Influence And Suppression Of Perturbation In Dispersion-Managed OTDM System

As one of the most important inventions of this century, fiber-communication changed thoroughly communication mode of mankind. The superiority of fiber-communication is that not only it can provide "limitless" bandwidth, but also it can be used for long-haul even oversea telecommunication system. Because the group velocity dispersion (GVD) can be balanced by self phase modulation (SPM) in soliton system, optical solitons maybe become the ideal message carrier in long distance communication. It is well known that, apart from fiber loss, timing jitter is the key factor which limits the total transmission distance of the soliton system. Many perturbations can lead to timing jitter, and Gordon-Haus effect produced by amplified spontaneous emission (ASE) noise from EDFA is first studied widely. With the continuously increasing request for transmission rate, the dispersion-managed time-division-multiplexed (TDM) system is widespread which make the pulse width of soliton shorter and shorter. To the subpicosecond or femtosecond soliton system, the Gordon-Haus perturbation is not the main factor of timing jitter. High-order effects, such as the third-order dispersion (TOD) and Raman effect, nonlinear interactions between neighboring pulses caused by the narrow bit slot, and polarization-mode dispersion (PMD) arising from the random birefringence in fibers, also can lead to timing jitter and limit the maximal transmission distance.Analyzing these perturbations, we developed an extended soliton perturbation model which was based on the nonlinear SchrÇ’dinger equation (NLS) considering the effects above. To validate the veracity of this model, on the one hand, we obtain the approximate solution of the modified NLS using variational approach. On the other hand, we make direct numerical simulations by use of the famous split-step Fourier method. The results show that this model is correct in subpicosecond or femtosecond for timing jitter. Subsequently, we discuss the influence of perturbations for dispersion-managed soliton in Optical-TDM system, and indicate that the control scheme with the combining of the nonlinear gain, the filter and the dispersion compensation (including TOD & PMD) is very effective for suppress of timing jitter.