Toshiba and Orange test quantum encryption on traditional network

Toshiba and Orange have carried out an experiment to test quantum-safe networking that could be applied in existing fibre optic networks.

The two companies announced they have conducted a detailed series of successful evaluations that delivered quantum key distribution (QKD) coexisting alongside conventional dense wavelength-division multiplexing (DWDM) data signals. They also showed 400Gbps quantum secure data transmission with QKD encryption over a 184km fibre link.

According to Toshiba and Orange, the lab evaluations replicated the network architectures, data transmission and multiplexing schemes currently in use, and showed that today’s networks and data can easily and practically be protected from attack by quantum computers.

QKD uses the quantum properties of light to generate and propagate quantum bits used to establish secure keys. This provides protection against key theft threats.

The two companies said that ongoing evaluations, which began earlier this year, show that QKD-secured signals can coexist with classical data transmissions on the same fibre network and demonstrate how QKD technology can be deployed on today’s existing fibre networks alongside existing classical data services. Using QKD on existing fibre networks with QKD transmission offers significant cost savings and increased deployment speed, according to Toshiba and Orange, as it removes the need to use dedicated fibres for QKD transmission.

Following the success of this first phase of evaluations, Toshiba and Orange said they ran further experiments aiming to evaluate QKD deployment in a more complex architecture emulating current fibre network deployments. They said researchers set up a 184km-long network, consisting of three QKD links deployed over sections of standard single-mode fibre and two trusted nodes, representing a typical metro-based fibre network.
 
Each section of the 184km three-link QKD network was equipped with Toshiba’s commercial QKD systems, with quantum-secure encrypted data transmission of a 100Gbps tributary encapsulated in a 400Gbps channel, reflecting transfer rates commonly used in commercial settings.

As part of the evaluation, Toshiba and Orange tested two different types of QKD technology in the end-to-end system. Two 67km sections used Toshiba’s Long-Distance QKD technology, which uses two fibres to carry both quantum and classical signals, while one 50km section used Toshiba’s Multiplexed (MU) QKD technology on which the quantum channel co-propagates with the data channels.

Laurent Leboucher, group chief technology officer and senior vice-president at Orange Innovation Networks, said: “Our last work demonstrates that quantum key distribution can be integrated into existing regional network infrastructures, marking a significant advancement in quantum-secure communications. Working with Toshiba was essential to demonstrate that such innovations could benefit our customers.”

Last year, HSBC joined the BT and Toshiba commercial quantum-secure metro network, connecting its global HQ in Canary Wharf and a datacentre in Berkshire. The quantum-secure transmission test involved sending data over fibre-optic cables between its global HQ in Canary Wharf and the datacentre.