CN101621329A - Method and system for measuring bias points of double-parallel modulator - Google Patents

Abstract

The embodiment of the present invention discloses a method and system for measuring the bias point of a dual-parallel modulator. The method includes: controlling the amplitude value of the bias voltage acting on the dual-parallel modulator to increase by a first step value; The optical signal output by the dual parallel modulator under the action of the bias voltage is converted into an electrical signal; the amplitude value of the electrical signal is detected, and when the amplitude value of the electrical signal meeting the measurement bias point condition appears, stop incrementing the The amplitude value of the bias voltage; according to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage, scan the electrical signal satisfying the measurement bias point condition with a second step value The magnitude value of the bias voltage corresponding to the magnitude value is used to calculate the bias point; the first step value is greater than the second step value. Adopting the embodiment of the present invention has the advantages of reducing the interference between multiple frequencies and improving the efficiency of measuring the bias point.

Description

Method and system for measuring bias point of dual parallel modulator

technical field

The invention relates to the access network technology of the mobile communication network, in particular to a method and system for measuring the bias point of a dual parallel modulator.

Background technique

The signal will be affected by dispersion during the transmission in the optical fiber. The so-called dispersion is the waveform distortion of the signal caused by the different frequency components of the signal transmitted in the optical fiber or the various mode components of the signal. The main impact of dispersion on optical transmission It is to cause inter-symbol interference between data pulses, and the damage caused by dispersion to system performance cannot be ignored. Generally, optical fiber transmission systems with a transmission rate above 10Gbit/s require dispersion compensation technology to ensure the transmission function of the system.

The dispersion compensation technology widely used at present is to realize the dispersion compensation through the dispersion compensation fiber (DCF, Dispersion Compensation Fiber) whose dispersion characteristic is opposite to that of the transmission fiber. Although this dispersion compensation method is easy to apply, it also has disadvantages, that is, the volume is large, the signal has a delay, and the amplifier needs to compensate for the additional loss, and the cost is high, and this compensation method cannot flexibly provide variable dispersion compensation. Although it is very practical in a point-to-point optical transmission system, when it is applied to a complex network with wavelength up/down, especially in a dynamically reconfigurable flexible network, due to the different transmission paths that the optical compensation passes through, the experienced The dispersion is also different, and the DCF compensation method is difficult to meet the application requirements.

In recent years, electrical domain dispersion compensation has attracted the attention of technicians. The so-called electrical domain dispersion compensation refers to partially or completely compensating for the degradation of the transmission signal caused by dispersion in the optical transmission system transmitting module or receiving module through electrical domain signal processing. . The post-compensation of electrical dispersion at the receiving end is mainly limited by the square detection of the photodetector, so its compensation capability is limited, while the electrical domain dispersion pre-compensation at the sending end has long-distance dispersion compensation capabilities.

The dispersion pre-compensation method at the sending end can realize the compensation of the transmission distance of thousands of kilometers, but it must be received near the predetermined compensation distance. If the transmission distance is changed due to reasons such as wavelength routing, the electrical field of the transmitter also needs to change the parameters of the digital processing and the parameters of the transmitter hardware. Experiments have shown that different transmission distances require different bias voltages for electro-optical modulators. The electro-optic modulator here can use a special modulator—Dual Parallel Mach-zehnder (DPMZ, Dual Parallel Mach-zehnder).

The DPMZ modulator can be regarded as two amplitude modulation modulators, that is, Mach-Zender modulator (MZM, Mach-zender Modulator), such as MZM1 and MZM2 in the figure and a phase modulation modulator (usually a phase of p/2 Shifter) composition.

It should be noted that, after the data signal to be transmitted is precoded, two channels of data are obtained as Iin and Qin. The light output by the light source is divided into upper and lower channels and output to the upper and lower MZM modulators respectively. Iin and Qin modulate each channel of light to obtain a differential phase shift keying code (DPSK, DifferentialPhase Shift Keying), and output to the upper MZM One path of light of the modulator is phase-shifted by P/2, so that a Differential Quadrature Phase Shift Keying (DQPSK, Differential Quadrature Phase Shift Keying) optical signal is obtained at the output end.

Since any bias point of the DPMZ modulator needs to be adjusted, it is necessary to measure the initial voltage V0 and the half-wave voltages Vpi and Vpi' of the DPMZ modulator.

The initial voltage V0 and half-wave voltage Vpi of the DPMZ modulator are shown in Figure 2:

In Figure 2, V0 is the voltage value corresponding to the first optical power peak of the modulator. For MZM1 and MZM2, Vpi is the difference between the voltage value corresponding to the peak point and the adjacent peak point. For the phase modulation modulator In other words, Vpi is the difference between the voltage value corresponding to the peak value and the adjacent valley point.

The prior art provides a way to stabilize the bias point of the DPMZ modulator, as shown in Figure 3:

In this method, three scrambling frequencies f1, f2 and f3 are used to form three loops 15.1, 15.2 and 15.3 respectively, and the bias point of the dual parallel modulator 1 uses 20G PD13 for receiving detection.

The third bias point is the Vpi/2 detection point. It needs to be detected bit by bit to know whether the phase difference between the data is kept at Vpi/2. If it is not at Vpi/2, the output will have a small peak. This peak is difficult to detect, and high-speed A photodetector (PD, Photo Detector) is required, and a PD with peak detection capability is required to detect it, and such a PD device is very expensive.

The inventor finds in the process of implementing the present invention that the prior art has the following problems:

The existing technology uses multiple scrambling frequencies for control, which will cause mutual interference, and the receiving PD uses a high-speed PD tube, which is expensive.

