The research team is led by Professor Polina Bayvel, Dr Lidia Galdino and Professor Robert Killey at UCL’s Electronic and Electrical Engineering Department, the co-investigators on the TRANSNET Programme Grant. The team behind the record included researchers and students on the programme and also two of the project partner companies, Xtera and KDDI Research to achieve data transmission rate of 178 terabits a second (178,000,000 megabits a second) – a speed at which it would be possible to download the entire Netflix library in less than a few seconds. There is some debate as to the size of the Netflix library – varying between 100 and a few thousand terabytes. Even for the higher estimate, it would take only a couple of minutes. “However, this is not just about entertainment”, said Professor Polina Bayvel, the Principal Investigator of TRANSNET, “high communications speed and a world-leading digital communications infrastructure will enable a vast array of applications such as remote medicine and tele-care and scientific computing’.
The record, which is double the capacity of any system currently deployed in the world, was achieved by transmitting data through a much wider range of colours of light, or wavelengths, than is typically used in optical fibre. To do this, researchers combined different amplifier technologies needed to boost the signal power over this wider bandwidth and maximised speed by developing new geometric shaping (GS) constellations (patterns of signal combinations that make best use of the phase, brightness and polarisation properties of the light), manipulating the properties of each individual wavelength.
The new record, demonstrated in a UCL lab, is a fifth faster than the previous world record held by a team in Japan. At this speed, it would take less than an hour to download the data that made up the world’s first image of a black hole (which, because of its size, had to be stored on half a ton of hard drives and transported by plane). The speed is close to the theoretical limit of data transmission set out by American mathematician Claude Shannon in 1948.
Lead researcher and author of the paper, Dr Lidia Galdino, a Lecturer at UCL and a Royal Academy of Engineering Research Fellow, said: “While current state-of-the-art cloud data-centre interconnections are capable of transporting up to 35 terabits a second, we are working with new technologies that utilise the existing infrastructure more efficiently, making better use of optical fibre bandwidth and enabling a world record transmission rate of 178 terabits a second.”
Since the start of the COVID-19 crisis, demand for broadband communication services has soared, with some operators experiencing as much as a 60% increase in internet traffic compared to before the crisis. In this unprecedented situation, the resilience and capability of broadband networks has become even more critical. Prof Polina Bayvel, the PI of TRANSNET continued ‘This result helps to maintain the UK leadership in optical communications & networks, and advance this strategically hugely important research area”.
Dr Galdino added: “But, independent of the Covid-19 crisis, internet traffic has increased exponentially over the last 10 years and the growth in data demand is related to the cost per bit going down. The development of new technologies is crucial to maintaining this trend towards lower costs while meeting future data rate demands that will continue to increase, with as yet unthought-of applications that will transform people’s lives.”
This work is also supported by the Royal Academy of Engineering, and a research grant from the Royal Society.