Research On Timing Synchronization Technology In Ultra-high Speed Optical Signal Acquisition System

In the 100 G rate level coherent optical receiving system,under non-ideal conditions,the sampling signal sequence cannot be at the optimal sampling time,resulting in a sharp increase in the bit error rate of the signal.Therefore,the clock synchronization algorithm is the key to achieve high-quality signal transmission.Clock synchronization algorithms,however,are particularly sensitive to the relationship between signal sampling rate and symbol rate sampling.At present,mainstream algorithms are mainly aimed at optical communication signals with a sampling rate of two times the symbol rate or a higher sampling rate.Due to the sharp rise of the signal bandwidth and the limitation of the sampling rate of the domestic ADC,in the coherent receiving process,the sampling rate of the ADC cannot reach the required two times the symbol rate.In addition,due to different professional specifications and private agreements,the speed of each equipment manufacturer will be different.The access of various mainstream signal formats results in that the relationship between the signal sampling rate and the symbol rate is no longer fixed.Traditional clock synchronization algorithms fail in this scenario.Aiming at the limitations of traditional clock synchronization algorithms in high-speed multi-system signal access,this paper proposes a scheme to solve the clock synchronization of coherent optical receiving systems in the scenario where the sampling rate is lower than twice the symbol rate in non-cooperative communication.The main content of the article is:(1)Studied the effects of clock jitter characteristics,laser noise and dispersion in optical fibers on clock synchronization,and analyzed the feasibility of coherent optical receiving systems with ultra-high-rate communication and sampling rate less than twice the symbol rate.(2)The related theory of clock synchronization is studied,and based on the traditional clock synchronization algorithm,a clock synchronization algorithm for coherent optical receiving system is proposed in the case of non-cooperative communication with sampling rate lower than twice the symbol rate.MATLAB is used to build a system simulation platform in order to simulate and analyze the performance of the clock synchronization algorithm.(3)The parallelization method of the clock synchronization algorithm is studied to realize the real-time signal processing,and the effectiveness of the parallelized clock synchronization algorithm is verified by MATLAB simulation.And the RTL-level description and verification of the clock synchronization algorithm is preliminarily realized.