Contents of the invention

The embodiment of the present invention provides a method and system for measuring a bias point of a dual parallel modulator, which reduces interference between multiple frequencies and improves the efficiency of measuring the bias point.

An embodiment of the present invention provides a method for measuring a bias point of a dual parallel modulator, including:

controlling the amplitude value of the bias voltage applied to the dual parallel modulator to increase by a first step value;

converting the optical signal output by the dual parallel modulator under the action of the bias voltage into an electrical signal;

Detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage when the amplitude value of the electrical signal meeting the measurement bias point condition appears;

According to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage, scanning the offset voltage corresponding to the amplitude value of the electrical signal satisfying the measurement bias point condition with a second step value The amplitude value of , calculate the bias point; the first step value is greater than the second step value.

Correspondingly, an embodiment of the present invention provides a measurement system for a bias point of a dual parallel modulator, including:

a controller, configured to control the amplitude value of the bias voltage applied to the dual parallel modulator to increase by a first step value;

a dual parallel modulator, configured to output an optical signal under the action of the bias voltage;

A detection circuit for converting the optical signal output by the dual parallel modulator under the action of the bias voltage into an electrical signal; and detecting the amplitude value of the electrical signal;

When the amplitude value of the electrical signal meeting the measurement bias point condition appears, the controller stops incrementing the amplitude value of the bias voltage;

The detection circuit is further configured to scan the amplitude of the electrical signal satisfying the measurement bias point condition with a second step value according to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage The magnitude value of the bias voltage corresponding to the value is used to calculate the bias point; the first step value is greater than the second step value.

Implement the present invention, have following beneficial effect:

The embodiment of the present invention provides a method and system for measuring the bias point of a dual parallel modulator, which does not need to use multiple frequencies to control, reduces the interference between multiple frequencies, simplifies the system structure, and improves the measurement bias. point of efficiency.

Description of drawings

FIG. 1 is a schematic diagram of the composition of a DPMZ in the prior art;

FIG. 2 is a schematic diagram of an initial voltage and a half-wave voltage of a DPMZ in the prior art;

FIG. 3 is a schematic diagram of performing bias point detection on a DPMZ in the prior art;

4 is a schematic structural diagram of a first embodiment of a measurement system for a bias point of a dual parallel modulator provided by an embodiment of the present invention;

5 is a schematic structural diagram of a second embodiment of a measurement system for a bias point of a dual parallel modulator provided by an embodiment of the present invention;

FIG. 6 is a schematic flowchart of a first embodiment of a method for measuring a bias point of a dual parallel modulator provided by an embodiment of the present invention;

7 is a schematic flowchart of a second embodiment of a method for measuring a bias point of a dual parallel modulator provided by an embodiment of the present invention;

FIG. 8 is a schematic flowchart of a third embodiment of a method for measuring a bias point of a dual parallel modulator provided by an embodiment of the present invention.

Detailed ways

Referring to Fig. 4, the measurement system of the dual parallel modulator bias point provided by the embodiment of the present invention consists of a dual parallel modulator 1 (DPMZ1), a controller 2, a bias controller 3 (BC, Bias Control), and a detection circuit 4 composition.

First of all, the so-called bias point of the dual-parallel modulator actually refers to the voltage value that makes the two MZM modulators and the phase modulation modulator in the dual-parallel modulator work stably. Therefore, to measure the bias point, that is When the MZM modulator and the phase modulation modulator in the dual parallel modulator work stably, the initial voltage and the half-wave voltage of the bias controllers connected to the two MZM modulators and the phase modulation modulator are measured.

The controller 2 is connected to each port of the dual parallel modulator 1 (DPMZ1) to be detected through the bias controller 3 and the bias T10, and connected to the detection circuit 4 for receiving and storing the detection output from the detection circuit 4 As a result, the detection result is converted into a control signal and output to the bias controller 3; it should be noted that the function of the control signal is to control the bias voltage output by the bias controller 3;

The bias controller 3 is used to connect the controller 2 and the bias T10 of the dual parallel modulator 1, and under the control of the output control signal of the controller 2, output the bias voltage to the bias T10; it needs to be explained Yes, the bias voltage is essentially the voltage applied to the dual parallel modulator 1;

The bias T10 is used to connect the bias controller 3, receive the bias voltage of the bias controller 3 and superimpose it with the data signal, and output the bias voltage data signal to the dual parallel modulator 1; it should be noted that, The data signal superimposed with the bias voltage is a pre-coded data signal to be transmitted, which is well known to those skilled in the art, and is also described in detail in the background technology section, and will not be repeated here.

Dual parallel modulator 1, consisting of two MZM modulators up and down and a phase modulation modulator (usually a p/2 phase shifter), the phase modulation modulator is connected to the upper MZM modulator, the two The MZM modulator, under the action of the bias voltage data signal, modulates the light input therein respectively to obtain a QPSK optical signal, and the phase modulation modulator connected to the MZM modulator performs p on the light after MZM modulation /2 phase shift, finally output DQPSK optical signal;

The detection circuit 4 is used to convert the DQPSK optical signal output by the dual parallel modulator 1 into an electrical signal; and perform amplitude detection on the electrical signal, according to the amplitude value of the electrical signal and the offset output by the bias controller Calculate the initial voltage and the half-wave voltage of the bias controller 3 based on the relationship between the amplitude values of the set voltage; it should be noted that the bias controller 3 outputs different values of the bias voltage, and the dual The optical signal output by the parallel modulator 1 will change accordingly, and correspondingly, the amplitude value of the electrical signal will also change with the change of the bias voltage. The relationship between the values of the bias voltage, find out the value of the corresponding bias voltage when the amplitude value of the electrical signal is the peak value, which is the initial voltage of the bias controller 3, for the connection with the MZM modulator The bias controller 3, the difference between the values of the bias voltage corresponding to the two peaks of the electrical signal is the half-wave voltage of the bias controller 32, for the bias connected to the phase modulation modulator For the controller 3 , the difference between the value of the bias voltage corresponding to the peak value of the electrical signal and the adjacent valley value is the half-wave voltage of the bias controller 3 .

