Performances comparison of a coherent optical OFDM system

This paper addresses OFDM (orthogonal frequency division multiplexing) transmission over optical links with high spectral efficiency, i.e. by using high-order QAM-modulation schemes as a mapping method prior to the OFDM multicarrier representation. Here we address especially coherent optical OFDM modem in long distance. Numerical simulations of the coherent optical orthogonal frequency division multiplexing modems are undertaken to investigate the effect of the number of sub-carriers, the cyclic prefix (CP) length, data rates on a single mode fibre (SMF). In addition, simulation results show that in order to enhance distance length of the optical OFDM modem equalization is needed for combating both chromatic dispersion and fiber non linearity. Keywords— Coherent OFDM, CP, EVM, training.