Amplified-spontaneous noise limit of optical OFDM lightwave systems

Optical Orthogonal Frequency Division Multiplexing (O-OFDM) systems use electronic digital computation to provide dispersion compensation that can be rapidly adapted to changes in the optical link or optical network. Recent demonstrations have shown compensation of several thousand kilometers. Earlier simulations and analysis showed better sensitivities than non-return to zero systems; however, they assumed optical filters with very narrow bandwidths and narrow-linewidth lasers. This paper explores the effect of the optical filter bandwidths and laser linewidths for both coherent and direct-detection systems using analysis and simulations.