It should be noted that the initial voltage and the half-wave voltage of the bias controller 3 are the detection results of the detection circuit 4, and the detection circuit will provide the detection results to the controller 2, and the controller 2 stores the detected results. The detection result is used as a control signal for controlling the dual parallel modulator 1.

Implementing the measurement system of the bias point of the dual parallel modulator provided by the embodiment of the present invention does not need to use multiple frequencies to control, reduces the interference between multiple frequencies, simplifies the system structure, and improves the efficiency of measuring the bias point .

Referring to FIG. 5 , the implementation of the present invention provides a measurement system for the bias point of a dual parallel modulator.

Described measurement system is made up of DPMZ1, bias T, controller 2, bias controller 3 (BC3), and detection circuit 4, and wherein detection circuit 4 is made up of light splitter 40, PD tube 41, amplifier 42 with adjustable amplitude , a filter 43, and an analog-to-digital converter 44 (ADC44).

It should be noted that there are two bias Ts of the dual parallel modulator 1, as shown in FIG. port 111 (port111) of the modulator.

The bias controller 3 (BC3) includes three, namely the bias controller 30 (BC30) connected to the bias T100, the bias controller 31 (BC31) connected to the bias T101 and A bias controller 32 directly connected to the DPMZ1.

The bias controller 30 (BC30) outputs the bias voltage to the bias T100 under the control of the first control signal output by the controller 2, and the bias T100 superimposes the bias voltage and the data signal (Data), and outputs the bias Set the voltage data signal to the port 110 (port110) of DPMZ1;

The DPMZ1 outputs an optical signal under the action of the bias voltage input by the bias controller 30;

The detection circuit 4 converts the optical signal output by the DPMZ1 into an electrical signal, and detects the amplitude of the electrical signal, detects the first initial voltage and the first half-wave voltage of the bias controller 30, and outputs it as a detection result into controller 2.

At this time, the controller 2 stores the first initial voltage and the first half-wave voltage corresponding to the detection result, and sets the value of the bias voltage output by the bias controller 30 as the first initial voltage, And output the second control signal to the bias controller 31, and the bias controller 31 outputs the bias voltage to the bias T101 under the control of the second control signal, and the bias T101 combines the bias voltage and the data signal ( Data) is superimposed, and the output bias voltage data signal is sent to port 111 (port111) of DPMZ1;

The DPMZ1 outputs an optical signal under the action of the bias voltage input by the bias controller 31;

The detection circuit 4 converts the optical signal output by the DPMZ1 into an electrical signal, and detects the amplitude of the electrical signal, detects the second initial voltage and the second half-wave voltage of the bias controller 31, and outputs it as a detection result into controller 2.

At this time, the controller 2 stores the second initial voltage and the second half-wave voltage corresponding to the detection result, sets the value of the output bias voltage of the bias controller 31 as the second initial voltage, and Outputting the third control signal to the bias controller 32, the bias controller 32 outputs the bias voltage to the port 112 (port112) of the DPMZ1 under the control of the second control signal;

The DPMZ1 outputs an optical signal under the action of the bias voltage input by the bias controller 32;

The detection circuit 4 converts the optical signal output by the DPMZ1 into an electrical signal, and detects the amplitude of the electrical signal, detects the third initial voltage and the third half-wave voltage of the bias controller 32, and outputs it as a detection result into controller 2.

At this time, the controller 2 stores the third initial voltage and the third half-wave voltage corresponding to the detection result.

The first initial voltage and the first half-wave voltage of the bias controller 30, the second initial voltage and the second half-wave voltage of the bias controller 31, the third initial voltage and the third half-wave voltage of the bias controller 32 , which is the bias point of each bias controller, the controller 2 stores the various bias points, and in the optical transmission process, according to the needs of different transmission distances, modulates the DPMZ1.

The function and structure of the detection circuit 4 will be described in detail below. Specifically, the detection circuit 4 converts the optical signal output by the DPMZ1 into an electrical signal, and performs amplitude detection on the electrical signal to detect the bias controller 30. The first initial voltage and the first half-wave voltage are output to the controller 2 as detection results for illustration.

