WO2016116004A1

WO2016116004A1 - Method and device for controlling voltage of bias point of modulator

Info

Publication number: WO2016116004A1
Application number: PCT/CN2016/070902
Authority: WO
Inventors: 尚冬冬; 吉勇宁; 李蒙
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-01-23
Filing date: 2016-01-14
Publication date: 2016-07-28
Also published as: CN105871770B; CN105871770A

Abstract

Disclosed are a method and a device for controlling a voltage of a bias point of a modulator. The method comprises: acquiring a first voltage value of a preset bias point, and sending the first voltage value to a modulator; acquiring first average optical power of a first feedback optical signal of the modulator; repeating the following operations, until a voltage value meeting a preset condition is obtained: adjusting the first voltage value of the bias point to a second voltage value according to a predetermined step length, and sending the second voltage value to the modulator; acquiring second average optical power of a second feedback optical signal of the modulator; and if a difference between the second average optical power and the first average optical power is less than a preset threshold, using the second voltage value as the voltage value meeting the preset condition; and sending the voltage value meeting the preset condition to the modulator, to control a voltage of the bias point. By means of the present invention, at least the problem in related technologies that a control loop is complex due to the fact that a modulator needs multiple pilot signals is solved.

Description

Modulator bias point voltage control method and device

Technical field

The present invention relates to the field of communications, and in particular to a method and apparatus for controlling a modulator bias point voltage.

Background technique

Since the advent of optical fiber communication, it has been developing in the direction of ultra-high-speed systems and ultra-large-capacity wavelength division multiplexing systems. People are pursuing higher speeds, and the steps of larger capacity systems have not stopped. With the large-scale commercialization of the 100G polarization-multiplexed Quadrature Phase Shift Keying (PM-QPSK) system, the super 100G The system enters people's horizons. The optical phase modulation method represented by the 16QAM (Quadrature Amplitude Modulation) system has received more and more attention from the industry. The hexadecimal quadrature amplitude modulation method is a combination of amplitude modulation and phase modulation. Its spectrum utilization is 4bit/s·Hz, which is twice that of QPSK, which can double the overall system capacity and meet the future. The need for high speed communication.

In the new 16QAM modulation system, since the Euclidean distance of the constellation point (also called the vector endpoint) is relatively short, in order to ensure better system performance, the accuracy of the bias point of the modulator is particularly important. The 16QAM system modulator uses a lithium niobate modulator. The lithium niobate modulator has its transmission characteristics, or the bias point, changes with temperature and stress due to the characteristics of its own material. Therefore, the bias point of the lithium niobate modulator must be kept in real time by a certain method. ,stable.

At present, like the QPSK modulation system, the modulator bias point for the 16QAM modulation system is controlled by adding pilot signals of various frequencies to the modulated signal of the lithium niobate modulator, and then separating from the output modulated signals. The information of these pilot signals or their difference frequency signals is analyzed to control the stability of the bias point. Since multiple pilot signals are required, the control loop is complicated, and the pilot signal itself means that the stability of the bias point is limited.

In view of the problem that the modulator needs a plurality of pilot signals in the related art and the control loop is complicated, an effective solution has not been proposed yet.

Summary of the invention

Embodiments of the present invention provide a method and an apparatus for controlling a bias point voltage of a modulator to solve at least the problem that a modulator needs a plurality of pilot signals in the related art, so that the control loop is complicated.

According to an embodiment of the present invention, a method for controlling a modulator bias point voltage is provided, including:

Obtaining a first voltage value of a preset bias point, and transmitting the first voltage value to a modulator;

Obtaining a first average optical power of the first feedback optical signal of the modulator, where the first feedback optical signal corresponds to the first voltage value;

Repeating the following operations until a voltage value that satisfies a preset condition is obtained: the first voltage value of the bias point is adjusted to a second voltage value in a predetermined step size, and the second voltage value is sent to a modulator; acquiring a second average optical power of the second feedback optical signal of the modulator, the second feedback optical signal corresponding to the second voltage value; if the second average optical power is The difference between the first average optical power is less than a preset threshold, and the second voltage value is used as the voltage value that meets the preset condition;

The voltage value that satisfies the preset condition is sent to the modulator to control the voltage of the bias point.

