Abstract

Recent theoretical results have predicted digital all-optical switching in nonlinear symmetric X-junctions (NLXJ's).^{1, 2} These devices use the optically induced index change to break the symmetry of the structure, thereby changing the relative proportions of the zero and first order modes present in the double mode center section. The output then routes the signal, depending on the magnitude of the first order component. We have fabricated a range of NLXJ's in AlGaAs; the devices were designed for operation in the half band gap region, where the detrimental effects of two-photon absorption are minimized and purely refractive nonlinearities were observed. We will present experimental switching characteristics for symmetric and asymmetric NLXJ's and compare them with those expected from theory. Autocorrelation measurements were performed on the separated outputs and suggest that the response is instantaneous and digital-like.

© 1992 Optical Society of America