Institute of Communications and Connected Systems


Beyond Exabit Optical Communications: from new devices, via new dimensions to new systems

Background image of a stylised version of fibre supporting multiple modes, foreground image showing experimental data that presents several cross section of the fibre coloured showing different modes

1 November 2020

Expanding Internet capacity through massive spatial parallelism in optical fibres by combining spatial light modulation with machine learning.

Funder UKRI
Amount 1,200,000 GBP


Research topics High-capacity optical transmission | Massive spatial parallelism | Spatial light modulation


The aim of this fellowship is to develop disruptive approaches through theory and experiment to unlock the capacity of future information systems. To go beyond current channel limits is arguably the greatest challenge faced by digital optical communications. To target it, the proposed research will combine techniques from information theory, coding, higher-dimensional modulation formats, digital signal processing, advanced photonic design, and machine learning to make possible breakthrough developments to ensure a robust communications infrastructure beyond tomorrow.

Optical communications have to-date been able to fulfil the ever-growing data demand whilst simultaneously reducing cost and energy-per bit. However, it is now recognised that systems are rapidly approaching the fundamental information capacity of current transmission technologies, a trend with potential negative impact on the economy and social progress.

To meet future demands with prospective cost and energy savings and avoid the impending exhaust of fibre capacity, the only solution is the emergent technology of spatial division multiplexing (SDM). It provides much wider conduits of information by offering additional means for transporting channels over one single fibre, using multi-mode and multi-core fibres. However, SDM has not yet found a viable path to access this much higher information capacity.

State-of-the-art SDM transceivers are only compatible with few-mode/few-core fibres (~10 paths). This completely defeats SDM's purpose, the installation of new fibres must allow for several decades of capacity growth to offset the high deployment costs of new cables.
This fellowship envisages how to transform SDM technology to drive future optical networks by addressing the key issue overlooked by the research community since the introduction of SDM concepts: optical transceivers must undergo >100-fold integration to enable the benefits of multi-mode/core.


F. M. Ferreira, E. Sillekens, B. Karanov and R. Killey, "Digital Back Propagation via Sub-Band Processing in Spatial Multiplexing Systems," in Journal of Lightwave Technology, vol. 39, no. 4, pp. 1020-1026, 15 Feb.15, 2021, doi: 10.1109/JLT.2020.3046076.

View Principal Investigator's Publications