Low-Complexity Optical FFT Scheme Enabling Tbit/s All-Optical OFDM Communication

A practical scheme to perform the fast Fourier transform in the optical domain is introduced. Optical real-time FFT signal processing is done at speeds far beyond the limits of electronic digital processing, and at a negligible energy expenditure. To illustrate the power of the method we demonstrate an optical 400 Gbit/s OFDM receiver. It performs an optical real-time FFT on the consolidated OFDM data stream, thereby demultiplexing the signal into lower bit rate subcarrier tributaries, which can then be processed electronically.