A driving circuit of an electro-optical modulator and an electro-optical modulator

Abstract

The present invention discloses a driving circuit of an electro-optic modulator and an electro-optic modulator, which relates to the field of communication technology. A bias circuit is arranged in the electro-optic modulator, and the bias circuit includes a current limiting resistor and a thermistor connected to the first end of a signal electrode. The resistance of the thermistor changes with the change of the ambient temperature, and the voltage output to the first end of the signal electrode after the voltage division by the current limiting resistor and the thermistor also changes accordingly, so that the change of the resistance of the first thermistor is used to realize the passive adjustment of the bias voltage applied to the first end of the signal electrode according to the change of the ambient temperature, and compensate the working point deviation caused by the temperature change in the electro-optic modulator, thereby realizing the passive calibration of the working wavelength of light, and ensuring the accuracy of the modulation process of the electro-optic modulator to light. The compensation of the working wavelength can be realized without consuming additional energy, and the size of the optical chip itself will not be increased, and the preparation process of the chip will not be affected.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a driving circuit of an electro-optic modulator and an electro-optic modulator. Background Art

[0002] In the digital society, the rapid development of communication technology has put forward higher requirements for data transmission and processing. Silicon-based optoelectronic technology has become one of the key driving forces for promoting high-speed communication and data center applications with its high integration and process maturity. Traditional copper wire transmission systems face limitations in high-speed data transmission, while silicon photonics can easily achieve high-speed, high-bandwidth data transmission and computing. However, the field of silicon photonics also faces some challenges. In optical chips, the optical properties of Si materials are mainly used to realize data processing, but silicon materials themselves are sensitive to temperature, and have high thermoelectric coefficients and thermo-optical coefficients. The high temperature sensitivity and thermo-optical effect cause the electro-optic modulator to use Si material waveguides for optical fiber transmission. The working point will shift due to changes in ambient temperature, that is, the DC bias voltage applied to the signal electrode in the electro-optic modulator will shift, resulting in the wavelength drift of the final output optical signal, resulting in serious signal distortion, affecting the quality of data transmission and calculation, and the calculation accuracy of bit error rate and optoelectronic parameters will deteriorate.

[0003] It can be seen that how to avoid the working point deviation of the electro-optic modulator is a problem that needs to be solved by those skilled in the art. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a driving circuit of an electro-optic modulator and an electro-optic modulator, which can solve the problem of operating point deviation of the electro-optic modulator caused by temperature change during light transmission.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a driving circuit of an electro-optic modulator, comprising:

[0006] A bias circuit connected to the signal electrodes in the electro-optic modulator in a one-to-one correspondence, the bias circuit comprising a current limiting resistor and a thermistor connected in series, a first end of the circuit formed by the series connection of the current limiting resistor and the thermistor being connected to a DC voltage, a second end being grounded, and a point of series connection of the current limiting resistor and the thermistor being connected to a first end of the corresponding signal electrode;

[0007] The current limiting resistor is used to limit the current in the series circuit;

[0008] The thermistor is used to adjust the voltage applied to the first end of the signal electrode according to temperature changes, so as to control the voltage of the first end of the signal electrode to remain at a target bias voltage.

[0009] On the one hand, it also includes:

[0010] The first resistor connected in parallel at both ends of the thermistor is used to limit the change value of the voltage at the first end of the signal electrode to within a first preset range.

[0011] On the one hand, it also includes:

[0012] The RF signal output module has an input end connected to a preset RF signal, a first output end connected to the first end of the signal electrode, and a second output end connected to the second end of the signal electrode, and is used to provide an AC modulated signal for the signal electrode.

[0013] On the one hand, the radio frequency signal output module includes:

[0014] An amplifier, an input end of which is connected to a preset radio frequency signal, and is used to amplify the preset radio frequency signal;

[0015] The first filtering module has an input end connected to the output end of the amplifier, an output end connected to a DC voltage, and respectively connected to the second end of the signal electrode and the first end of a circuit in which the current limiting resistor and the thermistor are connected in series.

[0016] On the one hand, the first filtering module includes:

[0017] A first filter capacitor, a first end of which is connected to the output end of the amplifier;

[0018] The first filter resistor has a first end connected to a DC voltage and connected to the second end of the signal electrode, and a second end connected to the second end of the first filter capacitor and the first end of a circuit in which the current limiting resistor and the thermistor are connected in series.

[0019] On the one hand, the radio frequency signal output module also includes:

[0020] The second filtering module has an input end connected to the output end of the first filtering module and an output end connected to the second end of the signal electrode.

[0021] On the one hand, the second filtering module includes:

[0022] a second filter resistor, a first end of which is connected to the first end of the first filter resistor;

[0023] A second filter capacitor has a first end connected to the second end of the second filter resistor, and a second end connected to the second end of the signal electrode.

[0024] On the one hand, it also includes:

[0025] A first feedback resistor has a first end connected to the first end of the signal electrode and a second end connected to the input end of the amplifier, and is used to feed back the voltage of the first end of the signal electrode to the amplifier.

[0026] On the one hand, if the signal electrode in the electro-optic modulator includes a first electrode and a second electrode; the bias circuit corresponding to the first electrode is a first bias subcircuit, the bias circuit corresponding to the second electrode is a second bias subcircuit, the first bias subcircuit includes a first current limiting subresistor and a first thermistor, and the second bias subcircuit includes a second current limiting subresistor and a second thermistor;

[0027] The first current limiting sub-resistor and the first thermistor are connected in series, and the first end of the circuit formed by the first current limiting sub-resistor and the first thermistor are connected in series is connected to the first DC sub-voltage, the second end is grounded, and the series connection point of the first current limiting sub-resistor and the first thermistor is connected to the first end of the first electrode; the second current limiting sub-resistor and the second thermistor are connected in series, and the first end of the circuit formed by the second current limiting sub-resistor and the second thermistor are connected in series is connected to the second DC sub-voltage, the second end is grounded, and the series connection point of the second current limiting sub-resistor and the second thermistor is connected to the first end of the second electrode.

[0028] On the one hand, it also includes:

[0029] A comparison module, wherein a first input terminal is connected to a first terminal of the first electrode, and a second input terminal is respectively connected to a first terminal of the second electrode and an output terminal thereof, and is used for adjusting a voltage at a first terminal of the second electrode based on a voltage difference between a first terminal of the first electrode and a first terminal of the second electrode, so as to control a voltage difference between a first terminal of the first electrode and a first terminal of the second electrode within a second preset range.

[0030] On the one hand, it also includes:

[0031] a first voltage-dividing resistor, a first end of which is respectively connected to the first input end of the comparison module and the series connection point of the first current-limiting sub-resistor and the first thermistor sub-resistor, and a second end of which is connected to the first end of the first electrode;

[0032] A second voltage-dividing resistor has a first end connected to the second input end of the comparison module, the output end of the comparison module, and the series connection point of the second current-limiting sub-resistor and the second thermistor, and a second end connected to the first end of the second electrode.

