Numerical simulations of discrete propagations of light waves in optically induced planar waveguide arrays

We numerically study how the parameters of the externally biased field, the probe beams and array writing beams influence the propagation dynamics and self-localized states in optically induced planar waveguide arrays. By employing split-step BPM, the evolutions of probe beams in waveguide arrays are investigated in detail, and the properties of the discrete solitons in waveguide arrays with different parameters are discussed by utilizing the Petviashvili iteration method. The results reveal that all the parameters remarkably affect the linear and nonlinear beam propagation dynamics. Additionally the band-gap structures as well as the properties of discrete solitons strongly depend on the parameters of the waveguide arrays. Dramatically due to the photorefractive saturation effect, with the increase of the intensity of array writing beam, probe beams may be delocalized from soliton states. The saturation effect results in an upper limit for the ranges of propagation constants of the discrete solitons.