Lithium niobate modulator driving circuit

Abstract

The utility model provides a lithium niobate modulator drive circuit, which comprises a control module, a conversion module, an amplification module and a lithium niobate photoelectric modulator, and is characterized in that the control module is used for outputting digital modulation signals; the input end of the conversion module is electrically connected with the output end of the control module, and the conversion module is used for converting the digital signal into an analog signal; the input end of the amplification module is electrically connected with the output end of the conversion module, the output end of the amplification module is electrically connected with the input end of the lithium niobate photoelectric modulator, and the amplification module is used for amplifying an analog signal and driving the lithium niobate photoelectric modulator; through the conversion module and the amplification module, the driving circuit has wide dynamic range adjustment capability, high precision and high bandwidth performance, the modulation efficiency of the electro-optical modulator can be improved, and the light polarization controller can be accurately modulated.

Description

Technical Field

[0001] The utility model relates to the technical field of light polarization control, in particular to a lithium niobate modulator driving circuit. Background Art

[0002] Lithium niobate modulators are usually devices used to modulate and demodulate optical signals. The principle is that the electrical signal passes through the electrodes in the modulator, generating an electric field, causing the lithium niobate lattice to distort, thereby changing the dielectric constant and achieving light modulation. Therefore, a changing electrical signal can be used to drive the lithium niobate modulator to achieve modulation of the control optical signal transmission.

[0003] A dual-driven differential thin-film lithium niobate electro-optic modulator chip with publication number CN117991526B includes: a first waveguide arm, a first traveling wave electrode pair arranged on both sides of the first waveguide arm, a second waveguide arm, and a second traveling wave electrode pair arranged on both sides of the second waveguide arm; the first traveling wave electrode pair is used to receive a positive polarity differential signal generated by a signal generator and generate a first electric field so that the first waveguide arm is modulated according to the first electric field; the second traveling wave electrode pair is used to receive a negative polarity differential signal generated by the signal generator and generate a second electric field so that the second waveguide arm is modulated according to the second electric field; the direction of the first electric field is opposite to the direction of the second electric field.

[0004] The adjustable range of the driving circuit voltage, transmission bandwidth, slew rate, noise coefficient, etc. will affect the modulation signal applied to the optical polarization controller. The current driving circuit's wide dynamic range, accuracy and bandwidth cannot meet the driving requirements, and thus cannot effectively and accurately modulate the optical polarization controller. Utility Model Content

[0005] In view of this, the utility model proposes a lithium niobate modulator driving circuit, which has wide dynamic range adjustment capability, high precision and high bandwidth performance, can improve the modulation efficiency of the electro-optic modulator, and accurately modulate the optical polarization controller.

[0006] The technical solution of the utility model is implemented as follows: The utility model provides a lithium niobate modulator driving circuit, including a control module, a conversion module, an amplification module and a lithium niobate photoelectric modulator, wherein:

[0007] The control module is used to output a digital modulation signal;

[0008] The input end of the conversion module is electrically connected to the output end of the control module, and the conversion module is used to convert the digital signal into an analog signal;

[0009] The input end of the amplification module is electrically connected to the output end of the conversion module, and the output end of the amplification module is electrically connected to the input end of the lithium niobate photoelectric modulator. The amplification module is used to amplify the analog signal and drive the lithium niobate photoelectric modulator.

[0010] On the basis of the above technical solution, preferably, the conversion module includes a digital-to-analog conversion unit and a voltage conversion unit, wherein the input end of the digital-to-analog conversion unit is electrically connected to the output end of the control module, for converting the digital modulation signal of the control module into a differential current signal, and the input end of the voltage conversion unit is electrically connected to the output end of the digital-to-analog conversion unit, for converting the differential current signal into a voltage signal.

[0011] On the basis of the above technical scheme, preferably, the digital-to-analog conversion unit includes a connector P1, a digital-to-analog conversion chip U1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6 and a filter L1, wherein the output end of the control module 1 is electrically connected to the input end of the connector P1, the output end of the connector P1 is electrically connected to the input end of the digital-to-analog conversion chip U1, the digital voltage input end of the digital-to-analog conversion chip U1 is electrically connected to the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4 and the external first power supply end, respectively, and the other ends of the capacitors C1, C2, C3 and C4 are commonly grounded; the analog voltage input end of the digital-to-analog conversion chip U1 is electrically connected to the capacitor C5, the capacitor C6 and the filter L1, respectively, the other ends of the capacitors C5 and C6 are commonly grounded, and the other end of the filter L1 is electrically connected to the first power supply end.

