DIFFERENTIAL OPTICAL LOGIC ARRANGEMENT

Apparatus having a first electrical circuit, comprising a plurality of photodetectors interconnected such that the first circuit corresponds to any given logic function, is connected in series with a second circuit comprising a plurality of photodetectors interconnected as the conduction complement of the connections of the first circuit. The apparatus performs optical logic without optical cascading since the first and second circuits control the generation of an optical output beam based on the value that the given logic function assumes in response to a plurality of optical signal beams incident on the photodetectors of the first circuit and a plurality of complementary beams incident on the photodetectors of the second circuit. A complementary optical output is obtained and time-sequential operation is effected when two, serially connected quantum well pin diodes comprising an S-SEED are used to generate optical output beams in response to the voltage developed by the first circuit.