Novel all-optical switching mechanisms in media with quadratic nonlinearity

Summary form only given. Quadratic nonlinearities offer unique possibilities to control light with light. Many all-optical switching devices based on second harmonic generation have been proposed and implemented recently. However, the required operation powers remain too high for commercial applications. We identify novel dynamic scenarios that allow for considerable reduction of required power levels. In practice one often encounters a situation when several nonlinear processes act simultaneously in the same medium. Examples are interaction between several modes in waveguides, multi-step third-harmonic generation, multiple frequency-mixing etc. Since the phase matching condition is usually fulfilled for only one process, other interaction channels are typically ignored. We show that even a weak nonlinear coupling into additional waves can substantially change the system´s behavior. We develop a generic analytical approach toward multiple wave mixing in quadratic media and identify novel mechanisms of all-optical modulation.