Optionally, if the difference between the second average optical power and the first average optical power is not less than the preset threshold, adjusting the second voltage value to the third step by using the predetermined step size And a third voltage value is sent to the modulator to obtain a third average optical power of the third feedback optical signal of the modulator, the third feedback optical signal corresponding to the third voltage value.

Optionally, if the second voltage value is a voltage value obtained by increasing the first voltage value by the predetermined step, the third voltage value increases the second voltage value. a voltage value obtained after the predetermined step size; if the second voltage value is a voltage value obtained by decreasing the first voltage value by the predetermined step size, the third voltage value is The second voltage value decreases the voltage value obtained after the predetermined step size.

Optionally, the acquiring the first average optical power of the first feedback optical signal of the modulator includes:

Receiving an output optical signal from the modulator;

Dividing the output optical signal into a first output optical signal for the modulator output, and the first feedback optical signal;

Performing photoelectric conversion on the first feedback optical signal to obtain an electrical signal corresponding to the first feedback optical signal;

The first average optical power is obtained from the electrical signal.

Optionally, the method for controlling the voltage of the modulator bias point further includes:

The voltage value that satisfies the preset condition is stored.

According to another embodiment of the present invention, there is provided a control device for a modulator bias point voltage, comprising: a first acquisition module configured to acquire a first voltage value of a preset bias point, and to a voltage value is sent to the modulator;

a second acquiring module, configured to acquire a first average optical power of the first feedback optical signal of the modulator, where the first feedback optical signal corresponds to the first voltage value;

a processing module configured to repeatedly perform the following operations until a voltage value that satisfies a preset condition is obtained: the first voltage value of the bias point is adjusted to a second voltage value in a predetermined step size, and the Transmitting a voltage value to the modulator; acquiring a second average optical power of the second feedback optical signal of the modulator, the second feedback optical signal corresponding to the second voltage value; if the second average And the difference between the optical power and the first average optical power is less than a preset threshold, and the second voltage value is used as the voltage value that meets the preset condition;

And a control module configured to send the voltage value satisfying the preset condition to the modulator to control a voltage of the bias point.

Optionally, the processing module is further configured to: if the difference between the second average optical power and the first average optical power is not less than the preset threshold, The second voltage value is adjusted to a third voltage value, and the third voltage value is sent to the modulator to acquire a third average optical power of the third feedback optical signal of the modulator, the third feedback light The signal corresponds to the third voltage value.

Optionally, the second obtaining module includes:

a receiving unit configured to receive an output optical signal from the modulator;

An optical coupling unit configured to divide the output optical signal into a first output optical signal for the modulator output, and the first feedback optical signal;

The photoelectric conversion unit is configured to perform photoelectric conversion on the first feedback optical signal to obtain an electrical signal corresponding to the first feedback optical signal;

The optical power detecting unit is configured to obtain the first average optical power according to the electrical signal.

Optionally, the control device for the modulator bias point voltage further includes:

a storage unit configured to store the voltage value that satisfies a preset condition.

According to the embodiment of the present invention, the first voltage value of the preset bias point is obtained, and the first voltage value is sent to the modulator, and the first feedback light corresponding to the first voltage value of the modulator is acquired. After the first average optical power of the signal, the following operations are repeatedly performed until a voltage value that satisfies a preset condition is obtained: the first voltage value of the bias point is adjusted to a second voltage value in a predetermined step size, and Transmitting the second voltage value to the modulator; acquiring a second average optical power of the second feedback optical signal of the modulator, the second feedback optical signal corresponding to the second voltage value; The difference between the second average optical power and the first average optical power is less than a preset a threshold, the second voltage value is used as the voltage value satisfying the preset condition, and further, the voltage value satisfying the preset condition is sent to the modulator to control the voltage of the bias point The technical solution solves the problem that the modulator needs a plurality of pilot signals in the related art, which makes the control loop complicated, thereby achieving the effects of low cost, simple control loop and high stability.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a flow chart of a method of controlling a modulator bias point voltage according to an embodiment of the present invention;

2 is a block diagram showing the structure of a control device for a modulator bias point voltage according to an embodiment of the present invention;