The detection circuit 4 first splits a small part of the optical signal (generally 5%) from the optical signal output by the DPMZ1 through the optical splitter 40, and the small part of the optical signal passes through the photodetector (PD) 41 and is converted into Electric signal; because the amplitude of the electric signal is relatively weak, it is generally necessary to use the amplifier 42 to amplify it, and the specific magnification is controlled by the controller 2. After the amplified electric signal is filtered by the filter 43, the amplitude is determined by the ADC44 Quantization, and the initial voltage and half-wave voltage of the bias controller 30 corresponding to the amplitude value of the electrical signal are output to the controller 2 as the detection result;

In the embodiment of the present invention, the controller 2 outputs the first control signal to the bias controller 30, and under the control of the first control signal, the bias voltage output by the bias controller 30 increases by a large margin, for example, by 0.5V The amplitude increases, and the detection circuit 4 detects the amplitude of the electrical signal with a larger step value (for example, an interval of 0.5V), and the electrical signal is output by the DPMZ1 under the action of the bias voltage output by the bias controller 30 The electrical signal that the optical signal is converted into; The detection circuit 4 scans and calculates the initial voltage and the half-wave voltage of the bias controller 30 with a smaller step value (for example, the interval is 0.05V), specifically, first detects that the DPMZ1 is in the bias Under the action of the bias voltage output by the controller 30, the output optical signal is converted into the peak value of the electrical signal; The difference between the set voltages is recorded as the first half-wave voltage, and the value of the bias voltage corresponding to the first peak value is recorded as the first initial voltage;

The detection circuit 4 outputs the first initial voltage and the first half-wave voltage to the controller 2 as detection results;

Then, the value of the bias voltage output by the bias controller 30 is set as the first initial voltage, and the controller 2 then outputs a second control signal to the bias controller 31, and under the control of the second control signal, the bias The bias voltage output by the controller 31 increases greatly, for example, by 0.5V, and the detection circuit 4 detects the amplitude of the electrical signal with a larger step value (for example, an interval of 0.5V), and the electrical signal is DPMZ1 Under the action of the bias voltage output by the bias controller 31, the output optical signal is converted into an electrical signal; the detection circuit 4 scans and calculates the initial value of the bias controller 31 with a smaller step value (for example, the interval is 0.05V). Voltage and half-wave voltage, specifically, first detect the peak value of the optical signal output by the DPMZ1 under the action of the bias voltage output by the bias controller 31 into an electrical signal; after detecting the peak value of two adjacent electrical signals At the peak value, the difference between the bias voltage corresponding to the first peak value and the second peak value is recorded as the second half-wave voltage, and the value of the bias voltage corresponding to the first peak value is recorded as the second initial voltage;

The detection circuit 4 outputs the second initial voltage and the second half-wave voltage to the controller 2 as detection results;

Then, the value of the bias voltage output by the bias controller 31 is set as the second initial voltage, and the controller 2 outputs a third control signal to the bias controller 32. Under the control of the third control signal, the bias The bias voltage output by the controller 32 increases greatly, for example, by 0.5V, and the detection circuit 4 detects the amplitude of the electrical signal with a larger step value (for example, an interval of 0.5V), and the electrical signal is DPMZ1 Under the action of the bias voltage output by the bias controller 32, the output optical signal is converted into an electrical signal, and the detection circuit 4 scans and calculates the initial value of the bias controller 32 with a smaller step value (for example, the interval is 0.05V). Voltage and half-wave voltage, specifically, first detect the peak value and valley value of the optical signal output by the DPMZ1 under the action of the bias voltage output by the bias controller 32 into an electrical signal; When the peak value and the valley value of the electrical signal, the difference value of the bias voltage corresponding to the peak value and the valley value is recorded as the third half-wave voltage, and the value of the bias voltage corresponding to the peak value is recorded as the third initial voltage;

The detection circuit 4 outputs the third initial voltage and the third half-wave voltage to the controller 2 as detection results;

The first initial voltage and the first half-wave voltage of the bias controller 30, the second initial voltage and the second half-wave voltage of the bias controller 31, the third initial voltage and the third half-wave voltage of the bias controller 32 , which is the bias point of each bias controller, the controller 2 stores the various bias points, and in the optical transmission process, according to the needs of different transmission distances, modulates the DPMZ1.

The above is only one implementation mode, and the present invention also provides another way to calculate the initial voltage and half-wave voltage of each bias controller, specifically:

The controller 2 outputs a first control signal to a bias controller 30 and a bias controller 32, the bias controller 30 outputs a bias voltage to a bias T100 for amplitude modulation, and the bias T100 converts the bias Set the voltage and the data signal to be superimposed, converted into a bias voltage data signal, and output to the dual parallel modulator 1 through the port 110 (port110); the bias controller 32 is controlled by the first control signal through the port 112 (port112) outputs the bias voltage to the dual-parallel modulator 1; it should be noted that, under the control of the first control signal, the bias voltage output by the bias controller 30 and the bias controller 32 has a large amplitude Increase, for example, by 0.5V;

The detection circuit 4 detects the magnitude of the conversion of the optical signal output by the DPMZ1 into an electrical signal under the action of the bias voltage output by the bias controller 30 with a relatively large step value (for example, an interval of 0.5V), Under the action of the bias voltage output by the controller 32, the optical signal output by the DPMZ1 is converted into the amplitude of the electrical signal for detection;

The detection circuit 4 then scans and calculates the initial voltage and the half-wave voltage of the bias controller 30 and the bias controller 32 with a smaller step value (for example, the interval is 0.05V), specifically, scans two adjacent electrical signals The bias voltage corresponding to the peak value, record the coordinates (x1, y1) and (x2, y2) corresponding to the first peak value and the second peak value; wherein the X coordinate represents the value of the bias voltage output by the bias controller 30, Y The coordinate representation is the value of the bias voltage output by the bias controller 32;

Compare the sizes of x1 and x2, determine the smaller of the two as the first initial voltage value corresponding to the bias controller 30, compare the sizes of y1 and y2, and determine the smaller of the two as the bias controller 32 a corresponding third initial voltage value;

Calculate the difference between x1 and x2, which is the first half-wave voltage corresponding to the bias controller 30, and calculate the difference between y1 and y2, which is the third half-wave corresponding to the bias controller 32 Voltage;

