Successive Decoding of Anti-Periodic OFDM Signals in IM/DD Optical Channel

Abstract

This paper investigates Orthogonal Frequency- Division Multiplexing (OFDM) transmission in intensity modulated, direct-detected (IM/DD) optical systems. Due to the unipolarity of the IM/DD optical channel, DC biasing and associated nonlinear clipping distortion (NLCD) is inevitable, unless an anti-periodic signal is created by limiting bit loading to only half of the available bandwidth. To generalize this idea, we first provide a class of such signals generated with different subchannel combinations. Using the theoretical characterization of NLCD on these signals, we show that by parallel transmission and successive decoding, a set of anti-periodic OFDM signals can be transmitted simultaneously and recovered without a distortion penalty. The proposed method requires minimum change on the existing optical plant, and has the potential to achieve both high power and high spectral efficiencies.