All-optical parity checker with bit-differential delay

Abstract

We demonstrate an all-optical digital processing circuit that can check the parity of a binary optical word. The circuit operates by repetitively inputting the binary word to be checked into an optical memory whose capacity differs from the repeat time of the input word by one bit. The accumulated parity of the input word is generated by applying the XOR logical function to the repeated input word and the time-shifted stored word in the memory.