Optical Fibre Capacity Optimisation via Continuous Bandwidth Amplification and Geometric Shaping

• Published in: IEEE photonics technology letters Vol. 32; no. 17; pp. 1021 - 1024
• Main Authors: Galdino, Lidia, Edwards, Adrian, Yi, Wenting, Sillekens, Eric, Wakayama, Yuta, Gerard, Thomas, Pelouch, Wayne Sheldon, Barnes, Stuart, Tsuritani, Takehiro, Killey, Robert I., Lavery, Domanic, Bayvel, Polina
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-09-2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplification; Bandwidth; Bandwidths; Broadband transmission system; Constellations; Continuous fibers; Doped fibers; Erbium-doped fiber amplifiers; Gain; geometric shaping; high order modulation format; Optical modulation; Optical noise; Optimization; Rare earth elements; Signal to noise ratio; Throughput
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2020.3007591

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 <inline-formula> <tex-math notation="LaTeX">\times25 </tex-math></inline-formula> GBd channels over 40 km, resulting in a record single mode fibre net throughput of 178.08 Tbit/s.