  We numerically demonstrate an all-optical nonlinearity pre-compensation
module for state-of-the-art long-reach Raman-amplified unrepeatered links. The
compensator design is optimized in terms of propagation symmetry to maximize
the performance gains under WDM transmission, achieving 4.0dB and 2.6dB of SNR
improvement for 250-km and 350-km links.
