WO2023071255A1 - Method and apparatus for realizing locking of phase bias point of mz silicon optical modulator - Google Patents

Method and apparatus for realizing locking of phase bias point of mz silicon optical modulator Download PDF

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WO2023071255A1
WO2023071255A1 PCT/CN2022/101747 CN2022101747W WO2023071255A1 WO 2023071255 A1 WO2023071255 A1 WO 2023071255A1 CN 2022101747 W CN2022101747 W CN 2022101747W WO 2023071255 A1 WO2023071255 A1 WO 2023071255A1
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thermo
silicon
phase shifter
optical
result
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PCT/CN2022/101747
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French (fr)
Chinese (zh)
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陈宏刚
张博
胡蕾蕾
梁雪瑞
李凤
丁兰
程媛
甘霖飞
胡毅
罗勇
胡强高
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武汉光迅科技股份有限公司
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Publication of WO2023071255A1 publication Critical patent/WO2023071255A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/0147—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on thermo-optic effects
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/0121—Operation of devices; Circuit arrangements, not otherwise provided for in this subclass
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/015—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on semiconductor elements having potential barriers, e.g. having a PN or PIN junction

Definitions

  • the invention belongs to the technical field of optical communication interconnection, and more specifically relates to a method and a device for realizing phase bias point locking of an MZ silicon optical modulator.
  • the Mach-Zehnder structure (MZ) silicon optical modulator is used as the core optical device in the silicon photonics ecological chain to realize the high-speed electro-optical modulation function of the signal.
  • MZ silicon optical modulator When the MZ silicon optical modulator is used as an external modulator, it needs to be based on different The modulation format selects different phase offset operating points. For example, when the MZ silicon light modulator works in the intensity modulation format, the phase bias point needs to be set to 90 degrees, which is the Quad point. When the MZ silicon light modulator works in the phase modulation format, the phase bias point needs to be set to 180 degrees, the Null point. In addition, the phase bias point of the MZ silicon optical modulator will drift randomly with temperature and environmental changes.
  • the MZ silicon optical modulator will deviate from the optimal operating point, which will eventually lead to the degradation of the modulation performance of the MZ silicon optical modulator and reduce the transmission signal. Quality, under serious conditions, post-correction errors will occur, causing adverse consequences of service interruption. Therefore, the introduction of automatic bias voltage control to realize the closed-loop locking of the phase bias point of the MZ silicon optical modulator is a must for the practical use of the MZ silicon optical modulator Require.
  • the first one is to use the average optical power detection to realize the closed-loop control, and the output optical signal through the light splitting is detected by the photodetector to detect the average photocurrent to realize the closed-loop locking.
  • this method is only suitable for intensity modulation formats and is susceptible to changes in the input optical signal, so the average optical power locking method has relatively low accuracy and is only suitable for optical signal transmission in a simple coding method such as NRZ; another method is the disturbance The detection method realizes closed-loop control.
  • the part of the optical signal at the output end of the MZ silicon optical modulator is amplified and detected through an AC amplifier circuit.
  • the back-end sampling circuit and control circuit realize the detection of the same-frequency or double-frequency electrical signal, and the closed-loop control of the phase bias point is realized by controlling the phase bias point to minimize the same-frequency or double-frequency signal, but this method is complex , requires a signal generator, a multi-stage AC amplifier circuit, a high-order analog bandpass filter and a signal detector of the same frequency, and the related circuit components are difficult to put into ultra-small packages such as QDD, OSFP and other high-speed optical modules middle.
  • the present invention provides a method and device for realizing the phase bias point locking of MZ silicon optical modulator, the purpose of which is to automatically adjust the thermal optical signal according to the output optical signal of MZ silicon optical modulator
  • the adjustment amount of the phase shifter is used to complete the phase bias point locking of the MZ silicon optical modulator, thereby solving the technical problem that the phase bias point locking of the MZ silicon optical modulator in the current small optical module requires the use of various circuit components.
  • a method for realizing phase bias point locking of an MZ silicon optical modulator comprising:
  • the output optical signal of the laser is input into the MZ silicon optical modulator through an optical fiber;
  • the MZ silicon optical modulator guides the two optical signals separated by the main optical path into the first photodetector and the second photodetector with a phase difference of 180 degrees by means of light splitting, and the main optical path serves as the MZ The optical path of the output optical signal of the silicon optical modulator;
  • the first photodetector and the second photodetector respectively output a first photocurrent and a second photocurrent, and the first photodetector is used to detect light in the same direction as the output phase of the MZ silicon light modulator signal, the second photodetector is used to detect an optical signal that is opposite in phase to the output of the MZ silicon optical modulator;
  • the adjustment amount of the thermo-optic phase shifter in the MZ silicon light modulator is determined by the first photocurrent, the second photocurrent and the thermal The thermal power of the optical phase shifter is calculated.
  • the present invention also includes the following additional technical features.
  • the adjustment amount of the thermo-optic phase shifter in the MZ silicon optical modulator is calculated from the first photocurrent, the second photocurrent and the thermal power of the thermo-optic phase shifter, specifically include:
  • the first voltage signal and the second voltage signal are synchronously sampled by a dual data sampling unit to obtain a first average photocurrent and a second average photocurrent;
  • thermo-optic phase shifter An adjustment amount of the thermo-optic phase shifter is calculated according to the first result and the thermal power of the thermo-optic phase shifter.
  • thermo-optic phase shifter by using the first result and the thermal power of the thermo-optic phase shifter, specifically includes:
  • thermo-optic phase shifter calculating the first derivative of the second result with respect to the thermal power of the thermo-optic phase shifter to obtain a third result
  • the adjustment amount of the thermo-optic phase shifter is the difference between the third result and 0, and after the thermo-optic phase shifter completes the adjustment, the The MZ silicon light modulator is locked at the quad point.
  • the adjustment amount of the thermo-optical phase shifter in the MZ silicon optical modulator is determined by the first result and the thermo-optic phase shifter
  • the relationship function between the thermal power is calculated, including:
  • thermo-optic phase shifter calculating the first derivative and the second derivative of the first result with respect to the thermal power of the thermo-optic phase shifter to obtain a fourth result and a fifth result respectively;
  • the adjustment amount of the thermo-optic phase shifter is the error of the fourth result relative to the Null point and divided by the fifth result. After the thermo-optic phase shifter is adjusted, the MZ silicon optical modulator locks At the null point.
  • the fifth result is obtained through calculation, including:
  • thermo-optic phase shifter calculating the first derivative of the first result corresponding to the bias voltage of the thermo-optic phase shifter relative to the thermal power of the thermo-optic phase shifter to obtain the fourth result
  • thermo-optic phase shifter if the fifth result is positive, the bias voltage of the thermo-optic phase shifter is increased;
  • a device for realizing phase bias point locking of an MZ silicon optical modulator comprising: a laser, an optical fiber, an MZ silicon optical modulator, a processing unit, and a reverse drive assembly, wherein :
  • the output optical signal of the laser is input into the MZ silicon optical modulator through the optical fiber;
  • the MZ silicon optical modulator divides the input optical signal into optical signals with a phase difference of 180 degrees for output;
  • the processing unit calculates the relationship between the normalized result of the output optical signal of the MZ silicon optical modulator and the thermal power of the thermo-optical phase shifter in the MZ silicon optical modulator,
  • the reverse driving component drives the reverse PN junction of the MZ silicon light modulator
  • the processing unit calculates the adjustment amount of the thermo-optic phase shifter, so that the MZ silicon optical modulator completes the locking of the corresponding bias point.
  • the MZ silicon optical modulator guides the two optical signals separated by the main optical path into the first photodetector and the second photodetector with a phase difference of 180 degrees by means of light splitting, and the main optical path As the optical path of the output optical signal of the MZ silicon optical modulator, wherein:
  • the first photodetector and the second photodetector respectively output a first photocurrent and a second photocurrent
  • the first photodetector is used to detect an optical signal in the same direction as the output phase of the MZ silicon optical modulator
  • the second photodetector is used to detect an optical signal whose phase is opposite to that output by the MZ silicon optical modulator.
  • the processing unit includes a dual-channel transimpedance amplifier, a dual analog-to-digital converter, a processor, and a dual-channel digital-to-analog converter, wherein:
  • the first photocurrent and the second photocurrent output by the first photodetector and the second photodetector are respectively converted into a first voltage signal and a second voltage signal by the dual-channel transimpedance amplifier. voltage signal;
  • the first voltage signal and the second voltage signal are synchronously sampled by the dual analog-to-digital converter
  • the processor performs data processing on the first voltage signal and the second voltage signal, and outputs an analog voltage to the dual-channel digital-to-analog converter;
  • the analog voltage output by the dual digital-to-analog converter is respectively applied to the bias point of the thermo-optical phase shifter and the reverse PN junction according to the calculation result of the processor.
  • the backdrive component includes a pulse code source generator and a voltage amplifier, wherein:
  • the pulse code source generator outputs a modulation voltage signal, the modulation voltage signal is amplified by the voltage amplifier, and the amplified voltage acts on the radio frequency modulation unit through the pin V RF to drive the reverse PN junction .
  • the MZ silicon optical modulator further includes an input MMI, a thermo-optic phase shifter, a radio frequency modulation unit, and an output MMI, wherein:
  • the optical signal is output after passing through the input MMI, the thermo-optic phase shifter, the radio frequency modulation unit and the output MMI;
  • the input MMI interferes with the optical signal
  • the output MMI is reversely connected to the second photodetector
  • the output MMI is connected to the first photodetector in the same direction;
  • thermo-optic phase shifter sets a bias point with the processing unit through a pin V bias ;
  • the radio frequency modulation unit sets the reverse PN junction voltage with the processing unit through the pin V PN .
  • the phase bias point locking method of the MZ silicon optical modulator can automatically adjust the adjustment amount of the thermo-optic phase shifter according to the output optical signal of the MZ silicon optical modulator, and realize the precise locking of any bias point of the MZ silicon optical modulator ;
  • the software and hardware design of the phase bias point locking device of the MZ silicon optical modulator is simple, and it is easy to be transplanted as a whole into high-speed silicon optical modules in ultra-small packages such as QDD and OSFP.
  • FIG. 1 is a schematic diagram of a device for realizing phase bias point locking of an MZ silicon optical modulator provided by the present invention
  • Fig. 2 is a function graph of the first output photodetector and the second output photodetector as the normalized bias voltage of the thermo-optic phase shifter changes;
  • Fig. 3 is a function graph of the normalized photocurrent ratio changing with the normalized bias voltage of the thermo-optic phase shifter
  • Fig. 4 is the first-order derivative function curve graph of the normalized photocurrent ratio when the Quad point is locked and the normalized photocurrent ratio when the Null point is locked with respect to the normalized thermal power change of the thermo-optic phase shifter;
  • Figure 5 is a flow chart of the Quad point locking of the MZ silicon light modulator
  • Fig. 6 is a flow chart of the Null point locking of the MZ silicon light modulator.
  • a first feature being “on” or “under” a second feature may include direct contact between the first and second features, and may also include the first and second features Not in direct contact but through another characteristic contact between them.
  • “above”, “above” and “above” the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.
  • “Below”, “beneath” and “under” the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.
  • Embodiment 1 provides a method for realizing phase bias point locking of an MZ silicon optical modulator, as shown in FIG. 1 , the method includes:
  • the output optical signal of the laser is input into the MZ silicon optical modulator through the optical fiber.
  • the laser continuously outputs optical signals, which can be input to the MZ silicon optical modulator through optical fibers.
  • the MZ silicon optical modulator guides the two optical signals separated by the main optical path into the first photodetector and the second photodetector with a phase difference of 180 degrees by means of light splitting, and the main optical path serves as the MZ silicon optical modulation
  • the optical path of the output optical signal of the device is as follows:
  • the modulation signal is a signal that changes with time
  • the output optical signal intensity of the MZ silicon optical modulator can be obtained as:
  • P IN is the intensity of the input optical signal
  • formula (2) is simplified as:
  • P OUT_DC (t) and P OUT_AC (t) are coefficients of DC component and AC component of the output optical power of the MZ silicon optical modulator, respectively, which vary with time.
  • radio frequency signal causes the phase change of the MZ silicon light modulator, and can be determined by the radio frequency signal V RF (t) third-order polynomial to represent:
  • ⁇ RF_A_1, 2, 3, 4 and are the polynomial factors of the phase shift of the upper and lower arms of the MZ silicon optical modulator relative to the reverse PN junction bias voltage, and V PN is the DC reverse bias voltage of the reverse PN junction.
  • thermo-optic phase shifter According to the phase modulation principle of the thermo-optic phase shifter, the expression of the DC bias phase introduced by the thermo-optic phase shifter is V bias is the DC voltage applied by the thermo-optic phase shifter, V ⁇ is the half-wave voltage of the thermo-optic phase shifter, that is, the corresponding DC voltage when the phase bias is ⁇ , so the output optical signal of the MZ silicon optical modulator is shifted with the thermo-optic phase
  • the relationship between the phase converter bias voltage can be expressed as formula (9):
  • the first photodetector and the second photodetector respectively output a first photocurrent and a second photocurrent
  • the first photodetector is used to detect
  • the MZ silicon optical modulator outputs an optical signal with the same phase
  • the second photodetector is used to detect the optical signal at the opposite end of the multimode interference coupler whose phase is different from the output of the MZ silicon optical modulator by 180 degrees.
  • the difference of 180 degrees is used to distinguish the strongest interference signal and the weakest interference signal of the multimode interference coupler. Under the strongest interference signal of the multimode interference coupler, the light signal of the first photodetector (same direction) is the strongest, and the light signal of the second photodetector (reverse direction) is the weakest.
  • the adjustment amount of the thermo-optic phase shifter in the MZ silicon light modulator is determined by the first photocurrent, the second photocurrent and the thermo-optic phase shifter The thermal power is calculated.
  • thermo-optic phase shifter in the MZ silicon optical modulator is calculated from the first photocurrent, the second photocurrent and the thermal power of the thermo-optic phase shifter, specifically including:
  • the first voltage signal and the second voltage signal are synchronously sampled by a dual data sampling unit to obtain a first average photocurrent and a second average photocurrent;
  • thermo-optic phase shifter An adjustment amount of the thermo-optic phase shifter is calculated according to the first result and thermal power of the thermo-optic phase shifter.
  • the average photocurrents of the first output photodetector and the second output photodetector can be expressed as:
  • R INPHASE and R OUTERPHASE represent the responsivity of the first output photodetector and the second output photodetector respectively, and R INPHASE and R OUTERPHASE are determined by the first output photodetector and the second output
  • the photodetector decides by itself and is not affected by time.
