Cascaded and Multisection Sagnac Interferometers for Scalable and Tunable All-Optical OFDM DEMUX

With cascaded and multisection Sagnac interferometers, all-optical fast Fourier transform (FFT) has been demonstrated for optical demultiplexing (DEMUX) of orthogonal frequency division multiplexing (OFDM) signals. The transmission characteristics of the interferometers have been investigated theoretically and experimentally. The scalability and tunability of the all-optical OFDM DEMUX are analyzed and demonstrated for 5-channel OFDM signals.