[0012] On the basis of the above technical solution, preferably, the voltage conversion unit includes a differential operational amplifier chip U2, a capacitor C7, a capacitor C8, a capacitor C9, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7, wherein the digital-to-analog conversion chip U1 has two output ends, a first output end of the digital-to-analog conversion chip U1 is electrically connected to one end of the resistor R2, the resistor R6 and the capacitor C8, respectively, the other end of the resistor R2 is electrically connected to the resistor R1 and the differential input negative pole of the differential operational amplifier chip U2, the other end of the resistor R1 is electrically connected to the resistor R4 and the output end of the differential operational amplifier chip U2, and the second output end of the digital-to-analog conversion chip U1 is electrically connected to the output end of the differential operational amplifier chip U2. The ends are electrically connected to the other end of capacitor C8, resistor R5 and one end of resistor R3 respectively, the other end of resistor R3 and the other end of resistor R6 are commonly grounded, the other end of resistor R3 is electrically connected to resistor R7 and the differential input positive pole of differential operational amplifier chip U2 respectively, the other end of resistor R7 is grounded, the negative power supply end of differential operational amplifier chip U2 is electrically connected to the second inverting power supply end and capacitor C9 respectively, the positive power supply end of differential operational amplifier chip U2 is electrically connected to the second positive power supply end and capacitor C7 respectively, the other end of resistor R7, the other end of capacitor C9 and the other end of capacitor C7 are grounded respectively, and the other end of resistor R4 serves as the output end of the conversion module.

[0013] On the basis of the above technical solution, preferably, the amplification module includes an operational amplifier unit and an isolation unit, wherein the input end of the operational amplifier unit is electrically connected to the output end of the voltage conversion unit for amplifying the voltage signal; the input end of the isolation unit is electrically connected to the output end of the operational amplifier unit, the output end of the isolation unit is electrically connected to the lithium niobate photoelectric modulator, and the isolation unit is used to isolate the operational amplifier unit from being directly connected to the lithium niobate photoelectric modulator.

[0014] On the basis of the above technical solution, preferably, the operational amplifier unit includes an operational amplifier chip U3, a resistor R8, a resistor R16, a resistor R17, a resistor R21, a capacitor C22, an electrolytic capacitor C17, a capacitor C18, an electrolytic capacitor C12 and a capacitor C11, wherein the other end of the resistor R4 is electrically connected to the resistor R8, the other end of the resistor R8 is respectively electrically connected to the capacitor C11 and the pin 1 of the operational amplifier chip U3, the pin 6 of the operational amplifier chip U3 is respectively electrically connected to the input end of the isolation unit 32, the resistor R21 and the capacitor C22, the pin 2 of the operational amplifier chip U3 is respectively electrically connected to the other end of the resistor R21, the capacitor C22 The other end of the operational amplifier chip U3 is electrically connected to the resistor R17, the pin 7 of the operational amplifier chip U3 is electrically connected to the resistor R16, the pin 4 of the operational amplifier chip U3 is electrically connected to the negative electrode of the electrolytic capacitor C17, the capacitor C18 and the third inverting power supply end, the positive electrode of the electrolytic capacitor C17 is electrically connected to the other end of the capacitor C18 and is grounded, the pin 5 of the operational amplifier chip U3 is electrically connected to the negative electrode of the electrolytic capacitor C12, the capacitor C13 and the third positive power supply end, the positive electrode of the electrolytic capacitor C12 is electrically connected to the other end of the capacitor C13 and is grounded, and the other end of the capacitor C11, the other end of the resistor R17 and the other end of the resistor R16 are grounded respectively.

