Fiber-Nonlinearity-Tolerant Superchannel Transmission via Nonlinear Noise Squeezing and Generalized Phase-Conjugated Twin Waves

We present fiber-nonlinearity-tolerant transmission of polarization-division multiplexed binary phase-shift keying (PDM-BPSK) through a nonlinear noise squeezing (NLNS) effect that is achieved by optimized digital electronic dispersion precompensation. With the improved nonlinear tolerance, a 406.6- Gb/s superchannel consisting of eight 37.5-GHz-spaced 32-Gbaud Nyquist-filtered PDM-BPSK signals is transmitted over a 12,800- km (160×80-km) EDFA-only amplified dispersion-unmanaged non-zero-dispersion-shifted fiber link. We establish a connection between the beneficial NLNS effect and the recently reported phase-conjugated twin wave (PCTW) concept and further generalize the PCTW concept to vector twin waves that are traveling through a fiber link along orthogonal dimensions such as time and space. Moreover, we apply the PCTW concept to wavelength-division-multiplexed (WDM) superchannel transmission by treating the entire WDM superchannel as a twin wave to further mitigate inter-channel nonlinear effects. Through numerical simulations, we show that the generalized PCTW technique can effectively mitigate inter-channel nonlinear impairments, in addition to mitigating intra-channel nonlinear impairments.