Compensation method and device for multipath crosstalk of optical communication link

Abstract

The invention provides a method and a device for compensating multipath crosstalk of an optical communication link. The method comprises the following steps that: an analog-to-digital converter acquires a signal output by an analog front end, converts the signal into a digital signal and outputs the digital signal to a feed-forward equalizer; the feed-forward equalizer uses the data after feed-forward equalization to subtract a target value used in the feed-forward equalization process to calculate and obtain a feed-forward equalization error value; judging whether the feed-forward equalizer converges or not, if yes, outputting a feed-forward equalization error value to a filter, and filtering the feed-forward equalization error value by the filter to obtain a multipath crosstalk noise quantity; performing compensation calculation by using the multipath crosstalk noise amount, and outputting compensated data to a decision feedback equalizer; wherein when the analog-to-digital converter collects the signals output by the analog front end, the signals output by the analog front end are extracted according to a preset proportion in each clock period. The device can realize the method. According to the invention, the method can adapt to the rapid change of the multipath crosstalk noise of an optical communication link and carry out effective compensation processing.

Description

Technical Field

[0001] The present invention relates to the technical field of optical communication, and in particular to a method for compensating multipath crosstalk of an optical communication link and a device for implementing the method. Background Art

[0002] With the development of 5G communication technology, artificial intelligence technology and big data technology, higher requirements are put forward for the computing power of chips, and the demand for network bandwidth has also increased exponentially. Whether it is a data center or a telecommunications communication network, the optical interconnection solution between switches almost evolves one generation every three years. With the rapid increase and iteration of the switching chip capacity of data centers and telecommunications communications, the high-speed connection between each level in the network architecture needs to be matched and upgraded. Due to the rapid evolution of data rates, more advanced modulation technology is required, that is, the evolution from NRZ to PAM4 technology has been achieved. For 100G PAM4 direct modulation and direct detection technology of optical fiber communication, the impact of multipath crosstalk (MPI) on the signal has received more and more attention, and optical communication systems often need to compensate for multipath crosstalk.

[0003] See also Figure 1 A typical high-speed optical communication system uses a first optical module 11 and a second optical module 21 as carriers for signal transmission and reception. The host 10 communicates with the slave 30 through the first optical module 11, the optical fiber 20, and the second optical module 21. A first DSP chip 12 is provided in the first optical module 11, and a first transmitting DSP 13 and a first receiving DSP 14 are provided in the first DSP chip 12. A second DSP chip 22 is provided in the second optical module 21, and a second transmitting DSP 23 and a second receiving DSP 24 are provided in the second DSP chip 22. In the downlink, the signal sent by the host 20 passes through the first transmitting DSP 13 and the first optoelectronic device 15 in turn to the optical fiber 20, and then passes through the third optoelectronic device 25 and the second transmitting DSP 23 to reach the slave 30. In the uplink, the signal sent by the slave 30 passes through the second receiving DSP 24 and the fourth optoelectronic device 26 in turn to reach the optical fiber 20, and passes through the second optoelectronic device 16 and the first receiving DSP 14 to reach the host 10. Since the optoelectronic channel formed by various optoelectronic devices and the optical fiber 20 is not an ideal channel, there may be various damages and noises that cause signal distortion or degradation of the signal-to-noise ratio.

[0004] See also Figure 2In a simplified typical 500m to 40km multi-connector optical fiber transmission channel of a data center and a telecommunication network, there are multiple optical fiber connectors between the first optical module end face 31 and the second optical module end face 35, such as the first optical fiber connector 32, the second optical fiber connector 33 and the third optical fiber connector 34, and each optical fiber connector is connected by an optical fiber. Due to the reflection of each optical fiber connector, and with the aging of the optical fiber and the dirtiness of the optical fiber connector, the light reflection will become more serious, and multiple reflections will be formed in the optical fiber channel, and finally multipath crosstalk noise will be formed, which will form multipath crosstalk to the received signal. Since there are no very strict regulations and requirements for the number of optical fiber connectors, the end face reflectivity, and the length of the optical fiber segment, there will be various combinations to adapt to the actual application scenarios. The number of connectors will lead to uncertainty in the noise variable, the increase in reflectivity will lead to an increase in noise energy, and the change in the length of the optical fiber will lead to a change in the crosstalk symbol delay. Therefore, for DSP, there is no way to compensate and detect the multipath crosstalk noise by finding the source position. When there are multiple large delays, there is no way to use the traditional feed forward equalizer (FFE) solution to track and compensate in engineering applications.

