Vector similaritons in two-mode optical media with cubic-quintic nonlinearity and four-wave mixing

Abstract

We present the discovery of chirped vector similaritons which can propagate through inhomogeneous two-mode media exhibiting four-wave mixing and quintic nonlinearity. The transmission of nonlinear wave packets in such optical waveguiding medium is studied in the framework of a generalized system of coupled nonlinear Schrödinger equations in (3+1)-dimensions which accounts for spatially inhomogeneous diffraction/dispersion, third-order self- and cross-nonlinear effects, fifth-order self-nonlinear effects, four-wave mixing, and linear gain/loss. It is shown that two distinct families of coupled self-similar periodic waves taking the \(\textrm{dn}\)-\(\textrm{dn}\) and \(\textrm{cn}\)-\(\textrm{cn}\) configurations on continuous wave backgrounds exist in the medium. A family of spatiotemporal bright-dark vector similaritons is identified in the long-wave limit of the generated coupled periodic waves. As a practical application, we investigate the propagation dynamics of the obtained chirped vector similaritons in an exponential dispersion-decreasing fiber as well as a periodic distributed fiber system. The results indicate that a proper selection of diffraction/dispersion and gain/loss profiles allows diverse propagation trajectories for the three-dimensional bright-dark vector similaritons. It is also demonstrated that the chirp parameter enables us to manipulate the amplitude and the width of vector similariton pulses as they propagate through the inhomogeneous media in accordance with the system parameters.