Transmission of a net 467-Gb/s PDM-16QAM Nyquist-spaced superchannel is reported with an intra-superchannel net spectral efficiency (SE) of 6.6 (b/s)/Hz, over 364-km SMF-28 ULL ultra-low loss optical fiber, enabled by bi-directional second-order Raman amplification and digital nonlinearity compensation. Multi-channel digital back-propagation (MC-DBP) was applied to compensate for nonlinear interference; an improvement of 2 dB in Q2 factor was achieved when 70-GHz DBP bandwidth was applied, allowing an increase in span length of 37 km.
Bibliographical noteFunding: EPSRC (EP/J017582/1).
Galdino, L., Tan, M., Lavery, D., Rosa, P., Maher, R., Phillips, I. D., Ania Castañón, J. D., Harper, P., Killey, R. I., Thomsen, B. C., Makovejs, S., & Bayvel, P. (2015). Unrepeatered Nyquist PDM-16QAM transmission over 364 km using Raman amplification and multi-channel digital back-propagation. Optics Letters, 40(13), 3025-3028. https://doi.org/10.1364/OL.40.003025