IQ modulator bias automatic control method and device

Abstract

This specification provides an automatic bias control method and apparatus for an IQ modulator, wherein the automatic bias control method includes: modulating a modulated electrical baseband signal I and a modulated electrical baseband signal Q onto an optical carrier using an IQ modulator to obtain a modulated optical signal; passing the modulated optical signal through an optical fiber beam splitter to determine an input optical signal; converting the input optical signal into an electrical signal, and processing the electrical signal to obtain a digital signal; performing digital signal processing on the digital signal using a processor to obtain a bias control signal, and performing bias control based on the bias control signal. By passing the modulated optical signal through an optical fiber beam splitter to determine the input optical signal; converting the input optical signal into an electrical signal; and processing the electrical signal to obtain a digital signal; and by performing digital signal processing on the digital signal using a processor to obtain the bias control signal, bias control is performed based on the bias control signal, thereby improving control accuracy.

Description

Technical Field

[0001] The embodiments of the present specification relate to the field of signal modulation technology, and in particular to an automatic bias control method for an IQ modulator. Background Art

[0002] Modulation is the method of inserting the original signal into the carrier signal. Modulation methods are divided into: digital signal modulation, analog signal modulation and pulse modulation. The original signal of digital signal modulation is a digital signal, and the original signal of analog signal modulation and pulse modulation is an analog signal. The constellation diagram is a concept under digital signal modulation and quadrature amplitude modulation (QAM).

[0003] Since the frequency band occupied by the actual signal to be transmitted (baseband signal) usually starts at low frequency, and the actual communication channel is often bandpass, in order to communicate in this case, it is necessary to modulate the signal containing information to achieve the shift of the baseband signal spectrum to suit the transmission of the actual channel. That is, use the baseband signal to control certain parameters of the carrier signal so that these parameters of the carrier change with the change of the baseband signal. Because of the special advantages of the sinusoidal signal (such as: simple form, easy to generate and receive, etc.), in most digital communication systems, we use sinusoidal signals as carriers. Obviously, we can use the amplitude, frequency, and phase of the sinusoidal signal to carry the original digital baseband signal, which are called amplitude modulation, frequency modulation, and phase modulation. Of course, we can also use a combination of two of these methods to realize the transmission of digital signals, such as amplitude modulation-phase modulation, so as to achieve some better characteristics. IQ modulation is that the data is divided into two channels, and the carrier modulation is performed separately, and the two carriers are orthogonal to each other. I: in-phase, q: quadrature.

[0004] The current IQ modulation control method has poor control accuracy, and therefore, a better solution is urgently needed. Summary of the invention

[0005] In view of this, the embodiments of this specification provide an IQ modulator bias automatic control method. One or more embodiments of this specification also relate to an IQ modulator bias automatic control device, a computing device, a computer readable storage medium and a computer program to solve the technical defects existing in the prior art.

[0006] According to a first aspect of an embodiment of this specification, there is provided an IQ modulator bias automatic control method, comprising:

[0007] The modulated electrical baseband signal I and the modulated electrical baseband signal Q are modulated onto an optical carrier through an IQ modulator to obtain a modulated optical signal;

[0008] Passing the modulated optical signal through the optical fiber splitter to determine the input optical signal;

[0009] Convert the input optical signal into an electrical signal, and obtain a digital signal by signal processing the electrical signal;

[0010] The digital signal is processed by the processor to obtain a bias control signal, and bias control is performed based on the bias control signal.

[0011] In a possible implementation, the fiber beam splitter is 1:99 or 10:90.

[0012] In a possible implementation, converting an input optical signal into an electrical signal includes:

[0013] Convert the input optical signal into a current signal through photoelectric detection;

[0014] determining a voltage signal based on the current signal and the current-to-voltage amplifier;

[0015] An electrical signal is determined based on the voltage signal and a low noise amplifier.

[0016] In a possible implementation, the electrical signal includes a modulated signal and a pilot signal;

[0017] The amplitude of the pilot signal is smaller than the modulating signal.

