All-optical logic or gate using two cascaded semiconductor optical amplifiers

A novel all-optical logic OR gate based on cross-gain modulation (XGM) using a two-cascaded semiconductor optical amplifiers (SOAs) in a counterpropagating topology is presented. The attractive issue of the proposed method is that the logic OR gate call be obtained at a probe wavelength by taking advantage of the positive gain variation of one of the two used SOAs in the counterpropagating configuration. This reported feasibility study shows the all-optical logic OR gate can be easily achieved with an extinction ratio higher than 7 dB. (C) 2007 Wiley Periodicals, Inc.