Fiber Nonlinearities In Wavelength Division Multiplexed Optical Fiber Transmission Systems And Their Effects On Performances Of The Systems

The technology of WDM combined with EDFA can take fully advantage ofcaPability of fibers, being a premium method of realizing high-caPacity,long-haul, high-speed communications. For the long time, the allenuation,dispersion and nonlinearity of fibers are three major limitations to fibercommunication systems. Because of using of EDFA, the allenuation of fiberswas not an imPortant transmission limitation. At the same time, dispersionmanagements and dispersion-supported techniques can be used to imProveWDM system performances. Howeven the undesired questions fiber nonlineareffects cause still don't crack. What's more, with the light power obviouslyintensifying and tunnel noticeably increasing, fiber nonlinearities have become amainly imPortant limitation imposing on systems. System specifications such astotal tfansmission distance, amPlifier spacing, the number of WDM channelsand the power per channel are all affected by the fiber nonlinear effects.Therefore, studying on electromagnetic fields tfaveling in single mode fiberswhere anenuations, dispersions and nonlinear effects exist has absolutelysignificant theoretical and practical meanings. lt is eXPected to help augmentfiber caPacity and imProve the communication quality.The objective of this thesis is to directly obtain the nonlinear transmissionequation that govems proPagation of oPtical pulses in single fibers, onlyemploying field temporal-spatial Fourier transform. This equation cancompletely describe light pulse transmission actions under numerouscircumstances including the fiber dispersidi, attenuation and nonlinearity, andeven the polarization state of light. Detailed analyses are carried to dig up thisresult, beginning with Maxwell's equations and some imPortant concepts andusing reasonable assumPtions in real and actual fibers. It is found that theresultant NLSE can be aPplied into WDM fiber communication systemsconveniently to research and evaluate non1inear effects on system performancesIIand thus to provide the important theoretical foundation for real system designs.Then, the thesis continues to deal with the cause, character and effect onWDM systems of some kinds ofnonlinearities, such as SPM, XPM, FWM, SRSand SBS, with the emphasis on multi-tunnel nonlinear effects (XPM, FWM andSRS). Some more reasonable modes for study and various techniques andsuggestions to reduce the imPairment effects are also provided and discussed.The analysis and conclusions of this thesis is definitely helpful for systemdesigner to maximize the system performances.