Database Based Phase Noise Compensation in CO-OFDM Transmission
It is important to investigate the optical phase noise impact due to fiber linear and nonlinear effects and establish the optimal approach to estimate the phase evolution of OFDM signals in order to ascertain its suitability for optical transmission. Many dispersion compensation techniques have been proposed and demonstrated. Pilot aided and data aided proposals have already proved themselves as successful phase estimation methods. Adaptive tracking scheme that reduces the effect of laser phase noise and consequently relaxes the laser line-width requirement has been proposed. The impact of system nonlinearity on the OFDM symbol can be moderated by partially filling the OFDM spectrum, or assigning zero values to particular OFDM subcarrier.