[0033] On the one hand, the comparison module includes:

[0034] A comparator, wherein the first input end is respectively connected to the first end of the first voltage-dividing resistor and the series connection point of the first current-limiting sub-resistor and the first thermistor, and is used for outputting a first signal to control the voltage of the first end of the second electrode to increase when the voltage of the first end of the first electrode is greater than the voltage of the first end of the second electrode, so as to control the voltage difference between the first end of the first electrode and the first end of the second electrode to be within a second preset range; and outputting a second signal to control the voltage of the first end of the second electrode to decrease when the voltage of the first end of the first electrode is less than the voltage of the first end of the second electrode, so as to control the voltage difference between the first end of the first electrode and the first end of the second electrode to be within a second preset range;

[0035] The regulating resistor has a first end connected to the output end of the comparator, and a second end respectively connected to the second input end of the comparator, the first end of the second electrode, and the series connection point of the second current limiting sub-resistor and the second thermistor sub-resistor.

[0036] On the one hand, it also includes:

[0037] A DC isolation module, wherein a first end is connected to a first end of a circuit in which the first current limiting sub-resistor and the first thermistor are connected in series, and a second end is respectively connected to a first end of the second electrode and a series connection point of the second current limiting sub-resistor and the second thermistor.

[0038] On the one hand, the DC isolation module is an isolation capacitor.

[0039] To solve the above technical problems, an embodiment of the present invention further provides an electro-optical modulator, comprising a signal electrode and a driving circuit of the electro-optical modulator as described above, wherein the input end of the driving circuit of the electro-optical modulator is connected to a DC voltage, and the output end is connected to the first end of the signal electrode.

[0040] It can be seen from the above technical solution that by setting a bias circuit in the electro-optic modulator, the bias circuit includes a current limiting resistor and a thermistor connected to the first end of the signal electrode, the resistance of the thermistor will change with the change of the ambient temperature, and the voltage output to the first end of the signal electrode after the voltage division by the current limiting resistor and the thermistor will also change accordingly, so that the change of the resistance of the first thermistor is used to realize the passive adjustment of the bias voltage applied to the first end of the signal electrode according to the change of the ambient temperature, compensate for the deviation of the working point caused by the temperature change in the electro-optic modulator, and then realize the passive calibration of the working wavelength of the light, ensuring the accuracy of the modulation process of the electro-optic modulator to the light. The beneficial effect of the present invention is that the compensation of the working wavelength can be realized without consuming additional energy, and the size of the optical chip itself will not be increased, and the preparation process of the chip will not be affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 A schematic diagram of the structure of a driving circuit of an electro-optic modulator provided by an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of the arrangement of electrodes in an electro-optic modulator provided by an embodiment of the present invention;

[0044] Figure 3 A schematic diagram of the structure of a driving circuit when there is only one signal electrode in the electro-optic modulator provided by an embodiment of the present invention;

[0045] Figure 4 A schematic structural diagram of a driving circuit when there are two signal electrodes in an electro-optic modulator provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] The terms "including" and "having" in the specification of the present invention and the above-mentioned drawings, as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but may include steps or units that are not listed.

[0048] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0049] Next, a driving circuit of an electro-optic modulator provided by an embodiment of the present invention is described in detail. Figure 1 As shown, Figure 1 A schematic diagram of a driving circuit of an electro-optic modulator provided in an embodiment of the present invention, the driving circuit comprising:

[0050] A bias circuit connected one-to-one with the signal electrodes in the electro-optic modulator, the bias circuit comprising a current limiting resistor RL and a thermistor RT connected in series, a first end of the circuit of the current limiting resistor RL and the thermistor RT connected in series is connected to a DC voltage Vb, a second end is grounded, and a series connection point of the current limiting resistor RL and the thermistor RT is connected to the first end of the corresponding signal electrode;

[0051] The current limiting resistor RL is used to limit the current in the series circuit;

[0052] The thermistor RT is used to adjust the voltage applied to the first end of the signal electrode according to temperature changes, so as to control the voltage of the first end of the signal electrode to be maintained at a target bias voltage.

[0053] It should be noted that the electro-optic modulator is a key component in the optical communication system, responsible for converting electrical signals into optical signals for signal transmission in optical fibers. At the same time, the electro-optic modulator modulates the optical carrier, and the modulated optical signal is multiplexed into a single optical fiber for transmission. Therefore, the performance of the electro-optic modulator directly affects the subsequent data transmission rate and signal quality. The upper and lower arms and electrodes in the electro-optic modulator are the key parts for realizing optical signal modulation. The input optical carrier will be divided into two beams and transmitted through two different optical waveguide arms. The optical waveguide arm is referred to as a waveguide. During the modulation process, different voltages need to be applied to these two arms to change the propagation characteristics of the light waves in these arms, so as to generate a phase difference when the two light waves are recombined to achieve modulation of the optical signal. In this process, the electrode is used to apply voltage to control the refractive index of the optical waveguide, thereby affecting the propagation phase of the light wave.

[0054] Specifically, the electrodes in the electro-optic modulator include a signal electrode (S) and a ground electrode (G). The signal electrode and the ground electrode are respectively arranged on both sides of the waveguide, and the signal electrode is surrounded by two ground electrodes. By applying a voltage to the signal electrode, the signal electrode generates an electric field under the action of the voltage. This electric field interacts with the light waves in the waveguide, causing the refractive index of the waveguide to change, thereby controlling the phase and amplitude of the light waves transmitted therein, and effectively exerting the multiplexing and parallel characteristics of light.

[0055] It should be noted that the operating point of the electro-optical modulator refers to the optimal operating point of the modulator on its transmission characteristic curve. At this point, the modulator operates in the linear region, and the output optical signal of the modulator can approximately linearly reflect the changes in the input electrical signal, thereby achieving linear modulation. The linear region of the modulator refers to the region on its transmission characteristic curve where the output signal is linearly related to the input signal. In this region, the response of the modulator is uniform, which can reduce signal distortion and improve the transmission quality of the signal. In order to achieve high linearity modulation, the modulator usually needs to be precisely biased and driven. Therefore, the DC bias voltage applied to the signal electrode in the modulator needs to be maintained at a precise target bias voltage to enable the modulator to operate stably in the linear region and ensure the transmission quality of the final output signal.

[0056] Considering the advantages of silicon photonics in high-speed, high-bandwidth data transmission and computing, the waveguides in electro-optic modulators are generally implemented with Si waveguides. However, due to the high temperature sensitivity and thermo-optical effect of Si itself, when the working environment temperature of the electro-optic modulator changes, the carriers and refractive index of the Si waveguide will be affected by the temperature change. The change in the waveguide will also cause the voltage on the signal electrode to change, causing the voltage applied to the signal electrode to be unable to stabilize at the target bias voltage, and the working point of the modulator will shift. Once the working point of the modulator shifts, the optical signal output by the electro-optic modulator will also have a wavelength drift, and in severe cases, there may be channel crosstalk.

