Optical switching in nonlinear waveguide arrays with a longitudinally decreasing coupling coefficient

An analysis of the switching properties of nonlinear waveguide arrays with longitudinally decreasing coupling coefficients is presented. It is shown that one can achieve both phase- and amplitude-controlled optical switching with a high extinction ratio by providing axially decreasing mutual coupling, which induces adiabatic narrowing of spatial light-wave distributions in the waveguide arrays.