All-optical logic OR gate based on cross gain modulatilon in Semiconductor Optical Amplilfiers

Semiconductor optical amplifiers (SOAs) are very attractive components for optical communication systems. We have already shown that two-cascaded SOAs in a counterpropagating configuration (TC-SOA-CC) based on XGM is interesting for all-optical signal processing (Kim et al., 2000). The contra-directional input signals are injected in SOA. In this configuration, a negative feedback controls the evolution of the SOA gains. The presence of a positive gain variation in SOA can be useful to perform all-optical logic OR gate at the output of SOA.