  • the above two average photocurrents are normalized to obtain the normalized photocurrent, as shown in Figure 3:
  • the normalized photocurrent and the thermal power of the thermo-optic phase shifter are further calculated to obtain the adjustment amount of the thermo-optic phase shifter in the MZ silicon optical modulator, so as to realize the precise locking of any bias point of the MZ silicon optical modulator.
  • thermo-optic phase shifter is used to calculate the adjustment amount of the thermo-optic phase shifter, specifically including:
  • thermo-optic phase shifter calculating the first derivative of the second result with respect to the thermal power of the thermo-optic phase shifter to obtain a third result
  • the adjustment amount of the thermo-optic phase shifter is the difference between the third result and 0, and after the thermo-optic phase shifter completes the adjustment, the The MZ silicon light modulator is locked at the quad point.
  • the DC bias point of the thermo-optic phase shifter needs to be locked at the Quad point, which is the voltage of the bias point of the thermo-optic phase shifter
  • k is a positive integer; k is determined by the cycle of actually selecting the bias voltage. For example, it is 0 in the first cycle and 1 in the second cycle. Considering the sensitivity of the modulation curve, generally at least the second cycle is selected.
  • thermo-optic phase shifter V Quad . Therefore, construct a function whose expression is I RATIO (t)-I RATIO_Quad , and assume that the expression of the first derivative of this function relative to the thermal power of the thermo-optic phase shifter is:
  • the specific steps of locking the MZ silicon light modulator at the Quad point include:
  • thermo-optic phase shifter In the initialization stage, it is necessary to set the bias voltage of the thermo-optic phase shifter to 0; then turn on the laser; and then turn on the radio frequency modulation signal.
  • thermo-optic phase shifter is scanned for n ⁇ periods, and the minimum value of n is 2, that is, the phase change of the thermo-optic phase shifter is scanned for at least 2 ⁇ periods.
  • S104 Calculate a responsivity ratio between the first output photodetector and the second output photodetector and use it as a reference point.
  • the MZ silicon light modulator completes the lock after finding the Quad point.
  • K slope_Quad_now (V bias ) is greater than or equal to K slope_Quad_last (V bias ), further determine whether K slope_Quad_now (V bias ) is greater than 0.
  • S106 to S113 form a closed-loop control state in which the MZ silicon optical modulator is locked at the Quad point, and the closed-loop control of the Quad point is always performed on the MZ silicon optical modulator.
  • the normalized photocurrent ratio of the two low-speed photodetectors inside the MZ silicon light modulator that is, the first output photodetector and the second output photodetector
  • the normalized photocurrent ratio and the first output photodetector The difference between the responsivity ratio of the sensor and the second output photodetector, calculate the first derivative of the difference with respect to the thermal power of the thermo-optic phase shifter, that is, the adjustment amount of the bias voltage of the thermo-optic phase shifter, and calculate at the same time
  • the error of the current first-order derivative result relative to 0 is used to obtain the correction value of the bias voltage of the thermo-optic phase shifter, that is, to realize the precise locking of the Quad point of the MZ silicon optical modulator.
  • thermo-optic phase shifter in the MZ silicon optical modulator performs the Null point
  • the adjustment amount of the thermo-optic phase shifter in the MZ silicon optical modulator is calculated from the relationship function between the first result and the thermal power of the thermo-optic phase shifter, specifically including:
  • thermo-optic phase shifter calculating the first derivative and the second derivative of the first result with respect to the thermal power of the thermo-optic phase shifter to obtain a fourth result and a fifth result respectively;
  • the adjustment amount of the thermo-optic phase shifter is the error of the fourth result relative to the Null point and divided by the fifth result. After the thermo-optic phase shifter is adjusted, the MZ silicon optical modulator locks At the null point.
  • thermo-optic phase shifter When the MZ silicon optical modulator works in the phase modulation format, the DC bias point of the thermo-optic phase shifter needs to be locked at the Null point, and the relationship between the voltage corresponding to the Null point and the half-wave voltage is Wherein k is a positive integer; seek I RATIO (t) with respect to the first order derivative and the second order derivative of thermo-optic phase shifter, its expression is respectively:
  • ⁇ V is the single-step adjustment amount of the bias voltage of the thermo-optic phase shifter; therefore, for the Null point locking of the MZ silicon optical modulator, it is necessary to judge the sign of K' slope_null in addition to adjusting the K slope_null to an absolute value of 0.
  • the specific steps of locking the MZ silicon light modulator at the Null point include:
  • thermo-optic phase shifter In the initialization stage, it is necessary to set the bias voltage of the thermo-optic phase shifter to 0; then turn on the laser; and then turn on the radio frequency modulation signal.
  • thermo-optic phase shifter is scanned for n ⁇ periods, and the minimum value of n is 2, that is, the phase change of the thermo-optic phase shifter is scanned for at least 2 ⁇ periods.
  • V bias corresponding to K slope_null (V bias ) being 0 and K' slope_null_now (V bias ) greater than 0, and record it as V DC_SET_null .
  • the MZ silicon optical modulator completes the lock after finding the Null point.
  • K slope_null_now (V bias ) is greater than or equal to K slope_null_last (V bias ), determine whether K slope_null_now (V bias ) is greater than 0.
  • S206 to S213 form a closed-loop control state in which the MZ silicon optical modulator is locked at the Null point, and the closed-loop control of the Null point is always performed on the MZ silicon optical modulator.
  • the normalized photocurrent ratio relative to the thermal light shift is calculated
  • the first derivative and the second derivative of the thermal power of the phase shifter by adjusting the bias voltage of the thermo-optic phase shifter, the first derivative approaches 0 and at the same time judges the sign of the second derivative, the result of the first derivative determines the thermo-optic phase shift
  • the adjustment amount of the bias voltage of the thermo-optical phase shifter, the second-order derivative determines the adjustment direction.
  • the adjustment direction and adjustment amount of the bias voltage of the thermo-optic phase shifter can be determined, that is, to realize the MZ silicon Precise locking of the Null point of the light modulator.
  • thermo-optic phase shifter in order to judge the adjustment direction of the thermo-optic phase shifter when the MZ silicon optical modulator is locked at the Null point, there is also a preferred implementation scheme in combination with the embodiment of the present invention, specifically, as shown in 6, the calculation method of the fifth result is:
  • the first derivative of the first result corresponding to the bias voltage of the thermo-optic phase shifter with respect to the thermal power of the thermo-optic phase shifter is obtained through calculation to obtain a fourth result.
  • the fourth result is the amount of adjustment of the thermo-optic phase shifter bias voltage.
  • the magnitude of the bias voltage determines the DC bias phase point of the thermo-optic phase shifter. If the DC bias phase point is not at the optimum point, the performance of the modulator will deteriorate sharply.
  • thermo-optic phase shifter if the fifth result is positive, the bias voltage of the thermo-optic phase shifter is increased;
  • the fifth result is used to judge the adjustment direction of the bias voltage of the thermo-optic phase shifter.
  • the magnitude of the bias voltage determines the DC bias phase point of the thermo-optic phase shifter. If the DC bias phase point is not at the optimum point, the performance of the modulator will be affected. Rapid deterioration.
  • the first embodiment provides a method for locking the phase bias point of the MZ silicon optical modulator without introducing a sinusoidal or square wave jitter signal, by detecting the first output photodetector and the second output of the MZ silicon optical modulator respectively.
  • the photodetector calculates the thermal power of the first photocurrent, the second photocurrent and the thermo-optic phase shifter to obtain the adjustment amount of the thermo-optic phase shifter, so as to lock the phase bias point.
  • the second embodiment provides a device for realizing the phase bias point locking of the MZ silicon optical modulator, which is used to implement the method in the first embodiment.
  • the device of the second embodiment includes: a laser 1, an optical fiber 2, and an MZ silicon optical modulator 3.
  • the output optical signal of the laser 1 is input into the MZ silicon optical modulator 3 through the optical fiber 2 .
  • the MZ silicon optical modulator 3 divides the input optical signal into output optical signals with a phase difference of 180 degrees.
  • the MZ silicon light modulator contains two photodetectors, one is the first photodetector 32 in the same direction as the output light signal of the MZ silicon light modulator, and is used to detect the average photocurrent output by the MZ silicon light modulator; the other is The second output photodetector 33, which is opposite to the output optical signal of the MZ silicon light modulator, is used to detect the photocurrent at the reverse end of the MZ silicon light modulator output 2X2MMI, and the MMI is a multi-mode interference coupler (multi-mode interferometer, MMI ), the phase difference between the output optical signal of the second output photodetector and the output of the MZ silicon optical modulator is 180 degrees.
  • MMI multi-mode interference coupler
  • Two input ports are selected to input two types of interference light, and the output signal of 2X2MMI is the optical signal after the interference of the input optical signal, and the phase difference between the two output signals is 180 degrees.
  • the processing unit 4 calculates the relationship between the normalized result of the output optical signal of the MZ silicon optical modulator 3 and the thermal power of the thermo-optical phase shifter 35 in the MZ silicon optical modulator 3 .
  • the photocurrent of the first output photodetector 32 and the photocurrent of the second output photodetector 33 are simultaneously amplified by the dual-way transimpedance amplifier 41, and are synchronously sampled by the dual-way digital-to-analog converter 42, and the processor 43 converts the first
  • the first output photodetector 32 and the sampling voltage value of the second output photodetector 33 are divided to obtain a normalized operation result, and the output is an analog voltage, and then the analog voltage corresponding to the first output photodetector 32 is used as the applied thermal
  • the voltage at the bias point of the optical phase shifter 35 and the analog voltage corresponding to the second output photodetector 33 are used as the reverse bias voltage of the reverse PN junction.
  • the reverse driving component 5 drives the reverse PN junction of the MZ silicon light modulator 3 .
  • the reverse PN junction electro-optic modulator needs to be in a depleted state when the PN junction is working in reverse bias, and the carriers do drift movement under the action of the electric field, so its movement speed is fast.
  • the back drive component 5 needs to use a high-speed voltage amplifier.
  • the processing unit 4 calculates the adjustment amount of the thermo-optic phase shifter 35 so that the MZ silicon optical modulator 3 completes the locking of the corresponding bias point.
  • the adjustment amount of the thermo-optic phase shifter in the MZ silicon light modulator 3 is determined by the first photocurrent, the second photocurrent and the thermo-optic shift
  • the thermal power of the phase device is calculated.
  • phase offset point of the MZ silicon optical modulator 3 is adjusted by a thermo-optic phase shifter based on the silicon waveguide thermo-optic effect, and its phase offset is proportional to the thermal power loaded on the thermo-optic phase shifter.
  • the MZ silicon optical modulator 3 guides the two optical signals separated by the main optical path into the first photodetector 32 and the second photodetector 33 with a phase difference of 180 degrees by means of light splitting.
  • the optical path is used as the optical path of the output optical signal of the MZ silicon optical modulator, wherein:
  • the first photodetector 32 and the second photodetector 33 respectively output a first photocurrent and a second photocurrent.
  • the first photodetector 32 is used to detect the optical signals output by the MZ silicon optical modulator 3 with the same phase.
  • the second photodetector 33 is used to detect the optical signal at the reverse end of the multimode interference coupler whose phase difference is 180 degrees from the output of the MZ silicon optical modulator 3 .
  • the light splitting ratio of the first photodetector 32 is 1-10%. In the same output direction of the MZ silicon light modulator 3, the first photodetector 32 splits the light by 1-10%, and the output of the MZ silicon light modulator can be calculated. photocurrent.
  • the processing unit 4 includes a dual-channel transimpedance amplifier 41, a dual-channel analog-to-digital converter 42, a processor 43 and a dual-channel digital-to-analog converter 44, wherein:
  • the first photocurrent and the second photocurrent output by the first photodetector 32 and the second photodetector 33 are respectively converted into a first voltage signal and a second voltage by the dual-channel transimpedance amplifier 41 Signal;
  • the first voltage signal and the second voltage signal are synchronously sampled by the dual analog-to-digital converter 42;
  • the processor 43 performs data processing on the first voltage signal and the second voltage signal, and outputs an analog voltage to the dual-way digital-to-analog converter 44;
  • the dual digital-to-analog converter 44 applies the analog voltage output by the processor 43 to the forward voltage of the bias point of the thermo-optical phase shifter 35 and the reverse voltage of the reverse PN junction, respectively, for adjusting The bias point of the thermo-optic phase shifter and the reverse bias position of the RF PN junction.
  • the processor 43 uses the analog voltage corresponding to the first output photodetector 32 as the voltage applied to the bias point of the thermo-optic phase shifter 35, and the analog voltage corresponding to the second output photodetector 33 as the reverse bias of the reverse PN junction. set the voltage.
  • the reverse drive component 5 includes a pulse code source generator 51 and a voltage amplifier 52, wherein:
  • the pulse code source generator 51 outputs a modulation voltage signal, the modulation voltage signal is amplified by the voltage amplifier 52, and the amplified voltage acts on the radio frequency modulation unit 36 through the pin V RF to drive the reverse PN junction.
  • the reverse PN type electro-optic modulator needs to be in a depleted state when it works in reverse bias, and the carriers do drift movement under the action of the electric field, so its movement speed is fast, which is conducive to the realization of high-speed electro-optic modulation, so It has become a common structure for realizing MZ silicon light modulators.
  • the MZ silicon The optical modulator 3 also includes an input MMI 34, a thermo-optic phase shifter 35, a radio frequency modulation unit 36 and an output MMI 37, wherein:
  • the optical signal is output after passing through the input MMI 34, the thermo-optic phase shifter 35, the radio frequency modulation unit 36 and the output MMI 37;
  • the input MMI 34 interferes with the optical signal
  • the output MMI 37 is reversely connected with the second photodetector 33;
  • the output MMI 37 is connected in the same direction with the first photodetector 32;
  • thermo-optic phase shifter 35 sets a bias point through the pin Vbias and the processing unit 4;
  • the radio frequency modulation unit 36 sets the reverse PN junction voltage through the pin V PN and the processing unit 4 .
  • the input MMI 34 is two types of interference light input through two input ports, and the output MMI 37 is the optical signal after the interference of the input optical signal, and the phase difference between the two output signals is 180 degrees.
  • the device for realizing the phase bias point locking of the MZ silicon optical modulator provided in the second embodiment can realize the precise locking of any bias point of the MZ silicon optical modulator, and at the same time, the design is simple, and it is easy to be transplanted to ultra-small packages such as QDD, OSFP, etc. Packaged form of high-speed silicon optical modules.