[0015] On the basis of the above technical solution, preferably, the isolation unit includes an operational amplifier chip U4, a resistor R18, a resistor R19, a resistor R20, a resistor R22, a capacitor C16, an electrolytic capacitor C19, a capacitor C20, a capacitor C14, a capacitor C15, a capacitor C21 and a connector P3, wherein the other end of the resistor R18 is electrically connected to the resistor R8, the other end of the resistor R18 is electrically connected to the capacitor C16 and the pin 1 of the operational amplifier chip U4, respectively, the pin 6 of the operational amplifier chip U4 is electrically connected to the resistor R20 and the resistor R22, respectively, the other end of the resistor R22 is electrically connected to the pin 2 of the operational amplifier chip U4, and the pin 7 of the operational amplifier chip U4 is electrically connected to the resistor R19. , the other end of the resistor R20 is respectively connected to the capacitor C21 and the connector P2, the pin 4 of the operational amplifier chip U4 is respectively electrically connected to the negative electrode of the electrolytic capacitor C19, the capacitor C20 and the third inverting power supply end, the positive electrode of the electrolytic capacitor C19 is electrically connected to the other end of the capacitor C20 and is grounded, the pin 5 of the operational amplifier chip U4 is respectively electrically connected to the negative electrode of the electrolytic capacitor C14, the capacitor C15 and the third positive power supply end, the positive electrode of the electrolytic capacitor C14 is electrically connected to the other end of the capacitor C15 and is grounded, the other end of the capacitor C11, the other end of the resistor R17, the other end of the resistor R16 and the other end of the capacitor C21 are respectively grounded, and the connector P3 is electrically connected to the lithium niobate photoelectric modulator.

[0016] Based on the above technical solution, preferably, the voltage of the first power supply terminal is 3.3V, the voltage of the second positive power supply terminal is +5V, the voltage of the second negative power supply terminal is -5V, the voltage of the third positive power supply terminal is +40V, and the voltage of the third negative power supply terminal is -40V.

[0017] On the basis of the above technical solution, preferably, the operational amplifier chip U3 and the operational amplifier chip U4 are both of model OPA453, and the amplification factor of the operational amplifier chip U3 is 8 times.

[0018] On the basis of the above technical solution, preferably, the model of the digital-to-analog conversion chip U1 is AD9763.

[0019] The lithium niobate modulator drive circuit of the utility model has the following beneficial effects compared with the prior art:

[0020] (1) The control module is configured to output a digital modulation signal to the conversion module, the conversion module converts the digital signal into an analog signal, and then the analog signal is amplified by the amplification module and applied to the electrode of the lithium niobate modulator. The conversion module and the amplification module are configured to enable the driving circuit to have a wide dynamic range adjustment capability, high precision and high bandwidth performance, which can improve the modulation efficiency of the electro-optic modulator and accurately modulate the optical polarization controller;

[0021] (2) Through the cooperation of the digital-to-analog conversion unit and the voltage conversion unit, the conversion module can efficiently convert the digital modulation signal output by the control module into a voltage signal suitable for driving the lithium niobate modulator; in this process, not only the accuracy and stability of the digital signal are maintained, but also the anti-interference ability and transmission efficiency of the signal are enhanced through the conversion process of the differential current signal and the voltage signal;

[0022] (3) The operational amplifier unit can effectively amplify the input voltage signal, and ensure the stability and accuracy of the output signal through filtering and negative feedback mechanism;

[0023] (4) The isolation unit is set to improve the load capacity of the overall output and prevent interference or damage caused by direct electrical connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1This is a principle block diagram of the lithium niobate modulator driving circuit of the utility model;

[0026] Figure 2 It is a circuit diagram of a digital-to-analog conversion unit of a lithium niobate modulator driving circuit of the utility model;

[0027] Figure 3 This is a circuit diagram of a voltage conversion unit of a lithium niobate modulator driving circuit of the utility model;

[0028] Figure 4 It is a circuit diagram of an operational amplifier unit of a lithium niobate modulator driving circuit of the utility model;

[0029] Figure 5 This is a circuit diagram of an isolation unit of a lithium niobate modulator driving circuit of the utility model. DETAILED DESCRIPTION

[0030] The following will be combined with the implementation of the utility model to clearly and completely describe the technical solutions in the implementation of the utility model. Obviously, the described implementation is only a part of the implementation of the utility model, not all of the implementations. Based on the implementation of the utility model, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] At present, the lithium niobate modulator 4 is generally a device used to modulate and demodulate optical signals. Its working principle is that the electrical signal passes through the electrodes in the modulator, generates an electric field, causes the distortion of the lithium niobate lattice, thereby changing the dielectric constant and realizing the modulation of light; therefore, a changing electrical signal can be used to drive the lithium niobate modulator 4 to realize the modulation of the control optical signal transmission.