3 is a block diagram showing the structure of a control device for another modulator bias point voltage according to an embodiment of the present invention;

4 is a schematic structural diagram of another apparatus for controlling a bias point voltage of a modulator according to an embodiment of the present invention;

5 is a schematic diagram showing the hardware structure of a control device for a modulator bias point voltage according to a preferred embodiment of the present invention;

6a is a schematic flow chart of a method for controlling a bias point voltage of a modulator according to an embodiment of the present invention;

6b is another flow diagram of a method of controlling a modulator bias point voltage in accordance with an implementation of the present invention.

detailed description

The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

In the embodiment, a method for controlling a modulator bias point voltage is provided. FIG. 1 is a flowchart of a method for controlling a modulator bias point voltage according to an embodiment of the present invention. As shown in FIG. 1, the process includes The following steps:

Step S102, acquiring a first voltage value of a preset bias point, and transmitting the first voltage value to the modulator;

Step S104, acquiring a first average optical power of the first feedback optical signal of the modulator, where the first feedback optical signal corresponds to the first voltage value;

Step S106, repeating the following operations until a voltage value that satisfies the preset condition is obtained: the first voltage value of the bias point is adjusted to the second voltage value in a predetermined step size, and the second voltage value is sent to the modulator; Acquisition modulation The second average optical power of the second feedback optical signal, the second feedback optical signal corresponds to the second voltage value; if the difference between the second average optical power and the first average optical power is less than a preset threshold, the second The voltage value is a voltage value that satisfies a preset condition;

Step S108, transmitting a voltage value satisfying the preset condition to the modulator to control the voltage of the bias point.

Through the above steps, by determining whether to adjust the magnitude of the voltage value input to the modulator according to the difference between the first average optical power and the first average optical power, it is necessary to add a plurality of frequencies to the modulated signal in relation to the related art. The frequency signal makes the control loop complicated, and the method that the modulator does not need to add any pilot signal does not only solve the problem that the modulator needs multiple pilot signals in the related art, and the control loop is complicated, and the cost is low. The control loop is simple and has a high stability effect, and the bias point voltage can also be controlled.

Optionally, if the difference between the second average optical power and the first average optical power is not less than a preset threshold, the second voltage value is adjusted to a third voltage value in a predetermined step size, and the third voltage value is sent To the modulator, a third average optical power of the third feedback optical signal of the modulator is obtained, and the third feedback optical signal corresponds to the third voltage value. That is, if the difference between the second average optical power and the first average optical power is not less than the preset threshold, the voltage value is continuously adjusted to quickly and efficiently determine the voltage of the optimal bias point.

Optionally, if the second voltage value is a voltage value obtained by increasing the first voltage value by a predetermined step, the third voltage value is a voltage value obtained by increasing the second voltage value by a predetermined step size; If the second voltage value is a voltage value obtained by decreasing the first voltage value by a predetermined step, the third voltage value is a voltage value obtained by decreasing the second voltage value by a predetermined step. That is, in the case where the difference between the second average optical power and the first average optical power is not less than the preset threshold, the voltage value can be adjusted in the same step size, thereby quickly and efficiently determining the voltage of the optimal bias point.

Optionally, acquiring the first average optical power of the first feedback optical signal of the modulator comprises: receiving an output optical signal from the modulator; dividing the output optical signal into a first output optical signal for the modulator output, and a first feedback optical signal; photoelectrically converting the first feedback optical signal to obtain an electrical signal corresponding to the first feedback optical signal; and obtaining a first average optical power according to the electrical signal. That is, the detection of the average optical power is realized by photoelectric conversion.

Optionally, the method for controlling the modulator bias point voltage of the embodiment of the present invention further includes: storing a voltage value that meets a preset condition. The voltage value is stored in the ROM and will be used directly after power-on.

