2.56-Tb/s (64 x 42.7 Gb/s) WDM transmission over 6000 km using all-Raman amplified inverse double-hybrid spans

Transmission of 2.56 Tb/s over 6000 km was achieved using all-Raman amplified inverse double-hybrid spans. This required not only the use of a low-nonlinearity dispersion-managed line but also the taking of countermeasures for stimulated Raman scattering tilt and deviation of average dispersion, both of which increased due to signal bandwidth extension.