[0018] In a possible implementation, the electrical signal is processed to obtain a digital signal, including:

[0019] The electrical signal is filtered through a plurality of narrow bandpass filters to obtain a filtered signal;

[0020] The filtered signal is processed based on the ADC module, the long correlator group, the DDS group and the control group to obtain a digital signal.

[0021] In a possible implementation, the filtered signal is processed based on the ADC module, the long correlator group, the DDS group and the control group to obtain a digital signal, including:

[0022] Processing the filtered signal based on the ADC module to determine the initial digital signal;

[0023] Performing long correlation processing on the initial digital signal through the long correlator group and the DDS group to determine the long correlation signal;

[0024] The long correlation signal is processed by the DDS group and the control group to determine the digital signal.

[0025] In a possible implementation, the amplitude of the pilot signal output by the DDS group is 20mV~200mV;

[0026] The amplitude of the modulated electrical baseband signal output by the IQ modulator is 10V~14V.

[0027] According to a second aspect of an embodiment of this specification, there is provided an IQ modulator bias automatic control device, comprising:

[0028] The optical carrier modulation module is configured to modulate the modulated electrical baseband signal I and the modulated electrical baseband signal Q onto the optical carrier through an IQ modulator to obtain a modulated optical signal;

[0029] The optical signal module is configured to pass the modulated optical signal through the optical fiber splitter to determine the input optical signal;

[0030] A signal processing module is configured to convert the input optical signal into an electrical signal, and obtain a digital signal by signal processing the electrical signal;

[0031] The bias control module is configured to perform digital signal processing on the digital signal through a processor to obtain a bias control signal, and perform bias control based on the bias control signal.

[0032] According to a third aspect of an embodiment of this specification, a computing device is provided, including:

[0033] Memory and processor;

[0034] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the above-mentioned IQ modulator bias automatic control method are implemented.

[0035] According to a fourth aspect of the embodiments of this specification, a computer-readable storage medium is provided, which stores computer-executable instructions, and when the instructions are executed by a processor, the steps of the above-mentioned IQ modulator bias automatic control method are implemented.

[0036] According to a fifth aspect of the embodiments of this specification, a computer program is provided, wherein when the computer program is executed in a computer, the computer is caused to execute the steps of the above-mentioned IQ modulator bias automatic control method.

[0037] The embodiments of this specification provide an automatic bias control method and device for an IQ modulator, wherein the automatic bias control method for an IQ modulator includes: modulating a modulated electrical baseband signal I and a modulated electrical baseband signal Q onto an optical carrier through an IQ modulator to obtain a modulated optical signal; passing the modulated optical signal through an optical fiber splitter to determine an input optical signal; converting the input optical signal into an electrical signal, and subjecting the electrical signal to signal processing to obtain a digital signal. Performing digital signal processing on the digital signal through a processor to obtain a bias control signal, and performing bias control based on the bias control signal. The modulated optical signal is passed through an optical fiber splitter to determine the input optical signal; converting the input optical signal into an electrical signal, and subjecting the electrical signal to signal processing to obtain a digital signal. Performing digital signal processing on the digital signal through a processor to obtain a bias control signal, and performing bias control based on the bias control signal, thereby improving control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a flow chart of an IQ modulator bias automatic control method provided by one embodiment of this specification;

[0039] Figure 2 is a framework diagram of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0040] Figure 3 This is a first signal processing schematic diagram of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0041] Figure 4 is a second signal processing schematic diagram of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0042] Figure 5 It is a third signal processing schematic diagram of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0043] Figure 6 It is a first ideal bias voltage schematic diagram of an IQ modulator bias voltage automatic control method provided by an embodiment of this specification;

[0044] Figure 7 is a schematic diagram of a second ideal bias voltage of an IQ modulator bias voltage automatic control method provided by an embodiment of this specification;

[0045] Figure 8 It is a first biased schematic diagram of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0046] Fig. 9 It is a second biased schematic diagram of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0047] Fig.10 is a schematic diagram of a first bias error of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0048] Fig.11 is a schematic diagram of a second bias error of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0049] Fig.12 It is a first automatic bias control schematic diagram of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0050] Fig.13 It is a second automatic bias control schematic diagram of an IQ modulator bias automatic control method provided by an embodiment of this specification;

[0051] Fig.14 It is a structural schematic diagram of an IQ modulator bias automatic control device provided by an embodiment of this specification;

[0052] Fig.15 It is a structural block diagram of a computing device provided by an embodiment of this specification. DETAILED DESCRIPTION

[0053] Many specific details are described in the following description to facilitate a full understanding of this specification. However, this specification can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of this specification, so this specification is not limited to the specific implementation disclosed below.