[0032] like Figure 1-5 As shown, the utility model provides a lithium niobate modulator driving circuit, including a control module 1, a conversion module 2, an amplifying module 3 and a lithium niobate photoelectric modulator 4, wherein the control module 1 is used to output a digital modulation signal; the input end of the conversion module 2 is electrically connected to the output end of the control module 1, and the conversion module 2 is used to convert the digital signal into an analog signal; the input end of the amplifying module 3 is electrically connected to the output end of the conversion module 2, and the output end of the amplifying module 3 is electrically connected to the input end of the lithium niobate photoelectric modulator 4, and the amplifying module 3 is used to amplify the analog signal to drive the lithium niobate photoelectric modulator 4.

[0033] It should be noted that the control module 1 outputs a digital modulation signal to the conversion module 2, the conversion module 2 converts the digital signal into an analog signal, and then amplifies the analog signal through the amplification module 3. When it is applied to the electrode of the lithium niobate modulator 4, an electric field will be generated in the lithium niobate crystal, thereby causing lattice distortion and changes in the dielectric constant. This change will change the refractive index or absorption characteristics of the crystal to light, thereby realizing modulation of the optical signal. Due to the high precision of the digital signal and the precise control of the conversion module and the amplification module, high-precision modulation of the optical signal can be achieved. A larger voltage output range can be achieved through the amplification module, covering a wider optical signal modulation range, and adapting to different application scenarios and signal strength requirements. Therefore, the driving circuit has a wide dynamic range adjustment capability, high precision and high bandwidth performance, which can improve the modulation efficiency of the electro-optic modulator and the precise modulation of the optical polarization controller.

[0034] The conversion module 2 in this embodiment includes a digital-to-analog conversion unit 21 and a voltage conversion unit 22, wherein the input end of the digital-to-analog conversion unit 21 is electrically connected to the output end of the control module 1, and is used to convert the digital modulation signal of the control module 1 into a differential current signal, and the input end of the voltage conversion unit 22 is electrically connected to the output end of the digital-to-analog conversion unit 21, and is used to convert the differential current signal into a voltage signal.

[0035] It should be noted that the digital-to-analog conversion unit 21 converts the digital modulation signal from the control module 1 into a differential current signal. The differential current signal is a current signal transmitted on two wires with opposite directions and equal amplitudes. The difference between them represents the information to be transmitted. The voltage conversion unit 22 converts the differential current signal into a voltage signal. The lithium niobate modulator 4 usually responds directly to the voltage signal.

[0036] In this embodiment, through the cooperation of the digital-to-analog conversion unit 21 and the voltage conversion unit 22, the conversion module 2 can efficiently convert the digital modulation signal output by the control module 1 into a voltage signal suitable for driving the lithium niobate modulator; in this process, not only the accuracy and stability of the digital signal are maintained, but also the anti-interference ability and transmission efficiency of the signal are enhanced through the conversion process of the differential current signal and the voltage signal.

[0037] The digital-to-analog conversion unit 21 in this embodiment comprises a connector P1, a digital-to-analog conversion chip U1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6 and a filter L1, wherein the output end of the control module (1) is electrically connected to the input end of the connector P1, the output end of the connector P1 is electrically connected to the input end of the digital-to-analog conversion chip U1, the digital voltage input end of the digital-to-analog conversion chip U1 is electrically connected to the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4 and the first power supply end, respectively, and the other ends of the capacitors C1, C2, C3 and C4 are commonly grounded; the analog voltage input end of the digital-to-analog conversion chip U1 is electrically connected to the capacitor C5, the capacitor C6 and the filter L1, respectively, the other ends of the capacitors C5 and C6 are commonly grounded, and the other end of the filter L1 is electrically connected to the first power supply end.

[0038] It should be noted that when the control module 1 outputs digital modulated signals, these signals enter the conversion module through the connector P1; inside the digital-to-analog conversion chip U1, the digital signals are converted into corresponding analog voltage signals. In this process, capacitors C1, C2, C3 and C4 are used to remove high-frequency noise in the digital signals, and capacitors C5, C6 and filter inductor L1 filter the analog output signals to improve the purity and stability of the signals, thereby improving the anti-interference ability and reliability of the circuit and ensuring the stable operation of the entire system.

[0039] Specifically, the model of the digital-to-analog conversion chip U1 in this embodiment is AD9763, which is a 10-bit dual-channel transmit digital-to-analog converter that supports an update rate of up to 125MSPS. Its output is a differential current signal with a range of 0-20mA output from U1 Pin45 and Pin46.