According to the embodiment of the present invention, the first voltage value of the preset bias point is obtained, and the first voltage value is sent to the modulator to obtain the first of the first feedback optical signal of the modulator corresponding to the first voltage value. After the average optical power, the following operations are repeatedly performed until a voltage value that satisfies the preset condition is obtained: the first voltage value of the bias point is adjusted to the second voltage value in a predetermined step size, and the second voltage value is sent to the modulation Obtaining a second average optical power of the second feedback optical signal of the modulator, where the second feedback optical signal corresponds to the second voltage value; if the difference between the second average optical power and the first average optical power is less than a preset threshold, Then, the second voltage value is used as a voltage value that satisfies a preset condition, and further, a voltage solution that satisfies the preset condition is sent to the modulator to control the voltage of the bias point. In the related art, the modulator needs a plurality of pilot signals, which makes the control loop complicated, thereby achieving the effects of low cost, simple control loop and high stability.

In the embodiment, a control device for the bias point voltage of the modulator is also provided, and the device is configured to implement the above-mentioned embodiments and preferred embodiments, and the description thereof has been omitted. As used below, the term "module" may implement a combination of software and/or hardware of a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware, is also possible and contemplated.

2 is a structural block diagram of a control device for a modulator bias point voltage according to an embodiment of the present invention. As shown in FIG. 2, the device includes:

The first obtaining module 202 is configured to acquire a first voltage value of a preset bias point, and send the first voltage value to the modulator;

The second obtaining module 204 is configured to obtain a first average optical power of the first feedback optical signal of the modulator, where the first feedback optical signal corresponds to the first voltage value;

The processing module 206 is configured to repeatedly perform the following operations until a voltage value that satisfies the preset condition is obtained: the first voltage value of the bias point is adjusted to the second voltage value in a predetermined step size, and the second voltage value is sent to a modulator; obtaining a second average optical power of the second feedback optical signal of the modulator, the second feedback optical signal corresponding to the second voltage value; if the difference between the second average optical power and the first average optical power is less than a preset threshold And using the second voltage value as a voltage value that satisfies a preset condition;

The control module 208 is configured to send a voltage value that satisfies the preset condition to the modulator to control the voltage of the bias point.

Optionally, the processing module 206 is further configured to adjust the second voltage value to a third voltage value by a predetermined step if the difference between the second average optical power and the first average optical power is not less than a preset threshold. And transmitting a third voltage value to the modulator to obtain a third average optical power of the third feedback optical signal of the modulator, the third feedback optical signal corresponding to the third voltage value.

Optionally, if the second voltage value is a voltage value obtained by increasing the first voltage value by a predetermined step, the third voltage value is a voltage value obtained by increasing the second voltage value by a predetermined step size; If the second voltage value is a voltage value obtained by decreasing the first voltage value by a predetermined step, the third voltage value is a voltage value obtained by decreasing the second voltage value by a predetermined step.

Optionally, as shown in FIG. 3, the second obtaining module 204 includes:

The receiving unit 302 is configured to receive an output optical signal from the modulator;

The optical coupling unit 304 is configured to divide the output optical signal into a first output optical signal for the modulator output, And a first feedback optical signal;

The photoelectric conversion unit 306 is configured to perform photoelectric conversion on the first feedback optical signal to obtain an electrical signal corresponding to the first feedback optical signal;

The optical power detecting unit 308 is configured to obtain a first average optical power according to the electrical signal.

Optionally, FIG. 4 is a schematic structural diagram of another apparatus for controlling a bias point voltage of a modulator according to an embodiment of the present invention. As shown in FIG. 4, a device for controlling a bias point voltage of a modulator according to an embodiment of the present invention is further provided. include:

The storage unit 402 is configured to store a voltage value that satisfies a preset condition.

According to the embodiment of the present invention, the first voltage value of the preset bias point is obtained, and the first voltage value is sent to the modulator to obtain the first of the first feedback optical signal of the modulator corresponding to the first voltage value. After the average optical power, the following operations are repeatedly performed until a voltage value that satisfies the preset condition is obtained: the first voltage value of the bias point is adjusted to the second voltage value in a predetermined step size, and the second voltage value is sent to the modulation Obtaining a second average optical power of the second feedback optical signal of the modulator, where the second feedback optical signal corresponds to the second voltage value; if the difference between the second average optical power and the first average optical power is less than a preset threshold, Then, the second voltage value is used as a voltage value that satisfies a preset condition, and further, a voltage solution that satisfies a preset condition is sent to the modulator to control the voltage of the bias point, and the modulator needs to be solved in the related art. The pilot signals make the control loop complicated, and thus achieve the effects of low cost, simple control loop and high stability.