[0054] The terms used in one or more embodiments of this specification are only for the purpose of describing specific embodiments, and are not intended to limit one or more embodiments of this specification. The singular forms of "a" and "the" used in one or more embodiments of this specification and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items.

[0055] It should be understood that although the terms first, second, etc. may be used to describe various information in one or more embodiments of this specification, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of this specification, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0056] In this specification, an IQ modulator bias automatic control method is provided. This specification also relates to an IQ modulator bias automatic control device, a computing device, and a computer-readable storage medium, which are described in detail one by one in the following embodiments.

[0057] See also Figure 1 , Figure 1 A flow chart of an IQ modulator bias automatic control method provided according to an embodiment of the present specification is shown, which specifically includes the following steps.

[0058] Step 101: modulate the modulated electrical baseband signal I and the modulated electrical baseband signal Q onto an optical carrier through an IQ modulator to obtain a modulated optical signal.

[0059] In practical applications, see Figure 2 ,IQ modulator bias automatic control mainly includes photoelectric detection module, narrow bandpass filter group, ADC (analog-to-digital converter) module, long correlator group, DDS group, control group and DAC (digital-to-analog converter) module. The IQ modulator modulates the modulated electrical baseband signal I and the modulated electrical baseband signal Q onto the optical carrier to obtain a modulated optical signal.

[0060] Step 102: The modulated optical signal passes through an optical fiber splitter to determine an input optical signal.

[0061] In practical applications, the modulated optical signal passes through a fiber optic beam splitter and is split into two, one of which is the output modulated optical signal and the other is the input optical signal for automatic bias control of the IQ modulator.

[0062] In a possible implementation, the fiber beam splitter is 1:99 or 10:90.

[0063] In practical applications, the optical fiber splitter can use a 1:99 or 10:90 beam splitter to split the modulated optical signal, of which 1% or 10% of the optical signal is used as the input optical signal for the automatic bias control of the IQ modulator to extract the bias control errors of the I, Q and P channels of the IQ modulator.

[0064] Step 103: convert the input optical signal into an electrical signal, and process the electrical signal to obtain a digital signal.

[0065] In practical applications, after photoelectric detection, the input optical signal is converted into an electrical signal, then filtered through 6 narrow bandpass filters, and then sampled by 6 ADCs and converted into a digital signal.

[0066] In a possible implementation, converting the input optical signal into an electrical signal includes: converting the input optical signal into a current signal through photoelectric detection; determining a voltage signal based on the current signal and a current-voltage amplifier; and determining an electrical signal based on the voltage signal and a low-noise amplifier.

[0067] In practical applications, photodetection uses a photodiode to detect light signals, converts them into current, and then converts the weak current into voltage through an IV (current-voltage) amplifier and amplifies it through a low-noise amplifier. The amplification gain is controlled by a digital signal processing module.

[0068] In a possible implementation, the electrical signal includes a modulation signal and a pilot signal; the amplitude of the pilot signal is smaller than that of the modulation signal.

[0069] In practical applications, the photoelectric detection output signal contains the modulation signal and the pilot. In order not to affect the quality of the output modulated optical signal, the pilot amplitude is designed to be much smaller than the modulation signal (40-50dB weaker), resulting in the pilot in the photoelectric detection output signal being submerged in the modulation signal.

[0070] In one possible implementation, the electrical signal is processed to obtain a digital signal, including: filtering the electrical signal through multiple narrow bandpass filters to obtain a filtered signal; processing the filtered signal based on an ADC module, a long correlator group, a DDS group and a control group to obtain a digital signal.

