Optical soliton propagation in erbium-doped fibre with variable dispersion and nonlinear effects

Abstract

We propose a coupled system of generalized nonlinear Schrodinger and Maxwell-Bloch equations with variable coefficients which describes propagation of an optical soliton in an inhomogeneous nonlinear waveguide doped with two-level resonant atoms. The Lax pair of this model is derived using the Ablowitz-Kaup-Newell-Segur (AKNS) formalism. The one-soliton solution is constructed through a Darboux-Backlund transformation (BT). The coupled system is found to allow soliton propagation. We explain the soliton control by the effect of distributed amplification with varying group velocity dispersion, nonlinearity and gain or loss parameters.