Coherent Detection WDM Optical OFDM System

Abstract: Orthogonal frequency division multiplexing (OFDM) is an attractive modulation format that recently received a lot of attention in the fiber-optic community. The main advantage of optical OFDM is that it can cope with virtually unlimited amount of inter symbol interference (ISI). In high-speed optical transmission systems, ISI is caused for instance by chromatic dispersion and it is serious issue in long-haul systems whose bit rate is higher. High order dispersion such as a third-order and higher-order dispersion effects are not fully compensated using the traditional dispersion compensating devices such as Dispersion compensating fiber (DCF), Optical Filters etc. Thus the received signals at the receiver end would be distorted dramatically, even if only a small outside effect affects the transmission link. The Phase modulator system is proposed in this work at the receiver end to recover higher-order dispersion which would not be compensated by DCF fiber and Optical Filters.

Keywords: Bit error Rate, Coherent Detection, Phase Modulator, Optical OFDM, Third order dispersion.