[0005] After the multipath crosstalk noise is squared and detected at the receiving end, high-frequency and low-frequency noise exist simultaneously. However, due to the interference of the signal and the noise, the high-frequency noise is weakened, and the impact of the multipath crosstalk noise is ultimately concentrated on the low frequency. According to the experimental data of the application scenario, the frequency of the multipath crosstalk noise is usually less than 100MHz, and in severe cases, the signal-to-noise ratio will be greater than 5%. The low-frequency noise of the multipath crosstalk noise needs to be eliminated through DSP algorithm processing.

[0006] See also Figure 3 An existing multipath crosstalk noise compensation method is to use an analog-to-digital converter 42 to collect data from an analog front end 41 in a receiving end DSP, and then use a low-frequency noise compensator 43 to average the collected data in sections or process it through a sliding window average, which is similar to a low-pass filter process to obtain low-frequency noise, and then subtract the low-frequency noise from the signal to achieve multipath crosstalk noise compensation. The compensated data is output to a feedforward equalizer 44, and finally output to a decision feedback equalizer 45 for re-equalization. However, the data segment averaging solution has the problems of large tracking error and large jitter, while the sliding window averaging solution has the problems of high complexity and difficulty in implementation.

[0007] On the other hand, the invention patent application with publication number CN118554892A discloses a noise compensation method for a transimpedance amplifier, which uses a filter to filter the signal, but the method is mainly used for noise compensation of a transimpedance amplifier. In the application scenario of an optical communication link, since the change cycle of multipath crosstalk noise is faster than that of the transimpedance amplifier, this method cannot meet the needs of multipath crosstalk noise compensation in an optical communication link. Summary of the invention

[0008] The first object of the present invention is to provide a method for compensating multipath crosstalk of an optical communication link that can meet the multipath crosstalk noise variation period requirement of the optical communication link.

[0009] The second object of the present invention is to provide a multipath crosstalk compensation device that implements the multipath crosstalk compensation method of the above optical communication link.

[0010] To achieve the first purpose of the present invention, the method for compensating multipath crosstalk of an optical communication link provided by the present invention includes: an analog-to-digital converter collecting a signal output by an analog front end, converting it into a digital signal, and then outputting it to a feedforward equalizer; the feedforward equalizer uses the data after feedforward equalization to subtract the target value used in the feedforward equalization process to calculate a feedforward equalization error value; judging whether the feedforward equalizer converges, and if so, outputting the feedforward equalization error value to a filter, and the filter filters the feedforward equalization error value to obtain the amount of multipath crosstalk noise; using the multipath crosstalk noise amount to perform compensation calculations, and outputting the compensated data to a decision feedback equalizer; wherein, when the analog-to-digital converter collects the signal output by the analog front end, the signal output by the analog front end is extracted according to a preset ratio in each clock cycle.

[0011] It can be seen from the above scheme that, in view of the fast changing cycle of multipath crosstalk noise in the optical communication link, the analog-to-digital converter of the present invention acquires the signal by extracting a certain proportion of the signal in each clock cycle when acquiring the signal of the analog front end, so that the amount of data to be processed is greatly reduced. Moreover, since a certain signal is extracted in each clock cycle, it can ensure that a certain signal is collected in each clock cycle, thereby ensuring the accuracy of multipath crosstalk noise processing.