[0057] In order to avoid the influence of temperature on the modulator, the present invention provides a driving circuit, which includes a bias circuit connected to the signal electrodes in the electro-optical modulator in a one-to-one correspondence, and the bias circuit is used to provide a DC bias voltage for generating an electric field for the signal electrodes. The bias circuit includes a current limiting resistor RL and a thermistor RT connected in series, one end of the circuit after the current limiting resistor RL and the thermistor RT are connected in series is connected to a DC voltage Vb, and the other end is grounded to form a DC loop, and at the same time, the series connection point of the current limiting resistor RL and the thermistor RT is connected to the first end of the corresponding signal electrode, and the voltage of the series connection point is applied to the signal electrode to provide a DC bias voltage for the signal electrode. The resistance of the thermistor RT will change with the change of ambient temperature. At the same time, the voltage of the series connection point is the result of the current limiting resistor RL and the thermistor RT dividing the DC voltage Vb. Therefore, the voltage of the series connection point will change with the change of the resistance of the thermistor RT. When the ambient temperature changes and causes the modulator operating point to shift, the resistance of the thermistor RT will also change due to the change in ambient temperature, passively adjusting the voltage applied to the first end of the signal electrode, thereby maintaining the voltage of the first end of the signal electrode at the target bias voltage, thereby achieving compensation for the modulator operating point.

[0058] It should be noted that the specific types and implementation methods of the current limiting resistor RL and the thermistor RT are not specifically limited in this application. The current limiting resistor RL plays a current limiting role in the series circuit to avoid the burning of the device due to excessive current in the circuit. At the same time, it forms a voltage divider circuit with the thermistor RT to realize the process of applying a DC bias voltage to the signal electrode. The current limiting resistor RL can be implemented by a fixed resistor or the like, and the thermistor RT is not limited to resistor devices, but can also be implemented by other types of thermistors. The specific value of the target bias voltage is not specifically limited in this application, and it needs to be set and adjusted according to the specific modulation requirements of the electro-optical modulator.

[0059] Furthermore, the thermistor RT includes a PTC (Positive Temperature Coefficient) resistor and an NTC (Negative Temperature Coefficient) resistor. When one end of the thermistor RT in the series circuit is grounded, the smaller the resistance of the thermistor RT is, the smaller the voltage applied to the first end of the signal electrode is. At this time, the PTC resistor can achieve positive compensation for the modulator working point, and the NTC can achieve negative compensation for the modulator working point. Therefore, the specific implementation of the thermistor RT can be selected and set according to the actual offset of the working point in the modulator under the influence of temperature. When the modulator is prepared using materials with different thermo-optical coefficients, the specific offset of its working point under the influence of temperature will also be different. For example, when the voltage at the first end of the signal electrode in the modulator increases with the increase of temperature, the thermistor RT needs to passively reduce the voltage at the first end of the signal electrode to the target bias voltage when the temperature increases. At this time, a grounded NTC resistor can be used to implement the thermistor RT.

[0060] See also Figure 2 As shown, Figure 2 A schematic diagram of the arrangement of electrodes in an electro-optic modulator provided by an embodiment of the present invention; Figure 2 The figure shows a GSG (Ground-Signal-Ground) modulator, where an upper arm waveguide W is set between the signal electrode and the ground electrode. up and the lower arm waveguide W down The material of waveguide is generally Si, Si 3 N 4 , polymers, etc., generally Si waveguide, its thickness is generally 0.2-0.5μm or 3μm; the thickness of the cladding layer is generally 0.6-5μm, and the material of the cladding layer is generally SiO 2 、Al 2 O 3 , polymer, etc. Upper arm waveguide Wup and the lower arm waveguide W down In general, the waveguide W of the upper arm should be designed to be of different sizes to reduce the temperature sensitivity. For the GSGSG modulator, considering the symmetry of the positive and negative bias circuits, the upper arm waveguide W up and the lower arm waveguide W down The sizes of the two are usually set equal. up and the lower arm waveguide W down The thickness should be greater than 300 nm, and the maximum value should generally be less than 900 nm. The present application does not specifically limit the specific dimensions and implementation methods of the waveguide in the modulator.

[0061] The present invention designs a set of passive compensation circuits for the working point of high-speed GSG electrode modulators by connecting thermistors RT and current-limiting resistors RL in series, which can achieve fine adjustment of the working point without consuming any additional energy. At the same time, the present invention provides a construction idea and method for a temperature-insensitive photonic information network. It can be effectively applied to micro-ring modulators and lumped modulators to achieve temperature stability control of ultra-large-scale optical chips. Without consuming any additional energy, it is expected that the temperature sensitivity of the chip can reach the level of 100pm / K or even lower. It can be applied to optical computing chips, optical communication chips and optical fiber communication networks, and the temperature sensitivity characteristics of the system can be passively and finely compensated according to the linearity, working point position and temperature changes of the system, so as to enhance the integration capability of the optical chip and improve the data processing accuracy. In addition to being used in photonic devices or photonic information networks, it can also be applied to sensor networks that need to maintain temperature stability.

[0062] In order to solve the above problems, the present invention innovatively proposes an adaptive electro-optic modulator bias voltage control circuit based on thermistor RT material. The bias circuit forms a voltage divider circuit by connecting a thermistor RT and a current limiting resistor RL in series. One end of the series circuit is placed at the ground end. The resistance value of the thermistor RT changes with the ambient temperature to adjust the voltage output to the first end of the signal electrode, so that the bias voltage applied to the GSGSG (Ground-Signal-Ground-Signal-Ground, ground electrode-signal electrode-ground electrode-signal electrode-ground electrode) electrode can be passively adjusted according to the change of ambient temperature to compensate for the deviation of the working point caused by the temperature change, thereby realizing the passive calibration of the working wavelength. This scheme uses the characteristics of the thermistor RT itself to passively adjust the DC bias voltage of the signal electrode in the electro-optic modulator without active control, thereby realizing the compensation of the working wavelength without consuming additional energy. The entire driving circuit can be implemented in the form of an integrated circuit and integrated in the driving module of the electro-optic modulator, which will not significantly increase the size of the optical chip itself and will not affect the chip preparation process.

