Simple optoelectronic frequency-offset estimator for coherent optical OFDM

We propose a carrier frequency-offset estimator for optical OFDM systems using off-the-shelf optical components and simple digital processing as a replacement for the purely digital signal processing using the cyclostationarity property of optical OFDM signals with cyclic prefix. Simulations show the system accuracy of <4% estimate error within the range [-1250 + 1250] MHz offsets for a single polarization 28-Gbaud OFDM signal with 15% cyclic prefix. The effects of the system parameters on the performance are investigated.