Research On The Influence Of Dispersion And Nonlinear Effects On High-speed Optical Communication System And Their Solutions

In high-speed optical communication, the enlargement of transmission capacity,the improvement of transmission rate, and the extension of transmission distance areall closely linked with loss, dispersion and nonlinear effects. With widened applicationof EDFA, the loss problem in fiber is basically solved. Therefore, dispersion andnonlinear effects become the mainly factors that restrict the performance of thetransmission of optical signal. Hence, how to solve the problems dispersion andnonlinear effects bring into high-speed optical communication has become a hotresearch topic in recent years. This thesis focuses on the individual and comprehensiveinfluence of dispersion and nonlinear effects on high-speed optical communicationsystem, and the corresponding solutions are studied. The main work of mine is asfollows:Firstly, starting from the Maxwell’s equations, we have inferred the optical pulsestransmission of the nonlinear Schrodinger equation and the generalized nonlinearSchrodinger equation. And based on the generalized nonlinear Schrodinger equation,we have developed the computer program that can simulate the process of nonlinearpropagation of optical pulses. The step Fourier method and the realization process ofnumerical simulation program are also introduced.Secondly, the theory analysis and numerical simulation being combined, theindividual and comprehensive influence of dispersion and nonlinear effects onhigh-speed optical communication system are studied. The results of the study showthat, dispersion induces pulse broadening. It is no doubt that this will causeintersymbol interference in the high-speed optical communication, and the error ratesare increased. Besides, nonlinear effects induce pulse compression and spectralbroadening, which exert a serious negative impact on the quality of high-speed opticalcommunication. In abnormal dispersion, the balance of dispersion and nonlineareffects of the pulse will cause a very compelling phenomenon—solitons.Thirdly, the solutions to the individual and comprehensive influence of dispersionand nonlinear effects on high-speed optical communication system are studied. Thephysical properties of solitons are studied by theoretical analysis and numericalsimulation. We have also discussed the soliton communication tests, and pointed outthe problems which must be solved urgently in soliton communication theory andtechnology.