[0063] As a specific embodiment, see Figure 3 As shown, Figure 3 A schematic diagram of the structure of a driving circuit when there is only one signal electrode in the electro-optic modulator provided by an embodiment of the present invention; Figure 3 The figure shows the schematic diagram of the structure of the driving circuit when applied to a single-channel GSG traveling wave electrode modulator. Vb0 is a DC voltage. The driving circuit has a temperature passive compensation function and is used to drive the signal electrode in the modulator to generate an electric field. The driving circuit uses resistors RL0 and RT0 connected in series to adjust the working voltage of the S electrode. Among them, the resistor RT0 is a thermistor, and a resistor R0 connected in parallel with the resistor RT0 is added to avoid excessive voltage changes at the first end of the signal electrode. For example, under the condition of using an NTC thermistor, when the temperature rises, the resistance value of (R0 / / RT0) decreases slightly, thereby slightly reducing the voltage value of the N0 node, thereby adjusting the phenomenon of △α upper arm ≠△α lower arm caused by the increase in the phase shift value of the two arms due to the change in the working point caused by the temperature rise, so that the modulator working voltage returns to its original size as much as possible, and finally makes the phase shift difference between the upper and lower arms tend to be equal, realizing the temperature insensitive characteristic. The optical signal output by the electro-optic modulator can still be output to the MPD (Monitor Photodetector). When the driving circuit provided by the present invention is used to compensate the working point of the modulator, it will not affect the subsequent working voltage calibration solution through the MPD. The two can work at the same time to achieve an extremely low light sensitivity modulation device of the order of 100pm / K (or even lower).

[0064] As a specific embodiment, see Figure 4 As shown, Figure 4 A schematic structural diagram of a driving circuit when there are two signal electrodes in an electro-optic modulator provided by an embodiment of the present invention. Figure 4The figure shows a schematic diagram of the structure of the driving circuit when applied to the differential traveling wave electrode GSGSG electrode modulator. There are two signal electrodes in the modulator. The circuit uses a resistor RL1 and a resistor RT1 connected in series to adjust the working voltage of the first electrode, and uses a resistor RL2 and a resistor RT2 connected in series to adjust the working voltage of the second electrode. Among them, the resistor RT1 and the resistor RT2 are thermistors, and a resistor R1 connected in parallel with the resistor RT1 and a resistor R2 connected in parallel with the resistor RT2 are added to avoid excessive changes in the working voltage of the signal electrode. For example, when using an NTC thermistor, when the temperature rises, the overall resistance of the parallel thermistor-non-thermistor, that is, the resistance of (R1 / / RT1) or (R2 / / RT2) decreases slightly, which will slightly decrease the voltage value of the node N1 or N2 near it, thereby reducing the absolute value of the voltage applied to the corresponding S electrode, thereby offsetting the increase in the phase shift value of the two arms caused by the temperature rise and the change in the working point, so that the phase shift difference caused by the temperature change of the upper and lower arms tends to be equal.

[0065] On the one hand, it also includes:

[0066] The first resistor connected in parallel at both ends of the thermistor RT is used to limit the change value of the voltage at the first end of the signal electrode to within a first preset range.

[0067] It is not difficult to understand that the working point offset of the electro-optic modulator caused by temperature change may be relatively small. If the resistance of the thermistor RT changes greatly with temperature, it may lead to over-compensation of the voltage at the first end of the signal electrode. In order to avoid the over-compensation problem caused by the large change in the resistance of the thermistor RT and the circuit instability problem caused by the large change in the resistance of the thermistor RT, a first resistor connected in parallel with the thermistor RT can be further added at both ends of the thermistor RT. The adjustment sensitivity is determined by setting the resistance of the parallel thermistor-non-thermistor under room temperature conditions to achieve the adjustment and setting of the specific compensation accuracy. The specific type and implementation method of the first resistor are not specifically limited in this application. The resistance selection of the first resistor and the relationship between its resistance and the resistance of the thermistor RT can be adjusted and set according to the actual working point offset. The specific value of the first preset range is not specifically limited in this application. It depends on the relationship between the resistance of the first resistor and the resistance of the thermistor RT. The first resistor can also be implemented by a variable resistor to facilitate application in different working scenarios of the electro-optic modulator. Figure 3 As shown, the first resistor is implemented by using resistor R0, such as Figure 4 As shown, the first resistor is implemented by using resistors R1 and R2.

[0068] Specifically, the present invention utilizes a parallel thermistor-thermistor to realize real-time adjustment and calibration of the modulator operating point, innovatively constructs a combined thermistor module with a smaller temperature variation, and realizes fine adjustment of the overall resistance value. The parallel thermistor-thermistor structure can not only realize effective passive adjustment of the bias voltage, but also avoid the over-compensation problem caused by excessive change in the resistance value of a single thermistor RT, thereby improving the stability and reliability of the entire drive circuit.

[0069] On the one hand, it also includes:

[0070] The RF signal output module has an input end connected to a preset RF signal, a first output end connected to a first end of a signal electrode, and a second output end connected to a second end of the signal electrode, and is used to provide an AC modulated signal for the signal electrode.

[0071] It is understandable that, in the process of modulating the optical signal, the electro-optic modulator not only needs to apply a DC bias voltage to the signal electrode to generate an electric field, but also needs to apply an AC signal at both ends of the signal electrode to control the rapid change of the carriers inside the waveguide. The application of the AC signal to the S electrode will cause the electric field between the electrodes to change, thereby changing the refractive index of the waveguide to achieve modulation of the light wave. Therefore, the electric field generated by the signal electrode is the result of the combined action of the DC bias voltage and the AC modulation signal. In general, the AC modulation signal is implemented in the form of a radio frequency signal, so an RF signal output module that is connected to a preset radio frequency signal can be added to the circuit to apply an AC modulation signal to the signal electrode. The specific type and implementation method of the RF signal output module are not particularly limited in this application. The specific parameters of the preset radio frequency signal can be set and adjusted according to the modulation requirements.

[0072] Specifically, considering that the modulator also requires the participation of an AC signal when modulating the optical signal, a radio frequency signal output module is added to the driving circuit to provide an radio frequency signal to the signal electrode, so that the driving circuit can simultaneously implement the process of applying a DC bias voltage and an AC signal to the signal electrode, so that the modulator can directly modulate the optical signal under the action of the driving circuit provided by the present invention.

[0073] On the one hand, the RF signal output module includes:

[0074] An amplifier U, whose input terminal is connected to a preset radio frequency signal, and is used to amplify the preset radio frequency signal;

[0075] The first filter module has an input end connected to the output end of the amplifier U, an output end connected to the DC voltage Vb, and respectively connected to the second end of the signal electrode and the first end of the circuit in which the current limiting resistor RL and the thermistor RT are connected in series.