[0012] A preferred solution is that extracting the signal output by the analog front end according to a preset ratio in each clock cycle includes: extracting a preset number of signals output by the analog front end in each clock cycle.

[0013] It can be seen that since the number of signals extracted in each clock cycle is preset and can be adjusted according to actual conditions, it can meet the usage requirements in different usage scenarios.

[0014] A further solution is to determine the position of the signal extracted in each clock cycle in a polling manner when extracting a preset number of signals output by the analog front end in each clock cycle.

[0015] It can be seen that determining the position of the signal extracted in each clock cycle in a polling manner can avoid the problem of inaccurate calculation of multipath crosstalk noise caused by extracting the signal at a fixed position.

[0016] A further solution is to perform a clock recovery operation before calculating the feedforward equalization error value. Performing the clock recovery operation can ensure that the clock signal can remain synchronized during the calculation of the feedforward equalization error value.

[0017] An optional solution is that the filter is a first-order digital low-pass filter; when using the multipath crosstalk noise amount for compensation calculation, the multipath crosstalk noise amount is used to compensate the data after feed-forward equalization of the feed-forward equalizer: the data after feed-forward equalization of the feed-forward equalizer in the current clock cycle is subtracted from the multipath crosstalk noise amount to obtain the compensation data of the current clock cycle.

[0018] It can be seen that the backward compensation method can compensate for the multipath crosstalk noise in the current clock cycle, so that the multipath crosstalk noise compensation has high timeliness.

[0019] An optional solution is that the filter is a second-order loop filter; when using the multipath crosstalk noise amount for compensation calculation, the compensation data for the next clock cycle is obtained by subtracting the multipath crosstalk noise amount calculated in the current cycle from the data after feedforward equalization by the feedforward equalizer in the next clock cycle.

[0020] It can be seen that the forward compensation method can use the multipath crosstalk noise amount of the current clock cycle to compensate the data of the next clock cycle.

[0021] A further solution is that after calculating the compensation data of the next clock cycle, the following is further performed: in the next clock cycle, calculating the feedforward equalization error value of the clock cycle.

[0022] It can be seen that in each clock cycle, the feedforward equalization error value of the clock cycle is calculated, and the multipath crosstalk noise of the clock cycle is compensated.

[0023] To achieve the above-mentioned second purpose, the present invention provides a compensation device for multipath crosstalk of an optical communication link, including: an analog-to-digital converter, which is used to collect signals output by an analog front end and convert them into digital signals; a feedforward equalizer, which is used to receive the signals from the analog-to-digital converter and perform feedforward equalization processing, and the data after feedforward equalization is subtracted from the target value used in the feedforward equalization process to calculate the feedforward equalization error value; a filter, which receives the feedforward equalization error value input when the feedforward equalizer converges, and filters the feedforward equalization error value to obtain the multipath crosstalk noise amount; an adder, which uses the multipath crosstalk noise amount to perform compensation calculation; a decision feedback equalizer, which receives the compensated data and performs equalization processing on the compensated data again; wherein, when the analog-to-digital converter collects the signals output by the analog front end, it extracts the signals output by the analog front end according to a preset ratio in each clock cycle.

[0024] As can be seen from the above scheme, since the optical communication link has the characteristic of a fast changing cycle of multipath crosstalk noise, the present invention acquires the signal by extracting a certain proportion of the signal in each clock cycle when collecting the analog front-end signal through the analog-to-digital converter, so that the amount of data to be processed is greatly reduced. Moreover, since a certain signal is extracted in each clock cycle, it can ensure that a certain signal is collected in each clock cycle, thereby ensuring the accuracy of multipath crosstalk noise processing.

[0025] A preferred solution is that the sampling rate of the analog-to-digital converter is greater than or equal to the baud rate of the analog front-end output signal.

[0026] It can be seen that the sampling rate of the analog-to-digital converter is higher than the baud rate of the analog front-end output signal, ensuring that the analog-to-digital converter can accurately extract the signal of each clock cycle.