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Abstract

The present invention discloses a method and apparatus for realizing the locking of a phase bias point of an MZ silicon optical modulator. The method comprises: inputting an output optical signal of a laser into an MZ silicon optical modulator by means of an optical fiber; the MZ silicon optical modulator respectively importing, by means of light splitting, two optical signals, which are separated from a main optical path, into a first photoelectric detector and a second photoelectric detector, the phase difference between which is 180 degrees, wherein the main optical path serves as an optical path of an output optical signal of the MZ silicon optical modulator; and the first photoelectric detector and the second photoelectric detector respectively outputting a first photocurrent and a second photocurrent, wherein the first photoelectric detector is used for detecting an optical signal, which has the same phase as an output phase of the MZ silicon optical modulator, the second photoelectric detector is used for detecting an optical signal, which has the opposite phase to the output phase of the MZ silicon optical modulator, and when the MZ silicon optical modulator performs Quad point or Null point locking, an adjustment quantity of a thermo-optical phase shifter in the MZ silicon optical modulator is obtained by means of calculating thermal powers of the first photocurrent, the second photocurrent and the thermo-optical phase shifter.

Description

一种实现MZ硅光调制器相位偏置点锁定的方法及装置A method and device for realizing phase bias point locking of MZ silicon light modulator 技术领域technical field
本发明属于光通信互连技术领域，更具体地，涉及一种实现MZ硅光调制器相位偏置点锁定的方法及装置。The invention belongs to the technical field of optical communication interconnection, and more specifically relates to a method and a device for realizing phase bias point locking of an MZ silicon optical modulator.
背景技术Background technique
马赫-曾德尔结构(Mach-Zehnder，简称MZ)硅光调制器作为硅光子生态链中的核心光器件用于实现信号高速电光调制功能，MZ硅光调制器作为外调制器时需根据不同的调制格式选取不同的相位偏置工作点。例如当MZ硅光调制器工作在强度调制格式时，相位偏置点需要设定为90度，即Quad点，当MZ硅光调制器工作在相位调制格式时，相位偏置点需要设定为180度，即Null点。另外MZ硅光调制器的相位偏置点会随温度和环境变化出现随机漂移现象，这时MZ硅光调制器会偏离最佳工作点，最终导致MZ硅光调制器调制性能下降而降低传输信号质量，严重状态下会产生纠后误码，引起业务中断的不良后果，因此引入自动偏置电压控制实现MZ硅光调制器相位偏置点的闭环锁定是MZ硅光调制器实用化的必备要求。The Mach-Zehnder structure (MZ) silicon optical modulator is used as the core optical device in the silicon photonics ecological chain to realize the high-speed electro-optical modulation function of the signal. When the MZ silicon optical modulator is used as an external modulator, it needs to be based on different The modulation format selects different phase offset operating points. For example, when the MZ silicon light modulator works in the intensity modulation format, the phase bias point needs to be set to 90 degrees, which is the Quad point. When the MZ silicon light modulator works in the phase modulation format, the phase bias point needs to be set to 180 degrees, the Null point. In addition, the phase bias point of the MZ silicon optical modulator will drift randomly with temperature and environmental changes. At this time, the MZ silicon optical modulator will deviate from the optimal operating point, which will eventually lead to the degradation of the modulation performance of the MZ silicon optical modulator and reduce the transmission signal. Quality, under serious conditions, post-correction errors will occur, causing adverse consequences of service interruption. Therefore, the introduction of automatic bias voltage control to realize the closed-loop locking of the phase bias point of the MZ silicon optical modulator is a must for the practical use of the MZ silicon optical modulator Require.
当前MZ硅光调制器自动偏置电压控制技术有两种实现方式，第一种是采用平均光功率探测实现闭环控制，通过分光的输出光信号经过光电探测器检测其平均光电流来实现闭环锁定，这种方法仅适用于强度调制格式并且易受输入光信号变化的影响，因此平均光功率锁定法精度比较低，仅适用于NRZ这种简单编码方式的光信号传输；另外一种方法是扰动探测法实现闭环控制，通过给MZ硅光调制器的相位偏置引脚引入小信号低频率 的正弦波或方波，通过交流放大电路将MZ硅光调制器输出端部分光信号进行放大探测，后端采样电路及控制电路实现同频或倍频电信号的检测，通过控制相位偏置点将同频或倍频信号调节至最小来实现相位偏置点的闭环控制，但是这种方法实现复杂，需要信号发生器，多级交流放大电路，高阶模拟带通滤波器以及同频信号探测器，且相关的电路元件很难放入到超小型封装例如QDD，OSFP等封装形式的高速光模块中。At present, there are two ways to realize the automatic bias voltage control technology of the MZ silicon optical modulator. The first one is to use the average optical power detection to realize the closed-loop control, and the output optical signal through the light splitting is detected by the photodetector to detect the average photocurrent to realize the closed-loop locking. , this method is only suitable for intensity modulation formats and is susceptible to changes in the input optical signal, so the average optical power locking method has relatively low accuracy and is only suitable for optical signal transmission in a simple coding method such as NRZ; another method is the disturbance The detection method realizes closed-loop control. By introducing a small-signal low-frequency sine wave or square wave to the phase bias pin of the MZ silicon optical modulator, the part of the optical signal at the output end of the MZ silicon optical modulator is amplified and detected through an AC amplifier circuit. The back-end sampling circuit and control circuit realize the detection of the same-frequency or double-frequency electrical signal, and the closed-loop control of the phase bias point is realized by controlling the phase bias point to minimize the same-frequency or double-frequency signal, but this method is complex , requires a signal generator, a multi-stage AC amplifier circuit, a high-order analog bandpass filter and a signal detector of the same frequency, and the related circuit components are difficult to put into ultra-small packages such as QDD, OSFP and other high-speed optical modules middle.
鉴于此，克服该现有技术所存在的缺陷是本技术领域亟待解决的问题。In view of this, it is an urgent problem to be solved in this technical field to overcome the defects in the prior art.
发明内容Contents of the invention
针对现有技术的以上缺陷或改进需求，本发明提供了一种实现MZ硅光调制器相位偏置点锁定的方法及装置，其目的在于根据MZ硅光调制器的输出光信号自动调节热光移相器的调节量，从而完成MZ硅光调制器相位偏置点锁定，由此解决目前小型光模块中MZ硅光调制器相位偏置点锁定需要借助多种电路元件的技术问题。Aiming at the above defects or improvement needs of the prior art, the present invention provides a method and device for realizing the phase bias point locking of MZ silicon optical modulator, the purpose of which is to automatically adjust the thermal optical signal according to the output optical signal of MZ silicon optical modulator The adjustment amount of the phase shifter is used to complete the phase bias point locking of the MZ silicon optical modulator, thereby solving the technical problem that the phase bias point locking of the MZ silicon optical modulator in the current small optical module requires the use of various circuit components.
为实现上述目的，按照本发明的一个方面，提供了一种实现MZ硅光调制器相位偏置点锁定的方法，该方法包括：In order to achieve the above object, according to one aspect of the present invention, a method for realizing phase bias point locking of an MZ silicon optical modulator is provided, the method comprising:
激光器的输出光信号通过光纤输入到所述MZ硅光调制器中；The output optical signal of the laser is input into the MZ silicon optical modulator through an optical fiber;
所述MZ硅光调制器通过分光的方式，将主光路分出的两路光信号分别导入相位相差180度的第一光电探测器和第二光电探测器中，所述主光路作为所述MZ硅光调制器的输出光信号的光路；The MZ silicon optical modulator guides the two optical signals separated by the main optical path into the first photodetector and the second photodetector with a phase difference of 180 degrees by means of light splitting, and the main optical path serves as the MZ The optical path of the output optical signal of the silicon optical modulator;
所述第一光电探测器和所述第二光电探测器分别输出第一光电流和第二光电流，所述第一光电探测器用于探测与所述MZ硅光调制器输出相位同向的光信号，所述第二光电探测器用于探测与所述MZ硅光调制器输出相位反向的光信号；The first photodetector and the second photodetector respectively output a first photocurrent and a second photocurrent, and the first photodetector is used to detect light in the same direction as the output phase of the MZ silicon light modulator signal, the second photodetector is used to detect an optical signal that is opposite in phase to the output of the MZ silicon optical modulator;
所述MZ硅光调制器进行Quad点或Null点锁定时，所述MZ硅光调制器中热光移相器的调节量由所述第一光电流、所述第二光电流和所述热 光移相器的热功率计算得到。When the MZ silicon light modulator performs Quad point or Null point locking, the adjustment amount of the thermo-optic phase shifter in the MZ silicon light modulator is determined by the first photocurrent, the second photocurrent and the thermal The thermal power of the optical phase shifter is calculated.
作为对上述方案进一步的完善和补充，本发明还包括以下附加技术特征。As a further improvement and supplement to the above solution, the present invention also includes the following additional technical features.
在一个示例中，所述MZ硅光调制器中所述热光移相器的调节量由所述第一光电流、第二光电流和所述热光移相器的热功率计算得到，具体包括：In an example, the adjustment amount of the thermo-optic phase shifter in the MZ silicon optical modulator is calculated from the first photocurrent, the second photocurrent and the thermal power of the thermo-optic phase shifter, specifically include:
通过双路跨阻放大器将所述第一光电流和所述第二光电流同时放大并转换为第一电压信号和第二电压信号；simultaneously amplifying and converting the first photocurrent and the second photocurrent into a first voltage signal and a second voltage signal through a dual-channel transimpedance amplifier;
所述第一电压信号和所述第二电压信号通过双路数据采样单元进行同步采样，得到第一平均光电流和第二平均光电流；The first voltage signal and the second voltage signal are synchronously sampled by a dual data sampling unit to obtain a first average photocurrent and a second average photocurrent;
将所述第二平均光电流与所述第一平均光电流相除，得到第一结果；以及dividing the second average photocurrent by the first average photocurrent to obtain a first result; and
通过所述第一结果与所述热光移相器的热功率计算所述热光移相器的调节量。An adjustment amount of the thermo-optic phase shifter is calculated according to the first result and the thermal power of the thermo-optic phase shifter.
在一个示例中，通过所述第一结果与所述热光移相器的热功率计算所述热光移相器的调节量，具体包括：In an example, calculating the adjustment amount of the thermo-optic phase shifter by using the first result and the thermal power of the thermo-optic phase shifter, specifically includes:
将所述第一结果减去所述第一光电探测器和所述第二光电探测器的响应度的比值，得到第二结果；subtracting the ratio of the responsivity of the first photodetector to the second photodetector from the first result to obtain a second result;
计算所述第二结果相对于所述热光移相器的热功率的一阶导数，得到第三结果；calculating the first derivative of the second result with respect to the thermal power of the thermo-optic phase shifter to obtain a third result;
若所述第三结果为0，所述热光移相器的相位偏置在Quad点；If the third result is 0, the phase offset of the thermo-optic phase shifter is at the Quad point;
若所述第三结果小于第一预设阈值，所述热光移相器的调节量为所述第三结果与0之间的差值，所述热光移相器完成调节后，所述MZ硅光调制器锁定在Quad点。If the third result is less than the first preset threshold, the adjustment amount of the thermo-optic phase shifter is the difference between the third result and 0, and after the thermo-optic phase shifter completes the adjustment, the The MZ silicon light modulator is locked at the quad point.
在一个示例中，所述MZ硅光调制器进行Null点锁定时，所述MZ硅光调制器中所述热光移相器的调节量由所述第一结果与所述热光移相器的 热功率之间的关系函数计算得到，具体包括：In one example, when the MZ silicon optical modulator performs Null point locking, the adjustment amount of the thermo-optical phase shifter in the MZ silicon optical modulator is determined by the first result and the thermo-optic phase shifter The relationship function between the thermal power is calculated, including:
计算所述第一结果相对于所述热光移相器的热功率的一阶导数和二阶导数，分别得到第四结果和第五结果；calculating the first derivative and the second derivative of the first result with respect to the thermal power of the thermo-optic phase shifter to obtain a fourth result and a fifth result respectively;
若所述第四结果为0时，所述热光移相器的相位偏置在Null点；If the fourth result is 0, the phase offset of the thermo-optic phase shifter is at the Null point;
所述热光移相器的调节量为所述第四结果相对于Null点的误差并除以所述第五结果，所述热光移相器完成调节后，所述MZ硅光调制器锁定在Null点。The adjustment amount of the thermo-optic phase shifter is the error of the fourth result relative to the Null point and divided by the fifth result. After the thermo-optic phase shifter is adjusted, the MZ silicon optical modulator locks At the null point.
在一个示例中，计算得到所述第五结果，包括：In an example, the fifth result is obtained through calculation, including:
遍历所述热光移相器的偏置电压；traverse the bias voltage of the thermo-optic phase shifter;
计算得到所述热光移相器的偏置电压对应的第一结果相对于所述热光移相器的热功率一阶导数，得到所述第四结果；calculating the first derivative of the first result corresponding to the bias voltage of the thermo-optic phase shifter relative to the thermal power of the thermo-optic phase shifter to obtain the fourth result;
将所述第四结果进行线性拟合，所述第五结果为所述第四结果的斜率；performing linear fitting on the fourth result, the fifth result being the slope of the fourth result;
若所述第五结果为正，所述热光移相器的偏置电压增大；if the fifth result is positive, the bias voltage of the thermo-optic phase shifter is increased;
若所述第五结果为负，所述热光移相器的偏置电压减小。If the fifth result is negative, the bias voltage of the thermo-optic phase shifter is decreased.
按照本发明的另一方面，提供了一种实现MZ硅光调制器相位偏置点锁定的装置，所述装置包括：激光器、光纤、MZ硅光调制器、处理单元和反向驱动组件，其中：According to another aspect of the present invention, a device for realizing phase bias point locking of an MZ silicon optical modulator is provided, said device comprising: a laser, an optical fiber, an MZ silicon optical modulator, a processing unit, and a reverse drive assembly, wherein :
所述激光器的输出光信号通过所述光纤输入到所述MZ硅光调制器中；The output optical signal of the laser is input into the MZ silicon optical modulator through the optical fiber;
所述MZ硅光调制器把所述输入的光信号分为相位相差180度的光信号输出；The MZ silicon optical modulator divides the input optical signal into optical signals with a phase difference of 180 degrees for output;
所述处理单元计算所述MZ硅光调制器输出光信号归一化的结果与所述MZ硅光调制器中热光移相器的热功率之间的关系，The processing unit calculates the relationship between the normalized result of the output optical signal of the MZ silicon optical modulator and the thermal power of the thermo-optical phase shifter in the MZ silicon optical modulator,
所述反向驱动组件驱动所述MZ硅光调制器的反向PN结；The reverse driving component drives the reverse PN junction of the MZ silicon light modulator;
所述处理单元计算得到所述热光移相器的调节量，以便所述MZ硅光调制器完成相应偏置点的锁定。The processing unit calculates the adjustment amount of the thermo-optic phase shifter, so that the MZ silicon optical modulator completes the locking of the corresponding bias point.
