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BT trials quantum-secure communications over hollow core fibre

UK incumbent operator BT has conducted a trial of Quantum Key Distribution (QKD) over hollow core fibre cable, from Southampton University spin out, Lumenisity.

Earlier this year the operator trialled Nested Anti-Resonant Nodeless Fibre (NANF) hollow core fibre at its Ipswich lab to test the potential benefits of the technology for different scenarios. This latest trial saw researchers successfully operate a s QKD system that was provided on loan by the EU OpenQKD project, using commercial equipment over a 6km-long Lumenisity CoreSmart cable with a hollow, air-filled centre. This, the researchers believe, revealed potential benefits such as reduced latency and no appreciable crosstalk.

In QKD systems, quantum light is transmitted on a single photon channel, which has traditionally necessitated the use of a separate fibre, due to crosstalk interfering with a quantum signal carried over the same fibre. Hollow core fibre is designed to negate this, as it doesn’t have internal material so there should be less light scattering and less crosstalk between channels, even at a single photon level. 

The researchers found that the hollow core cable demonstrated additional benefits for QKD deployment, as commercial telecommunications equipment will not need to be optimised in order to send a data-encrypted key. This is important because the equipment can be used normally without modifications for sending secure signals over standard fibre.

Professor Andrew Lord, BT’s head of optical network research, said: ‘This is an exciting milestone for BT, accelerating the UK’s lead in quantum technologies that will play an important role in future communications systems globally.  We’ve proven a range of benefits that can be realised by deploying hollow core fibre for quantum-secure communication. Hollow core fibre’s low latency and ability to send QKD over a single fibre with other signals is a critical advancement for the future of secure communications.’

Tony Pearson, VP sales and marketing at Lumenisity, added: ‘We are excited to be identifying new applications for our field deployable CoreSmart cable solutions and working with the BT team on the first trial in the world of this kind. This milestone further accentuates not just the capability of our hollow core cable solutions, offering low latency and high bandwidth, but also demonstrating the potential CoreSmart has in new applications thanks to ultra low non-linearity and dispersion across a broad spectrum, perfect for networks operated by our Carrier partners.’


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