[0040] The voltage conversion unit 22 in this embodiment includes a differential operational amplifier chip U2, a capacitor C7, a capacitor C8, a capacitor C9, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7, wherein the digital-to-analog conversion chip U1 has two output ends, the first output end of the digital-to-analog conversion chip U1 is electrically connected to one end of the resistor R2, the resistor R6 and the capacitor C8, the other end of the resistor R2 is electrically connected to the resistor R1 and the differential input negative electrode of the differential operational amplifier chip U2, the other end of the resistor R1 is electrically connected to the resistor R4 and the output end of the differential operational amplifier chip U2, and the second output end of the digital-to-analog conversion chip U1 is electrically connected to the capacitors R6 and R7, respectively. The other end of C8, resistor R5 and one end of resistor R3 are electrically connected, the other end of resistor R3 and the other end of resistor R6 are commonly grounded, the other end of resistor R3 is respectively electrically connected to resistor R7 and the differential input positive pole of differential operational amplifier chip U2, the other end of resistor R7 is grounded, the negative power supply end of differential operational amplifier chip U2 is respectively electrically connected to the second inverting power supply end and capacitor C9, the positive power supply end of differential operational amplifier chip U2 is respectively electrically connected to the second positive power supply end and capacitor C7, the other end of resistor R7, the other end of capacitor C9 and the other end of capacitor C7 are respectively grounded, and the other end of resistor R4 serves as the output end of conversion module 2.

[0041] It should be noted that the two output ends of the digital-to-analog conversion chip U1 provide the positive and negative electrodes of the differential signal respectively. These differential signals enter the differential input pins of the differential operational amplifier chip U2 through resistors R2, R3, R5, R6 and capacitor C8. Inside the differential operational amplifier chip U2, the differential input signal is converted into a single-ended voltage output. Resistors R4, R1 and the output end of the differential operational amplifier chip U2 form a feedback loop; a part of the output voltage is fed back to the input end of the differential operational amplifier chip U2 after being divided by R4 and R1; this feedback mechanism helps to stabilize the output voltage and reduce fluctuations caused by external interference or load changes. The converted single-ended voltage is output from the output end of the differential operational amplifier chip U2 and connected to the output end of the conversion module 2 through resistor R4. At the same time, capacitors C7 and C9 are respectively connected between the positive power supply terminal and the negative power supply terminal of the differential operational amplifier chip U2 and the ground, playing the role of filtering and decoupling; the voltage conversion unit 22 can convert the differential signal output by the digital-to-analog conversion chip U1 into a stable single-ended voltage signal, and output it to the subsequent amplification module or lithium niobate modulator, which not only improves the stability and reliability of the signal, but also ensures the accuracy and consistency of the output voltage through the feedback mechanism.

[0042] The amplification module 3 in this embodiment includes an operational amplifier unit 31 and an isolation unit 32, wherein the input end of the operational amplifier unit 31 is electrically connected to the output end of the voltage conversion unit 22 for amplifying the voltage signal; the input end of the isolation unit 32 is electrically connected to the output end of the operational amplifier unit 31, and the output end of the isolation unit 32 is electrically connected to the lithium niobate photoelectric modulator 4, and the isolation unit 32 is used to isolate the operational amplifier unit 31 from being directly connected to the lithium niobate photoelectric modulator 4.

[0043] The operational amplifier unit 31 in this embodiment includes an operational amplifier chip U3, a resistor R8, a resistor R16, a resistor R17, a resistor R21, a capacitor C22, an electrolytic capacitor C17, a capacitor C18, an electrolytic capacitor C12 and a capacitor C11, wherein the other end of the resistor R4 is electrically connected to the resistor R8, the other end of the resistor R8 is electrically connected to the capacitor C11 and the pin 1 of the operational amplifier chip U3, the pin 6 of the operational amplifier chip U3 is electrically connected to the input end of the isolation unit 32, the resistor R21 and the capacitor C22, and the pin 2 of the operational amplifier chip U3 is electrically connected to the other end of the resistor R21, the other end of the capacitor C22 and Resistor R17 is electrically connected, pin 7 of the operational amplifier chip U3 is electrically connected to resistor R16, pin 4 of the operational amplifier chip U3 is electrically connected to the negative electrode of electrolytic capacitor C17, capacitor C18 and the third inverting power supply end, the positive electrode of electrolytic capacitor C17 is electrically connected to the other end of capacitor C18 and is grounded, pin 5 of the operational amplifier chip U3 is electrically connected to the negative electrode of electrolytic capacitor C12, capacitor C13 and the third positive power supply end, the positive electrode of electrolytic capacitor C12 is electrically connected to the other end of capacitor C13 and is grounded, and the other end of capacitor C11, the other end of resistor R17 and the other end of resistor R16 are grounded, respectively.