[0076] It is not difficult to understand that, considering that in some high-speed optical communication systems, since the radio frequency signal may be attenuated during the transmission process, an amplifier U can be used to compensate for these losses. By setting an amplifier U in the radio frequency signal output module to enhance the power of the radio frequency signal, it is ensured that the modulator can receive a sufficiently strong signal to achieve effective modulation. At the same time, a first filter module can be set at the output end of the amplifier U to filter out interference signals such as noise in the AC signal output by the amplifier U. By setting the filter parameters of the first filter module, an AC signal of a specific frequency can be selected to be applied to the signal electrode. The specific type and implementation method of the amplifier U and the first filter module are not particularly limited in this application. Parameters such as the gain of the amplifier U and the filter parameters of the first filter module can also be set and adjusted according to actual application requirements, and the application does not make any special restrictions here.

[0077] Specifically, the amplifier U can enhance the radio frequency signal, and the first filter module can filter out interference signals. By setting the amplifier U and the first filter module to process the radio frequency signal, the signal electrode can obtain a sufficiently strong specific radio frequency signal, thereby realizing an accurate and effective modulation process of the optical signal, thereby improving the performance of the entire electro-optical modulator.

[0078] On the one hand, the first filtering module includes:

[0079] A first filter capacitor C1, a first end of which is connected to the output end of the amplifier U;

[0080] The first filter resistor RC1 has a first end connected to the DC voltage Vb and to the second end of the signal electrode, and a second end connected to the second end of the first filter capacitor C1 and the first end of a circuit in which the current limiting resistor RL and the thermistor RT are connected in series.

[0081] It is understandable that the first filtering module can be implemented in a specific manner using RC filtering, by providing a first filtering capacitor C1 and a first filtering resistor RC1 connected in parallel at the output end of the amplifier U to form an RC filtering structure, and the first filtering resistor RC1 is connected in series between the DC voltage Vb and the current limiting resistor RL, and can pass the DC voltage Vb to ensure that the signal electrode can receive the DC bias voltage. The specific type and implementation method of the first filtering capacitor C1 and the first filtering resistor RC1 are not particularly limited in this application.

[0082] Specifically, the RC filtering structure can effectively realize the filtering process of AC signals. The filtering parameters can be directly realized by adjusting the capacitance of the filter capacitor and the resistance of the filter resistor. It is simple, effective and easy to implement. The devices used are low in cost and small in size, which is conducive to the simple implementation of the entire drive circuit.

[0083] On the one hand, the RF signal output module also includes:

[0084] The second filter module has an input end connected to the output end of the first filter module, and an output end connected to the second end of the signal electrode.

[0085] It is not difficult to understand that, considering that the AC signal needs to be applied to the first end and the second end of the signal electrode at the same time, but the first filter resistor RC1 is connected in series in the DC circuit, in order to avoid the DC voltage Vb from being output to the second end of the signal electrode, and also to avoid interference signals such as noise generated during the output of the RF signal to the second end of the signal electrode, a second filter module can be set between the DC voltage Vb and the second end of the signal electrode. The specific type, implementation method and value of the filter parameters of the second filter module are not specifically limited in this application, and can be set and adjusted according to actual application requirements. Figure 3 As shown, a resistor RC0 may be added between the DC voltage and the second filter module to limit the current.

[0086] Specifically, a second filtering module may be added to process the AC signal output to the second end of the signal electrode, thereby ensuring the accuracy and reliability of the AC signal output to the second end of the signal electrode and ensuring an accurate and effective modulation process of the optical signal, thereby improving the performance of the entire electro-optical modulator.

[0087] On the one hand, the second filtering module includes:

[0088] A second filter resistor RC2, a first end of which is connected to a first end of the first filter resistor RC1;

[0089] The second filter capacitor C2 has a first end connected to the second end of the second filter resistor RC2 and a second end connected to the second end of the signal electrode.

[0090] It is understandable that the second filtering module can be implemented in a specific manner using RC filtering, by providing a second filter capacitor C2 and a second filter resistor RC2 connected in series between the second end of the signal electrode and the DC voltage Vb to form an RC filtering structure, and the second filter capacitor C2 is connected in series between the DC voltage Vb and the second end of the signal electrode to play a role in isolating DC. The specific type and implementation of the second filter capacitor C2 and the second filter resistor RC2 are not particularly limited in this application.

[0091] Specifically, the RC filtering structure can effectively realize the filtering process of AC signals. The filtering parameters can be directly realized by adjusting the capacitance of the filter capacitor and the resistance of the filter resistor. It is simple, effective and easy to implement. The devices used are low in cost and small in size, which is conducive to the simple implementation of the entire drive circuit.

[0092] On the one hand, it also includes:

[0093] The first feedback resistor has a first end connected to the first end of the signal electrode and a second end connected to the input end of the amplifier U, and is used to feed back the voltage of the first end of the signal electrode to the amplifier U.

[0094] It is not difficult to understand that, when the driving circuit simultaneously applies a DC bias voltage and an AC signal to the signal electrode, a first feedback resistor can be further added to the circuit. The first feedback resistor can feed back the voltage condition of the first end of the signal electrode to the input end of the amplifier U, and perform feedback adjustment on the working voltage of the amplifier U of the driving circuit. The present application does not specifically limit the specific type and implementation method of the first feedback resistor. When the signal electrode includes a first electrode and a second electrode, the structure of this feedback resistor can be set at the first end of the first resistor for feedback, or can be set at the first end of the second electrode for feedback, such as Figure 3 As shown in FIG. 1 , a resistor Rf1 is set as the first feedback resistor. Figure 4 As shown, the resistor Rf2 is set as the first feedback resistor.

[0095] Specifically, a feedback control loop is formed between the voltage at the first end of the signal electrode and the operating voltage of the amplifier U by setting a first feedback resistor, and the operating voltage of the amplifier U is feedback-regulated, so that the compensation of the voltage at the first end of the signal electrode by the thermistor RT is also fed back to the input end of the amplifier U, and the operating voltage of the amplifier U is also compensated, thereby ensuring the temperature-insensitive characteristic of the entire driving circuit.

[0096] On the one hand, if the signal electrode in the electro-optic modulator includes a first electrode and a second electrode; the bias circuit corresponding to the first electrode is a first bias subcircuit, the bias circuit corresponding to the second electrode is a second bias subcircuit, the first bias subcircuit includes a first current limiting subresistor RL1 and a first thermal subresistor RT1, and the second bias subcircuit includes a second current limiting subresistor RL2 and a second thermal subresistor RT2;

[0097] The first current limiting sub-resistor RL1 and the first thermistor RT1 are connected in series, and the first end of the circuit formed by the series connection of the first current limiting sub-resistor RL1 and the first thermistor RT1 is connected to the first DC sub-voltage Vb1, the second end is grounded, and the series connection point of the first current limiting sub-resistor RL1 and the first thermistor RT1 is connected to the first end of the first electrode; the second current limiting sub-resistor RL2 and the second thermistor RT2 are connected in series, and the first end of the circuit formed by the series connection of the second current limiting sub-resistor RL2 and the second thermistor RT2 is connected to the second DC sub-voltage Vb2, the second end is grounded, and the series connection point of the second current limiting sub-resistor RL2 and the second thermistor RT2 is connected to the first end of the second electrode.

