Supratransmission in waveguide arrays with saturable nonlinearity

Abstract

A semi-infinite discrete nonlinear Schrödinger equation with saturable nonlinearity driven at one edge by a driving force is considered. The equation models the dynamics of coupled photorefractive waveguide arrays. It has been reported that when the frequency of the driving force is in the forbidden band, energy can be transmitted along the lattices provided that the driving amplitude is above a critical value. This nonlinear tunneling is called supratransmission. Here, the source of supratransmission is explained using geometric illustrations.