[0071] In practical applications, since the modulated signal is a broadband signal and the pilot is a narrowband signal (single tone signal), in order to accurately extract the pilot signal, a narrowband filter group is designed. After filtering, the signal-to-interference ratio of the pilot signal can be significantly improved. The center frequencies of the six narrowband filter groups are designed as fq-fp, fq+fp, fi-fp, fi+fp, fi-fq, and fi+fq, respectively. Among them, fi is the frequency of the I-path pilot signal, fq is the frequency of the Q-path pilot signal, and fp is the frequency of the P-path pilot signal.

[0072] In a possible implementation, a filtered signal is processed based on an ADC module, a long correlator group, a DDS group, and a control group to obtain a digital signal, including: processing the filtered signal based on the ADC module to determine an initial digital signal; performing long correlation processing on the initial digital signal through a long correlator group and a DDS group to determine a long correlation signal; processing the long correlation signal through a DDS group and a control group to determine a digital signal.

[0073] In practical applications, see Figure 3 The digital signal processing module includes a DDS (Direct Digital Synthesis) group, a long correlator group, and a control group. The DDS group contains 9 DDSs, which generate single tone signals with frequencies of fi, fq, fp, fq-fp, fq+fp, fi-fp, fi+fp, fi-fq, and fi+fq, respectively, denoted as

[0074]

[0075] in, is the initial phase, which can be set to 0, and t is the time variable.

[0076] , and There are three pilot signals, namely I pilot, Q pilot and P pilot. are 6 local correlation signals, used for long correlation processing with the 6 signals sampled by ADC. Figure 2 As shown. The 6-channel ADC sampling signal is recorded as , then the integral output result is:

[0077]

[0078] Where T is the integration time. In order to obtain better integration performance, the integration time T is designed to be much longer than the period of the local correlation signal, so it is called long correlation. The control of the integration time is completed by NCO (numerically controlled oscillator). According to the designed time T, NCO generates an integration clear pulse to control the integration start and end time of the integrator. When the integration clear pulse is valid, it outputs the current integration result and the integration valid pulse, and clears the integrator at the same time to start the next round of integration.

[0079] Furthermore, the control group includes three bias controllers, namely, an I bias controller, a Q bias controller and a P bias controller. The bias controller mainly controls the three biases of the IQ modulator and has working modes such as bias scanning, manual bias control and automatic bias control. The three bias controllers are independent of each other and are implemented in exactly the same way.

[0080] In a possible implementation, the amplitude of the pilot signal output by the DDS group is 20mV~200mV; the amplitude of the modulated electrical baseband signal output by the IQ modulator is 10V~14V.

[0081] Specifically, the I-way bias controller implementation block diagram is as follows: Figure 4 As shown. The pilot signal generated by DDS is designed to have an output signal amplitude that can be set between 20mV and 200mV after amplitude gain control. The amplitude of the electrical baseband signal input by the IQ modulator is 1.6 to 2 times the half-wave voltage, about 10V to 14V. Therefore, the amplitude of the signal after gain control is very small compared to the electrical baseband signal, and does not affect the quality of the modulated optical signal. The signal after gain control is recorded as a micro-disturbance signal.

[0082] See also Figure 4 After the output results of the two long correlators are added, the bias control error is obtained through the PID (Proportion Integration Differentiation) controller, and then added to the preset bias value and the scanned bias value to obtain the bias voltage. After the micro-disturbance signal and the bias voltage are added, the bias voltage + disturbance information is output to the IQ modulator.

[0083] See also Figure 5 ,The amplitude of the micro-disturbance signal is designed to be settable. Different amplitudes will lead to inconsistent effective information power of ADC sampling. In order to achieve near-full amplitude sampling of ADC (improve system performance), the signal processing module uses AGC (Automatic Gain Control) technology according to the output signal amplitude of the long correlator to output gain control information and control the amplification factor of the photoelectric detection module.

