Optical logic device responsive to pulsed signals

An optical logic device which performs a logic operation on a plurality of input light signals representing information in bit form and having bit rates of 10 Gbps or more, comprising:

• a photoelectric conversion portion comprising a plurality of photoreceivers, said plurality of photoreceivers being operative to simultaneously receive separate input light signals having bit rates of 10 Gbps or more and to produce a plurality of separate photocurrents;
• said plurality of photocurrents being added up directly to produce a combined electric output signal, and
• a comparator operative to periodically compare a voltage level of the combined electric output signal with a predetermined voltage level,
• wherein said photoreceivers comprise an anode and a cathode, and the anodes of said plurality of photoreceivers are electrically coupled together and the cathodes of said plurality of photoreceivers are electrically coupled together, whereby there is direct addition of the pulsed outputs of said photoreceivers.