Setting the value of the bias voltage output by the bias controller 30 as the determined first initial voltage, and setting the value of the bias voltage output by the bias controller 32 as the determined third initial voltage;

The controller 2 outputs the second control signal to the bias controller 31 of the dual parallel modulator 1, and the bias controller 31 outputs the bias voltage to the bias T101 for amplitude modulation, and the bias T101 performs the bias voltage with the data signal Superposition, converted into a bias voltage data signal, output to the dual parallel modulator 1 through port 111 (port111); it should be noted that, under the control of the second control signal, the bias voltage output by the bias controller 31 Increase by a large amount, for example, by 0.5V;

The detection circuit 4 detects the magnitude of the conversion of the optical signal output by the DPMZ1 into an electrical signal under the action of the bias voltage output by the bias controller 31 with a larger step value (for example, an interval of 0.5V);

The detection circuit 4 then scans and calculates the initial voltage and the half-wave voltage of the bias controller 31 with a smaller step value (for example, the interval is 0.05V). Under the action of the set voltage, the output optical signal is converted into the peak value of the electrical signal; when the peak values of two adjacent electrical signals are detected, the difference of the bias voltage corresponding to the first peak value and the second peak value is recorded as For the second half-wave voltage, the value of the bias voltage corresponding to the first peak value is recorded as the second initial voltage;

The first initial voltage and the first half-wave voltage of the bias controller 30, the second initial voltage and the second half-wave voltage of the bias controller 31, the third initial voltage and the third half-wave voltage of the bias controller 32 , which is the bias point of each bias controller, the controller 2 stores the various bias points, and in the optical transmission process, according to the needs of different transmission distances, modulates the DPMZ1.

Referring to FIG. 6 , it is a schematic flowchart of a first embodiment of a method for measuring a bias point of a dual parallel modulator provided by an embodiment of the present invention.

The method for measuring the bias point of the dual parallel modulator provided in this embodiment includes:

Step 100, control the amplitude value of the bias voltage acting on the dual parallel modulator to increase by the first step value; it should be noted that the step value is every voltage amplitude value, for example, the control acts on the dual parallel modulator The amplitude value of the bias voltage is incremented every 0.5V;

Step 101, converting the optical signal output by the dual parallel modulator under the action of the bias voltage into an electrical signal;

Step 102, detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage when the amplitude value of the electrical signal meeting the measurement bias point condition appears;

It should be noted that the measurement bias point conditions include:

When there are two peaks in the amplitude value of the electrical signal; or

When there is a peak value or a valley value in the amplitude value of the electrical signal.

Step 103, according to the corresponding relationship between the magnitude value of the electrical signal and the magnitude value of the bias voltage, scan the electric voltage satisfying the measurement bias point condition with a second step value (for example, every 0.05V). The magnitude value of the bias voltage corresponding to the magnitude value of the signal is used to calculate the bias point; the first step value is greater than the second step value.

Specifically, according to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage, the amplitude value of the bias voltage corresponding to the two peaks is scanned with a second step value, and the calculated The difference between the amplitude values of the bias voltage corresponding to the two peaks is recorded as the half-wave voltage, and the amplitude value of the bias voltage corresponding to the first peak value is recorded as the initial voltage; the half-wave voltage and the initial voltage are double the bias point of the parallel modulator; or

According to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage, scan the amplitude value of the bias voltage corresponding to the peak value and the valley value with a second step value, and calculate the peak value The difference between the amplitude value of the offset voltage corresponding to the valley value and the valley value is recorded as the half-wave voltage, and the amplitude value of the offset voltage corresponding to the first peak value is recorded as the initial voltage; the half-wave voltage and the initial voltage are double parallel Modulator bias point.

Implementing the method for measuring the bias point of the dual parallel modulator provided by the embodiment of the present invention does not need to use multiple frequencies for control, reduces the interference between multiple frequencies, and improves the efficiency of measuring the bias point.

Referring to FIG. 7 , it is a schematic flowchart of a second embodiment of a method for measuring a bias point of a dual parallel modulator provided by an embodiment of the present invention.

In this embodiment, the dual parallel modulator is composed of a first amplitude modulation modulator, a second amplitude modulation modulator, and a third phase modulation modulator, and the method for measuring the bias point of the dual parallel modulator includes:

Step 200, sending a first control signal to a first bias controller connected to the first AM modulator, controlling the amplitude value of the bias voltage output by the first bias controller to increase by a first step value;

Step 201, converting the optical signal output by the dual parallel modulator under the action of the bias voltage output by the first bias controller into an electrical signal;

Step 202, detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage output by the first bias controller when two peak values appear in the electrical signal;

Step 203, according to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage output by the first bias controller, scan the two peak values of the electrical signal with a second step value Corresponding to the amplitude value of the bias voltage, calculate the difference between the amplitude values of the bias voltage corresponding to the two peaks, which is recorded as the first half-wave voltage, and the amplitude value of the bias voltage corresponding to the first peak value is recorded as the first half-wave voltage An initial voltage; the first half-wave voltage and the first initial voltage are the first bias point of the dual parallel modulator, and the first step value is greater than the second step value;

Step 204, setting the bias voltage output by the first bias controller connected to the first AM modulator as the first initial voltage;

Step 205, sending a second control signal to a second bias controller connected to the second AM modulator, controlling the amplitude value of the bias voltage output by the second bias controller to increase by a first step value;

Step 206, converting the optical signal output by the dual parallel modulator under the action of the bias voltage output by the second bias controller into an electrical signal;

Step 207, detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage output by the second bias controller when the electrical signal has two peak values;