在一个示例中，所述MZ硅光调制器通过分光的方式，将主光路分出 的两路光信号分别导入相位相差180度的第一光电探测器和第二光电探测器，所述主光路作为所述MZ硅光调制器的输出光信号的光路，其中：In one example, the MZ silicon optical modulator guides the two optical signals separated by the main optical path into the first photodetector and the second photodetector with a phase difference of 180 degrees by means of light splitting, and the main optical path As the optical path of the output optical signal of the MZ silicon optical modulator, wherein:
所述第一光电探测器和所述第二光电探测器分别输出第一光电流和第二光电流；The first photodetector and the second photodetector respectively output a first photocurrent and a second photocurrent;
所述第一光电探测器用于探测与所述MZ硅光调制器输出相位同向的光信号；The first photodetector is used to detect an optical signal in the same direction as the output phase of the MZ silicon optical modulator;
所述第二光电探测器用于探测与所述MZ硅光调制器输出相位反向的光信号。The second photodetector is used to detect an optical signal whose phase is opposite to that output by the MZ silicon optical modulator.
在一个示例中，所述处理单元包括双通道跨阻放大器、双路模数转换器、处理器和双路数模转换器，其中：In one example, the processing unit includes a dual-channel transimpedance amplifier, a dual analog-to-digital converter, a processor, and a dual-channel digital-to-analog converter, wherein:
通过所述双路跨阻放大器分别将所述第一光电探测器和所述第二光电探测器输出的所述第一光电流和所述第二光电流分别转换为第一电压信号和第二电压信号；The first photocurrent and the second photocurrent output by the first photodetector and the second photodetector are respectively converted into a first voltage signal and a second voltage signal by the dual-channel transimpedance amplifier. voltage signal;
所述第一电压信号和所述第二电压信号通过所述双路模数转换器进行同步采样；The first voltage signal and the second voltage signal are synchronously sampled by the dual analog-to-digital converter;
所述处理器将所述第一电压信号和所述第二电压信号进行数据处理，向所述双路数模转换器输出模拟电压；The processor performs data processing on the first voltage signal and the second voltage signal, and outputs an analog voltage to the dual-channel digital-to-analog converter;
所述双路数模转换器输出的模拟电压根据所述处理器的计算结果分别施加在所述热光移相器的偏置点和所述反向PN结上。The analog voltage output by the dual digital-to-analog converter is respectively applied to the bias point of the thermo-optical phase shifter and the reverse PN junction according to the calculation result of the processor.
在一个示例中，所述反向驱动组件包括脉冲码源发生器和电压放大器，其中：In one example, the backdrive component includes a pulse code source generator and a voltage amplifier, wherein:
所述脉冲码源发生器输出调制电压信号，所述调制电压信号经过所述电压放大器放大，放大的电压通过引脚V RF作用于所述射频调制单元上，用于驱动所述反向PN结。 The pulse code source generator outputs a modulation voltage signal, the modulation voltage signal is amplified by the voltage amplifier, and the amplified voltage acts on the radio frequency modulation unit through the pin V RF to drive the reverse PN junction .
在一个示例中，所述MZ硅光调制器还包括输入MMI、热光相移器、射频调制单元和输出MMI，其中：In one example, the MZ silicon optical modulator further includes an input MMI, a thermo-optic phase shifter, a radio frequency modulation unit, and an output MMI, wherein:
光信号经过所述输入MMI、所述热光相移器、所述射频调制单元和所述输出MMI后输出；The optical signal is output after passing through the input MMI, the thermo-optic phase shifter, the radio frequency modulation unit and the output MMI;
所述输入MMI对光信号进行干涉；The input MMI interferes with the optical signal;
所述输出MMI与所述第二光电探测器反向连接；The output MMI is reversely connected to the second photodetector;
所述输出MMI与所述第一光电探测器同向连接；The output MMI is connected to the first photodetector in the same direction;
所述热光相移器通过引脚V bias与所述处理单元设定偏置点； The thermo-optic phase shifter sets a bias point with the processing unit through a pin V bias ;
所述射频调制单元通过引脚V PN与所述处理单元设定反向PN结电压。 The radio frequency modulation unit sets the reverse PN junction voltage with the processing unit through the pin V PN .
总体而言，通过本发明所构思的以上技术方案与现有技术相比，具有如下有益效果：Generally speaking, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:
一方面，MZ硅光调制器相位偏置点锁定的方法可以根据MZ硅光调制器的输出光信号自动调节热光移相器的调节量，实现MZ硅光调制器任意偏置点的精确锁定；On the one hand, the phase bias point locking method of the MZ silicon optical modulator can automatically adjust the adjustment amount of the thermo-optic phase shifter according to the output optical signal of the MZ silicon optical modulator, and realize the precise locking of any bias point of the MZ silicon optical modulator ;
另一方面，MZ硅光调制器相位偏置点锁定的装置的软硬件设计简单，易于整体移植到超小型封装例如QDD，OSFP等封装形式的高速硅光模块中。On the other hand, the software and hardware design of the phase bias point locking device of the MZ silicon optical modulator is simple, and it is easy to be transplanted as a whole into high-speed silicon optical modules in ultra-small packages such as QDD and OSFP.
附图说明Description of drawings
图1是本发明提供实现MZ硅光调制器相位偏置点锁定的装置示意图；1 is a schematic diagram of a device for realizing phase bias point locking of an MZ silicon optical modulator provided by the present invention;
图2是第一输出光电探测器和第二输出光电探测器随热光移相器归一化偏置电压变化的函数曲线图；Fig. 2 is a function graph of the first output photodetector and the second output photodetector as the normalized bias voltage of the thermo-optic phase shifter changes;
图3是归一化光电流比值随热光移相器归一化偏置电压变化的函数曲线图；Fig. 3 is a function graph of the normalized photocurrent ratio changing with the normalized bias voltage of the thermo-optic phase shifter;
图4是Quad点锁定时的构造函数和Null点锁定时的归一化光电流比值分别相对于热光移相器归一化热功率变化的一阶导数函数曲线图；Fig. 4 is the first-order derivative function curve graph of the normalized photocurrent ratio when the Quad point is locked and the normalized photocurrent ratio when the Null point is locked with respect to the normalized thermal power change of the thermo-optic phase shifter;
图5是MZ硅光调制器Quad点锁定流程图；Figure 5 is a flow chart of the Quad point locking of the MZ silicon light modulator;
图6是MZ硅光调制器Null点锁定流程图。Fig. 6 is a flow chart of the Null point locking of the MZ silicon light modulator.
在所有附图中，相同的附图标记用来表示相同的元件或结构，其中：Throughout the drawings, the same reference numerals are used to designate the same elements or structures, wherein:
1-激光器；2-光纤；3-MZ硅光调制器；32-第一光电探测器；33-第二光电探测器；34-输入MMI；35-热光相移器；36-射频调制单元；37-输出MMI；4-控制单元；41-双路跨阻放大器；42-双路数模转换器；43-处理器；44-双路数模转换器；5-反向驱动组件；51-脉冲码源发生器；52-电压放大器。1-laser; 2-fiber; 3-MZ silicon optical modulator; 32-first photodetector; 33-second photodetector; 34-input MMI; 35-thermo-optic phase shifter; 36-radio frequency modulation unit ;37-output MMI; 4-control unit; 41-dual transimpedance amplifier; 42-dual digital-to-analog converter; 43-processor; 44-dual digital-to-analog converter; 5-reverse drive component; 51 - pulse code source generator; 52 - voltage amplifier.
具体实施方式Detailed ways
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。此外，下面所描述的本发明各个实施方式中所涉及到的技术特征只要彼此之间未构成冲突就可以相互组合。In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.
在本发明的描述中，术语“内”、“外”、“纵向”、“横向”、“上”、“下”、“顶”、“底”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明而不是要求本发明必须以特定的方位构造和操作，因此不应当理解为对本发明的限制。In the description of the present invention, the orientation or positional relationship indicated by the terms "inner", "outer", "longitudinal", "transverse", "upper", "lower", "top", "bottom" etc. are based on the drawings The orientations or positional relationships shown are only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation, and thus should not be construed as limiting the invention.
在本发明中，除非另有明确的规定和限定，第一特征在第二特征之“上”或之“下”可以包括第一和第二特征直接接触，也可以包括第一和第二特征不是直接接触而是通过它们之间的另外的特征接触。而且，第一特征在第二特征“之上”、“上方”和“上面”包括第一特征在第二特征正上方和斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”包括第一特征在第二特征正下方和斜下方，或仅仅表示第一特征水平高度小于第二特征。In the present invention, unless otherwise clearly specified and limited, a first feature being "on" or "under" a second feature may include direct contact between the first and second features, and may also include the first and second features Not in direct contact but through another characteristic contact between them. Moreover, "above", "above" and "above" the first feature on the second feature include that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. "Below", "beneath" and "under" the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.
实施例一：Embodiment one:
本实施例一提供一种实现MZ硅光调制器相位偏置点锁定的方法，如图1所示，该方法包括： Embodiment 1 provides a method for realizing phase bias point locking of an MZ silicon optical modulator, as shown in FIG. 1 , the method includes:
激光器的输出光信号通过光纤输入到MZ硅光调制器中。其中，激光器连续输出光信号，可以通过光纤输入到MZ硅光调制器中。The output optical signal of the laser is input into the MZ silicon optical modulator through the optical fiber. Among them, the laser continuously outputs optical signals, which can be input to the MZ silicon optical modulator through optical fibers.
所述MZ硅光调制器通过分光的方式，将主光路分出的两路光信号导入相位相差180度的第一光电探测器和第二光电探测器中，所述主光路作为MZ硅光调制器的输出光信号的光路。其中，MZ硅光调制器输出光场复振幅表达式如下：The MZ silicon optical modulator guides the two optical signals separated by the main optical path into the first photodetector and the second photodetector with a phase difference of 180 degrees by means of light splitting, and the main optical path serves as the MZ silicon optical modulation The optical path of the output optical signal of the device. Among them, the expression of the complex amplitude of the output optical field of the MZ silicon optical modulator is as follows:
Figure PCTCN2022101747-appb-000001
Figure PCTCN2022101747-appb-000001
其中：i，j代表虚数单位；(t)表示信号随时间变化；E IN为连续输出激光器输出光场的复振幅；γ为MZ硅光调制器的分光比；w 0为输入光信号的载波频率；A为MZ硅光调制器上臂，B为MZ硅光调制器下臂，α RF_A(t)和α RF_B(t)分别为MZ硅光调制器上臂和下臂的吸收损耗因子，吸收损耗因子通常是由调制信号引起的吸收参数，调制信号是随时间变化的信号，因此吸收参数和吸收损耗因子也随时间变化；φ RF_A(t)和φ RF_B(t)分别为MZ硅光调制器上下臂的调制相移量，是由调制信号引起的相位变化参数，调制信号是随时间变化的信号，因此相位变化量也随时间变化；φ BIAS为热光移相器引入的直流偏置相位。 Among them: i, j represent the imaginary unit; (t) represents the signal changes with time; E IN is the complex amplitude of the output light field of the continuous output laser; γ is the splitting ratio of the MZ silicon optical modulator; w 0 is the carrier of the input optical signal Frequency; A is the upper arm of the MZ silicon optical modulator, B is the lower arm of the MZ silicon optical modulator, α RF_A (t) and α RF_B (t) are the absorption loss factors of the upper and lower arms of the MZ silicon optical modulator, and the absorption loss The factor is usually the absorption parameter caused by the modulation signal, and the modulation signal is a time-varying signal, so the absorption parameter and absorption loss factor also change with time; φ RF_A (t) and φ RF_B (t) are the MZ silicon optical modulator The modulation phase shift of the upper and lower arms is the phase change parameter caused by the modulation signal. The modulation signal is a signal that changes with time, so the phase change also changes with time; φ BIAS is the DC bias phase introduced by the thermo-optic phase shifter .
通过公式(1)可以得到MZ硅光调制器的输出光信号强度为：Through the formula (1), the output optical signal intensity of the MZ silicon optical modulator can be obtained as:
Figure PCTCN2022101747-appb-000002
Figure PCTCN2022101747-appb-000002
其中，P IN为输入光信号强度，对公式(2)进行简化为： Among them, P IN is the intensity of the input optical signal, and formula (2) is simplified as:
Figure PCTCN2022101747-appb-000003
Figure PCTCN2022101747-appb-000003
Figure PCTCN2022101747-appb-000004
Figure PCTCN2022101747-appb-000004
其中：P OUT_DC(t)和P OUT_AC(t)分别为MZ硅光调制器输出光功率的直流分量和交流分量系数，随时间变化。 Where: P OUT_DC (t) and P OUT_AC (t) are coefficients of DC component and AC component of the output optical power of the MZ silicon optical modulator, respectively, which vary with time.
将公式(3)和公式(4)联合得到：Combine formula (3) and formula (4) to get:
P OUT(t)＝P OUT_DC(t)+P OUT_AC(t)[<cos(φ RF_A(t)-φ RF_B(t))>cosφ BIAS+<sin(φ RF_A(t)-φ RF_B(t))>sinφ BIAS]     (5) P OUT (t)＝P OUT_DC (t)+P OUT_AC (t)[<cos(φ RF_A (t)-φ RF_B (t))>cosφ BIAS +<sin(φ RF_A (t)-φ RF_B (t ))>sinφ BIAS ] (5)
其中<cos(φ RF_A(t)-(φ RF_B(t))>和<sin(φ RF_A(t)-(φ RF_B(t))>分别表示为调制相位随时间变化的积分函数，由于第一光电探测器和第二光电探测器均为低速光电流探测器，两者输出的光电流均为平均光电流，另外射频信号引起MZ硅光调制器的相位变化量，并且可以由射频信号V RF(t)三阶多项式来表示： where <cos(φ RF_A (t)-(φ RF_B (t))> and <sin(φ RF_A (t)-(φ RF_B (t))> are respectively expressed as the integral function of the modulation phase changing with time, because the Both the first photodetector and the second photodetector are low-speed photocurrent detectors, and the photocurrent output by both is the average photocurrent. In addition, the radio frequency signal causes the phase change of the MZ silicon light modulator, and can be determined by the radio frequency signal V RF (t) third-order polynomial to represent:
Figure PCTCN2022101747-appb-000005
Figure PCTCN2022101747-appb-000005
Figure PCTCN2022101747-appb-000006
Figure PCTCN2022101747-appb-000006
α RF_A_1，2，3，4和
Figure PCTCN2022101747-appb-000007
分别为MZ硅光调制器上臂和下臂的相移相对于反向PN结偏压的多项式因子，V PN为反向PN结的直流反向偏置电压。 α RF_A_1, 2, 3, 4 and
Figure PCTCN2022101747-appb-000007
are the polynomial factors of the phase shift of the upper and lower arms of the MZ silicon optical modulator relative to the reverse PN junction bias voltage, and V PN is the DC reverse bias voltage of the reverse PN junction.
