Riemann problem for the light pulses in optical fibers for the generalized Chen-Lee-Liu equation

Abstract

We provide the classification of possible wave structures evolving from initially discontinuous profiles for the photon fluid propagating in a normal dispersion fiber. The dynamics of light field is described by the generalized Chen-Lee-Liu equation, which belongs to the family of the nonlinear Schr\"odinger equations with a self-steepening type term appearing due to retardation of the fiber material response to variations of the electromagnetic signal. This equation is also used in investigations of the dynamics of modulated waves propagating through a single nonlinear transmission network. We describe its periodic solutions and the corresponding Whitham modulation equations. The wave patterns generated by the initial parameter profiles are composed of different building blocks which are presented in detail. It is shown that evolution dynamics in this case is much richer than that for the nonlinear Schr\"odinger equation. Complete classification of possible wave structures is given for all possible jump conditions at the discontinuity. Our analytic results are confirmed by numerical simulations.