[0098] It is understandable that when there are multiple signal electrodes in the electro-optic modulator, it is necessary to set up multiple bias circuits connected to each signal electrode in a one-to-one correspondence to realize the process of applying a DC bias voltage to each signal electrode. Taking the case where there are two signal electrodes in the electro-optic modulator as an example, the first bias subcircuit is a bias circuit connected to the first electrode, and the second bias subcircuit is a bias circuit connected to the second electrode, and each bias subcircuit can adopt a structure of a series current limiting resistor RL and a thermistor RT to realize passive compensation of the voltage at the first end of each signal electrode. The DC voltage of the two signal electrodes can also be realized by two DC voltages respectively, so that the first bias subcircuit and the second bias subcircuit can respectively use the first DC sub-voltage Vb1 and the second DC sub-voltage Vb2 to passively compensate the voltage at the first end of the first electrode and the second electrode, so as to facilitate independent passive control.

[0099] It should be noted that when there are multiple signal electrodes in the electro-optic modulator, a structure in which a current limiting resistor RL and a thermistor RT are connected in series can be used in the bias circuit corresponding to each signal electrode to achieve compensation for the working point of the modulator, or a structure in which a current limiting resistor RL and a thermistor RT are connected in series can be used for compensation only in the bias circuit corresponding to one or part of the signal electrodes. The same DC voltage can also be used to apply a DC bias voltage to each signal electrode, and is not limited to the method of applying a DC bias voltage using corresponding multiple DC sub-voltages in this embodiment. This application does not make any special restrictions on the number of signal electrodes in the electro-optic modulator and the implementation method, and the corresponding DC voltage and the specific implementation method of the bias circuit can also be adjusted and set according to the working point offset of the modulator in actual applications.

[0100] Specifically, by setting a first bias sub-circuit and a first DC sub-voltage Vb1 corresponding to the first electrode and a second bias sub-circuit and a second DC sub-voltage Vb2 corresponding to the second electrode, and setting a series current limiting resistor RL and a thermistor RT structure in the first bias sub-circuit and the second bias sub-circuit, independent passive compensation processes for the two signal electrodes are respectively realized, thereby improving the accuracy and reliability of the operating point compensation of the entire modulator and ensuring the performance of the modulator.

[0101] On the one hand, it also includes:

[0102] A comparison module, wherein the first input terminal is connected to the first end of the first electrode, and the second input terminal is respectively connected to the first end of the second electrode and its own output terminal, and is used to adjust the voltage of the first end of the second electrode based on the voltage difference between the first end of the first electrode and the first end of the second electrode, so as to control the voltage difference between the first end of the first electrode and the first end of the second electrode within a second preset range.

[0103] It can be understood that when there are two signal electrodes, the first electrode and the second electrode, in the modulator, in order to avoid the phase difference between the optical signals output by the upper arm and the lower arm of the modulator, it is necessary to ensure that the DC bias voltage applied to the first end of the first electrode and the DC bias voltage applied to the first end of the second electrode are equal, that is, the voltage difference between the first end of the first electrode and the first end of the second electrode is within the second preset range. Therefore, a comparison module can also be set in the driving circuit to compare the voltage difference between the two, and output different signals according to the comparison result to adjust the voltage of the first end of the second electrode, so that the voltage of the first end of the first electrode and the voltage of the first end of the second electrode always tend to be equal. The specific value and implementation method of the second preset range are not particularly limited in this application. The optimal embodiment is to control the voltage of the first end of the first electrode and the voltage of the first end of the second electrode to always remain equal. The specific type and implementation method of the comparison module are not particularly limited in this application. The comparison module can also achieve control by adjusting the voltage of the first end of the first electrode, which is not limited to the implementation method of adjusting the voltage of the first end of the second electrode in this embodiment.

[0104] Specifically, a comparison module is set to compare the voltage at the first end of the first electrode and the voltage at the first end of the second electrode. At the same time, the comparison module also adjusts the voltage at the first end of the second electrode according to the comparison result, thereby further compensating for the phase difference between the optical signals output by the two arms of the modulator caused by factors such as temperature changes, avoiding the occurrence of channel crosstalk caused by the phase difference, and further ensuring the accuracy of the light modulation process of the electro-optical modulator.

[0105] On the one hand, it also includes:

[0106] A first voltage-dividing resistor RL3, a first end of which is respectively connected to the first input end of the comparison module and the series connection point of the first current-limiting sub-resistor RL1 and the first thermal-sensitive sub-resistor RT1, and a second end of which is connected to the first end of the first electrode;

[0107] The second voltage-dividing resistor RL4 has a first end connected to the second input end of the comparison module, the output end of the comparison module, and the series connection point of the second current-limiting sub-resistor RL2 and the second thermistor RT2, and a second end connected to the first end of the second electrode.

[0108] It is not difficult to understand that a first voltage-dividing resistor RL3 can be added between the series connection point of the first current-limiting sub-resistor RL1 and the first thermistor RT1 and the first end of the first electrode. The first voltage-dividing resistor RL3 can further play a role in current limiting, and can also prevent the direct connection between the comparison module and the signal electrode, thereby avoiding the influence of the comparison module on the DC bias voltage applied to the first end of the signal electrode. Similarly, a second voltage-dividing resistor RL4 is added between the series connection point of the second current-limiting sub-resistor RL2 and the second thermistor RT2 and the first end of the second electrode, which plays the same role as the first voltage-dividing resistor RL3, and the present application will not repeat it here. The present application does not make any special restrictions on the specific types and implementation methods of the first voltage-dividing resistor RL3 and the second voltage-dividing resistor RL4.

[0109] Specifically, by further adding a first voltage-dividing resistor RL3 and a second voltage-dividing resistor RL4 in the driving circuit, the circuit can be further protected to avoid the influence of the comparison module on the DC bias voltage of the first end of the signal electrode, thereby improving the accuracy and stability of the DC bias voltage applied to the first end of the signal electrode, and ensuring the accuracy of the light modulation process of the electro-optical modulator.

[0110] On the one hand, the comparison module includes:

[0111] A comparator A0, wherein the first input terminal is respectively connected to the first terminal of the first voltage-dividing resistor RL3 and the series connection point of the first current-limiting sub-resistor RL1 and the first thermistor RT1, and is used for outputting a first signal to control the voltage of the first terminal of the second electrode to increase when the voltage of the first terminal of the first electrode is greater than the voltage of the first terminal of the second electrode, so as to control the voltage difference between the first terminal of the first electrode and the first terminal of the second electrode to be within a second preset range; and outputting a second signal to control the voltage of the first terminal of the second electrode to decrease when the voltage of the first terminal of the first electrode is less than the voltage of the first terminal of the second electrode, so as to control the voltage difference between the first terminal of the first electrode and the first terminal of the second electrode to be within a second preset range;

[0112] The regulating resistor Rcc has a first end connected to the output end of the comparator A0, and a second end connected to the second input end of the comparator A0, the first end of the second electrode, and the series connection point of the second current limiting sub-resistor RL2 and the second thermistor RT2.

