Broadband switching of polychromatic light in nonlinear waveguide couplers

In this work, we demonstrate that the operating bandwidth of a conventional coupler created by pair of parallel waveguides can be dramatically improved by introducing periodic bending of waveguide axes in the propagation direction. We suggest a novel design of a nonlinear directional coupler which can be used for all-optical switching of polychromatic light with broad frequency spectrum such as the output of white-light and supercontinuum sources.