Image transcription between arrays of N-p-n-P optoelectronic switches

Double-heterojunction optical thyristors with a low holding current (0.2 μA/6×10^-4 cm²) and a low breakover current (70 nA/6×10^-4 cm²) have been fabricated. Such thyristors can be made to switch when receiving an optical input signal from a twin device. Excellent uniformity and stability of the characteristics are obtained in arrays of such thyristors. Monolithic arrays of 25 thyristors connected in parallel have been processed. Winner-takes-all operation can be achieved in such arrays: when applying a bias to the array, only the one thyristor receiving maximum input light switches on, while all others are inhibited from reaching the on-state. With this system, the maximum of a light input pattern can be detected with a resolution of 0.3 nW-or 30 pJ for pulsed input light signals. Image transcription between thyristor arrays is demonstrated: the on-state of more than one thyristor can be copied with a single electrical pulse to the corresponding thyristors of a twin array