[0027] A further solution is that when the analog-to-digital converter extracts the signal output by the analog front end according to a preset ratio in each clock cycle, a preset number of signals output by the analog front end are extracted in each clock cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a block diagram of the existing high-speed optical communication system structure.

[0029] Figure 2 It is a block diagram of the structure of a multi-connector optical fiber transmission channel for existing data centers and telecommunication networks.

[0030] Figure 3 It is a schematic diagram of an existing multipath crosstalk noise compensation method.

[0031] Figure 4 It is a structural block diagram of the first embodiment of the multipath crosstalk compensation device for an optical communication link of the present invention.

[0032] Figure 5 It is a flow chart of the first embodiment of the method for compensating multipath crosstalk of an optical communication link of the present invention.

[0033] Figure 6 It is a structural block diagram of the second embodiment of the multipath crosstalk compensation device for optical communication links of the present invention.

[0034] Figure 7 It is a flow chart of the second embodiment of the method for compensating multipath crosstalk of an optical communication link of the present invention.

[0035] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0036] The present invention aims at the situation where multipath crosstalk noise exists in an optical communication link, calculates and compensates the multipath crosstalk noise, thereby reducing the signal distortion in the optical communication link and ensuring the signal transmission quality of the optical communication link.

[0037] First embodiment: See also Figure 4 The multipath crosstalk compensation device of the optical communication link of this embodiment comprises a first analog-to-digital converter 51, a first feedforward equalizer 52, a first-order digital low-pass filter 53, a first decision feedback equalizer 54 and a first adder 55. Among them, the first analog-to-digital converter 51 is used to collect the analog signal output by the analog front end and convert the collected analog signal into a digital signal. Since the signal change rate of the analog front end is very fast in the optical communication link, in order to ensure accurate sampling of the data, the sampling rate of the first analog-to-digital converter 51 needs to be greater than or equal to the baud rate of the analog front end output signal. In addition, while converting the collected analog signal into a digital signal, the first analog-to-digital converter 51 also converts the serial signal into parallel data, so that the DSP chip can process the parallel data.

[0038] The first feedforward equalizer 52 is used to receive the digital signal output by the first analog-to-digital converter 51, and to compensate for the inter-symbol interference (ISI) damage of the received digital signal. Specifically, the first feedforward equalizer 52 obtains a stable feedforward equalization error through adaptive convergence calculation, which is recorded as FFE error. The process of feedforward equalization is to perform feedforward equalization calculation on the received data, such as convolution calculation on the input data and the feedforward equalization coefficient. The feedforward equalization coefficient used by the first feedforward equalizer 52 in the feedforward equalization calculation process is adaptively obtained by adopting the minimum mean square algorithm. After the feedforward equalization coefficient converges and stabilizes, the mean square error value of the minimum mean square algorithm will tend to be stable.

[0039] The first-order digital low-pass filter 53 is a first-order filter with a fixed coefficient structure, which is used to perform smoothing and averaging processing on the input signal and the historical signal, thereby achieving the effect of low-pass filtering the input signal. In this embodiment, by reasonably configuring the filter coefficients of the first-order digital low-pass filter 53, the bandwidth of the first-order digital low-pass filter 53 can be configured and adjusted to meet the usage requirements of different application scenarios. Since this embodiment is applied in an optical communication link and it is necessary to track and compensate for multipath crosstalk noise, the bandwidth of the first-order digital low-pass filter 53 is required to be greater than 10MHz.

[0040] The first adder 55 is used to receive the signals output by the first feedforward equalizer 52 and the first-order digital low-pass filter 53, and perform addition and subtraction processing on the signals of the two. Specifically, the signal output by the first feedforward equalizer 52 is subtracted from the signal output by the first-order digital low-pass filter 53, and the calculation result is output to the first decision feedback equalizer 54.

