51.5 Tb/s Capacity over 17,107 km in C+L Bandwidth Using Single-Mode Fibers and Nonlinearity Compensation

We transmit 51.5 Tb/s capacity over 17,107 km with C+L band erbium doped fiber amplifiers (EDFAs) and demonstrate a record single mode fiber capacity-distance product of 881 Pb/s × km. This is achieved by using a performance optimized multidimensional coded modulation format with hybrid probabilistic and geometric constellation shaping. This 4D-PS-7/12-40APSK modulation format is designed to approach the Shannon limit and to maximize the performance of nonlinearity compensation in comparison to conventional and probabilistically shaped two-dimensional formats. The receiver digital signal processing uses multistage nonlinearity compensation that includes fast least-mean-square equalizer and generalized filter in addition to digital back propagation. Adaptive linear filters are aided by coded modulation decisions. We experimentally study the contribution of each algorithm versus transmission distance and show a steady increase in the total nonlinearity compensation benefit up to ~10,000 km and saturation afterwards. An average total nonlinearity compensation benefit of 1.75 dBQ is achieved after 17,107 km over a 80 nm optical bandwidth at the designed amplifier power. In addition, we show that nonlinearity compensation techniques used in our experiments are not affected by potential correlation among neighboring channels.