Optoelectronic memory and logic device

Abstract

An optoelectronic memory and logic device has a function of a reset-set flip-flop (RS-FF) or an exclusive-OR (EOR) gate. The RS-FF includes a first and a second optical inverter circuits. The optical inverter circuit includes a parallel connection of a light emitting device and a phototransistor, and a load resistor connected in series. The phototransistor in the first (second) optical inverter circuit receives the light from the lihgt emitting device in the second (first) optical inverter circuit. The RS-FF has high contrast ratio in case of emitting high output power, and operates stably when the load resistance and the bias voltage are fluctuated. The EOR gate comprises a parallel connection of an adder circuit and a multiplier circuit, and a load resistor connected in series. The adder circuit is a series connection of a light emitting device and a first phototransistor. The multiplier circuit is a series connection of a second phototransistor and a third phototransistor. The first and the second phototransistors receive a first input light, and the first and the third phototransistors receive a second input light. The EOR gate is constituted with five devices, and emits a single output light corresponding to the EOR of two input lights.