[0084] Step 104: performing digital signal processing on the digital signal by a processor to obtain a bias control signal, and performing bias control based on the bias control signal.

[0085] In practical applications, the digital signal completes a series of digital signal processing in a processor (such as FPGA, ARM, DSP, etc.), and outputs three bias voltages and pilot to the I, Q and P bias control ports of the IQ modulator.

[0086] It should be noted that in order to quickly realize the fast operation of the IQ modulator, three working modes are designed, namely scanning mode, fixed bias mode and automatic bias mode. After the system is turned on, it first enters the scanning mode, superimposes the scanning voltage on the I, Q and P channels respectively, records the value of the PID controller input signal changing with the scanning voltage, and calculates the scanning voltage corresponding to the PID controller input signal when it is near 0, which is recorded as the tracking initial voltage. Then enter the fixed bias mode, set the bias of the I, Q and P channels to the tracking initial voltage obtained by scanning. Finally, enter the automatic tracking mode, adjust the bias voltage according to the PID control error, and achieve fast and precise control.

[0087] The embodiments of this specification provide an automatic bias control method and device for an IQ modulator, wherein the automatic bias control method for an IQ modulator includes: modulating a modulated electrical baseband signal I and a modulated electrical baseband signal Q onto an optical carrier through an IQ modulator to obtain a modulated optical signal; passing the modulated optical signal through an optical fiber splitter to determine an input optical signal; converting the input optical signal into an electrical signal, and subjecting the electrical signal to signal processing to obtain a digital signal. Performing digital signal processing on the digital signal through a processor to obtain a bias control signal, and performing bias control based on the bias control signal. The modulated optical signal is passed through an optical fiber splitter to determine the input optical signal; converting the input optical signal into an electrical signal, and subjecting the electrical signal to signal processing to obtain a digital signal. Performing digital signal processing on the digital signal through a processor to obtain a bias control signal, and performing bias control based on the bias control signal, thereby improving control accuracy.

[0088] Further, the key design of the embodiment of this specification is discussed through simulation analysis, wherein the simulation conditions are: the symbol rate is 1 Gbps, the modulation signal amplitude is 10 V, the I-way half-wave voltage is 7.5 V, the Q-way half-wave voltage is 7 V, and the P-way half-wave voltage is 9 V. The I-way pilot signal frequency is 9 KHz, the Q-way pilot signal frequency is 6 KHz, the P-way pilot signal frequency is 1 KHz, the pilot signal amplitude is 100 mV, the bandpass filter width is 1 KHz, the integration time is 0.01 seconds, and the signal-to-noise ratio is 20 dB.

[0089] See Figure 6 and Figure 7 , respectively, the spectrum of the sum of the 6 ADC collected signals after bandpass filtering when the ideal bias voltage is applied (I and Q channels work at the MIN point, and P channel works at the Q point), when the data is demodulated, and when the data is modulated. It can be seen from the figure that at the ideal bias voltage, the power of the 6 single-tone signals with frequencies of fq-fp, fq+fp, fi-fp, fi+fp, fi-fq, and fi+fq is very small. After passing through the long correlator, the error does not exceed 0.4 when the data is demodulated; the error does not exceed 10 when the data is modulated. It can be seen that for the pilot-based scheme, the extracted bias control error is basically 0 at the ideal bias voltage, which is in line with expectations.

[0090] Refer to Figures 8 and 9, which respectively show the spectrum of the sum of the signals collected by the six ADCs after bandpass filtering when there is bias (setting the I channel offset to -3V, the Q channel offset to 2V, and the P channel offset to -1V), when the data is demodulated and when the data is modulated. It can be seen from the figure that when there is bias, six single-tone signals with frequencies of fq-fp, fq+fp, fi-fp, fi+fp, fi-fq, and fi+fq appear, and the greater the bias offset, the stronger the signal power. After passing through the long correlator, when the data is demodulated, the control errors of the I channel, Q channel, and P channel are -384, 160, and 697, respectively; when the data is modulated, the control errors of the I channel, Q channel, and P channel are -87, 27, and 140, respectively. It can be seen that the pilot-based scheme, whether data is modulated or demodulated, can effectively extract the bias control error and reflect the direction of the bias control (it can reflect the positive and negative bias).