[0041] The first decision feedback equalizer 54 is used to perform equalization processing on the signal after the feedforward processing again, and adjust the decision feedback equalization coefficient according to the decision result of the signal output by the first feedforward equalizer 52, and perform decision feedback equalization processing in this way, so as to reduce the distortion of the signal. Specifically, after determining the current decision symbol, the first decision feedback equalizer 54 needs to adjust the decision feedback equalization coefficient according to the decision result of the previous decision symbol, and act on the current decision symbol, and then send the compensated current decision symbol to the decision device for decision, and output the decision result of the current decision symbol.

[0042] Combine the following Figure 5 The specific process of the multipath crosstalk compensation method of the optical communication link of this embodiment is introduced. First, step S1 is executed, and the first analog-to-digital converter 51 collects the analog signal output by the analog front end, and performs analog-to-digital conversion on the analog signal to obtain a digital signal, and converts the serial signal into a parallel signal. When the first analog-to-digital converter 51 samples the signal, it extracts the signal according to a certain ratio in each clock cycle. For example, in one clock cycle, the analog front end will output 64 or 32 signals, and the first analog-to-digital converter 51 will extract the signal according to a certain ratio or quantity from the multiple signals output by the analog front end, for example, 1 to 4 signals are extracted in each clock cycle. The number or ratio of the signals extracted by the first analog-to-digital converter 51 can be adjusted according to actual needs. The fewer the number of extracted signals, the less the subsequent calculation amount, which can improve the calculation speed and reduce the compensation delay, but the fewer the extracted signals, the more it will affect the accuracy of the compensation calculation. To this end, it is necessary to take into account the speed and accuracy of the compensation calculation and reasonably configure the number of extractions.

[0043] In addition, the position of the signal extracted in each clock cycle can be determined by sampling polling. For example, the number of signals extracted in each clock cycle is 4. In the first clock cycle, the signals at the 1st, 17th, 33rd, and 49th positions are extracted. In the second clock cycle, the extracted signaling is located at the 2nd, 18th, 34th, and 50th positions respectively. In the third clock cycle, the extracted signaling is located at the 3rd, 19th, 35th, and 51st positions respectively, and so on. In this way, in multiple adjacent clock cycles, the positions of the signals extracted in each clock cycle are different, which can avoid the problem of inaccurate calculation of multipath crosstalk noise due to repeated extraction of signals at the same position, and can improve the calculation accuracy of multipath crosstalk noise, so that the calculated compensation result is more accurate.

[0044] Then, step S2 is executed, the first feedforward equalizer 52 is started, and a clock recovery (Clock and Data Recovery) operation is performed. The first feedforward equalizer 52 will calculate a feedforward equalization error value (FFE error). Specifically, the first feedforward equalizer 52 uses the data obtained after feedforward equalization to subtract the target value used in the feedforward equalization process to calculate the feedforward equalization error value. Among them, the target value used in the feedforward equalization process is the data decision value after feedforward equalization.

[0045] Next, execute step S3 to determine whether the first feedforward equalizer 52 has converged. If it has not converged, it means that the data error is very large and cannot be compensated, then execute step S7 to directly output data to the first decision feedback equalizer 54. If the first feedforward equalizer 52 has converged, execute step S4 to turn on the first-order digital low-pass filter 53, and input the feedforward equalization error value calculated in step S2 to the first-order digital low-pass filter 53. In order to better filter the feedforward equalization error value, it is necessary to configure reasonable parameters of the first-order digital low-pass filter 53 according to the application scenario, so that the first-order digital low-pass filter 53 has a reasonable low-pass filter bandwidth. After receiving the feedforward equalization error value, the first-order digital low-pass filter 53 filters the feedforward equalization error value and obtains the filtering result, and estimates the multipath crosstalk noise amount according to the filtering result.

