Correlation Of Phase Noise's Influence Of Optical Comb On The Transmission Of Signal In Optical Fiber And The Analysis Of Its Performance

Wavelength Division Multiplexing(WDM)is one of the most successful technologies in the history of optical fiber communication,which can make use of the limited bandwidth resources of optical fiber to increase the transmission capacity of an optical fiber by several times to dozens of times compared with single Wavelength transmission.Within about 40 nm bandwidth available in the optical communications,and considering 25 GHz frequency separation between carriers,about 200 channels can be easily allocated by using WDM technology.In this scenario,an optical frequency comb generator allows for replacing the large number of lasers required in the transmitter by a single one and fixing the channel separation across the bandwidth with great accuracy.At the same time,with a large number of carriers and a tight carrier interval in the WDM system,the degradation of signal's quality caused by the fiber nonlinear effect is the main bottleneck that restricts the system performance.Although coherent optical communication technology can achieve perfect compensation for linear damage in optical fiber,the compensation for nonlinear effects in optical fiber,especially the inter-channel nonlinear effects in WDM system still needs to be improved.This thesis first introduced the structure of optical comb WDM coherent transmission system,and then analyzes the number of subcarriers of TB/s superchannel,optical comb in Dispersion Compensation Fiber(DCF)model link and the new modulation format-Amplitude Phase Shift Keying(APSK)'s application in optical comb WDM system these three aspects to analyze the performance of the optical comb WDM optical coherent transmission systems.In this thesis,the optimal subcarrier configuration of 4 Tb/s optical super-channel is determined by changing the gap of the line of optical frequency comb to accommodate different number of subcarriers in a certain frequency band.Then the paper explores the performance of optical frequency comb in the system including DCF link.In the process of simulation analysis,the nonlinear effect in the optical comb WDM system,especially the inter-channel nonlinear effect affects the signal's quality seriously.Therefore,this paper tries to use APSK,a new modulation format with better nonlinearity tolerance to combat with fiber nonlinearity.Then this thesis analyzes its performance in the optical comb WDM system.In the future,the transmission rate and transmission distance of WDM system will increase continuously,and the modulation format with better nonlinearity tolerance is just a temporary measure.Therefore,this paper analyzes the inter-channel nonlinearity compensation algorithm which is suitable for optical comb WDM system.this paper analyzed the performance of the common Digital Back Propagation(DBP)algorithm in single carrier system and optical comb WDM system and the full-field DBP algorithm and the MC-DBP algorithm.The results show that the two algorithms can improve the bit error rate of the system effectively compared with the common DBP algorithm.Based on the MC-DBP algorithm which is more practical,this paper proposes an efficient MC-DBP scheme with the help of multi-core digital signal processor.Simulation results show that the efficient MC-DBP scheme has better performance than linear equalization.