TRANSNET researchers achieve record high throughputs over field-deployed fibre using ultra-wideband S+C+L-band signals.
Optical networks underpin our Internet infrastructure and, to meet an ever-increasing demand for data transmission, we need to be able to support as much bandwidth as possible. Current infrastructure does not tap into all available wavelengths for transmission, but research into ultra-wideband (UWB) transmission systems explores how we can access these for bandwidth expansion. UWB has been gaining attention for its compatibility with existing resources and emerging fibre types, providing a cost effective and viable method to keep up with a growing digital communication culture.
The research, led by Dr Jiaqian Yang and accepted by Journal of Lightwave Technology, demonstrates a 202.3 Tb/s transmission over a 39 km deployed fibre link, and a 67.3 Tb/s throughput over a 1014 km recirculating loop based on field-deployed fibre, the highest throughput values known for deployed fibre transmission. These achievements are the result of using an ultra-wideband (UWB) approach that extends traditional C-band transmission to include the S- and L-band.
Traditional wavelength-division multiplexing (WDM) systems have primarily used C-band or C+L-band transmission, offering limited bandwidth and near-optimal spectral efficiency, making further increases in total throughput challenging. UWB systems have recently gained attention for their ability to leverage existing resources and maximise capacities, avoiding the expense of large-scale replacements of cable systems.
Prior research on UWB optical networks has generally been confined to idealised laboratory settings, failing to incorporate the limitations of real-world results. The research team restricted the total launch power to reflect real-world constraints on fibre networks, and mitigated inter-channel stimulated Raman scattering with the application of power pre-emphasis across the 15.6 THz optical bandwidth. With this minimisation of signal degradation, it was demonstrated that UWB transmission is able to work effectively under power constraints.
The research highlights a 51.2 % increase in throughput by incorporating the S-band, compared to traditional C+L-band systems. These findings confirm that S+C+L-band transmission is a viable and cost-effective upgrade for existing fibre infrastructure, enabling ultra-high-capacity data networks without major infrastructure replacement.
About the Paper
"Transmission Over Field-Deployed Standard Single-Mode Fibre using >100 nm S+C+L-band" JLT, (2025).
Authors: Jiaqian Yang, Eric Sillekens, Mindaugas Jarmolovicius, Benjamin J. Puttnam, Ronit Sohanpal, Romulo Aparecido, Henrique Buglia, Ruben S. Luis, Ralf Stolte, Polina Bayvel, and Robert I. Killey.