[0091] Referring to Figures 10 and 11, the bias control error is extracted by the present invention when the bias voltage exists when the data is de-tuned and the data is modulated, respectively. It can be seen from the figure that the bias integral control error can be effectively extracted by the present invention when the bias voltage error exists. After the bias integral control error passes through the PID controller, the bias voltage is adjusted to converge to the correct working point bias. Referring to Figures 12 and 13, the automatic bias control convergence curves when the data is de-tuned and the data is modulated are respectively given, wherein the initial bias voltage errors of the I and Q paths are preset to be 2V, and the initial bias voltage error of the P path is -2V. It can be seen from the figure that the scheme of the present invention can effectively converge in the I path, Q path and P path, and the control accuracy after convergence is extremely high (after the data is de-tuned, the control accuracy is about 0.1°; when the data is modulated, the control accuracy is about 0.2°).

[0092] The embodiments of this specification use narrowband filtering and long correlation processing methods to improve the bias control performance. As can be seen from Figures 11 and 12, after the bias control automatic tracking converges, the bias control jitter is very small and the performance is good. And the P-path tracking performance does not decrease. Compared with the method of using 2 pilots, the present invention uses a 3-pilot method, the P-path tracking performance will not decrease, and the bias control errors of the I-path, Q-path and P-path can be effectively extracted.

[0093] Furthermore, the embodiments of this specification can reflect the bias control direction. Compared with the FFT method, the present invention adopts a related method to extract the direction of bias control. The FFT method performs FFT operation on the signal to find the modulus, detects the ratio of the first-order power to the second-order power, and can extract the bias error, but it is impossible to know whether it is a positive error or a negative error.

[0094] Corresponding to the above method embodiment, this specification also provides an IQ modulator bias automatic control device embodiment, Fig.14 FIG. 2 shows a schematic diagram of the structure of an IQ modulator bias automatic control device provided by an embodiment of the present specification. Fig.14 As shown, the device comprises:

[0095] The optical carrier modulation module 1401 is configured to modulate the modulated electrical baseband signal I and the modulated electrical baseband signal Q onto an optical carrier through an IQ modulator to obtain a modulated optical signal;

[0096] The optical signal module 1402 is configured to pass the modulated optical signal through the optical fiber splitter to determine the input optical signal;

[0097] The signal processing module 1403 is configured to convert the input optical signal into an electrical signal, and obtain a digital signal by signal processing on the electrical signal.

[0098] The bias control module 1404 is configured to perform digital signal processing on the digital signal through a processor to obtain a bias control signal, and perform bias control based on the bias control signal.

[0099] In a possible implementation, the optical signal module 1402 is further configured as follows:

[0100] The fiber beam splitter is 1:99 or 10:90.

[0101] In a possible implementation, the signal processing module 1403 is further configured to:

[0102] Convert the input optical signal into a current signal through photoelectric detection;

[0103] determining a voltage signal based on the current signal and the current-to-voltage amplifier;

[0104] An electrical signal is determined based on the voltage signal and a low noise amplifier.

[0105] In a possible implementation, the signal processing module 1403 is further configured to:

[0106] The electrical signal includes a modulated signal and a pilot signal;

[0107] The amplitude of the pilot signal is smaller than the modulating signal.

[0108] In a possible implementation, the signal processing module 1403 is further configured to:

[0109] The electrical signal is filtered through a plurality of narrow bandpass filters to obtain a filtered signal;

[0110] The filtered signal is processed based on the ADC module, the long correlator group, the DDS group and the control group to obtain a digital signal.

[0111] In a possible implementation, the signal processing module 1403 is further configured to:

[0112] Processing the filtered signal based on the ADC module to determine the initial digital signal;

[0113] Performing long correlation processing on the initial digital signal through the long correlator group and the DDS group to determine the long correlation signal;

[0114] The long correlation signal is processed by the DDS group and the control group to determine the digital signal.

