Numerical study of random variations of span lengths and span path-average dispersions on dispersion-managed soliton system performance

We have studied the performance of dispersion-managed (DM) soliton systems with random variations of span lengths and span path-average dispersions by numerical simulation. We show that while DM solitons still exist in systems with nonperiodic dispersion maps, those nonperiodic maps tend to degrade system performance. We investigate the performance degradation of both on-off keyed and differential phase-shift keyed DM-soliton systems with random span lengths and random span path-average dispersions. We find that the impairment caused by the span path-average dispersion variation is larger than that caused by the span length variation, and that the reduction in quality factor due to the span length and the span path-average dispersion variations is less in dense wavelength-division multiplexing (WDM) than in single-channel transmission systems. In addition, we also show that keeping the overall path-average dispersion constant within a few spans can reduce the random dispersion map-induced performance degradation.