Toshiba Europe and Single Quantum have partnered to validate and deploy novel solutions for extending Quantum Key Distribution (QKD) beyond current limits. By combining Toshiba's QKD systems with Single Quantum's superconducting nanowire single photon detectors (SNSPDs), the companies have devised a solution that effectively doubles the transmission range of QKD from 150 km to 300 km over fibre connections.

Previously, extending QKD over longer distances presented significant difficulties. The traditional method required operators to link together fibre links with trusted nodes that housed QKD systems to relay secret keys. However, this setup is not feasible for certain networks, such as marine fibre links and cross-border fibre links.

These issues could become a thing of the past with this significant breakthrough in quantum secure communications. With the new solution developed by Toshiba and Single Quantum, networks that were previously impractical to secure with multi-node setups can now employ QKD technology. This technological advancement offers a step closer to a quantum secure future, particularly for various remote areas where suitable buildings for trusted nodes are absent.

The companies' partnership involved special validation testing of Toshiba’s QKD technology and Single Quantum’s SNSPD. The latter's SNSPDs have a distinctive capability to precisely detect single photons over higher optical loss fibre links. This in turn substantially extends the QKD transmission distance on a single fibre optic link.

This combined approach has enabled Toshiba and Single Quantum to extend the range of QKD transmission from 150km to distances beyond 300km. This breakthrough has been made possible by the lower noise and higher detection efficiency of Single Quantum’s SNSPDs, which also mitigates the challenges of identifying higher loss fibre links.

Moreover, Toshiba’s QKD technology integrated with Single Quantum’s SNSPDs presents a compact, stackable and rack-mountable solution for extended long-distance QKD transmission over a single fibre link. This development simplifies the process of setting up quantum-secure communications, making it more accessible and effective.

"Forward-thinking organisations are already deploying QKD on networks to protect their data from the risk posed by quantum computers," stated Dr Andrew Shields, Head of the Toshiba Quantum Technology Division. "The ability to provide users with long-distance networks, without the need for additional infrastructure to link together different nodes, is vital for ensuring that quantum-secure communications are accessible and effective."

Jessie Qin-Dregely, COO of Single Quantum, expressed excitement about the partnership with Toshiba: "Quantum technology has huge potential to revolutionise a wide range of sectors from security to telecommunications, through technologies such as QKD, quantum computing, and quantum networking." He stresses that the partnership aptly demonstrates how quantum companies can collaborate to overcome crucial challenges and fully harness the power of quantum technology.