BT has conducted what it says is the world’s first trial of Quantum Key Distribution (QKD), a cryptographic protocol involving quantum mechanics, over a hollow core fiber cable at the BT Labs in Ipswich, England, according to the company. The trials used a new type of optical fiber, Nested Anti-Resonant Nodeless Fiber (NANF) hollow core fiber made by Lumenisity. The QKD system used commercial equipment over a 3.7 mile-long Lumenisity CoreSmart® cable with a hollow, air-filled center.
The QKD system transmits quantum light on a single photon channel, which traditionally necessitates the use of a separate fiber because of “crosstalk.” Because a hollow core fiber doesn’t have internal material, there is less crosstalk, so it is possible to deliver both a high-speed encrypted data stream, and the faint quantum signal that carries the encryption key, over the same fiber.
“Quantum technologies will play an important role in future communications systems globally,” said Professor Andrew Lord, BT’s Head of Optical Network Research. “We’ve proven a range of benefits that can be realized by deploying hollow core fiber for quantum-secure communication. 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.”
Lumenisity’s cable also demonstrated further benefits for the deployment of QKD, as commercial telecommunications equipment will not need to be optimized in order to send a data-encrypted key. “This is critically important because the equipment can be used normally without modifications, an issue that creates added complications for sending secure signals over standard fiber,” Lord said.
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