All-optical XOR logic gate based on self-phase modulation of a semiconductor optical amplifier without an additional synchronized clock

The authors propose and experimentally demonstrate an ah-optical exclusive OR (XOR) logic gate based on self-phase modulation (SPM) of a semiconductor optical amplifier (SOA). The scheme is insensitive to the polarization of the input signal and requires no additional synchronized clock. The output of the XOR gate showed the contrast ratio of more than 17dB for the input signal at 2.5 GHz.