[0046] Next, step S5 is executed to compensate the data after feedforward equalization using the multipath crosstalk noise amount. Specifically, the data calculated by the first feedforward equalizer 52 after feedforward equalization is output to the first adder 55, and the multipath crosstalk noise amount calculated by the first-order digital low-pass filter 53 is output to the first adder 55, and the first adder 55 uses the data after feedforward equalization to subtract the multipath crosstalk noise amount to obtain compensated data.

[0047] Finally, step S6 is executed, the first adder 55 outputs the compensated data to the first decision feedback equalizer 54, and the first decision feedback equalizer 54 performs equalization processing on the data again.

[0048] It can be seen that the multipath crosstalk compensation device of the optical communication link of this embodiment is a backward compensation scheme, that is, the compensation of the multipath crosstalk noise is performed after the first feedforward equalizer 52. This scheme can supplement the multipath crosstalk noise of the current clock cycle within the same clock cycle, thereby ensuring the timeliness of the multipath crosstalk noise compensation.

[0049] Second embodiment: See also Figure 6 The multipath crosstalk compensation device of the optical communication link of this embodiment has a second analog-to-digital converter 61, a second feedforward equalizer 62, a second-order loop filter 63, a second decision feedback equalizer 64, and a second adder 65. Among them, the second analog-to-digital converter 61 is used to collect the analog signal output by the analog front end and convert the collected analog signal into a digital signal. Since the signal change rate of the analog front end is very fast in the optical communication link, in order to ensure accurate sampling of the data, the sampling rate of the second analog-to-digital converter 61 needs to be greater than or equal to the baud rate of the analog front end output signal. In addition, while converting the collected analog signal into a digital signal, the second analog-to-digital converter 61 also converts the serial signal into parallel data, so that the DSP chip can process the parallel data.

[0050] The second feedforward equalizer 62 is used to receive the digital signal output by the second analog-to-digital converter 61, and to compensate for inter-symbol interference damage on the received digital signal. For example, the second feedforward equalizer 62 obtains a stable feedforward equalization error through adaptive convergence calculation. The feedforward equalization process is to perform feedforward equalization calculation on the received data, such as performing convolution calculation on the input data and the feedforward equalization coefficient.

[0051] The second-order loop filter 63 uses two coefficients to form a fixed second-order filter, the two coefficients are the integral coefficient ki and the proportional coefficient kp, and the value of the proportional coefficient kp needs to be greater than or equal to the value of the integral coefficient ki to ensure the stability of the loop, realize the smooth average processing of the input signal and the historical signal, and play the effect of low-pass filtering. In this embodiment, the bandwidth of the second-order loop filter 63 can be adjusted by configuring different filter coefficients to meet the use requirements in various scenarios. In order to meet the needs of tracking multipath crosstalk noise, the bandwidth of the second-order loop filter 63 in this embodiment is greater than 10MHz.

[0052] The second-order loop filter 63 can receive the data output by the second feedforward equalizer 62, that is, receive the data obtained after the feedforward equalization, and filter the data after the feedforward equalization, and the result of the filtering process is output to the second adder 65. The second adder 65 is used to receive the signals output by the second analog-to-digital converter 61 and the second-order loop filter 63, and perform addition and subtraction processing on the signals of the two. Specifically, the signal output by the second analog-to-digital converter 61 is subtracted from the signal output by the second-order loop filter 63, and the calculation result is fed back to the second feedforward equalizer 62.

[0053] The second decision feedback equalizer 64 is used to perform equalization processing on the signal after the feedforward processing again, and adjust the decision feedback equalization coefficient according to the decision result of the signal output by the second feedforward equalizer 62, and perform decision feedback equalization processing in this way, so as to reduce the distortion of the signal. Specifically, after determining the current decision symbol, the second decision feedback equalizer 64 needs to adjust the decision feedback equalization coefficient according to the decision result of the previous decision symbol, and act on the current decision symbol, and then send the compensated current decision symbol to the decision device for decision, and output the decision result of the current decision symbol.

