Abstract

All-optical switching and routing of light is a topic of intense investigation due to their potential important applications to ultrafast signal processing devices. Optical solitons, both temporal and spatial are specially well suited for such purpose due to their unique properties. Under appropriate conditions, the propagation of light in cubic nonlinear media is described by the nonlinear Schröedinger equation (NLSE) which has both single and higher-order soliton solutions, and various types of devices based on such solitons have been proposed. However, solitons (more properly, solitary waves) also form in quadratic nonlinear media, and they have been observed experimentally in second-harmonic generation settings in KTP and LiNbO₃ crystals.¹ In this communication we show the principle of operation of a switching device based on the formation of spatial solitons in a planar waveguide made of a quadratic nonlinear material. We show numerically that under appropriate conditions the input beams launched in the waveguide either excite a single spatial soliton or they break apart into several solitons that emerge propagating in different directions. The transition from a single to a multiple branch output is governed by a digital change in the amplitude of the input beam.

© 1996 IEEE