由于加载在反向PN结上的射频信号通常为双极性信号，即相对于0点正负对称，因此可以得到<sin(φ RF_A(t)-φ RF_B(t))>≈0，这样公式(5)可以进一步简化为公式(8)： Since the RF signal loaded on the reverse PN junction is usually a bipolar signal, that is, positive and negative relative to the 0 point, it can be obtained <sin(φ RF_A (t)-φ RF_B (t))>≈0, so Formula (5) can be further simplified to formula (8):
P OUT(t)＝P OUT_DC(t)+P OUT_AC(t)<cos(φ RF_A(t)-φ RF_B(t))>cosφ BIAS       (8) P OUT (t)＝P OUT_DC (t)+P OUT_AC (t)<cos(φ RF_A (t)-φ RF_B (t))>cosφ BIAS (8)
根据热光相移器的相位调制原理，热光移相器引入的直流偏置相位表达式为
Figure PCTCN2022101747-appb-000008
V bias是热光移相器施加的直流电压，V π是热光移相器的半波电压即相位偏置为π时对应的直流电压，因此MZ硅光调制器输出光信号跟热光移相器偏置电压的关系可以表示为公式(9)： According to the phase modulation principle of the thermo-optic phase shifter, the expression of the DC bias phase introduced by the thermo-optic phase shifter is
Figure PCTCN2022101747-appb-000008
V bias is the DC voltage applied by the thermo-optic phase shifter, V π is the half-wave voltage of the thermo-optic phase shifter, that is, the corresponding DC voltage when the phase bias is π, so the output optical signal of the MZ silicon optical modulator is shifted with the thermo-optic phase The relationship between the phase converter bias voltage can be expressed as formula (9):
Figure PCTCN2022101747-appb-000009
Figure PCTCN2022101747-appb-000009
本实施例一中，如图2所示，所述第一光电探测器和所述第二光电探测器分别输出第一光电流和第二光电流，所述第一光电探测器用于探测与所述MZ硅光调制器输出相位同向的光信号，所述第二光电探测器用于探测与所述MZ硅光调制器输出相位相差180度的多模干涉耦合器反向端的光信号。相差180度是用于区别多模干涉耦合器最强的干涉信号与最弱的干涉信号。在多模干涉耦合器最强的干涉信号下，第一光电探测器(同向)的光信号最强，第二光电探测器(反向)的光信号最弱。In the first embodiment, as shown in FIG. 2, the first photodetector and the second photodetector respectively output a first photocurrent and a second photocurrent, and the first photodetector is used to detect The MZ silicon optical modulator outputs an optical signal with the same phase, and the second photodetector is used to detect the optical signal at the opposite end of the multimode interference coupler whose phase is different from the output of the MZ silicon optical modulator by 180 degrees. The difference of 180 degrees is used to distinguish the strongest interference signal and the weakest interference signal of the multimode interference coupler. Under the strongest interference signal of the multimode interference coupler, the light signal of the first photodetector (same direction) is the strongest, and the light signal of the second photodetector (reverse direction) is the weakest.
MZ硅光调制器进行Quad点或Null点锁定时，MZ硅光调制器中热光移相器的调节量由所述第一光电流、所述第二光电流和所述热光移相器的热功率计算得到。When the MZ silicon light modulator performs Quad point or Null point locking, the adjustment amount of the thermo-optic phase shifter in the MZ silicon light modulator is determined by the first photocurrent, the second photocurrent and the thermo-optic phase shifter The thermal power is calculated.
本实施例一中，为了对于第一输出光电探测器和第二输出光电探测器输出的信号进一步进行计算，结合本发明实施例，还存在一种优选的实现方案，具体的，如图3所示，所述MZ硅光调制器中热光移相器的调节量由所述第一光电流、所述第二光电流和所述热光移相器的热功率计算得到，具体包括：In the first embodiment, in order to further calculate the signals output by the first output photodetector and the second output photodetector, combined with the embodiment of the present invention, there is also a preferred implementation scheme, specifically, as shown in Figure 3 As shown, the adjustment amount of the thermo-optic phase shifter in the MZ silicon optical modulator is calculated from the first photocurrent, the second photocurrent and the thermal power of the thermo-optic phase shifter, specifically including:
通过双路跨阻放大器将所述第一光电流和所述第二光电流同时放大并转换为第一电压信号和第二电压信号；simultaneously amplifying and converting the first photocurrent and the second photocurrent into a first voltage signal and a second voltage signal through a dual-channel transimpedance amplifier;
所述第一电压信号和所述第二电压信号通过双路数据采样单元进行同步采样，得到第一平均光电流和第二平均光电流；The first voltage signal and the second voltage signal are synchronously sampled by a dual data sampling unit to obtain a first average photocurrent and a second average photocurrent;
将所述第二平均光电流与所述第一平均光电流相除，得到第一结果；以及dividing the second average photocurrent by the first average photocurrent to obtain a first result; and
通过所述第一结果与所述热光移相器热功率计算所述热光移相器的调节量。An adjustment amount of the thermo-optic phase shifter is calculated according to the first result and thermal power of the thermo-optic phase shifter.
第一输出光电探测器和第二输出光电探测器的平均光电流可以分别表示为：The average photocurrents of the first output photodetector and the second output photodetector can be expressed as:
Figure PCTCN2022101747-appb-000010
Figure PCTCN2022101747-appb-000010
Figure PCTCN2022101747-appb-000011
Figure PCTCN2022101747-appb-000011
公式(10)和公式(11)中R INPHASE和R OUTERPHASE分别表示第一输出光电探测器和第二输出光电探测器的响应度，R INPHASE和R OUTERPHASE由第一输出光电探测器和第二输出光电探测器自身决定，不受时间影响。公式(12)中将上述两路平均光电流做归一化处理得到归一化后的光电流，如图3所示： In formula (10) and formula (11), R INPHASE and R OUTERPHASE represent the responsivity of the first output photodetector and the second output photodetector respectively, and R INPHASE and R OUTERPHASE are determined by the first output photodetector and the second output The photodetector decides by itself and is not affected by time. In the formula (12), the above two average photocurrents are normalized to obtain the normalized photocurrent, as shown in Figure 3:
Figure PCTCN2022101747-appb-000012
Figure PCTCN2022101747-appb-000012
归一化后的光电流与热光移相器热功率进行进一步的计算得到MZ硅光调制器中热光移相器的调节量，实现MZ硅光调制器任意偏置点的精确锁定。The normalized photocurrent and the thermal power of the thermo-optic phase shifter are further calculated to obtain the adjustment amount of the thermo-optic phase shifter in the MZ silicon optical modulator, so as to realize the precise locking of any bias point of the MZ silicon optical modulator.
本实施例一中，为了将MZ硅光调制器锁定在Quad点，结合本发明实施例，还存在一种优选的实现方案，具体的，如图4所示，通过所述第一结果与所述热光移相器的热功率计算所述热光移相器的调节量，具体包括：In the first embodiment, in order to lock the MZ silicon light modulator at the Quad point, in combination with the embodiment of the present invention, there is also a preferred implementation solution. Specifically, as shown in FIG. 4 , through the first result and the The thermal power of the thermo-optic phase shifter is used to calculate the adjustment amount of the thermo-optic phase shifter, specifically including:
将所述第一结果减去所述第一光电探测器和所述第二光电探测器的响应度的比值，得到第二结果；subtracting the ratio of the responsivity of the first photodetector to the second photodetector from the first result to obtain a second result;
计算所述第二结果相对于所述热光移相器的热功率的一阶导数，得到第三结果；calculating the first derivative of the second result with respect to the thermal power of the thermo-optic phase shifter to obtain a third result;
若所述第三结果为0，热光移相器的相位偏置在Quad点；If the third result is 0, the phase offset of the thermo-optic phase shifter is at the Quad point;
若所述第三结果小于第一预设阈值，所述热光移相器的调节量为所述第三结果与0之间的差值，所述热光移相器完成调节后，所述MZ硅光调制器锁定在Quad点。If the third result is less than the first preset threshold, the adjustment amount of the thermo-optic phase shifter is the difference between the third result and 0, and after the thermo-optic phase shifter completes the adjustment, the The MZ silicon light modulator is locked at the quad point.
当MZ硅光调制器工作在强度调制格式下时，热光移相器的直流偏置点需要锁定在Quad点即热光相移器偏置点的电压
Figure PCTCN2022101747-appb-000013
其中，k为正整数；k由实际选择偏置电压的周期决定，例如第一个周期内就是0，第2个周期就是1，考虑到调制曲线的灵敏度，一般至少会选择第2个周期。 When the MZ silicon optical modulator works in the intensity modulation format, the DC bias point of the thermo-optic phase shifter needs to be locked at the Quad point, which is the voltage of the bias point of the thermo-optic phase shifter
Figure PCTCN2022101747-appb-000013
Among them, k is a positive integer; k is determined by the cycle of actually selecting the bias voltage. For example, it is 0 in the first cycle and 1 in the second cycle. Considering the sensitivity of the modulation curve, generally at least the second cycle is selected.
从公式(12)中可以得到当热光移相器的直流偏置点V bias＝V Quad，
Figure PCTCN2022101747-appb-000014
因此构造一个函数其表达式为I RATIO(t)-I RATIO_Quad，同时假定该函数相对于热光移相器热功率的一阶导数表达式为： From formula (12), it can be obtained that when the DC bias point V bias of the thermo-optic phase shifter = V Quad ,
Figure PCTCN2022101747-appb-000014
Therefore, construct a function whose expression is I RATIO (t)-I RATIO_Quad , and assume that the expression of the first derivative of this function relative to the thermal power of the thermo-optic phase shifter is:
Figure PCTCN2022101747-appb-000015
Figure PCTCN2022101747-appb-000015
由上式可以得到当V bias＝V Quad，则K slope_quad(V Quad)＝0，对于MZ硅光调制器Quad点的锁定只需要通过闭环控制保证K slope_quad位于绝对值为0即可。 From the above formula, it can be obtained that when V bias =V Quad , then K slope_quad (V Quad )=0, and the locking of the quad point of the MZ silicon optical modulator only needs to ensure that the absolute value of K slope_quad is 0 through closed-loop control.
如图5所示，MZ硅光调制器锁定在Quad点具体步骤包括：As shown in Figure 5, the specific steps of locking the MZ silicon light modulator at the Quad point include:
S101：初始化。S101: initialization.
初始化阶段需要将热光相移器偏置电压设为0；再开启激光器；再开启射频调制信号。In the initialization stage, it is necessary to set the bias voltage of the thermo-optic phase shifter to 0; then turn on the laser; and then turn on the radio frequency modulation signal.
S102：遍历V bias点范围为0-nV π 2，分别得到第一输出光电探测器和第二输出光电探测器的电光曲线。 S102: traverse the range of V bias points from 0 to nV π 2 , and obtain the electro-optical curves of the first output photodetector and the second output photodetector respectively.
扫描热光相移器的相位变化nπ周期，n的最小值为2，即至少扫描热光相移器的相位变化2π周期。The phase change of the thermo-optic phase shifter is scanned for nπ periods, and the minimum value of n is 2, that is, the phase change of the thermo-optic phase shifter is scanned for at least 2π periods.
S103：将相同V bias点的数据做比值得到归一化后的电光曲线。 S103: comparing the data of the same V bias point to obtain a normalized electro-optical curve.
S104：计算第一输出光电探测器和第二输出光电探测器的响应度比值并作为基准点。S104: Calculate a responsivity ratio between the first output photodetector and the second output photodetector and use it as a reference point.
S105：计算当前K slope_Quad(V bias)为0时，对应的V bias数值并记为V Quad。 S105: Calculate the corresponding value of V bias when the current K slope_Quad (V bias ) is 0, and record it as V Quad .
S106：保存当前K slope_Quad(V bias)记为K slope_Quad_last(V bias)。 S106: Save the current K slope_Quad (V bias ) as K slope_Quad_last (V bias ).
S107：开启锁定。S107: Turn on the lock.
开启锁定后，MZ硅光调制器在找到Quad点处后完成锁定。After the lock is turned on, the MZ silicon light modulator completes the lock after finding the Quad point.
S108：计算当前K slope_Quad_now(V bias)。 S108: Calculate the current K slope_Quad_now (V bias ).
S109：判断K slope_Quad_now(V bias)是否小于K slope_Quad_last(V bias)。 S109: Determine whether K slope_Quad_now (V bias ) is smaller than K slope_Quad_last (V bias ).
比较前后连续不同V bias的斜率，保证K slope_Quad_last(V bias)斜率收敛至绝对值为0。 Compare the slopes of different V bias before and after to ensure that the slope of K slope_Quad_last (V bias ) converges to an absolute value of 0.
S110：若K slope_Quad_now(V bias)小于K slope_Quad_last(V bias)，保存当前K slope_Quad_last(V bias)。 S110: If K slope_Quad_now (V bias ) is smaller than K slope_Quad_last (V bias ), save the current K slope_Quad_last (V bias ).
S111：若K slope_Quad_now(V bias)大于或等于K slope_Quad_last(V bias)，进一步判断K slope_Quad_now(V bias)是否大于0。 S111: If K slope_Quad_now (V bias ) is greater than or equal to K slope_Quad_last (V bias ), further determine whether K slope_Quad_now (V bias ) is greater than 0.
S112：若K slope_Quad_now(V bias)大于0，减小V bias。 S112: If K slope_Quad_now (V bias ) is greater than 0, decrease V bias .
S113：若K slope_Quad_now(V bias)小于或等于0，增大V bias。 S113: If K slope_Quad_now (V bias ) is less than or equal to 0, increase V bias .
S106至S113形成MZ硅光调制器锁定在Quad点的闭环控制状态，始终对MZ硅光调制器进行Quad点的闭环控制。S106 to S113 form a closed-loop control state in which the MZ silicon optical modulator is locked at the Quad point, and the closed-loop control of the Quad point is always performed on the MZ silicon optical modulator.
分别通过探测MZ硅光调制器内部的两个低速光电探测器即第一输出光电探测器和第二输出光电探测器的归一化光电流比值，归一化光电流比值跟第一输出光电探测器和第二输出光电探测器的响应度比值的差值，计算该差值相对于热光移相器的热功率的一阶导数，即热光移相器偏置电压的调节量，同时计算当前一阶导数结果相对于0的误差从而得到热光移相器偏置电压的修正值，即实现MZ硅光调制器Quad点的精确锁定。By detecting the normalized photocurrent ratio of the two low-speed photodetectors inside the MZ silicon light modulator, that is, the first output photodetector and the second output photodetector, the normalized photocurrent ratio and the first output photodetector The difference between the responsivity ratio of the sensor and the second output photodetector, calculate the first derivative of the difference with respect to the thermal power of the thermo-optic phase shifter, that is, the adjustment amount of the bias voltage of the thermo-optic phase shifter, and calculate at the same time The error of the current first-order derivative result relative to 0 is used to obtain the correction value of the bias voltage of the thermo-optic phase shifter, that is, to realize the precise locking of the Quad point of the MZ silicon optical modulator.