The technical problem to be solved by the embodiments of the present invention is to provide a control method and device for a bias point of a 16QAM system modulator that is low in cost, easy to implement, simple in control loop, and high in stability, so that the bias of the 16QAM system modulator is The set point is relatively stable and the control is simple, thereby improving the stability of the system.

The embodiment of the invention further provides a method for controlling a modulator bias point in a 16QAM modulation system, comprising the following steps:

Control the in-phase quadrature (In/phase/Quadrature, I/Q) offset to the correct position by detecting the minimum value of the photo diode (PD), and detect the PIN (PIN (positive-Intrinsic-negative) Type diode) minimum to control phase offset to the correct position.

Embodiments of the present invention provide a control device for a modulator bias point in a 16QAM modulation system, which may include the following components:

Photocoupler (coupler): 95/5, where the output light is 95% and the feedback light is 5%.

PIN tube: Bandwidth 10G, photoelectric conversion in the feedback loop.

Radio Frequency Power Detector (RFPD): Root Meam Square-Direct Current (RMS-DC) chip, the main function is Convert the rms value of the signal to a dc output.

Analog-to-Digital Converter (ADC): The analog quantity of the feedback optical path is converted into digital quantity.

Digital-to-Analog Converter (DAC): The digital quantity output by the digital algorithm unit is converted into an analog signal.

Micro Control Unit/digital signal processing (MCU/DSP) is set as the implementation of the feedback control algorithm.

Embodiments of the present invention provide a low-cost 16QAM modulator bias point control scheme based on digital processing, which has the following beneficial effects:

In the 16QAM modulator bias point control method of the embodiment of the present invention, the average power detection and digitization processing manner can achieve relatively stable bias point of the 16QAM modulator. Compared with other system control methods, the present invention does not require any additional pilot signals, has a simple and easy to implement structure, has the advantages of high precision, high reliability, high responsivity, and flexible and simple control loop, and achieves a bias of 16QAM modulator. Point control is more convenient and facilitates debugging.

The new 16QAM modulator system includes optocoupler, PIN tube, RF power detector, analog-to-digital converter, digital-to-analog converter and digital algorithm processing unit module to enable fast, stable and accurate implementation of 16QAM modulators. The locking of the bias point is not limited to the built-in PD bandwidth of the modulator, which is of great significance for the transmission of the ultra-100G dense wavelength division system.

In order to achieve the above control technical solution, an embodiment of the present invention provides a preferred embodiment as shown in FIG. 5. First, the optical signal emitted from the laser is divided into EV and EH through a polarization beam splitter (PBS). The EV and EH are respectively divided into I light by the first 3dB coupler and the second 3dB coupler. And Q light, wherein the I light of the EV is converted into IV light by a first interference type (Mach-Zehnder, abbreviated as MZ) modulator modulated by the first driver controlled by the DAC_V; the Q light of the EV is modulated by the first driver controlled by the DAC_V The second MZ modulator and the first 90 degree phase delay unit become QV light; the I light of EH passes through the third MZ modulator modulated by the second driver controlled by DAC_H to become IH light; the Q light of EH is controlled by DAC_H The second driver modulated fourth MZ modulator and the second 90 degree phase delay unit become QH light; secondly, IV light and QV light, IH light and QH light are respectively synthesized by a third 3dB coupler coupling and a fourth 3dB coupler After that, a beam of light is synthesized by the second polarization beam splitter PBC, and is divided into output light E ¹ OUT and feedback light through a 5:95 coupler; respectively, using two high-precision ADCs to separately detect the two built-in PDs. V-channel and H-channel light, digital signal processing chip (Digital Sig) Nal Processing (DSP for short), the DSP adjusts the bias point feedback control signal to be converted into an analog voltage signal by the DAC, respectively, to control the first MZ modulator, the second MZ modulator, the third MZ modulator and the fourth MZ modulator. Set the point so that the average power finally detected is minimized. Ultimately, the correct biasing of the IQ bias point of the 16QAM modulator can be achieved.

