Flip-flop operation in opto-thermal bistable devices with localized absorption

We consider nonlinear interferometric devices based on opto-thermal bistability with localized absorption and show how the introduction of composite structures within the interferometer makes feasible its setting and resetting between stable outputs by applying positive light pulses on different parts of the bistable device. Experimental demonstration of all-optical flip-flop operation is reported for two interferometric configurations, one of them being extremely simple and well suited for parallel processing.