本实施例一中，为了将MZ硅光调制器锁定在Null点，结合本发明实施例，还存在一种优选的实现方案，具体的，如图6所示，MZ硅光调制器进行Null点锁定时，MZ硅光调制器中热光移相器的调节量由所述第一结果与所述热光移相器的热功率之间的关系函数计算得到，具体包括：In the first embodiment, in order to lock the MZ silicon light modulator at the Null point, combined with the embodiment of the present invention, there is also a preferred implementation scheme. Specifically, as shown in FIG. 6, the MZ silicon light modulator performs the Null point When locked, the adjustment amount of the thermo-optic phase shifter in the MZ silicon optical modulator is calculated from the relationship function between the first result and the thermal power of the thermo-optic phase shifter, specifically including:
计算所述第一结果相对于所述热光移相器的热功率的一阶导数和二阶导数，分别得到第四结果和第五结果；calculating the first derivative and the second derivative of the first result with respect to the thermal power of the thermo-optic phase shifter to obtain a fourth result and a fifth result respectively;
若所述第四结果为0时，所述热光移相器的相位偏置在Null点；If the fourth result is 0, the phase offset of the thermo-optic phase shifter is at the Null point;
所述热光移相器的调节量为所述第四结果相对于Null点的误差并除以所述第五结果，所述热光移相器完成调节后，所述MZ硅光调制器锁定在Null点。The adjustment amount of the thermo-optic phase shifter is the error of the fourth result relative to the Null point and divided by the fifth result. After the thermo-optic phase shifter is adjusted, the MZ silicon optical modulator locks At the null point.
当MZ硅光调制器工作在相位调制格式下时，热光移相器的直流偏置点需要锁定在Null点，NULL点对应电压跟半波电压的关系为
Figure PCTCN2022101747-appb-000016
其中k为正整数；求I RATIO(t)相对于热光移相器的一阶导数和二阶导数，其 表达式分别为： When the MZ silicon optical modulator works in the phase modulation format, the DC bias point of the thermo-optic phase shifter needs to be locked at the Null point, and the relationship between the voltage corresponding to the Null point and the half-wave voltage is
Figure PCTCN2022101747-appb-000016
Wherein k is a positive integer; seek I RATIO (t) with respect to the first order derivative and the second order derivative of thermo-optic phase shifter, its expression is respectively:
Figure PCTCN2022101747-appb-000017
Figure PCTCN2022101747-appb-000017
Figure PCTCN2022101747-appb-000018
Figure PCTCN2022101747-appb-000018
当V bias＝V null，则K slope_null(V null)＝0且K' slope_null(V null)＞0，另外在实际锁定中，计算当前功率比值的斜率曲线可以采用下式： When V bias =V null , then K slope_null (V null )=0 and K' slope_null (V null )>0, and in actual locking, the slope curve for calculating the current power ratio can use the following formula:
Figure PCTCN2022101747-appb-000019
Figure PCTCN2022101747-appb-000019
其中，ΔV为热光移相器偏置电压单步调节量；因此对于MZ硅光调制器的Null点锁定除了需要将K slope_null调节至绝对值为0外还需要判断K' slope_null的符号性。 Among them, ΔV is the single-step adjustment amount of the bias voltage of the thermo-optic phase shifter; therefore, for the Null point locking of the MZ silicon optical modulator, it is necessary to judge the sign of K' slope_null in addition to adjusting the K slope_null to an absolute value of 0.
如图6所示，MZ硅光调制器锁定在Null点具体步骤包括：As shown in Figure 6, the specific steps of locking the MZ silicon light modulator at the Null point include:
S201：初始化。S201: Initialize.
初始化阶段需要将热光相移器偏置电压设为0；再开启激光器；再开启射频调制信号。In the initialization stage, it is necessary to set the bias voltage of the thermo-optic phase shifter to 0; then turn on the laser; and then turn on the radio frequency modulation signal.
S202：遍历V bias点范围为0-2V π 2，分别得到第一输出光电探测器和第二输出光电探测器的电光曲线。 S202: Traversing the V bias point range of 0-2V π 2 , respectively obtaining the electro-optic curves of the first output photodetector and the second output photodetector.
扫描热光相移器的相位变化nπ周期，n的最小值为2，即至少扫描热光相移器的相位变化2π周期。The phase change of the thermo-optic phase shifter is scanned for nπ periods, and the minimum value of n is 2, that is, the phase change of the thermo-optic phase shifter is scanned for at least 2π periods.
S203：将相同V bias点的数据做比值得到归一化后的电光曲线。 S203: comparing the data of the same V bias point to obtain a normalized electro-optic curve.
S204：取归一化的电光曲线相对于V bias 2的一阶导数和二阶导数，分别得到K slope_null(V bias)和K’ slope_null_now(V bias)。 S204: Obtain the first and second derivatives of the normalized electro-optic curve relative to V bias 2 to obtain K slope_null (V bias ) and K' slope_null_now (V bias ) respectively.
S205：计算K slope_null(V bias)为0且K’ slope_null_now(V bias)大于0对应的V bias并记为V DC_SET_null。 S205: Calculate V bias corresponding to K slope_null (V bias ) being 0 and K' slope_null_now (V bias ) greater than 0, and record it as V DC_SET_null .
S206：保存当前K slope_null(V bias)记为K slope_null_last(V bias)。 S206: Save the current K slope_null (V bias ) as K slope_null_last (V bias ).
S207：开启锁定。S207: Turn on the lock.
开启锁定后，MZ硅光调制器在找到Null点处后完成锁定。After the lock is turned on, the MZ silicon optical modulator completes the lock after finding the Null point.
S208：计算当前K slope_null_now(V bias)。 S208: Calculate the current K slope_null_now (V bias ).
S209：判断K slope_null_now(V bias)是否小于K slope_null_last(V bias)。 S209: Determine whether K slope_null_now (V bias ) is smaller than K slope_null_last (V bias ).
比较前后连续不同V bias的斜率，保证K slope_null_last(V bias)斜率收敛至绝对值为0。 Compare the slopes of different V bias before and after to ensure that the slope of K slope_null_last (V bias ) converges to an absolute value of 0.
S210：若K slope_null_now(V bias)小于K slope_null_last(V bias)，保存当前K slope_null_last(V bias)。 S210: If K slope_null_now (V bias ) is smaller than K slope_null_last (V bias ), save the current K slope_null_last (V bias ).
S211：若K slope_null_now(V bias)大于等于K slope_null_last(V bias)，判断K slope_null_now(V bias)是否大于0。 S211: If K slope_null_now (V bias ) is greater than or equal to K slope_null_last (V bias ), determine whether K slope_null_now (V bias ) is greater than 0.
S212：若K’ slope_null_now(V bias)大于0，增大V bias。 S212: If K' slope_null_now (V bias ) is greater than 0, increase V bias .
S213：若K’ slope_null_now(V bias)小于等于0，减小V bias。 S213: If K' slope_null_now (V bias ) is less than or equal to 0, decrease V bias .
S206至S213形成MZ硅光调制器锁定在Null点的闭环控制状态，始终对MZ硅光调制器进行Null点的闭环控制。S206 to S213 form a closed-loop control state in which the MZ silicon optical modulator is locked at the Null point, and the closed-loop control of the Null point is always performed on the MZ silicon optical modulator.
分别通过探测MZ硅光调制器内部的两个低速光电探测器即第一输出光电探测器和第二输出光电探测器的归一化光电流比值，计算归一化光电流比值相对于热光移相器热功率的一阶导数和二阶导数，通过调节热光移相器偏置电压将一阶导数趋近于0同时判断二阶导数的符号性，一阶导数的结果决定热光移相器偏置电压的调节量，二阶导数决定的是调节方向，得到一阶导数和二阶导数的结果后，可以确定热光移相器偏置电压的调节方向与调节量，即实现MZ硅光调制器Null点的精确锁定。By detecting the normalized photocurrent ratios of the two low-speed photodetectors inside the MZ silicon light modulator, that is, the first output photodetector and the second output photodetector, the normalized photocurrent ratio relative to the thermal light shift is calculated The first derivative and the second derivative of the thermal power of the phase shifter, by adjusting the bias voltage of the thermo-optic phase shifter, the first derivative approaches 0 and at the same time judges the sign of the second derivative, the result of the first derivative determines the thermo-optic phase shift The adjustment amount of the bias voltage of the thermo-optical phase shifter, the second-order derivative determines the adjustment direction. After obtaining the results of the first-order derivative and the second-order derivative, the adjustment direction and adjustment amount of the bias voltage of the thermo-optic phase shifter can be determined, that is, to realize the MZ silicon Precise locking of the Null point of the light modulator.
本实施例一中，为了在MZ硅光调制器锁定在Null点时对于热光移相器调整的方向进行判断，结合本发明实施例，还存在一种优选的实现方案，具体的，如图6所示，所述第五结果的计算方法为：In the first embodiment, in order to judge the adjustment direction of the thermo-optic phase shifter when the MZ silicon optical modulator is locked at the Null point, there is also a preferred implementation scheme in combination with the embodiment of the present invention, specifically, as shown in 6, the calculation method of the fifth result is:
遍历所述热光移相器的偏置电压；traverse the bias voltage of the thermo-optic phase shifter;
计算得到所述热光移相器的偏置电压对应的第一结果相对于热光移相器的热功率一阶导数，得到第四结果。The first derivative of the first result corresponding to the bias voltage of the thermo-optic phase shifter with respect to the thermal power of the thermo-optic phase shifter is obtained through calculation to obtain a fourth result.
第四结果是热光移相器偏置电压的调节量。偏置电压大小决定了热光相移器的直流偏置相位点，直流偏置相位点不在最佳点会导致调制器性能急剧劣化。The fourth result is the amount of adjustment of the thermo-optic phase shifter bias voltage. The magnitude of the bias voltage determines the DC bias phase point of the thermo-optic phase shifter. If the DC bias phase point is not at the optimum point, the performance of the modulator will deteriorate sharply.
将所述第四结果进行线性拟合，所述第五结果为所述第四结果的斜率；performing linear fitting on the fourth result, the fifth result being the slope of the fourth result;
若所述第五结果为正，所述热光移相器的偏置电压增大；if the fifth result is positive, the bias voltage of the thermo-optic phase shifter is increased;
若所述第五结果为负，所述热光移相器的偏置电压减小。If the fifth result is negative, the bias voltage of the thermo-optic phase shifter is decreased.
第五结果用来判断热光移相器的偏置电压调节方向，偏置电压大小决定了热光相移器的直流偏置相位点，直流偏置相位点不在最佳点会导致调制器性能急剧劣化。The fifth result is used to judge the adjustment direction of the bias voltage of the thermo-optic phase shifter. The magnitude of the bias voltage determines the DC bias phase point of the thermo-optic phase shifter. If the DC bias phase point is not at the optimum point, the performance of the modulator will be affected. Rapid deterioration.
本实施例一提供了一种不需要引入正弦或方波抖动信号的MZ硅光调制器相位偏置点锁定方法，分别通过探测MZ硅光调制器内部的第一输出光电探测器和第二输出光电探测器，计算第一光电流、第二光电流和热光移相器的热功率得到热光移相器的调节量，从而对相位偏置点进行锁定。The first embodiment provides a method for locking the phase bias point of the MZ silicon optical modulator without introducing a sinusoidal or square wave jitter signal, by detecting the first output photodetector and the second output of the MZ silicon optical modulator respectively. The photodetector calculates the thermal power of the first photocurrent, the second photocurrent and the thermo-optic phase shifter to obtain the adjustment amount of the thermo-optic phase shifter, so as to lock the phase bias point.
实施例二：Embodiment two:
本实施例二提供一种实现MZ硅光调制器相位偏置点锁定的装置，用于实施实施例一中的方法，本实施例二的装置包括：激光器1、光纤2、MZ硅光调制器3、处理单元4和反向驱动组件5，其中：The second embodiment provides a device for realizing the phase bias point locking of the MZ silicon optical modulator, which is used to implement the method in the first embodiment. The device of the second embodiment includes: a laser 1, an optical fiber 2, and an MZ silicon optical modulator 3. The processing unit 4 and the reverse drive assembly 5, wherein:
所述激光器1的输出光信号通过所述光纤2输入到所述MZ硅光调制器3中。The output optical signal of the laser 1 is input into the MZ silicon optical modulator 3 through the optical fiber 2 .
所述MZ硅光调制器3把输入的光信号分为相位相差180度的光信号输出。The MZ silicon optical modulator 3 divides the input optical signal into output optical signals with a phase difference of 180 degrees.
MZ硅光调制器内部包含两个光电探测器，一个是跟MZ硅光调制器输 出光信号同向的第一光电探测器32，用于探测MZ硅光调制器输出平均光电流；另一个是跟MZ硅光调制器输出光信号反向的第二输出光电探测器33，用于检测MZ硅光调制器输出2X2MMI反向端的光电流，MMI为多模干涉耦合器(multi-mode interferometer，MMI)，第二输出光电探测器的输出光信号跟MZ硅光调制器输出相位相差180度。The MZ silicon light modulator contains two photodetectors, one is the first photodetector 32 in the same direction as the output light signal of the MZ silicon light modulator, and is used to detect the average photocurrent output by the MZ silicon light modulator; the other is The second output photodetector 33, which is opposite to the output optical signal of the MZ silicon light modulator, is used to detect the photocurrent at the reverse end of the MZ silicon light modulator output 2X2MMI, and the MMI is a multi-mode interference coupler (multi-mode interferometer, MMI ), the phase difference between the output optical signal of the second output photodetector and the output of the MZ silicon optical modulator is 180 degrees.
选用2个输入端口输入2种的干涉光，2X2MMI的输出端信号为输入光信号干涉后的光信号，两个输出信号相位差为180度。Two input ports are selected to input two types of interference light, and the output signal of 2X2MMI is the optical signal after the interference of the input optical signal, and the phase difference between the two output signals is 180 degrees.
所述处理单元4计算所述MZ硅光调制器3输出光信号归一化的结果与所述MZ硅光调制器3中热光移相器35的热功率之间的关系。The processing unit 4 calculates the relationship between the normalized result of the output optical signal of the MZ silicon optical modulator 3 and the thermal power of the thermo-optical phase shifter 35 in the MZ silicon optical modulator 3 .
