Waveguide properties of arrays of dark spatial solitons in a Bi₁₂TiO₂₀ photorefractive crystal

The goal of this work is to present a study of waveguide properties of arrays of dark spatial solitons in Bi₁₂TiO₂₀ (BTO) crystal. We simulated arrays of dark spatial solitons by solving the nonlinear Schrödinger equation using first a tanh function and then a periodic function as initial conditions. When the periodic function was used, the output intensity distribution gives rise to an array of dark spatial solitons which, depending on the period, were separated by dark fringes. Nevertheless, the guiding ability of the arrays depends on the induced nonlinearity and the input angle of the probe beam. The guiding ability does not depend on the number of solitons in the array. We present experimental results for parallel propagation of one probe beam and the array of dark solitons generated by interference of two coherent laser beams in a photorefractive BTO crystal.