Terabit/s FFT processing – optics can do it on-the-fly

The discrete Fourier Transform (DFT) or its more popular efficient algorithm, the Fast Fourier Transform (FFT) is one of the important mathematical functions in the toolbox of signal processing. To this date its processing speed is limited by the underlying electronic processors. We show that FFT signal processing limitations can be overcome by performing the FFT in the optical domain and demonstrate the power of the technique by performing the FFT on a single source 10 Tbit/s OFDM signal.