[0113] It can be understood that the comparison module specifically includes a comparator A0 and an adjustment resistor Rcc, and the comparator A0 can output different signals according to the comparison result to control the voltage of the first end of the second electrode. The first signal and the second signal may specifically be current signals. For example, when the voltage V1 of the first input terminal is greater than the voltage V2 of the second input terminal, that is, the voltage of the first end of the first electrode is greater than the voltage of the first end of the second electrode, the comparator A0 may output a forward current, so that the current flowing to the second voltage-dividing resistor RL4 increases, thereby causing the voltage across the second voltage-dividing resistor RL4 to increase, thereby reducing the voltage at the first end of the second electrode; when the voltage V1 of the first input terminal is less than the voltage V2 of the second input terminal, that is, the voltage of the first end of the first electrode is less than the voltage of the first end of the second electrode, the comparator A0 may output a reverse current, so that the current flowing to the second voltage-dividing resistor RL4 decreases, thereby causing the voltage across the second voltage-dividing resistor RL4 to decrease, thereby increasing the voltage at the first end of the second electrode; the forward current refers to the current flowing from the output terminal of the comparator A0 to the regulating resistor Rcc, and the regulating resistor Rcc plays a role in current limiting, further protecting the circuit, and at the same time, the voltage across the regulating resistor Rcc can effectively feedback the voltage difference of the DC bias voltage between the two signal electrodes. The voltage at the first end of the second electrode may also be controlled by setting the adjustment resistor Rcc as a variable resistor.

[0114] As a specific embodiment, Figure 4 As shown, in order to further avoid the phase difference between the optical signals output by the two arms of the modulator and ensure the performance of the modulator, a preferred embodiment is RT1 / R1=RT2 / R2, Vb1=Vb2, or RT1 / R1≈RT2 / R2 according to the symmetry of the modulator. Rcc is used to feedback the absolute value of the difference in potential between the two S electrodes relative to the ground terminal. When the absolute value of the voltage of one of the S electrodes is large, the comparator A0 will output a current I0=k*(|V1|-|V2|), where k is the output voltage coefficient of the comparator A0. The output current I0 will adjust the DC loop corresponding to Vb2 through the adjusting resistor Rcc, so that the absolute values ​​of the bias voltages of the two S electrodes tend to be equal, thereby compensating for the change in the optical phase difference output by the two arms of the modulator caused by temperature changes and achieving temperature insensitivity. In the two S-electrode bias voltage loops, a preferred embodiment is RL2 / (R2 / / RT2)=RL1 / (R1 / / RT1). Resistor Rf1 serves as the first feedback resistor, and feeds back the voltage of the DC loop corresponding to Vb2 to the input end of the amplifier U to perform feedback adjustment on the working voltage of the amplifier U of the driving circuit, thereby ensuring the temperature insensitivity of the entire driving circuit.

[0115] On the one hand, it also includes:

[0116] The DC isolation module has a first end connected to the first end of the circuit in which the first current limiting sub-resistor RL1 and the first thermistor RT1 are connected in series, and a second end connected to the first end of the second electrode and the series connection point of the second current limiting sub-resistor RL2 and the second thermistor RT2.

[0117] It is not difficult to understand that when the modulator includes two signal electrodes, the first electrode and the second electrode, the AC signal output by the RF output module needs to be output to the first electrode and the second electrode. At this time, the DC bias voltage of the second electrode is applied through the second DC sub-voltage Vb2. Therefore, a DC isolation module can be added between the first DC sub-voltage Vb1 and the second DC sub-voltage Vb2. The DC isolation module can isolate the two DC voltages Vb of the first DC sub-voltage Vb1 and the second DC sub-voltage Vb2 from each other, but the RF signal can be output to the second electrode through the DC isolation module, thereby realizing the application of the AC signal to the two signal electrodes through an RF signal. The specific type and implementation method of the DC isolation module are not particularly limited in this application, and it is sufficient that it can play the role of isolating DC and passing AC.

[0118] Furthermore, if Figure 4 As shown, the RF signal output by the amplifier is only output to the first end of the first electrode and the first end of the second electrode. At this time, a matching resistor connected in series can be further added between the signal electrode and the corresponding ground electrode for impedance matching. Figure 4 As shown, the S electrode connected to the N1 point through the first voltage-dividing resistor RL3 serves as the first electrode, and the S electrode connected to the N2 point serves as the second electrode. The first electrode and a ground electrode constitute the lower arm of the modulator, so a matching resistor can be connected between the first electrode and the ground electrode for impedance matching; the second electrode and another ground electrode constitute the upper arm of the modulator, so a matching resistor can also be connected between the second electrode and the other ground electrode for impedance matching. The matching resistor can absorb all microwave power, so that the RF signal can be effectively transmitted to the modulator, avoiding the microwave power from being reflected back along the line, weakening the transmission signal of the signal electrode, and affecting the modulation performance.

[0119] Specifically, a DC isolation module can be added between the first DC sub-voltage Vb1 and the second DC sub-voltage Vb2 to achieve a process of outputting a radio frequency signal to two signal electrodes at the same time, thereby further simplifying the circuit structure of the driving circuit, saving costs, and reducing volume.

[0120] On the one hand, the DC isolation module is an isolation capacitor C0.

[0121] It can be understood that the capacitor can effectively isolate the DC voltage Vb, so the DC isolation module can be implemented using the isolation capacitor C0. Figure 4 As shown, after the RF signal is output from the first filter resistor RC1, it can be output to the second electrode through the isolation capacitor C0 and the second filter module, and can also be output from the second end of the first filter capacitor C1 to the first electrode.

[0122] Specifically, a capacitor may be used to implement a DC isolation module, which is simple, effective, and easy to implement, and is conducive to the simple implementation of the entire drive circuit.

[0123] To solve the above technical problems, an embodiment of the present invention further provides an electro-optic modulator, including a signal electrode and a driving circuit of the electro-optic modulator as described above, wherein the input end of the driving circuit of the electro-optic modulator is connected to a DC voltage, and the output end is connected to the first end of the signal electrode.

[0124] It is not difficult to understand that the driving circuit can provide the signal electrode with the DC bias voltage and AC signal required to adjust the light, thereby realizing the modulation process of the optical signal by the electro-optic modulator. The specific implementation method of the electrode in the electro-optic modulator is not particularly limited in this application.

[0125] The present invention provides a description of the features of an electro-optic modulator, which can be found in the relevant description of the embodiment of the driving circuit of the electro-optic modulator mentioned above, and will not be described in detail here.

