An optical flip-flop circuit which includes an electrical power source for providing an electrical signal, a light-receiving element provided in series with the power source for switching the electrical signal in response to an optical signal, a light-emitting element for emitting the optical signal in response to the electric signal, an electrical signal path between the light-receiving element and the light-emitting element, whereby the electrical signal passes from the power source to the light-emitting element in response to the optical signal received by the light-receiving element, a light path for directing the optical signal from the light-emitting element to the light-receiving element, wherein the light path and the electrical signal path form a signal loop through which a signal circulates, said circulating signal comprising the electrical signal through the electrical signal path portion of the signal loop and the optical signal through the light path portion of the signal loop, and input/output means for providing an input optical signal to the light-receiving element and for emitting a portion of the optical signal directed by the light path.