C+L-Band System Design Enabling Spectrally Efficient 800G Long-Haul Terrestrial Transmission

Abstract

Homogeneous performance in long-haul wideband transmission systems can be challenging to achieve, as fundamental effects such as stimulated Raman scattering, Raman and EDFA gain ripple and band-specific component limitations contribute to spectrally non-uniform and co-dependent penalties. In this work we focus on the system design trade-offs needed to transmit 800 Gb/s error-free channels on every transponder across the entirety of a 9.6 THz C+L line system. The combination of hybrid Raman-EDFA amplification, high performance G.654.E fiber, digital-twin-based inter-band power optimization, and per-channel power emphasis allow the transmission of an aggregate 72 Tb/s over 1504 km using real-time 100.4 GBd digital subcarrier-based elastic optical transponders. This is, to the best of our knowledge, the highest real-time capacity-distance product of any multi-band system demonstrated to date, and the first real-time multi-band demonstration to sustain a spectral efficiency greater than 7 b/s/Hz over long-haul distances.