[0126] The above is a detailed introduction to a driving circuit of an electro-optic modulator and an electro-optic modulator provided by an embodiment of the present invention. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the electro-optic modulator disclosed in the embodiment, since it corresponds to the driving circuit disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the driving circuit part.

[0127] The above is a detailed introduction to the driving circuit of an electro-optic modulator and the electro-optic modulator provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A driving circuit for an electro-optic modulator, characterized in that: include: A bias circuit connected to the signal electrodes in the electro-optic modulator in a one-to-one correspondence, the bias circuit comprising a current limiting resistor and a thermistor connected in series, a first end of the circuit formed by the series connection of the current limiting resistor and the thermistor being connected to a DC voltage, a second end being grounded, and a point of series connection of the current limiting resistor and the thermistor being connected to a first end of the corresponding signal electrode; The current limiting resistor is used to limit the current in the series circuit; The thermistor is used to adjust the voltage applied to the first end of the signal electrode according to temperature changes, so as to control the voltage of the first end of the signal electrode to remain at a target bias voltage; The signal electrode in the electro-optic modulator includes a first electrode and a second electrode; the bias circuit corresponding to the first electrode is a first bias subcircuit, the bias circuit corresponding to the second electrode is a second bias subcircuit, the first bias subcircuit includes a first current limiting subresistor and a first thermistor, and the second bias subcircuit includes a second current limiting subresistor and a second thermistor; The first current limiting sub-resistor and the first thermistor are connected in series, and the first end of the circuit formed by the first current limiting sub-resistor and the first thermistor are connected in series is connected to the first DC sub-voltage, the second end is grounded, and the series connection point of the first current limiting sub-resistor and the first thermistor is connected to the first end of the first electrode; the second current limiting sub-resistor and the second thermistor are connected in series, and the first end of the circuit formed by the second current limiting sub-resistor and the second thermistor are connected in series is connected to the second DC sub-voltage, the second end is grounded, and the series connection point of the second current limiting sub-resistor and the second thermistor is connected to the first end of the second electrode; Also includes: a comparison module, wherein the first input terminal is connected to the first terminal of the first electrode, the second input terminal is respectively connected to the first terminal of the second electrode and the output terminal thereof, and is used for adjusting the voltage of the first terminal of the second electrode based on the voltage difference between the first terminal of the first electrode and the first terminal of the second electrode, so as to control the voltage difference between the first terminal of the first electrode and the first terminal of the second electrode to be within a second preset range; Also includes: a first voltage-dividing resistor, a first end of which is respectively connected to the first input end of the comparison module and the series connection point of the first current-limiting sub-resistor and the first thermistor sub-resistor, and a second end of which is connected to the first end of the first electrode; A second voltage-dividing resistor has a first end connected to the second input end of the comparison module, the output end of the comparison module, and the series connection point of the second current-limiting sub-resistor and the second thermistor, and a second end connected to the first end of the second electrode.

2. The driving circuit of the electro-optic modulator according to claim 1, characterized in that: Also includes: The first resistor connected in parallel at both ends of the first thermistor is used to limit the change value of the voltage at the first end of the first electrode to within a first preset range.

3. The driving circuit of the electro-optic modulator according to claim 1, characterized in that: Also includes: A radio frequency signal output module, wherein the input end is connected to a preset radio frequency signal, the first output end is connected to the first end of the first electrode, and the second output end is connected to the first end of the second electrode, and is used to provide an AC modulation signal for the first electrode and the second electrode.

4. The driving circuit of the electro-optic modulator according to claim 3, characterized in that: The radio frequency signal output module comprises: An amplifier, an input end of which is connected to a preset radio frequency signal, and is used to amplify the preset radio frequency signal; The first filtering module has an input end connected to the output end of the amplifier, an output end connected to a DC voltage, and respectively connected to the first end of the second electrode and the first end of the circuit in which the first current limiting sub-resistor and the first thermistor are connected in series.

5. The driving circuit of the electro-optic modulator according to claim 4, characterized in that: The first filtering module comprises: A first filter capacitor, a first end of which is connected to the output end of the amplifier; The first filter resistor has a first end connected to a DC voltage and connected to the first end of the second electrode, and a second end connected to the second end of the first filter capacitor and the first end of a circuit in which the first current limiting sub-resistor and the first thermistor are connected in series.

6. The driving circuit of the electro-optic modulator according to claim 5, characterized in that: The radio frequency signal output module also includes: The second filtering module has an input end connected to the output end of the first filtering module and an output end connected to the first end of the second electrode.

7. The driving circuit of the electro-optic modulator according to claim 6, characterized in that: The second filtering module comprises: a second filter resistor, a first end of which is connected to the first end of the first filter resistor; A second filter capacitor has a first end connected to the second end of the second filter resistor, and a second end connected to the first end of the second electrode.

8. The driving circuit of the electro-optic modulator according to claim 4, characterized in that: Also includes: A first feedback resistor has a first end connected to the first end of the second electrode and a second end connected to the input end of the amplifier, and is used to feed back the voltage of the first end of the second electrode to the amplifier.

9. The driving circuit of the electro-optic modulator according to claim 1, characterized in that: The comparison module comprises: A comparator, wherein the first input end is respectively connected to the first end of the first voltage-dividing resistor and the series connection point of the first current-limiting sub-resistor and the first thermistor, and is used for outputting a first signal to control the voltage of the first end of the second electrode to increase when the voltage of the first end of the first electrode is greater than the voltage of the first end of the second electrode, so as to control the voltage difference between the first end of the first electrode and the first end of the second electrode to be within a second preset range; and outputting a second signal to control the voltage of the first end of the second electrode to decrease when the voltage of the first end of the first electrode is less than the voltage of the first end of the second electrode, so as to control the voltage difference between the first end of the first electrode and the first end of the second electrode to be within a second preset range; The regulating resistor has a first end connected to the output end of the comparator, and a second end respectively connected to the second input end of the comparator, the first end of the second electrode, and the series connection point of the second current limiting sub-resistor and the second thermistor sub-resistor.

10. The driving circuit of the electro-optic modulator according to claim 1, characterized in that: Also includes: A DC isolation module, wherein a first end is connected to a first end of a circuit in which the first current limiting sub-resistor and the first thermistor are connected in series, and a second end is respectively connected to a first end of the second electrode and a series connection point of the second current limiting sub-resistor and the second thermistor.

11. The driving circuit of the electro-optic modulator according to claim 10, characterized in that: The DC isolation module is an isolation capacitor.

12. An electro-optic modulator, characterized in that: It comprises a signal electrode and a driving circuit of the electro-optic modulator as claimed in any one of claims 1 to 11, wherein the input end of the driving circuit of the electro-optic modulator is connected to a DC voltage, and the output end is connected to the first end of the signal electrode.

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