Optical Fibre Capacity Optimisation via Continuous Bandwidth Amplification and Geometric Shaping
Lídia Galdino, Adrian Edwards, Wenting Yi, Eric Sillekens, Yuta Wakayama, Thomas Gerard, Wayne Pelouch, Stuart Barnes, Takehiro Tsuritani, Robert I. Killey, Domaniç Lavery, Polina Bayvel
Abstract
The maximum data throughput in a single mode optical fibre is a function of both the signal bandwidth and the wavelength-dependent signal-to-noise ratio (SNR). In this paper, we investigate the use of hybrid discrete Raman & rare-earth doped fibre amplifiers to enable wide-band signal gain, without spectral gaps between amplification bands. We describe the widest continuous coherent transmission bandwidth experimentally demonstrated to date of 16.83 THz, achieved by simultaneously using the S-, C- and L-bands. The variation of fibre parameters over this bandwidth, together with the hybrid amplification method result in a significant SNR wavelength-dependence. To cope with this, the signal was optimised for each SNR, wavelength and transmission band. By using a system-tailored set of geometrically shaped constellations, we demonstrate the transmission of 660 × 25 GBd channels over 40 km, resulting in a record single mode fibre net throughput of 178.08 Tbit/s.