[0044] It should be noted that after the input voltage signal is divided by R4 and R8, it enters the input end of the operational amplifier chip U3. The operational amplifier chip U3 amplifies the signal through its internal amplifier and outputs the amplified voltage signal to the isolation unit 32 through the pin 6 output end. The negative feedback network composed of resistor R21 and capacitor C22 is connected to the output end through the negative feedback end of pin 2 to ensure the stability of the amplifier and the set amplification factor. The power supply end pins 7 and 4 are powered by an external power supply and filtered through C17, C18 and C12, C13 respectively to remove power supply noise. The amplified voltage signal is transmitted to the lithium niobate photoelectric modulator 4 through the isolation unit 32 to realize the modulation of the optical signal. The operational amplifier unit 31 set can effectively amplify the input voltage signal, and ensure the stability and accuracy of the output signal through filtering and negative feedback mechanism.

[0045] The isolation unit 32 in this embodiment includes an operational amplifier chip U4, a resistor R18, a resistor R19, a resistor R20, a resistor R22, a capacitor C16, an electrolytic capacitor C19, a capacitor C20, a capacitor C14, a capacitor C15, a capacitor C21 and a connector P3, wherein the other end of the resistor R18 is electrically connected to the resistor R8, the other end of the resistor R18 is electrically connected to the capacitor C16 and the pin 1 of the operational amplifier chip U4 respectively, the pin 6 of the operational amplifier chip U4 is electrically connected to the resistor R20 and the resistor R22 respectively, the other end of the resistor R22 is electrically connected to the pin 2 of the operational amplifier chip U4, the pin 7 of the operational amplifier chip U4 is electrically connected to the resistor R19, and the resistor R21 is electrically connected to the pin 1 of the operational amplifier chip U4. The other end of 0 is respectively connected to capacitor C21 and connector P2, pin 4 of the operational amplifier chip U4 is respectively electrically connected to the negative electrode of electrolytic capacitor C19, capacitor C20 and the third inverting power supply end, the positive electrode of electrolytic capacitor C19 is electrically connected to the other end of capacitor C20 and grounded, pin 5 of the operational amplifier chip U4 is respectively electrically connected to the negative electrode of electrolytic capacitor C14, capacitor C15 and the third positive power supply end, the positive electrode of electrolytic capacitor C14 is electrically connected to the other end of capacitor C15 and grounded, the other end of capacitor C11, the other end of resistor R17, the other end of resistor R16 and the other end of capacitor C21 are respectively grounded, and the connector P3 is electrically connected to the lithium niobate photoelectric modulator.

[0046] The amplified signal output by the operational amplifier chip U3 enters the operational amplifier chip U4. The operational amplifier chip U4 adopts a follower mode, so that the voltage signal output by it is approximately equal to the voltage signal output by the operational amplifier chip U3, thereby improving the load capacity of the overall output and preventing interference or damage caused by direct electrical connection.

[0047] Specifically, the operational amplifier chip U3 and the operational amplifier chip U4 in this embodiment are both of the type OPA453, and the amplification factor of the operational amplifier chip U3 is 8 times.

[0048] In this embodiment, the voltage of the first power supply terminal is 3.3V, the voltage of the second positive power supply terminal is +5V, the voltage of the second negative power supply terminal is -5V, the voltage of the third positive power supply terminal is +40V, and the voltage of the third negative power supply terminal is -40V.

[0049] Working principle:

[0050] The digital modulation signal output by the control module 1 is connected to the digital-to-analog conversion chip U1 chip via the P1 connector. The digital-to-analog conversion chip U1 chip converts the digital signal into a differential current signal with a range of 0-20mA. The differential current signal flows through the resistor R5 and the resistor R6 load and is converted into a + / -0.5V voltage signal. The + / -0.5V voltage signal is converted into a single-ended voltage signal via the differential operational amplifier chip U2. The amplification factor is 8 times, and the voltage range of the single-ended voltage signal is + / -4V. The differential operational amplifier chip U2 has a large gain-bandwidth product, extremely low operating noise, and very high input impedance. The single-ended voltage signal output by the differential operational amplifier chip U2 is input into the operational amplifier U3 for amplification. The output voltage signal of the operational amplifier chip U3 is approximately equal to the voltage signal input by the operational amplifier chip U3U4, and the voltage signal range is + / -36V. The voltage signal output by the operational amplifier chip U4 is input into the lithium niobate photoelectric modulator through the connector P3, and is output through the control module 1. After the driving circuit, the modulation signal output with a precision of + / -50mV, a dynamic range of + / -36V, and a bandwidth of 150KHz can be finally realized, which can realize the driving capability of the lithium niobate electro-optical modulator.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A lithium niobate modulator driving circuit, characterized in that: It comprises a control module (1), a conversion module (2), an amplification module (3) and a lithium niobate photoelectric modulator (4), wherein: The control module (1) is used to output a digital modulation signal; The input end of the conversion module (2) is electrically connected to the output end of the control module (1), and the conversion module (2) is used to convert the digital signal into an analog signal; The input end of the amplification module (3) is electrically connected to the output end of the conversion module (2), and the output end of the amplification module (3) is electrically connected to the input end of the lithium niobate photoelectric modulator (4). The amplification module (3) is used to amplify the analog signal and drive the lithium niobate photoelectric modulator (4).

2. The lithium niobate modulator driving circuit according to claim 1, characterized in that: The conversion module (2) comprises a digital-to-analog conversion unit (21) and a voltage conversion unit (22), wherein the input end of the digital-to-analog conversion unit (21) is electrically connected to the output end of the control module (1) and is used to convert the digital modulation signal of the control module (1) into a differential current signal, and the input end of the voltage conversion unit (22) is electrically connected to the output end of the digital-to-analog conversion unit (21) and is used to convert the differential current signal into a voltage signal.

3. The lithium niobate modulator driving circuit according to claim 2, characterized in that: The digital-to-analog conversion unit (21) comprises a connector P1, a digital-to-analog conversion chip U1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6 and a filter L1, wherein the output end of the control module (1) is electrically connected to the input end of the connector P1, the output end of the connector P1 is electrically connected to the input end of the digital-to-analog conversion chip U1, the digital voltage input end of the digital-to-analog conversion chip U1 is electrically connected to the capacitor C1, the capacitor C2, the capacitor C3, the capacitor C4 and the first power supply end, respectively, and the other ends of the capacitors C1, C2, C3 and C4 are commonly grounded; the analog voltage input end of the digital-to-analog conversion chip U1 is electrically connected to the capacitor C5, the capacitor C6 and the filter L1, respectively, the other ends of the capacitors C5 and C6 are commonly grounded, and the other end of the filter L1 is electrically connected to the first power supply end.

4. The lithium niobate modulator driving circuit according to claim 3, characterized in that: The voltage conversion unit (22) comprises a differential operational amplifier chip U2, a capacitor C7, a capacitor C8, a capacitor C9, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7, wherein the digital-to-analog conversion chip U1 has two output ends, the first output end of the digital-to-analog conversion chip U1 is electrically connected to one end of the resistor R2, the resistor R6 and the capacitor C8 respectively, the other end of the resistor R2 is electrically connected to the resistor R1 and the differential input negative electrode of the differential operational amplifier chip U2 respectively, the other end of the resistor R1 is electrically connected to the resistor R4 and the output end of the differential operational amplifier chip U2 respectively, and the second output end of the digital-to-analog conversion chip U1 is electrically connected to the capacitor C8 respectively. The other end of the resistor R5 and one end of the resistor R3 are electrically connected, the other end of the resistor R3 and the other end of the resistor R6 are commonly grounded, the other end of the resistor R3 is respectively electrically connected to the resistor R7 and the differential input positive pole of the differential operational amplifier chip U2, the other end of the resistor R7 is grounded, the negative power supply end of the differential operational amplifier chip U2 is respectively electrically connected to the second inverting power supply end and the capacitor C9, the positive power supply end of the differential operational amplifier chip U2 is respectively electrically connected to the second positive power supply end and the capacitor C7, the other end of the resistor R7, the other end of the capacitor C9 and the other end of the capacitor C7 are respectively grounded, and the other end of the resistor R4 serves as the output end of the conversion module (2).