[0115] In a possible implementation, the signal processing module 1403 is further configured to:

[0116] The amplitude of the pilot signal output by the DDS group is 20mV~200mV;

[0117] The amplitude of the modulated electrical baseband signal output by the IQ modulator is 10V~14V.

[0118] The embodiments of this specification provide an IQ modulator bias automatic control method and device, wherein the IQ modulator bias automatic control device includes: modulating the modulated electrical baseband signal I and the modulated electrical baseband signal Q onto an optical carrier through an IQ modulator to obtain a modulated optical signal; passing the modulated optical signal through an optical fiber splitter to determine the input optical signal; converting the input optical signal into an electrical signal, and processing the electrical signal to obtain a digital signal. Performing digital signal processing on the digital signal through a processor to obtain a bias control signal, and performing bias control based on the bias control signal. By passing the modulated optical signal through an optical fiber splitter to determine the input optical signal; converting the input optical signal into an electrical signal, and processing the electrical signal to obtain a digital signal. Performing digital signal processing on the digital signal through a processor to obtain a bias control signal, and performing bias control based on the bias control signal, the control accuracy is improved.

[0119] The above is a schematic scheme of an IQ modulator bias automatic control device of this embodiment. It should be noted that the technical scheme of the IQ modulator bias automatic control device and the technical scheme of the IQ modulator bias automatic control method described above belong to the same concept, and the details of the technical scheme of the IQ modulator bias automatic control device that are not described in detail can all be referred to the description of the technical scheme of the IQ modulator bias automatic control method described above.

[0120] Fig.15The block diagram of a computing device 1500 according to one embodiment of the present specification is shown. The components of the computing device 1500 include but are not limited to a memory 1510 and a processor 1520. The processor 1520 is connected to the memory 1510 via a bus 1530, and the database 1550 is used to store data.

[0121] The computing device 1500 also includes an access device 1540 that enables the computing device 1500 to communicate via one or more networks 1560. Examples of these networks include a public switched telephone network (PSTN), a local area network (LAN), a wide area network (WAN), a personal area network (PAN), or a combination of communication networks such as the Internet. The access device 1540 may include one or more of any type of network interface (e.g., a network interface card (NIC)) of wired or wireless, such as an IEEE 802.11 wireless local area network (WLAN) wireless interface, a world-wide interoperability for microwave access (Wi-MAX) interface, an Ethernet interface, a universal serial bus (USB) interface, a cellular network interface, a Bluetooth interface, and a near field communication (NFC).

[0122] In one embodiment of the present specification, the above components of the computing device 1500 and Fig.15 Other components not shown in the figure may also be connected to each other, for example, via a bus. It should be understood that Fig.15 The computing device structure block diagram shown is only for the purpose of illustration, and is not intended to limit the scope of this specification. Those skilled in the art can add or replace other components as needed.

[0123] The computing device 1500 may be any type of stationary or mobile computing device, including a mobile computer or mobile computing device (e.g., a tablet computer, a personal digital assistant, a laptop computer, a notebook computer, a netbook, etc.), a mobile phone (e.g., a smart phone), a wearable computing device (e.g., a smart watch, smart glasses, etc.), or other types of mobile devices, or a stationary computing device such as a desktop computer or a personal computer (PC). The computing device 1500 may also be a mobile or stationary server.

[0124] The processor 1520 is used to execute the following computer executable instructions, which implement the steps of the above-mentioned IQ modulator bias automatic control method when executed by the processor. The above is a schematic scheme of a computing device of this embodiment. It should be noted that the technical scheme of the computing device and the technical scheme of the above-mentioned IQ modulator bias automatic control method belong to the same concept, and the details of the technical scheme of the computing device that are not described in detail can all be referred to the description of the technical scheme of the above-mentioned IQ modulator bias automatic control method.

[0125] An embodiment of the present specification further provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the above-mentioned IQ modulator bias automatic control method.