Step 208, according to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage output by the second bias controller, scan the two peak values of the electrical signal with a second step value The amplitude value of the corresponding bias voltage, calculate the difference between the amplitude values of the bias voltage corresponding to the two peaks, which is recorded as the second half-wave voltage, and the amplitude value of the bias voltage corresponding to the first peak value is recorded as the first Two initial voltages; the second half-wave voltage and the second initial voltage are the second bias point of the dual parallel modulator;

Step 209, setting the bias voltage output by the second bias controller connected to the second AM modulator as the second initial voltage;

Step 210, sending a third control signal to a third bias controller connected to the third AM modulator, controlling the amplitude value of the bias voltage output by the third bias controller to increase by a first step value;

Step 211, converting the optical signal output by the dual parallel modulator under the action of the bias voltage output by the third bias controller into an electrical signal;

Step 212, detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage output by the third bias controller when the electrical signal has a peak value and a valley value;

Step 213, according to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage output by the third bias controller, scan the peak value and valley value of the electrical signal with a second step value The amplitude value of the corresponding bias voltage, calculate the difference between the amplitude value of the bias voltage corresponding to the peak value and the valley value, and record it as the third half-wave voltage, and the amplitude value of the bias voltage corresponding to the peak value is recorded as A third initial voltage; the third half-wave voltage and the third initial voltage are the third bias point of the dual parallel modulator;

Step 214, storing the first bias point, the second bias point, and the third bias point, which are used for modulating the bias voltage acting on the dual parallel modulator according to different transmission requirements.

Implementing the measurement method of the bias point of the dual parallel modulator provided by the embodiment of the present invention does not need to use multiple frequencies to control, reduces the interference between multiple frequencies, simplifies the system structure, and only needs to use cheap and low-speed PD The electric signal is detected, and the initial voltage and the half-wave voltage of the bias controller of the dual parallel modulator are calculated, which reduces the cost and improves the efficiency of measuring the bias point.

Referring to FIG. 8 , it is a schematic flowchart of a third embodiment of a method for measuring a bias point of a dual parallel modulator provided by an embodiment of the present invention.

In this embodiment, the dual parallel modulator is composed of a first amplitude modulation modulator, a second amplitude modulation modulator, and a third phase modulation modulator, and the method for measuring the bias point of the dual parallel modulator includes:

Step 300, send a first control signal to the first bias controller connected to the first AM modulator and the third bias controller connected to the third PM modulator, and control the first bias controller and The amplitude value of the bias voltage output by the third bias controller is incremented by a first step value;

Step 301, converting the optical signal output by the dual parallel modulator into an electrical signal under the action of the bias voltage output by the first bias controller and the third bias controller;

Step 302, detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude values of the bias voltages output by the first bias controller and the third bias controller when two peak values appear in the electrical signal;

Step 303, record the coordinates (x1, y1) and (x2, y2) corresponding to the first peak and the second peak, where X represents the value of the bias voltage output by the first bias controller, and Y represents the value of the third bias control The value of the bias voltage output by the device;

Step 304, according to the corresponding relationship between the magnitude value of the electrical signal and the magnitude value of the bias voltage output by the first bias controller and the third bias controller, scan the The magnitude value of the bias voltage corresponding to the two peak values of the electrical signal, calculate the difference (x1-x2) of the magnitude value (x1-x2) of the first bias controller output bias voltage corresponding to the two peak values, denoted as the first Half-wave voltage, calculate the difference (y1-y2) of the magnitude value (y1-y2) of the output bias voltage of the third bias controller corresponding to the two peak values, and record it as the third half-wave voltage, the smaller one of x1 and x2 corresponds to The amplitude value of the bias voltage is recorded as the first initial voltage; the amplitude value of the bias voltage corresponding to the smaller of y1 and y2 is recorded as the third initial voltage; the first half-wave voltage and the first initial voltage are The first bias point of the dual parallel modulator, the third half-wave voltage and the third initial voltage are the third bias point of the dual parallel modulator, and the first step value is greater than the second step value;

Step 305, set the bias voltage output by the first bias controller connected to the first AM modulator as the first initial voltage; connect the third bias controller connected to the third PM modulator to The output bias voltage is set to the third initial voltage;

Step 306, sending a second control signal to a second bias controller connected to the second AM modulator, controlling the amplitude value of the bias voltage output by the second bias controller to increase by a first step value;

Step 307, converting the optical signal output by the dual parallel modulator under the action of the bias voltage output by the second bias controller into an electrical signal;

Step 308, detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage output by the second bias controller when the electrical signal has two peak values;

Step 309, according to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage output by the second bias controller, scanning the two peak values of the electrical signal with a second step value The amplitude value of the corresponding bias voltage, calculate the difference between the amplitude values of the bias voltage corresponding to the two peaks, which is recorded as the second half-wave voltage, and the amplitude value of the bias voltage corresponding to the first peak value is recorded as the first Two initial voltages; the second half-wave voltage and the second initial voltage are the second bias point of the dual parallel modulator, and the first step value is greater than the second step value;

Step 310, storing the first bias point, the second bias point, and the third bias point for controlling the bias voltage acting on the dual parallel modulator according to different transmission requirements.

Implementing the method and system for measuring the bias point of the dual parallel modulator provided by the embodiment of the present invention does not need to use multiple frequencies to control, reduces the interference between multiple frequencies, simplifies the system structure, and only needs to use cheap low-speed The PD detects the electrical signal, and calculates the initial voltage and the half-wave voltage of the bias controller of the dual parallel modulator, which reduces the cost and improves the efficiency of measuring the bias point.

