Two-stage Sagnac demultiplexer

Cascading a semiconductor optical amplifier (SOA)-based Sagnac interferometer with a second Sagnac stage allows significant improvement in the overall demultiplexer performance. A theoretical analysis and simulations show that the exploitation of a two-stage architecture results in a demultiplexing window sharpness and time compression. Eye-diagram and Q-factor experimental characterization at 2.5 Gb/s of the demultiplexer is presented, showing a 25% compression in time of the two-stage switching window and a 4.7 Q-factor improvement.