Raman-Induced timing jitter in dispersion-managed optical communication systems

The moment method is used to calculate the Raman-induced timing jitter generated by amplifier-induced fluctuations in the energy, frequency, and position of optical pulses propagating inside dispersion-managed fiber links. Using a Gaussian form for chirped optical pulses in combination with the variational analysis, we obtain an analytic expression for the timing jitter whose predictions agree well with the numerical results obtained by solving the nonlinear Schrodinger equation directly. The effects of third-order dispersion are also included in the analysis. We also apply the moment method to standard solitons propagating inside dispersion-decreasing fiber as well as to chirped return-to-zero (CRZ) lightwave systems. We apply our results to a specific 160-Gb/s system and find that the Raman jitter resulting from intrapulse Raman scattering limits the transmission distance in all three cases.