Soliton-based optical switching in waveguide arrays

We analyze the propagation of discrete solitons in a periodic system of weakly coupled nonlinear optical waveguides, i.e., a waveguide array. Soliton reflection, transmission, and trapping, as well as coherent and incoherent interaction with a linear guided wave [which can exist owing to defect (inhomogeneous) coupling between two neighboring waveguides], are demonstrated numerically and investigated analytically with a collective-coordinate approach. Some potential schemes of controllable and steerable soliton-based optical switching in nonlinear waveguide arrays are discussed. For the first scheme it is suggested that unstable soliton modes be used to achieve easily steerable propagation of discrete bright and dark solitons. This is to avoid mode trapping by the effective Peierls-Nabarro potential, which always appears because of the system discreteness. The other scheme is based on soliton control with the help of a linear guided wave that can be excited in an inhomogeneous array. (C) 1996 Optical Society of America