Exact quasi-soliton solutions and soliton interaction for the inhomogeneous coupled Hirota–Maxwell–Bloch equations

Abstract

We propose the system of generalized inhomogeneous coupled Hirota–Maxwell–Bloch equations which describes propagation of an optical soliton in an inhomogeneous erbium-doped fiber with two-level resonant atoms. For this system, higher-order dispersion, self-steepening and self-Raman scattering are assumed to be inhomogeneous, like the group velocity dispersion. The exact analytical multisoliton solutions are obtained by employing the simple, straightforward Darboux transformation based on the obtained 3 × 3 Lax pair. As an example, the one- and two-soliton solutions in explicit forms are generated. Then, we give the relative numerical evolution and discuss the propagation characteristics of the pulse.