifth monitoring signal, and the sixth monitoring signal. The electro-optic modulator according to claim 5, further comprising:

7. The first optical splitting element further includes a second input port configured to receive a detection signal. The electro-optic modulator according to claim 5.

8. When the electro-optic modulator is in the detection state, the optical power input from the second input port is represented by P0, the optical power output from the first output port is represented by P4 = P0 * A%, the optical power output from the second output port is represented by P5 = P0 * (100 - A)%, the maximum optical power value output from the third output port is represented by P6, the maximum optical power value output from the fourth output port is represented by P7 = P6 * A%, and the transmission loss of the electro-optic modulator is represented by C = P6 / P4. The electro-optic modulator according to claim 7.

9. The first input port and the second input port of the first optical splitting element have exchange symmetry, and the first output port and the second output port of the first optical splitting element have exchange symmetry. The electro-optic modulator according to claim 8.

10. The third output port of the fourth optical splitting element and the fourth output port of the fourth optical splitting element have interchangeable symmetry. The electro-optic modulator according to claim 8.

11. The fifth output port of the fifth optical splitting element and the sixth output port of the fifth optical splitting element have interchangeable symmetry. The electro-optic modulator according to claim 8.

12. The seventh output port of the sixth optical splitting element and the eighth output port of the sixth optical splitting element have interchangeable symmetry. The electro-optic modulator according to claim 8.

13. The first output port of the third optical splitting element is configured to output the maximum optical power value of the coherently augmented signal of two branched optical signals with a phase difference of 2NP, where N is 0 or a natural number. The second and third output ports of the third optical splitting element are configured to output a set allocation ratio of the maximum optical power value of the coherently augmented signal of two branched optical signals with a phase difference of (2N+1)π, wherein the set allocation ratio is greater than 0 and less than 1. An electro-optic modulator according to any one of claims 1 to 12.

14. The third optical splitting element has an axially symmetric structure, and the second and third output ports of the third optical splitting element are arranged symmetrically with respect to the first output port. An electro-optic modulator according to any one of claims 1 to 12.

15. The electro-optic modulator is configured using either the NRZ coding scheme or the PAM4 coding scheme. An electro-optic modulator according to any one of claims 1 to 12.

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