通过双路跨阻放大器41将第一输出光电探测器32的光电流和第二输出光电探测器33的光电流同时放大，并通过双路数模转换器42进行同步采样，处理器43将第一输出光电探测器32和第二输出光电探测器33的采样电压值相除得到归一化的运算结果，输出为模拟电压，再将第一输出光电探测器32对应的模拟电压作为施加在热光移相器35偏置点的电压，第二输出光电探测器33对应的模拟电压作为反向PN结的反向偏置电压。The photocurrent of the first output photodetector 32 and the photocurrent of the second output photodetector 33 are simultaneously amplified by the dual-way transimpedance amplifier 41, and are synchronously sampled by the dual-way digital-to-analog converter 42, and the processor 43 converts the first The first output photodetector 32 and the sampling voltage value of the second output photodetector 33 are divided to obtain a normalized operation result, and the output is an analog voltage, and then the analog voltage corresponding to the first output photodetector 32 is used as the applied thermal The voltage at the bias point of the optical phase shifter 35 and the analog voltage corresponding to the second output photodetector 33 are used as the reverse bias voltage of the reverse PN junction.
所述反向驱动组件5驱动所述MZ硅光调制器3的反向PN结。反向PN结型电光调制器由于其工作在反向偏压时PN结需要处于耗尽状态，载流子在电场的作用下做漂移运动，因而其运动速度快。反向驱动组件5需要使用高速的电压放大器。The reverse driving component 5 drives the reverse PN junction of the MZ silicon light modulator 3 . The reverse PN junction electro-optic modulator needs to be in a depleted state when the PN junction is working in reverse bias, and the carriers do drift movement under the action of the electric field, so its movement speed is fast. The back drive component 5 needs to use a high-speed voltage amplifier.
所述处理单元4计算得到所述热光移相器35的调节量，以便所述MZ硅光调制器3完成相应偏置点的锁定。The processing unit 4 calculates the adjustment amount of the thermo-optic phase shifter 35 so that the MZ silicon optical modulator 3 completes the locking of the corresponding bias point.
MZ硅光调制器3进行Quad点或Null点锁定时，MZ硅光调制器3中热光移相器的调节量由所述第一光电流、所述第二光电流和所述热光移相器的热功率计算得到。When the MZ silicon light modulator 3 performs Quad point or Null point locking, the adjustment amount of the thermo-optic phase shifter in the MZ silicon light modulator 3 is determined by the first photocurrent, the second photocurrent and the thermo-optic shift The thermal power of the phase device is calculated.
MZ硅光调制器3的相位偏置点是通过基于硅波导热光效应的热光相移器来调节的，其相位偏置跟加载在热光相移器的热功率成正比。The phase offset point of the MZ silicon optical modulator 3 is adjusted by a thermo-optic phase shifter based on the silicon waveguide thermo-optic effect, and its phase offset is proportional to the thermal power loaded on the thermo-optic phase shifter.
本实施例二中，为了探测MZ硅光调制器输出的光电流以及MZ硅光调制器输出反向端的光电流，结合本发明实施例，还存在一种优选的实现方案，具体的，如图1所示，所述MZ硅光调制器3通过分光的方式，将主光路分出的两路光信号导入相位相差180度的第一光电探测器32和第二光电探测器33，所述主光路作为MZ硅光调制器的输出光信号的光路，其中：In the second embodiment, in order to detect the photocurrent output by the MZ silicon light modulator and the photocurrent at the output reverse end of the MZ silicon light modulator, combined with the embodiment of the present invention, there is also a preferred implementation scheme, specifically, as shown in As shown in 1, the MZ silicon optical modulator 3 guides the two optical signals separated by the main optical path into the first photodetector 32 and the second photodetector 33 with a phase difference of 180 degrees by means of light splitting. The optical path is used as the optical path of the output optical signal of the MZ silicon optical modulator, wherein:
所述第一光电探测器32和所述第二光电探测器33分别输出第一光电流和第二光电流。The first photodetector 32 and the second photodetector 33 respectively output a first photocurrent and a second photocurrent.
所述第一光电探测器32用于探测所述MZ硅光调制器3输出相位同向的光信号。The first photodetector 32 is used to detect the optical signals output by the MZ silicon optical modulator 3 with the same phase.
所述第二光电探测器33用于探测与所述MZ硅光调制器3输出相位相差180度的多模干涉耦合器反向端的光信号。The second photodetector 33 is used to detect the optical signal at the reverse end of the multimode interference coupler whose phase difference is 180 degrees from the output of the MZ silicon optical modulator 3 .
第一光电探测器32的分光比为1～10％，在MZ硅光调制器3的同向输出方向第一光电探测器32进行分光1～10％就可以计算得到MZ硅光调制器输出的光电流。The light splitting ratio of the first photodetector 32 is 1-10%. In the same output direction of the MZ silicon light modulator 3, the first photodetector 32 splits the light by 1-10%, and the output of the MZ silicon light modulator can be calculated. photocurrent.
本实施例二中，为了计算施加在热光移相器35偏置点的正向电压以及反向电压的大小，结合本发明实施例，还存在一种优选的实现方案，具体的，如图1所示，所述处理单元4包括双通道跨阻放大器41、双路模数转换器42、处理器43和双路数模转换器44，其中：In the second embodiment, in order to calculate the magnitude of the forward voltage and reverse voltage applied to the bias point of the thermo-optic phase shifter 35, combined with the embodiment of the present invention, there is also a preferred implementation scheme, specifically, as shown in 1, the processing unit 4 includes a dual-channel transimpedance amplifier 41, a dual-channel analog-to-digital converter 42, a processor 43 and a dual-channel digital-to-analog converter 44, wherein:
分别通过所述双路跨阻放大器41将所述第一光电探测器32和所述第二光电探测器33输出的第一光电流和第二光电流分别转换为第一电压信号和第二电压信号；The first photocurrent and the second photocurrent output by the first photodetector 32 and the second photodetector 33 are respectively converted into a first voltage signal and a second voltage by the dual-channel transimpedance amplifier 41 Signal;
所述第一电压信号和所述第二电压信号通过所述双路模数转换器42进行同步采样；The first voltage signal and the second voltage signal are synchronously sampled by the dual analog-to-digital converter 42;
所述处理器43将所述第一电压信号和所述第二电压信号进行数据处理，向所述双路数模转换器44输出模拟电压；The processor 43 performs data processing on the first voltage signal and the second voltage signal, and outputs an analog voltage to the dual-way digital-to-analog converter 44;
所述双路数模转换器44将所述处理器43输出的模拟电压分别施加在所述热光移相器35偏置点的正向电压和反向PN结的反向电压，用于调节热光移相器的偏置点以及射频PN结的反向偏置位置。The dual digital-to-analog converter 44 applies the analog voltage output by the processor 43 to the forward voltage of the bias point of the thermo-optical phase shifter 35 and the reverse voltage of the reverse PN junction, respectively, for adjusting The bias point of the thermo-optic phase shifter and the reverse bias position of the RF PN junction.
处理器43将第一输出光电探测器32对应的模拟电压作为施加在热光移相器35偏置点的电压，第二输出光电探测器33对应的模拟电压作为反向PN结的反向偏置电压。The processor 43 uses the analog voltage corresponding to the first output photodetector 32 as the voltage applied to the bias point of the thermo-optic phase shifter 35, and the analog voltage corresponding to the second output photodetector 33 as the reverse bias of the reverse PN junction. set the voltage.
本实施例二中，为了提高实现MZ硅光调制器相位偏置点精确的锁定，结合本发明实施例，还存在一种优选的实现方案，具体的，如图1所示，反向驱动组件5包括脉冲码源发生器51和电压放大器52，其中：In the second embodiment, in order to improve the precise locking of the phase bias point of the MZ silicon optical modulator, combined with the embodiment of the present invention, there is also a preferred implementation scheme. Specifically, as shown in FIG. 1, the reverse drive component 5 includes a pulse code source generator 51 and a voltage amplifier 52, wherein:
所述脉冲码源发生器51输出调制电压信号，调制电压信号经过电压放大器52放大，放大的电压通过引脚V RF作用于射频调制单元36上，用于驱动反向PN结。 The pulse code source generator 51 outputs a modulation voltage signal, the modulation voltage signal is amplified by the voltage amplifier 52, and the amplified voltage acts on the radio frequency modulation unit 36 through the pin V RF to drive the reverse PN junction.
反向PN型电光调制器由于其工作在反向偏压时PN结需要处于耗尽状态，载流子在电场的作用下做漂移运动，因而其运动速度快，有利于实现高速电光调制，因此成为实现MZ硅光调制器的常用结构。The reverse PN type electro-optic modulator needs to be in a depleted state when it works in reverse bias, and the carriers do drift movement under the action of the electric field, so its movement speed is fast, which is conducive to the realization of high-speed electro-optic modulation, so It has become a common structure for realizing MZ silicon light modulators.
本实施例二中，为了提高实现MZ硅光调制器相位偏置点精确的锁定，结合本发明实施例，还存在一种优选的实现方案，具体的，如图1所示，所述MZ硅光调制器3还包括输入MMI 34、热光相移器35、射频调制单元36和输出MMI 37，其中：In the second embodiment, in order to improve the precise locking of the phase bias point of the MZ silicon optical modulator, combined with the embodiment of the present invention, there is also a preferred implementation scheme. Specifically, as shown in Figure 1, the MZ silicon The optical modulator 3 also includes an input MMI 34, a thermo-optic phase shifter 35, a radio frequency modulation unit 36 and an output MMI 37, wherein:
光信号经过所述输入MMI 34、所述热光相移器35、所述射频调制单元36和所述输出MMI 37后输出；The optical signal is output after passing through the input MMI 34, the thermo-optic phase shifter 35, the radio frequency modulation unit 36 and the output MMI 37;
所述输入MMI 34对光信号进行干涉；The input MMI 34 interferes with the optical signal;
所述输出MMI 37与所述第二光电探测器33反向连接；The output MMI 37 is reversely connected with the second photodetector 33;
所述输出MMI 37与所述第一光电探测器32同向连接；The output MMI 37 is connected in the same direction with the first photodetector 32;
所述热光相移器35通过引脚Vbias与处理单元4设定偏置点；The thermo-optic phase shifter 35 sets a bias point through the pin Vbias and the processing unit 4;
所述射频调制单元36通过引脚V PN与处理单元4设定反向PN结电压。 The radio frequency modulation unit 36 sets the reverse PN junction voltage through the pin V PN and the processing unit 4 .
输入MMI 34为2个输入端口输入2种的干涉光，输出MMI 37为输入光信号干涉后的光信号，两个输出信号相位差为180度。The input MMI 34 is two types of interference light input through two input ports, and the output MMI 37 is the optical signal after the interference of the input optical signal, and the phase difference between the two output signals is 180 degrees.
本实施例二提供的实现MZ硅光调制器相位偏置点锁定的装置可以实现MZ硅光调制器任意偏置点的精确锁定，同时设计简单，易于整体移植到超小型封装例如QDD，OSFP等封装形式的高速硅光模块中。The device for realizing the phase bias point locking of the MZ silicon optical modulator provided in the second embodiment can realize the precise locking of any bias point of the MZ silicon optical modulator, and at the same time, the design is simple, and it is easy to be transplanted to ultra-small packages such as QDD, OSFP, etc. Packaged form of high-speed silicon optical modules.
本领域的技术人员容易理解，以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (10)

  1. 一种实现MZ硅光调制器相位偏置点锁定的方法，其特征在于，所述实现MZ硅光调制器相位偏置点锁定的方法包括：A method for realizing phase bias point locking of MZ silicon light modulator, characterized in that, the method for realizing phase bias point locking of MZ silicon light modulator comprises:
    激光器的输出光信号通过光纤输入到所述MZ硅光调制器中；The output optical signal of the laser is input into the MZ silicon optical modulator through an optical fiber;
    所述MZ硅光调制器通过分光的方式，将主光路分出的两路光信号分别导入相位相差180度的第一光电探测器和第二光电探测器中，所述主光路作为所述MZ硅光调制器的输出光信号的光路；The MZ silicon optical modulator guides the two optical signals separated by the main optical path into the first photodetector and the second photodetector with a phase difference of 180 degrees by means of light splitting, and the main optical path serves as the MZ The optical path of the output optical signal of the silicon optical modulator;
    所述第一光电探测器和所述第二光电探测器分别输出第一光电流和第二光电流，所述第一光电探测器用于探测与所述MZ硅光调制器输出相位同向的光信号，所述第二光电探测器用于探测与所述MZ硅光调制器输出相位反向的光信号；The first photodetector and the second photodetector respectively output a first photocurrent and a second photocurrent, and the first photodetector is used to detect light in the same direction as the output phase of the MZ silicon light modulator signal, the second photodetector is used to detect an optical signal that is opposite in phase to the output of the MZ silicon optical modulator;
    所述MZ硅光调制器进行Quad点或Null点锁定时，所述MZ硅光调制器中热光移相器的调节量由所述第一光电流、所述第二光电流和所述热光移相器的热功率计算得到。When the MZ silicon light modulator performs Quad point or Null point locking, the adjustment amount of the thermo-optic phase shifter in the MZ silicon light modulator is determined by the first photocurrent, the second photocurrent and the thermal The thermal power of the optical phase shifter is calculated.
  2. 如权利要求1所述的实现MZ硅光调制器相位偏置点锁定的方法，其特征在于，所述MZ硅光调制器中所述热光移相器的调节量由所述第一光电流、第二光电流和所述热光移相器的热功率计算得到，具体包括：The method for realizing phase bias point locking of an MZ silicon light modulator according to claim 1, wherein the adjustment amount of the thermo-optic phase shifter in the MZ silicon light modulator is determined by the first photocurrent , the second photocurrent and the thermal power of the thermo-optic phase shifter are calculated, specifically including:
    通过双路跨阻放大器将所述第一光电流和所述第二光电流同时放大并转换为第一电压信号和第二电压信号；simultaneously amplifying and converting the first photocurrent and the second photocurrent into a first voltage signal and a second voltage signal through a dual-channel transimpedance amplifier;
    所述第一电压信号和所述第二电压信号通过双路数据采样单元进行同步采样，得到第一平均光电流和第二平均光电流；The first voltage signal and the second voltage signal are synchronously sampled by a dual data sampling unit to obtain a first average photocurrent and a second average photocurrent;
    将所述第二平均光电流与所述第一平均光电流相除，得到第一结果；以及dividing the second average photocurrent by the first average photocurrent to obtain a first result; and
    通过所述第一结果与所述热光移相器的热功率计算所述热光移相器的 调节量。Calculate the adjustment amount of the thermo-optic phase shifter through the first result and the thermal power of the thermo-optic phase shifter.
