BT eyes quantum security boost with hollow core fiber trial

U.K. operator BT claimed a world first with trial of quantum key distribution (QKD) over hollow core fiber, touting the technology as a way to beef up security for data in transit.

Andrew Lord, BT’s Head of Optical Network Research, in a statement hailed the trial as “an exciting milestone,” adding “hollow core fiber’s low latency and ability to send QKD over a single fiber with other signals is a critical advancement for the future of secure communications.”

As the name suggests and unlike traditional fiber made of solid glass strands, hollow core fiber (HCF) is designed with an air-filled center channel surrounded by an outer glass shell. BT first unveiled its work with hollow core fiber in June, stating at the time it was testing a variety of characteristics related to performance.

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In its latest trial, the operator deployed a QKD system on loan from the European Union's OpenQKD project over a six kilometer-long stretch of HCF from vendor Lumenisity. QKD takes encryption a step beyond today’s technology by using a stream of photons to transmit encryption keys between locations for enhanced security. Any attempt to intercept the keys disrupts the photons and exposes a potential attack.

BT said in a press release the test showed HFC is an ideal conductor of QKD signals, enabling reduced latency and cutting down on interference between signals being transmitted over the fiber. It noted it was able to conduct the tests without modifying or optimizing Lumenisity's cable, which it touted as a "critically important" feature that would help avoid "added complications for sending secure signals over standard fiber."

The operator’s trial of QKD over HCF follows its deployment alongside Toshiba of the first industrial QKD network in the U.K. using standard fiber in October 2020.

Other operators around the globe have also been pursuing QKD: Deutsche Telekom, Orange and Telefonica are all listed as OpenQKD partners while Colt Technology Services tested the technology with ADVA earlier this year. In September 2020, U.S. operator Verizon detailed a trial of QKD over its fiber network in which it added an additional layer of security using a Quantum Random Number Generator.