[0126] The above is a schematic scheme of a computer-readable storage medium of this embodiment. It should be noted that the technical scheme of the storage medium and the technical scheme of the above-mentioned IQ modulator bias automatic control method belong to the same concept, and the details not described in detail in the technical scheme of the storage medium can be referred to the description of the technical scheme of the above-mentioned IQ modulator bias automatic control method.

[0127] An embodiment of the present specification further provides a computer program, wherein when the computer program is executed in a computer, the computer is caused to execute the steps of the above-mentioned IQ modulator bias automatic control method.

[0128] The above is an illustrative solution of a computer program of this embodiment. It should be noted that the technical solution of the computer program and the technical solution of the above-mentioned IQ modulator bias automatic control method belong to the same concept, and the details not described in detail in the technical solution of the computer program can be referred to the description of the technical solution of the above-mentioned IQ modulator bias automatic control method.

[0129] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0130] The computer instructions include computer program codes, which may be in source code form, object code form, executable files or some intermediate forms, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0131] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the embodiments of this specification are not limited by the order of the actions described, because according to the embodiments of this specification, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the embodiments of this specification.

[0132] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0133] The preferred embodiments of this specification disclosed above are only used to help explain this specification. The optional embodiments do not describe all the details in detail, nor do they limit the invention to only the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of the embodiments of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the embodiments of this specification, so that technicians in the relevant technical field can well understand and use this specification. This specification is only limited by the claims and their full scope and equivalents.

Claims

1. An IQ modulator bias automatic control method, characterized in that: include: The modulated electrical baseband signal I and the modulated electrical baseband signal Q are modulated onto an optical carrier through an IQ modulator to obtain a modulated optical signal; Passing the modulated optical signal through an optical fiber splitter to determine an input optical signal; Converting the input optical signal into an electrical signal, and processing the electrical signal to obtain a digital signal; Performing digital signal processing on the digital signal through a processor to obtain a bias control signal, and performing bias control based on the bias control signal; The step of converting the input optical signal into an electrical signal comprises: Converting the input optical signal into a current signal through photoelectric detection; determining a voltage signal based on the current signal and the current-to-voltage amplifier; determining an electrical signal based on the voltage signal and a low noise amplifier; The electrical signal includes a modulation signal and a pilot signal; The amplitude of the pilot signal is smaller than the modulation signal; The step of processing the electrical signal to obtain a digital signal comprises: The electrical signal is filtered through a plurality of narrow bandpass filters to obtain a filtered signal; Processing the filtered signal based on the ADC module, the long correlator group, the DDS group and the control group to obtain a digital signal; The method of processing the filtered signal based on the ADC module, the long correlator group, the DDS group and the control group to obtain a digital signal includes: Processing the filtered signal based on the ADC module to determine an initial digital signal; Performing long correlation processing on the initial digital signal by the long correlator group and the DDS group to determine a long correlation signal; The long correlation signal is processed by the DDS group and the control group to determine a digital signal.

2. The method according to claim 1, characterized in that The fiber optic beam splitter is 1:99 or 10:

90.

3. The method according to claim 1, characterized in that The amplitude of the pilot signal output by the DDS group is 20mV~200mV; The amplitude of the modulated electrical baseband signal output by the IQ modulator is 10V~14V.

4. An IQ modulator bias automatic control device, used to implement the steps of the IQ modulator bias automatic control method according to any one of claims 1 to 3, characterized in that: include: The optical carrier modulation module is configured to modulate the modulated electrical baseband signal I and the modulated electrical baseband signal Q onto the optical carrier through an IQ modulator to obtain a modulated optical signal; an optical signal module, configured to pass the modulated optical signal through an optical fiber splitter to determine an input optical signal; A signal processing module, configured to convert the input optical signal into an electrical signal, and obtain a digital signal by signal processing the electrical signal; The bias control module is configured to perform digital signal processing on the digital signal through a processor to obtain a bias control signal, and perform bias control based on the bias control signal.

5. A computing device, characterized in that: include: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the IQ modulator bias automatic control method according to any one of claims 1 to 3 are implemented.

6. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the IQ modulator bias automatic control method according to any one of claims 1 to 3.

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