Through the above description of the implementation manners, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary hardware platform, and of course can also be implemented entirely by hardware. Based on this understanding, all or part of the contribution made by the technical solution of the present invention to the background technology can be embodied in the form of software products, and the computer software products can be stored in storage media, such as ROM/RAM, magnetic disks, optical disks, etc. , including several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute the methods described in various embodiments or some parts of the embodiments of the present invention.

The above disclosure is only a preferred embodiment of the present invention, which certainly cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims (13)

1. A method for measuring a bias point of a dual parallel modulator, characterized in that it comprises: controlling the amplitude value of the bias voltage applied to the dual parallel modulator to increase by a first step value; converting the optical signal output by the dual parallel modulator under the action of the bias voltage into an electrical signal; Detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage when the amplitude value of the electrical signal meeting the measurement bias point condition appears; According to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage, scanning the offset voltage corresponding to the amplitude value of the electrical signal satisfying the measurement bias point condition with a second step value The amplitude value of , calculate the bias point; the first step value is greater than the second step value. 2. The method for measuring a bias point of a dual parallel modulator according to claim 1, wherein the conditions for measuring the bias point include: When there are two peaks in the amplitude value of the electrical signal; or When there is a peak value or a valley value in the amplitude value of the electrical signal. 3. The method for measuring the bias point of the dual parallel modulator according to claim 2, characterized in that, according to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage, the second The step value scans the amplitude value of the bias voltage corresponding to the amplitude value of the electrical signal satisfying the measurement bias point condition, and calculates the bias point of the dual parallel modulator, including: According to the corresponding relationship between the magnitude value of the electrical signal and the magnitude value of the bias voltage, scan the magnitude value of the bias voltage corresponding to the two peak values with a second step value, and calculate the two The difference between the amplitude values of the bias voltage corresponding to the peak value is recorded as the half-wave voltage, and the amplitude value of the bias voltage corresponding to the first peak value is recorded as the initial voltage; the half-wave voltage and the initial voltage are the dual parallel modulator the bias point of ; or According to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage, scan the amplitude value of the bias voltage corresponding to the peak value and the valley value with a second step value, and calculate the peak value The difference between the amplitude value of the offset voltage corresponding to the valley value and the valley value is recorded as the half-wave voltage, and the amplitude value of the offset voltage corresponding to the first peak value is recorded as the initial voltage; the half-wave voltage and the initial voltage are double parallel Modulator bias point. 4. The method for measuring the bias point of a dual-parallel modulator according to claim 3, wherein the dual-parallel modulator is composed of a first AM modulator, a second AM modulator, and a third PM modulator , the method also includes: Sending a first control signal to a first bias controller connected to the first AM modulator, controlling the amplitude value of the bias voltage output by the first bias controller to increase by a first step value; Converting the optical signal output by the dual parallel modulator under the action of the bias voltage output by the first bias controller into an electrical signal; Detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage output by the first bias controller when two peak values appear in the electrical signal; According to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage output by the first bias controller, scan the offset corresponding to the two peak values of the electrical signal with a second step value Calculate the amplitude value of the set voltage, calculate the difference between the amplitude values of the bias voltage corresponding to the two peaks, record it as the first half-wave voltage, and record the amplitude value of the bias voltage corresponding to the first peak value as the first initial voltage ; The first half-wave voltage and the first initial voltage are the first bias point of the dual parallel modulator, and the first step value is greater than the second step value. 5. The method for measuring the bias point of a dual-parallel modulator according to claim 4, wherein said dual-parallel modulator is composed of a first amplitude modulation modulator, a second amplitude modulation modulator, and a third phase modulation modulator , the method also includes: setting a bias voltage output by a first bias controller connected to the first AM modulator as the first initial voltage; Sending a second control signal to a second bias controller connected to the second AM modulator, controlling the amplitude value of the bias voltage output by the second bias controller to increase by a first step value; Converting the optical signal output by the dual parallel modulator under the action of the bias voltage output by the second bias controller into an electrical signal; Detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage output by the second bias controller when two peak values appear in the electrical signal; According to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage output by the second bias controller, scan the offset corresponding to the two peak values of the electrical signal with a second step value Calculate the amplitude value of the set voltage, calculate the difference between the amplitude values of the bias voltage corresponding to the two peaks, record it as the second half-wave voltage, and record the amplitude value of the bias voltage corresponding to the first peak value as the second initial voltage ; The second half-wave voltage and the second initial voltage are the second bias point of the dual parallel modulator, and the first step value is greater than the second step value. 6. The method for measuring the bias point of a dual parallel modulator according to claim 5, wherein the dual parallel modulator is composed of a first amplitude modulation modulator, a second amplitude modulation modulator, and a third phase modulation modulator , the method also includes: setting a bias voltage output by a second bias controller connected to the second AM modulator as the second initial voltage; Sending a third control signal to a third bias controller connected to the third AM modulator, controlling the amplitude value of the bias voltage output by the third bias controller to increase by a first step value; Converting the optical signal output by the dual parallel modulator under the action of the bias voltage output by the third bias controller into an electrical signal; Detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage output by the third bias controller when the electrical signal has a peak value and a valley value; According to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage output by the third bias controller, scanning the peak value and valley value of the electrical signal corresponding to the second step value For the amplitude value of the bias voltage, calculate the difference between the amplitude values of the bias voltage corresponding to the peak value and the valley value, which is recorded as the third half-wave voltage, and the amplitude value of the bias voltage corresponding to the peak value is recorded as the third initial voltage; the third half-wave voltage and the third initial voltage are the third bias point of the dual parallel modulator, and the first step value is greater than the second step value. 