Abstract: A nonlinear all-optical switching device including a waveguide of an organic conjugated material which forms a nonlinear optical medium. The nonlinear material has an index of refraction which is a function of the local intensity of light. Light beams passing through the waveguide intersect and interact causing diffraction into secondary beams. The intensity of the diffracted beams is a function of the intensity and frequency of the intersecting light beams. The nonlinear material can respond extremely fast and provide a bandwidth exceeding 500 GHz.