All-optical hysteresis control by means of cross-phase modulation in semiconductor optical amplifiers

We describe the principle of operation of an all-optical flip-flop based on dispersive bistability in a distributed feedback semiconductor optical amp lifier. Cross-phase modulation controls the photonic bandgap and Bragg reso nances of the amplifier, thereby shifting the hysteresis and switching thre sholds to higher or lower powers. We give the details of a simple theoretic al model that is used to simulate the set and reset operations. We also exp erimentally investigate the dependence on set-signal power and the response to back-to-back set signals, and we apply the theoretical model to underst and these experimental results. (C) 2001 Optical Society of America.