Mitigation of Fiber Nonlinear Impairments in Polarization-Division Multiplexed OFDM Transmission
Fiber nonlinear effects are found to cause severe signal degradation in long-haul coherent optical OFDM (CO-OFDM) transmission, particularly in dispersion- managed transmission. We present promising techniques to mitigate the fiber nonlinear impairments in both single-channel and wavelength-division-multiplexed (WDM) transmission. For singlechannel transmission, we discuss a joint self-phase modulation (SPM) compensation scheme that is applicable to polarization-division multiplexed (PDM) CO-OFDM signal. Experimental demonstration of this joint SPMC compensation scheme is also presented. For WDM transmission, we describe an OFDM frame design and a dispersion- management scheme that reduce the cross-phase-modulation (XPM) penalty among the WDM channels. Impact of XPM from WDM channels with different signal formats and data rates is briefly discussed.