  3. 如权利要求2所述的实现MZ硅光调制器相位偏置点锁定的方法，其特征在于，通过所述第一结果与所述热光移相器的热功率计算所述热光移相器的调节量，具体包括：The method for realizing phase bias point locking of an MZ silicon optical modulator according to claim 2, wherein the thermo-optic phase shifter is calculated by the first result and the thermal power of the thermo-optic phase shifter adjustments, including:
    将所述第一结果减去所述第一光电探测器和所述第二光电探测器的响应度的比值，得到第二结果；subtracting the ratio of the responsivity of the first photodetector to the second photodetector from the first result to obtain a second result;
    计算所述第二结果相对于所述热光移相器的热功率的一阶导数，得到第三结果；calculating the first derivative of the second result with respect to the thermal power of the thermo-optic phase shifter to obtain a third result;
    若所述第三结果为0，所述热光移相器的相位偏置在Quad点；If the third result is 0, the phase offset of the thermo-optic phase shifter is at the Quad point;
    若所述第三结果小于第一预设阈值，所述热光移相器的调节量为所述第三结果与0之间的差值，所述热光移相器完成调节后，所述MZ硅光调制器锁定在Quad点。If the third result is less than the first preset threshold, the adjustment amount of the thermo-optic phase shifter is the difference between the third result and 0, and after the thermo-optic phase shifter completes the adjustment, the The MZ silicon light modulator is locked at the quad point.
  4. 如权利要求2所述的实现MZ硅光调制器相位偏置点锁定的方法，其特征在于，所述MZ硅光调制器进行Null点锁定时，所述MZ硅光调制器中所述热光移相器的调节量由所述第一结果与所述热光移相器的热功率之间的关系函数计算得到，具体包括：The method for realizing phase bias point locking of an MZ silicon optical modulator according to claim 2, wherein when the MZ silicon optical modulator performs Null point locking, the thermal light in the MZ silicon optical modulator The adjustment amount of the phase shifter is calculated by the relationship function between the first result and the thermal power of the thermo-optic phase shifter, specifically including:
    计算所述第一结果相对于所述热光移相器的热功率的一阶导数和二阶导数，分别得到第四结果和第五结果；calculating the first derivative and the second derivative of the first result with respect to the thermal power of the thermo-optic phase shifter to obtain a fourth result and a fifth result respectively;
    若所述第四结果为0时，所述热光移相器的相位偏置在Null点；If the fourth result is 0, the phase offset of the thermo-optic phase shifter is at the Null point;
    所述热光移相器的调节量为所述第四结果相对于Null点的误差并除以所述第五结果，所述热光移相器完成调节后，所述MZ硅光调制器锁定在Null点。The adjustment amount of the thermo-optic phase shifter is the error of the fourth result relative to the Null point and divided by the fifth result. After the thermo-optic phase shifter is adjusted, the MZ silicon optical modulator locks At the null point.
  5. 如权利要求4所述的实现MZ硅光调制器相位偏置点锁定的方法， 其特征在于，计算得到所述第五结果，包括：The method for realizing the phase bias point locking of the MZ silicon optical modulator according to claim 4, wherein the calculation of the fifth result includes:
    遍历所述热光移相器的偏置电压；traverse the bias voltage of the thermo-optic phase shifter;
    计算得到所述热光移相器的偏置电压对应的第一结果相对于所述热光移相器的热功率一阶导数，得到所述第四结果；calculating the first derivative of the first result corresponding to the bias voltage of the thermo-optic phase shifter relative to the thermal power of the thermo-optic phase shifter to obtain the fourth result;
    将所述第四结果进行线性拟合，所述第五结果为所述第四结果的斜率；performing linear fitting on the fourth result, the fifth result being the slope of the fourth result;
    若所述第五结果为正，所述热光移相器的偏置电压增大；if the fifth result is positive, the bias voltage of the thermo-optic phase shifter is increased;
    若所述第五结果为负，所述热光移相器的偏置电压减小。If the fifth result is negative, the bias voltage of the thermo-optic phase shifter is decreased.
  6. 一种实现MZ硅光调制器相位偏置点锁定的装置，其特征在于，装置包括：激光器(1)、光纤(2)、MZ硅光调制器(3)、处理单元(4)和反向驱动组件(5)，其中：A device for realizing phase bias point locking of an MZ silicon optical modulator, characterized in that the device includes: a laser (1), an optical fiber (2), an MZ silicon optical modulator (3), a processing unit (4) and a reverse Drive assembly (5), wherein:
    所述激光器(1)的输出光信号通过所述光纤(2)输入到所述MZ硅光调制器(3)中；The output optical signal of the laser (1) is input into the MZ silicon optical modulator (3) through the optical fiber (2);
    所述MZ硅光调制器(3)把所述输入的光信号分为相位相差180度的光信号输出；The MZ silicon optical modulator (3) divides the input optical signal into output optical signals with a phase difference of 180 degrees;
    所述处理单元(4)计算所述MZ硅光调制器(3)输出光信号归一化的结果与所述MZ硅光调制器(3)中热光移相器(35)热功率之间的关系，The processing unit (4) calculates the difference between the normalized result of the output optical signal of the MZ silicon optical modulator (3) and the thermal power of the thermal optical phase shifter (35) in the MZ silicon optical modulator (3). Relationship,
    所述反向驱动组件(5)驱动所述MZ硅光调制器(3)的反向PN结；The reverse driving component (5) drives the reverse PN junction of the MZ silicon light modulator (3);
    所述处理单元(4)计算得到所述热光移相器(35)的调节量，以便所述MZ硅光调制器(3)完成相应偏置点的锁定。The processing unit (4) calculates the adjustment amount of the thermo-optic phase shifter (35), so that the MZ silicon optical modulator (3) completes the locking of the corresponding bias point.
  7. 如权利要求6所述的实现MZ硅光调制器相位偏置点锁定的装置，其特征在于，所述MZ硅光调制器(3)通过分光的方式，将主光路分出的两路光信号分别导入相位相差180度的第一光电探测器(32)和第二光电探测器(33)，所述主光路作为所述MZ硅光调制器的输出光信号的光路，其中：The device for realizing phase bias point locking of an MZ silicon optical modulator according to claim 6, wherein the MZ silicon optical modulator (3) divides the two optical signals from the main optical path by means of light splitting The first photodetector (32) and the second photodetector (33) with a phase difference of 180 degrees are imported respectively, and the main optical path is used as the optical path of the output optical signal of the MZ silicon optical modulator, wherein:
    所述第一光电探测器(32)和所述第二光电探测器(33)分别输出第一光电流和第二光电流；The first photodetector (32) and the second photodetector (33) respectively output a first photocurrent and a second photocurrent;
    所述第一光电探测器(32)用于探测与所述MZ硅光调制器(3)输出相位同向的光信号；The first photodetector (32) is used to detect an optical signal in the same direction as the output phase of the MZ silicon optical modulator (3);
    所述第二光电探测器(33)用于探测与所述MZ硅光调制器(3)输出相位反向的光信号。The second photodetector (33) is used to detect an optical signal whose phase is opposite to that output by the MZ silicon optical modulator (3).
  8. 如权利要求7所述的实现MZ硅光调制器相位偏置点锁定的装置，其特征在于，所述处理单元(4)包括双通道跨阻放大器(41)、双路模数转换器(42)、处理器(43)和双路数模转换器(44)，其中：The device realizing MZ silicon light modulator phase bias point locking as claimed in claim 7, is characterized in that, described processing unit (4) comprises two-channel transimpedance amplifier (41), two-way analog-to-digital converter (42 ), a processor (43) and a dual digital-to-analog converter (44), wherein:
    通过所述双路跨阻放大器(41)分别将所述第一光电探测器(32)和所述第二光电探测器(33)输出的所述第一光电流和所述第二光电流分别转换为第一电压信号和第二电压信号；The first photocurrent and the second photocurrent output by the first photodetector (32) and the second photodetector (33) are respectively output by the dual-way transimpedance amplifier (41). converted into a first voltage signal and a second voltage signal;
    所述第一电压信号和所述第二电压信号通过所述双路模数转换器(42)进行同步采样；The first voltage signal and the second voltage signal are sampled synchronously through the dual analog-to-digital converter (42);
    所述处理器(43)将所述第一电压信号和所述第二电压信号进行数据处理，向所述双路数模转换器(44)输出模拟电压；The processor (43) performs data processing on the first voltage signal and the second voltage signal, and outputs an analog voltage to the dual-channel digital-to-analog converter (44);
    所述双路数模转换器(44)输出的模拟电压根据所述处理器(43)的计算结果分别施加在所述热光移相器(35)的偏置点和所述反向PN结上。The analog voltage output by the dual-way digital-to-analog converter (44) is respectively applied to the bias point of the thermal-optical phase shifter (35) and the reverse PN junction according to the calculation result of the processor (43). superior.
  9. 如权利要求8所述的实现MZ硅光调制器相位偏置点锁定的装置，其特征在于，所述反向驱动组件(5)包括脉冲码源发生器(51)和电压放大器(52)，其中：The device for realizing phase bias point locking of an MZ silicon light modulator according to claim 8, characterized in that, the reverse drive assembly (5) includes a pulse code source generator (51) and a voltage amplifier (52), in:
    所述脉冲码源发生器(51)输出调制电压信号，所述调制电压信号经过所述电压放大器(52)放大，放大的电压通过引脚V RF作用于所述射频调制单元(36)上，用于驱动所述反向PN结。 The pulse code source generator (51) outputs a modulation voltage signal, the modulation voltage signal is amplified through the voltage amplifier (52), and the amplified voltage acts on the radio frequency modulation unit (36) through the pin V RF , used to drive the reverse PN junction.
  10. 如权利要求9所述的实现MZ硅光调制器相位偏置点锁定的装置，其特征在于，所述MZ硅光调制器(3)还包括输入MMI(34)、热光相移器(35)、射频调制单元(36)和输出MMI(37)，其中：The device for realizing phase bias point locking of MZ silicon light modulator as claimed in claim 9, characterized in that, said MZ silicon light modulator (3) also includes an input MMI (34), a thermo-optical phase shifter (35 ), radio frequency modulation unit (36) and output MMI (37), wherein:
    光信号经过所述输入MMI(34)、所述热光相移器(35)、所述射频调制单元(36)和所述输出MMI(37)后输出；The optical signal is output after passing through the input MMI (34), the thermo-optic phase shifter (35), the radio frequency modulation unit (36) and the output MMI (37);
    所述输入MMI(34)对光信号进行干涉；The input MMI (34) interferes with the optical signal;
    所述输出MMI(37)与所述第二光电探测器(33)反向连接；The output MMI (37) is reversely connected to the second photodetector (33);
    所述输出MMI(37)与所述第一光电探测器(32)同向连接；The output MMI (37) is connected to the first photodetector (32) in the same direction;
    所述热光相移器(35)通过引脚V bias与所述处理单元(4)设定偏置点； The thermo-optic phase shifter (35) sets a bias point through the pin V bias and the processing unit (4);
    所述射频调制单元(36)通过引脚V PN与所述处理单元(4)设定反向PN结电压。 The radio frequency modulation unit (36) sets the reverse PN junction voltage through the pin V PN and the processing unit (4).
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Publication number Priority date Publication date Assignee Title
CN114114719B (en) * 2021-10-28 2023-06-27 武汉光迅科技股份有限公司 Method and device for locking phase bias point of MZ silicon optical modulator
CN116500814B (en) * 2023-06-25 2023-09-15 之江实验室 High-linearity silicon-based film lithium niobate modulation chip and method based on full-light linearization

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102263718A (en) * 2011-07-19 2011-11-30 武汉电信器件有限公司 Operating point control system and method for return-to-zero-differential quadrature phase shift keying (RZ-DQPSK) modulation
CN104898306A (en) * 2014-03-05 2015-09-09 北京邮电大学 MZ modulator random point bias control device and method
CN106501969A (en) * 2015-09-03 2017-03-15 三星电子株式会社 Photomodulator and the data handling system using the photomodulator
CN113176693A (en) * 2021-04-30 2021-07-27 南京刻得不错光电科技有限公司 Multi-mode interference element and Mach-Zehnder modulator
CN114114719A (en) * 2021-10-28 2022-03-01 武汉光迅科技股份有限公司 Method and device for realizing phase bias point locking of MZ silicon optical modulator

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6181456B1 (en) * 1999-04-01 2001-01-30 Uniphase Telecommunications Products, Inc. Method and apparatus for stable control of electrooptic devices
ATE554422T1 (en) * 2007-06-25 2012-05-15 Bae Systems Plc OPTICAL SWITCHING DEVICE COMPRISING MULTIPLE ELECTRO-OPTICAL DUAL OUTPUT MODULATORS AND A BIAS CONTROLLER
CN103412594B (en) * 2013-07-31 2016-01-06 武汉电信器件有限公司 Electrooptic modulator working point control device and control method
CN106324866B (en) * 2015-06-19 2020-01-07 中兴通讯股份有限公司 Silicon-based modulator bias point control device
CN110138456B (en) * 2018-02-08 2021-07-09 华为技术有限公司 Optical device and optical signal processing method
US11509275B2 (en) * 2018-04-20 2022-11-22 Neophotonics Corporation Method and apparatus for bias control with a large dynamic range for Mach-Zehnder modulators
US11092871B2 (en) * 2019-06-28 2021-08-17 Morton Photonics Linearized Mach Zehnder interferometer (MZI) modulator
CN110361877B (en) * 2019-07-17 2022-12-16 武汉光迅科技股份有限公司 Silicon-based optical modulator light path monitoring structure
CN110849476A (en) * 2019-11-19 2020-02-28 北京无线电计量测试研究所 High-precision broadband balance photoelectric detection method and device
CN112751610A (en) * 2020-12-29 2021-05-04 武汉光迅科技股份有限公司 Method and system for measuring SMZM modulation arm phase shift function

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102263718A (en) * 2011-07-19 2011-11-30 武汉电信器件有限公司 Operating point control system and method for return-to-zero-differential quadrature phase shift keying (RZ-DQPSK) modulation
CN104898306A (en) * 2014-03-05 2015-09-09 北京邮电大学 MZ modulator random point bias control device and method
CN106501969A (en) * 2015-09-03 2017-03-15 三星电子株式会社 Photomodulator and the data handling system using the photomodulator
CN113176693A (en) * 2021-04-30 2021-07-27 南京刻得不错光电科技有限公司 Multi-mode interference element and Mach-Zehnder modulator
CN114114719A (en) * 2021-10-28 2022-03-01 武汉光迅科技股份有限公司 Method and device for realizing phase bias point locking of MZ silicon optical modulator

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