5. The lithium niobate modulator driving circuit according to claim 4, characterized in that: The amplification module (3) comprises an operational amplification unit (31) and an isolation unit (32), wherein the input end of the operational amplification unit (31) is electrically connected to the output end of the voltage conversion unit (22) for amplifying the voltage signal; the input end of the isolation unit (32) is electrically connected to the output end of the operational amplification unit (31), the output end of the isolation unit (32) is electrically connected to the lithium niobate photoelectric modulator (4), and the isolation unit (32) is used to isolate the operational amplification unit (31) from being directly connected to the lithium niobate photoelectric modulator (4).

6. The lithium niobate modulator driving circuit according to claim 5, characterized in that: The operational amplifier unit (31) comprises an operational amplifier chip U3, a resistor R8, a resistor R16, a resistor R17, a resistor R21, a capacitor C22, an electrolytic capacitor C17, a capacitor C18, an electrolytic capacitor C12 and a capacitor C11, wherein the other end of the resistor R4 is electrically connected to the resistor R8, the other end of the resistor R8 is respectively electrically connected to the capacitor C11 and a pin 1 of the operational amplifier chip U3, the pin 6 of the operational amplifier chip U3 is respectively electrically connected to the input end of the isolation unit (32), the resistor R21 and the capacitor C22, the pin 2 of the operational amplifier chip U3 is respectively electrically connected to the other end of the resistor R21, the other end of the capacitor C22 and Resistor R17 is electrically connected, pin 7 of the operational amplifier chip U3 is electrically connected to resistor R16, pin 4 of the operational amplifier chip U3 is electrically connected to the negative electrode of electrolytic capacitor C17, capacitor C18 and the third inverting power supply end, the positive electrode of electrolytic capacitor C17 is electrically connected to the other end of capacitor C18 and is grounded, pin 5 of the operational amplifier chip U3 is electrically connected to the negative electrode of electrolytic capacitor C12, capacitor C13 and the third positive power supply end, the positive electrode of electrolytic capacitor C12 is electrically connected to the other end of capacitor C13 and is grounded, and the other end of capacitor C11, the other end of resistor R17 and the other end of resistor R16 are grounded, respectively.

7. The lithium niobate modulator driving circuit according to claim 6, characterized in that: The isolation unit (32) includes an operational amplifier chip U4, a resistor R18, a resistor R19, a resistor R20, a resistor R22, a capacitor C16, an electrolytic capacitor C19, a capacitor C20, a capacitor C14, a capacitor C15, a capacitor C21 and a connector P3, wherein the other end of the resistor R18 is electrically connected to the resistor R8, the other end of the resistor R18 is respectively electrically connected to the capacitor C16 and the pin 1 of the operational amplifier chip U4, the pin 6 of the operational amplifier chip U4 is respectively electrically connected to the resistor R20 and the resistor R22, the other end of the resistor R22 is electrically connected to the pin 2 of the operational amplifier chip U4, the pin 7 of the operational amplifier chip U4 is electrically connected to the resistor R19, and the resistor R20 is electrically connected to the pin 1 of the operational amplifier chip U4. The other end of the operational amplifier chip U4 is respectively connected to the capacitor C21 and the connector P2, the pin 4 of the operational amplifier chip U4 is respectively electrically connected to the negative electrode of the electrolytic capacitor C19, the capacitor C20 and the third inverting power supply end, the positive electrode of the electrolytic capacitor C19 is electrically connected to the other end of the capacitor C20 and is grounded, the pin 5 of the operational amplifier chip U4 is respectively electrically connected to the negative electrode of the electrolytic capacitor C14, the capacitor C15 and the third positive power supply end, the positive electrode of the electrolytic capacitor C14 is electrically connected to the other end of the capacitor C15 and is grounded, the other end of the capacitor C11, the other end of the resistor R17, the other end of the resistor R16 and the other end of the capacitor C21 are respectively grounded, and the connector P3 is electrically connected to the lithium niobate photoelectric modulator.

8. The lithium niobate modulator driving circuit according to claim 7, characterized in that: The voltage of the first power supply terminal is 3.3V, the voltage of the second positive power supply terminal is +5V, the voltage of the second negative power supply terminal is -5V, the voltage of the third positive power supply terminal is +40V, and the voltage of the third negative power supply terminal is -40V.

9. The lithium niobate modulator driving circuit according to claim 8, characterized in that: The operational amplifier chip U3 and the operational amplifier chip U4 are both of model OPA453, and the amplification factor of the operational amplifier chip U3 is 8 times.

10. The lithium niobate modulator driving circuit according to claim 3, characterized in that: The model of the digital-to-analog conversion chip U1 is AD9763.

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