Abstract

Stable soliton propagation over many amplification periods, as currently envisaged for future communication systems, requires the soliton period, z_o to be a few times the amplifier spacing, z_a [1,2]. This condition arises because the fibre loss removes the continuous balance between group velocity dispersion (GVD) and self phase modulation (SPM), normally associated with the nonlinear Schrodinger equation, introducing a periodic perturbation to the propagating solitons. As z_o approaches z_a, the magnitude of these perturbations increases, setting limits on the admissible pulse width and corresponding data capacity. The results presented here consider the potential application of stepwise dispersion profiling to minimise these perturbations. We derive a simple scheme for optimal profiling and demonstrate numerically that it allows average soliton propagation beyond the usually accepted limits.

© 1993 Optical Society of America