[0054] Combine the following Figure 7 The specific process of the multipath crosstalk compensation method of the optical communication link of this embodiment is introduced. First, step S11 is executed, and the second analog-to-digital converter 61 collects the analog signal output by the analog front end, and performs analog-to-digital conversion on the analog signal to obtain a digital signal, and converts the serial signal into a parallel signal. When the second analog-to-digital converter 61 samples the signal, it extracts the signal according to a certain ratio in each clock cycle, for example, extracts 1 to 4 signals in one clock cycle. In addition, the number or ratio of the signals extracted by the second analog-to-digital converter 61 can be adjusted according to actual needs. In addition, the position of the signal extracted in each clock cycle can be determined by sampling polling, that is, in multiple adjacent clock cycles, the position of the signal extracted in each clock cycle changes in sequence, such as moving one position backward. This method can avoid the problem of inaccurate calculation of multipath crosstalk noise due to repeated extraction of signals at the same position.

[0055] Then, step S12 is executed, the second feedforward equalizer 62 is started, and the clock recovery (Clock and Data Recovery) operation is performed, and the second feedforward equalizer 62 calculates the feedforward equalization error value (FFE error). Specifically, the second feedforward equalizer 62 uses the data obtained after feedforward equalization in the current clock cycle minus the target value used in the feedforward equalization process in the current clock cycle to calculate the feedforward equalization error value.

[0056] Next, execute step S13 to determine whether the second feedforward equalizer 62 has converged. If it has not converged, it means that the data error is very large and cannot be compensated, then execute step S19 to directly output data to the second decision feedback equalizer 64. If the second feedforward equalizer 62 has converged, execute step S14 to turn on the second-order loop filter 63, and input the feedforward equalization error value calculated in step S12 to the second-order loop filter 63. In order to better filter the feedforward equalization error value, it is necessary to configure reasonable parameters of the second-order loop filter 63 according to the application scenario so that the second-order loop filter 63 has a reasonable low-pass filter bandwidth. After receiving the feedforward equalization error value, the second-order loop filter 63 filters the feedforward equalization error value and obtains the filtering result, and estimates the multipath crosstalk noise amount of the current clock cycle based on the filtering result.

[0057] On the other hand, in the next clock cycle, the second analog-to-digital converter 61 will collect the analog signal output by the analog front end in the next clock cycle, that is, execute step S15, and then execute step S16 to compensate the data of the next clock cycle using the multipath crosstalk noise amount calculated in the current clock cycle. Specifically, the second adder 65 uses the data obtained by the second analog-to-digital converter 61 in the next clock cycle minus the multipath crosstalk noise amount calculated in the current clock cycle to calculate the compensation data of the next clock cycle, that is, the data obtained in step S15 minus the data output by the second-order loop filter 63 in step S14 to obtain the compensation data of the next clock cycle.

[0058] Then, step S17 is executed, and the second feedforward equalizer 62 calculates a new feedforward equalization error value for the next clock cycle, and performs a clock recovery operation at the same time. In the next clock cycle, the data received by the second feedforward equalizer 62 is the data output from the second adder 65, so the data is the result of the calculation of the multipath crosstalk noise amount calculated in the current clock cycle minus the data obtained by the second analog-to-digital converter 61 in the next clock cycle. Finally, step S18 is executed, and the compensated data is output to the second decision feedback equalizer 64, and the second decision feedback equalizer 64 performs equalization processing on the data again.

[0059] It can be seen that the multipath crosstalk compensation device of the optical communication link in this embodiment is a forward compensation scheme, that is, the multipath crosstalk noise calculated by the current clock cycle is used to compensate the next clock cycle before the second feedforward equalizer 62 performs feedforward equalization.

[0060] Since the analog-to-digital converter of the present invention samples the data output by the analog front end through sampling, the amount of data to be subsequently processed can be reduced, and the position of the data extracted in each clock cycle is determined through polling, which is beneficial to improving the accuracy of multipath crosstalk noise compensation.