The output light is divided into output light and feedback light through a 5/95 coupler, 95% of which is used for the final 16QAM modulated output, and 5% of the output light is photoelectrically converted by the 10G PIN tube, and then the effective value of the signal is measured by RFPD. Converted to DC output, the high-precision ADC collects the power into the digital signal processing chip DSP, and the DSP adjusts the bias point feedback control signal to be converted into an analog voltage signal by the DAC to control the bias point of the 16QAM modulator, so that the average power is finally detected. The smallest, that is, the correct offset of the phase bias point of the 16QAM modulator can be achieved.

A digital algorithm flow chart for implementing bias point voltage control of a 16QAM modulator in a DSP according to an embodiment of the present invention is shown in FIG. 6a and FIG. 6b:

First, power on for the first time

1. Initialize the bias point of the 16QAM modulator: The DSP sends a midpoint value of the bias point (usually 3.5V), which is sent to the I and Q channels respectively through the DAC, and the output optical signal detected by the PD is collected by the ADC. The DSP reads the ADC data as the initial average optical power value.

2, according to the step size of 0.05V (according to the actual offset accuracy and modulation rate requirements can have different settings) increase / decrease the voltage value of the bias point, send again through the DSP, read the ADC value as new Average optical power value.

3. The DSP compares the new average optical power value with the initial average optical power value. If the new value is less than the initial value, the new average optical power value is taken as the initial average optical power value, and the voltage value of the bias point is continuously increased/decreased, and step 2 is repeated; if the new value is greater than the initial value, the initial average is maintained. The optical power value is unchanged, the voltage value of the bias point is decreased/increased, and the ADC value is read as a new average optical power value.

4. Repeat step 3 so that the new average optical power value minus the initial optical power value is less than a certain small amount (represented by the voltage value, generally considered to be less than 0.001V), then the bias point at this time is the optimal bias. point. Store the offset point in the ROM of the DSP and use it directly after power-on.

5. Repeat step 3 to follow the change in the bias point to ensure that the real-time bias point is in the proper position.

Second, power on again

1. Retrieve the value of the last saved offset point in the ROM of the DSP and send it.

2. Repeat steps 2 and 3 for the initial power-on and keep following the optimal bias point.

In the embodiment of the present invention, the relationship of the amplitude of the 16QAM signal: relative to the DAC output, the I/Q path has two voltage amplitudes respectively, such that the high voltages V _HI , V _HQ , the low voltages V _LI , V _LQ . In an ideal situation:

I/Q bias point automatic control: For I signal,

among them,

Representing the phase of the first layer and the second layer constellation point in the constellation diagram, respectively, V _π is the voltage required for the modulator phase change π.

Using the PD of the modulator to detect the optical power, the average optical power of the I channel is:

among them,

For the bias point phase,

The statistical results show that the probability of occurrence of each signal is the same, so it is reasonable to use the formula (2) to find the optical power.

Combined with formula (1), then

and so,

At the lowest point of the bias point, the average optical power has a minimum value; then, by feedback, the average output optical power is minimized to obtain the optimal bias point, that is, the lowest point of the bias point. Similarly, the Q way bias point is the same.

Therefore, the best IQ bias point is obtained when the PD detects the optical power to a minimum.

Phase control: By equation (1), the bias point for the ideal input signal is at the lowest point:

Wherein, when the I/Q signals are the same, take +, if not, take -, V _I denotes the voltage of I, V _bI denotes the bias voltage of I, V _Q denotes the voltage of Q, and V _bQ denotes Q Bias voltage,

Indicates the phase difference between I and Q.

For the output V, H two 16QAM debug signals, so the detected RF signal effective power is proportional to:

among them,

with

The phase operating points of the V and H polarization states, respectively.

Therefore, if the modulator output optical signal is detected with a PIN tube, an amplitude and

In proportion, the rate is a non-return to zero (NRZ) signal of the modulation signal rate. The power of a certain bandwidth of the signal is detected, and by changing the position of the phase offset point to minimize it, the phase bias point can be controlled.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

As described above, the method and apparatus for controlling the bias point voltage of a modulator provided by the embodiments of the present invention have the following beneficial effects: solving the problem that the modulator needs multiple pilot signals in the related art, and the control loop is complicated. In turn, the effect of low cost, simple control loop and high stability is achieved.