7. The method for measuring the bias point of a dual-parallel modulator according to claim 3, wherein the dual-parallel modulator is composed of a first amplitude modulation modulator, a second amplitude modulation modulator, and a third phase modulation modulator , the method also includes: Sending a first control signal to a first bias controller connected to the first AM modulator and a third bias controller connected to the third PM modulator to control the first bias controller and the third bias controller The amplitude value of the bias voltage output by the controller is incremented by the first step value; Converting the optical signal output by the dual parallel modulator under the action of the bias voltage output by the first bias controller and the third bias controller into an electrical signal; Detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage output by the first bias controller and the third bias controller when two peak values appear in the electrical signal; Record the coordinates (x1, y1) and (x2, y2) corresponding to the first peak value and the second peak value, where X represents the value of the bias voltage output by the first bias controller, and Y represents the value of the bias voltage output by the third bias controller the value of the bias voltage; According to the corresponding relationship between the amplitude value of the electrical signal and the amplitude values of the bias voltage output by the first bias controller and the third bias controller, scanning the electrical signal with a second step value For the amplitude values of the bias voltage corresponding to the two peaks, calculate the difference (x1-x2) between the amplitude values of the first bias controller output bias voltage corresponding to the two peaks, which is recorded as the first half-wave voltage , calculate the difference (y1-y2) of the magnitude of the output bias voltage of the third bias controller corresponding to the two peaks, which is recorded as the third half-wave voltage, and the bias corresponding to the smaller of x1 and x2 The amplitude value of the voltage is recorded as the first initial voltage; the amplitude value of the bias voltage corresponding to the smaller of y1 and y2 is recorded as the third initial voltage; the first half-wave voltage and the first initial voltage are double parallel modulation The first bias point of the modulator, the third half-wave voltage and the third initial voltage are the third bias point of the dual parallel modulator, and the first step value is greater than the second step value. 8. The method for measuring the bias point of a dual-parallel modulator according to claim 7, wherein the dual-parallel modulator is composed of a first amplitude modulation modulator, a second amplitude modulation modulator, and a third phase modulation modulator , the method also includes: Setting the bias voltage output by the first bias controller connected to the first AM modulator as the first initial voltage; setting the bias voltage output by the third bias controller connected to the third PM modulator The set voltage is set to the third initial voltage; Sending a second control signal to a second bias controller connected to the second AM modulator, controlling the amplitude value of the bias voltage output by the second bias controller to increase by a first step value; Converting the optical signal output by the dual parallel modulator under the action of the bias voltage output by the second bias controller into an electrical signal; Detecting the amplitude value of the electrical signal, and stopping incrementing the amplitude value of the bias voltage output by the second bias controller when two peak values appear in the electrical signal; According to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage output by the second bias controller, scan the offset corresponding to the two peak values of the electrical signal with a second step value Calculate the amplitude value of the set voltage, calculate the difference between the amplitude values of the bias voltage corresponding to the two peaks, record it as the second half-wave voltage, and record the amplitude value of the bias voltage corresponding to the first peak value as the second initial voltage ; The second half-wave voltage and the second initial voltage are the second bias point of the dual parallel modulator, and the first step value is greater than the second step value. 9. The method for measuring the bias point of the dual parallel modulator according to claim 6 or 8, characterized in that the method further comprises: The first bias point, the second bias point and the third bias point are stored for controlling the bias voltage acting on the dual parallel modulator according to different transmission requirements. 10. A measurement system for a bias point of a dual parallel modulator, characterized in that it comprises: a controller, configured to control the amplitude value of the bias voltage applied to the dual parallel modulator to increase by a first step value; a dual parallel modulator, configured to output an optical signal under the action of the bias voltage; A detection circuit for converting the optical signal output by the dual parallel modulator under the action of the bias voltage into an electrical signal; and detecting the amplitude value of the electrical signal; When the amplitude value of the electrical signal meeting the measurement bias point condition appears, the controller stops incrementing the amplitude value of the bias voltage; The detection circuit is further configured to scan the amplitude of the electrical signal satisfying the measurement bias point condition with a second step value according to the corresponding relationship between the amplitude value of the electrical signal and the amplitude value of the bias voltage The magnitude value of the bias voltage corresponding to the value is used to calculate the bias point; the first step value is greater than the second step value. 11. The system for measuring the bias point of a dual parallel modulator according to claim 10, wherein the dual parallel modulator comprises: A first AM modulator and a second AM modulator parallel to each other, and a third PM modulator connected to the first AM modulator. 12. The system for measuring the bias point of dual parallel modulators according to claim 11, characterized in that, the first AM modulator is also connected with a first bias controller, which is used to modulate to the first AM The device outputs a bias voltage, so that the dual parallel modulator outputs an optical signal under the action of the bias voltage; the second amplitude modulation modulator is also connected with a second bias controller for sending the second The amplitude modulation modulator outputs a bias voltage, so that the dual parallel modulator outputs an optical signal under the action of the bias voltage; the third phase modulation modulator is also connected with a third bias controller for sending The third AM modulator outputs a bias voltage, so that the dual parallel modulator outputs an optical signal under the action of the bias voltage. 13. The measurement system of the bias point of the dual parallel modulator according to claim 12, characterized in that the controller also stores the first bias point, the second bias point, and the third bias point, using According to different transmission requirements, the bias voltage acting on the dual parallel modulator is controlled.

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