[0061] Finally, it should be emphasized that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for compensating multipath crosstalk of an optical communication link, comprising: The analog-to-digital converter collects the signal output by the analog front end and converts it into a digital signal before outputting it to the feedforward equalizer; Features: The feedforward equalizer calculates a feedforward equalization error value by subtracting a target value used in the feedforward equalization process from the data after the feedforward equalization; Determine whether the feedforward equalizer converges, and if converged, output the feedforward equalization error value to a filter, and the filter filters the feedforward equalization error value to obtain a multipath crosstalk noise amount; Perform compensation calculation using the multipath crosstalk noise amount, and output the compensated data to a decision feedback equalizer; When the analog-to-digital converter collects the signal output by the analog front end, the signal output by the analog front end is extracted according to a preset ratio in each clock cycle.

2. The method for compensating multipath crosstalk of an optical communication link according to claim 1, characterized in that: Extracting the signal output by the analog front end according to a preset ratio in each clock cycle includes: A preset number of signals output by the analog front end are extracted in each clock cycle.

3. The method for compensating multipath crosstalk of an optical communication link according to claim 2, characterized in that: When a preset number of signals output by the analog front end are extracted in each of the clock cycles, the positions of the signals extracted in each of the clock cycles are determined in a polling manner.

4. The method for compensating multipath crosstalk of an optical communication link according to any one of claims 1 to 3, characterized in that: Before calculating the feedforward equalization error value, a clock recovery operation is also performed.

5. The method for compensating multipath crosstalk of an optical communication link according to any one of claims 1 to 3, characterized in that: The filter is a first-order digital low-pass filter; When using the multipath crosstalk noise amount for compensation calculation, the multipath crosstalk noise amount is used to compensate the data after feed-forward equalization of the feed-forward equalizer: the data after feed-forward equalization of the feed-forward equalizer in the current clock cycle is subtracted from the multipath crosstalk noise amount to obtain the compensation data of the current clock cycle.

6. The method for compensating multipath crosstalk of an optical communication link according to any one of claims 1 to 3, characterized in that: The filter is a second-order ring filter; When the multipath crosstalk noise amount is used for compensation calculation, the compensation data for the next clock cycle is obtained by subtracting the multipath crosstalk noise amount calculated in the current cycle from the data collected by the analog-to-digital converter in the next clock cycle.

7. The method for compensating multipath crosstalk of an optical communication link according to claim 6, characterized in that: After calculating the compensation data for the next clock cycle, it also executes: In the next clock cycle, the feedforward equalization error value of the clock cycle is calculated.

8. A device for compensating multipath crosstalk of an optical communication link, comprising: Analog-to-digital converter, used to collect the signal output by the analog front end and convert it into a digital signal; Features: A feedforward equalizer, used to receive the signal of the analog-to-digital converter and perform feedforward equalization processing, and calculate the feedforward equalization error value by subtracting the target value used in the feedforward equalization process from the data after the feedforward equalization; a filter, which receives the feedforward equalization error value input when the feedforward equalizer converges, and filters the feedforward equalization error value to obtain a multipath crosstalk noise amount; an adder, using the multipath crosstalk noise amount to perform compensation calculation; A decision feedback equalizer receives the compensated data and performs equalization again on the compensated data; When the analog-to-digital converter collects the signal output by the analog front end, the signal output by the analog front end is extracted according to a preset ratio in each clock cycle.

9. The multipath crosstalk compensation device for an optical communication link according to claim 8, characterized in that: The sampling rate of the analog-to-digital converter is greater than or equal to the baud rate of the analog front-end output signal.

10. The multipath crosstalk compensation device for an optical communication link according to claim 8 or 9, characterized in that: When the analog-to-digital converter extracts the signal output by the analog front end according to a preset ratio in each clock cycle, a preset number of signals output by the analog front end are extracted in each clock cycle.

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