FBG‐assisted ICI Reduction for AO‐OFDM Demultiplexed Signal

ABSTRACTIn an all‐optical orthogonal frequency division multiplexing (AO‐OFDM) system, the demultiplexed subcarriers from an optical discrete fourier transform circuit are needed to be sampled by optical gates in the intercarrier interference (ICI)‐free narrow interval. In this article, we present a theoretical investigation of fiber Bragg grating (FBG) assisted ICI reduction in an AO‐OFDM system in place of an optical sampling gate (SG). The optimum durations of SG and FBG are analyzed for different symbol rise times (trise) and the analysis is extended to chromatic dispersion (CD) effects. The proposed FBG device provides tolerance to dispersion, which causes shifting of narrowed ICI‐free region. The FBG achieves BER < 10−3 for transmission of 45 km without cyclic prefix, and synchronization with shifted ICI‐free region is not needed. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2320–2324, 2014