Soliton interaction for a variable-coefficient higher-order nonlinear Schrödinger equation in a dispersion-decreasing fiber

Under investigation in this paper is the interactions between the solitons in a dispersion-decreasing fiber, governed by a variable-coefficient higher-order nonlinear Schrödinger equation with the effects of third-order dispersion, Raman self-scattering and self-steepening. With the help of symbolic computation and Hirota method, the two soliton solutions of the equation are obtained. Based on these solutions, the interactions between the linear, parabolic-like and periodic-type solitons are illustrated and all the interactions are elastic. Through the interactions, soliton amplitudes and shapes keep invariant except for some phase shifts. Beside, we can also see that the soliton amplitude can be affected by the attenuation constant: When the attenuation constant is given a larger value, we can obtain the soliton with a larger amplitude.