To improve flexibility, energy efficiency, and speed of elastic optical orthogonal frequency division multiplexing systems, a reconfigurable multi-precision fast Fourier transform (FFT) is presented. The minimum required FFT word length for different criteria—namely, the bit error rate (BER), FFT size, modulation format, and optical signal-to-noise ratio—is determined using simulations. At run time, system performance is improved significantly by using a reconfigurable multi-precision FFT, while the target BER is satisfied. The proposed design is synthesized on an FPGA, and the results show that both energy efficiency and processing speed are improved about 79% and 78%, respectively, compared with the conventional design.
