  We propose a technique combining the singlechannel digital-back-propagation
(SC-DBP) with phaseconjugated-twin-wave (PCTW) to compensate nonlinearities in
CO-OFDM superchannel systems. This exhibits a similar performance as
multi-channel DBP while providing increased transmission reach compared to
SC-DBP, PCTW, and linear dispersion compensation (LDC).
