Researchers have tested an underwater fibre-optic cable to pass quantum communications between the Republic of Ireland and England.
Led by Professor Marco Lucamarini from the University of York’s Institute for Safe Autonomy, the researchers ran a series of experiments using the network cable, called Rockabill.
The fibre-optic cable is the longest used to enable quantum communications underwater, connecting Ireland to the UK. The cable runs 224 kilometres between Portrane in Ireland and Southport in England.
This network is owned and operated by euNetworks.
It is one of the newest commercial optical fibre systems in operation.
What are the limitations of quantum communications?
Quantum communications operate through particles of light that transmit data along optical cables in a highly fragile state. This means that the particles collapse if interfered with someone trying to manipulate or steal private data in transit.
Professor Lucamarini said: “Many large companies and organisations are interested in quantum communications to secure their data, but it has limitations, in particular the distance it can travel.
“The longer the distance, the more likely it is that photons – the particles of light that we use as carriers of quantum information – are lost, absorbed or scattered in the channel, which reduces the chances of the information reaching its target.
“This presents a problem when organisations need to send private information to other countries, where the additional challenge could be an ocean between the communications’ start and end point.”
How does an underwater cable remove this limitation?
The researchers used the underwater cable system between England and Ireland to reduce the chance of quantum information being lost. The underwater system allowed the particles to enter the link to reach the other end of the communication channel.
The link has very little time delay and therefore has a fast connection for sending and receiving data. This is extremely important for financial transactions.
Professor Lucamarini said: “This is a truly exciting step forward in realising the full potential of quantum communications and for the future of securing private data in an environment that is shaping the so-called “quantum internet”.
“This project also advances the real-world integration of quantum communication technology into existing global telecommunications and network infrastructure – taking it out of the lab into a ‘real-world’ scenario.”
The success was linked to sensitive detectors
The team believes that the success of the experiments was due to the highly sensitive detectors deployed at the Southport endpoint of the cable. These were used to reduce environmental, or noise, interference.
This interference is similar to the interference from the Sun on a laptop screen. When external light is reduce in this instance, the user can function as normal.
Paula Cogan, Chief Executive Officer of euNetworks, said: “We are proud to support a critical project that pushes the boundaries of quantum technology and has implications for the future of network security.
“The successful integration of quantum technology over commercial-grade optical fibre infrastructure at this distance is an exciting step forward. Rockabill, and the euNetworks’ Super Highway network it is part of, provide the ideal platform for new and progressive technologies that will enhance and innovate future network infrastructure.”
Future uses of the cable line
More experiments will be carried out using the same cable line to pave the way for innovations in quantum communications.
In the future, the team hope that the services offered by quantum technologies can be integrated into standard communications for industries sending private data between the UK and Ireland.
