Propagation of a solitonlike nonlinear pulse in average normal group-velocity dispersion and its unsuitability for high-speed, long-distance optical transmission

We detail the propagation characteristics of a solitonlike single nonlinear pulse in an average normal group-velocity dispersion (GVD) region under two-step dispersion management. We compare the pulse characteristics with numerical results obtained by the variational method. Even when the dispersion swing is large, a steady-state solitonlike solution can be obtained only when the average effective dispersion becomes anomalous. We describe a pulse-pulse interaction based on a pair of nonlinear pulses and show that there is a large pulse interaction in the average normal GVD region. We show with a Q-mapping technique that such a nonlinear pulse train is unsuitable for high-speed, long-distance optical communication because of this strong pulse interaction.