Claims

A method for controlling a bias point voltage of a modulator, comprising:

Obtaining a first voltage value of a preset bias point, and transmitting the first voltage value to a modulator;

Obtaining a first average optical power of the first feedback optical signal of the modulator, where the first feedback optical signal corresponds to the first voltage value;

Repeating the following operations until a voltage value that satisfies a preset condition is obtained: the first voltage value of the bias point is adjusted to a second voltage value in a predetermined step size, and the second voltage value is sent to a modulator; acquiring a second average optical power of the second feedback optical signal of the modulator, the second feedback optical signal corresponding to the second voltage value; if the second average optical power is The difference between the first average optical power is less than a preset threshold, and the second voltage value is used as the voltage value that meets the preset condition;

The voltage value that satisfies the preset condition is sent to the modulator to control the voltage of the bias point.
The method according to claim 1, wherein if the difference between the second average optical power and the first average optical power is not less than the preset threshold, the first step is The second voltage value is adjusted to a third voltage value, and the third voltage value is sent to the modulator to obtain a third average optical power of the third feedback optical signal of the modulator, the third feedback optical signal Corresponding to the third voltage value.
The method according to claim 2, wherein said third voltage value is a value if said second voltage value is a voltage value obtained by increasing said first voltage value by said predetermined step size a voltage value obtained by increasing the second voltage value by the predetermined step size; if the second voltage value is a voltage value obtained by decreasing the first voltage value by the predetermined step size, The third voltage value is a voltage value obtained by decreasing the second voltage value by the predetermined step size.
The method of claim 1, wherein the obtaining the first average optical power of the first feedback optical signal of the modulator comprises:

Receiving an output optical signal from the modulator;

Dividing the output optical signal into a first output optical signal for the modulator output, and the first feedback optical signal;

Performing photoelectric conversion on the first feedback optical signal to obtain an electrical signal corresponding to the first feedback optical signal;

The first average optical power is obtained from the electrical signal.
The method according to any one of claims 1 to 4, further comprising:

The voltage value that satisfies the preset condition is stored.
A control device for a bias point voltage of a modulator, comprising:

a first obtaining module, configured to acquire a first voltage value of a preset bias point, and send the first voltage value to a modulator;

a second acquiring module, configured to acquire a first average optical power of the first feedback optical signal of the modulator, where the first feedback optical signal corresponds to the first voltage value;

a processing module configured to repeatedly perform the following operations until a voltage value that satisfies a preset condition is obtained: the first voltage value of the bias point is adjusted to a second voltage value in a predetermined step size, and the Transmitting a voltage value to the modulator; acquiring a second average optical power of the second feedback optical signal of the modulator, the second feedback optical signal corresponding to the second voltage value; if the second average And the difference between the optical power and the first average optical power is less than a preset threshold, and the second voltage value is used as the voltage value that meets the preset condition;

And a control module configured to send the voltage value satisfying the preset condition to the modulator to control a voltage of the bias point.
The device according to claim 6, wherein the processing module is further configured to: if the difference between the second average optical power and the first average optical power is not less than the preset threshold, Determining the second voltage value to a third voltage value and transmitting the third voltage value to the modulator to obtain a third average optical power of the third feedback optical signal of the modulator The third feedback optical signal corresponds to the third voltage value.
The apparatus according to claim 7, wherein if said second voltage value is a voltage value obtained by increasing said first voltage value by said predetermined step size, said third voltage value is a voltage value obtained by increasing the second voltage value by the predetermined step size; if the second voltage value is a voltage value obtained by decreasing the first voltage value by the predetermined step size, The third voltage value is a voltage value obtained by decreasing the second voltage value by the predetermined step size.
The apparatus of claim 6, wherein the second acquisition module comprises:

a receiving unit configured to receive an output optical signal from the modulator;

An optical coupling unit configured to divide the output optical signal into a first output optical signal for the modulator output, and the first feedback optical signal;

The photoelectric conversion unit is configured to perform photoelectric conversion on the first feedback optical signal to obtain an electrical signal corresponding to the first feedback optical signal;

The optical power detecting unit is configured to obtain the first average optical power according to the electrical signal.
The apparatus according to any one of claims 6 to 9, further comprising:

a storage unit configured to store the voltage value that satisfies a preset condition.