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Toshiba Europe and Orange successfully evaluated quantum-secure solutions suitable for today’s telecoms networks

Cambridge, United Kingdom/ Paris, France, 22 February 2024: Toshiba Europe Ltd. and global telecommunications operator Orange have conducted a detailed series of successful evaluations that firstly delivered QKD co-existing alongside high number of conventional DWDM data signals and then showed 400Gbit/s quantum secure data transmission with QKD encryption over a 184km fibre link (three QKD links and two trusted nodes, with one having QKD and classical data co-existing).

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.

The growing power and availability of quantum computing means that current public key encryption methods could soon be rendered insecure. QKD, which uses the quantum properties of light to generate and propagate quantum bits used to establish secure keys, provides protection against key theft threats, but can face challenges in being successfully deployed on current networks that are designed to only carry classical data signals.

As a result of ongoing evaluations earlier this year, Toshiba and Orange demonstrated that QKD-secured signals can co-exist with classical data transmissions on the same fibre network, showing how QKD technology can be easily deployed on today’s existing fibre networks alongside existing classical data services. Using QKD on these already deployed fibre networks provides significant cost savings and increased deployment speed as it removes the need to use dedicated fibres for QKD transmission.

Following the success of this first phase of evaluations, Toshiba and Orange carried out further experiments which sought to evaluate QKD deployment in a more complex architecture emulating current fibre network deployments. 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.

The Toshiba Quantum Key Management System was used to ensure delivery of quantum secure keys across the network to encryption devices. Adtran’s FSP 3000 open optical transport technology and Adva Network Security’s ConnectGuard™ technology supported the encryption of data within the 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.

Overview of the end-to-end network

Researchers measured the overall secret key rates (SKRs) to evaluate the success of the QKD deployment across the network. The SKRs measured from tens to hundreds of kbps show that QKD secret keys could be easily exploited and employed by already deployed 100Gbps WDM systems and up-coming 400Gbps WDM channels with quantum bit error rates (QBER) comfortably below set thresholds despite the overall complexity of the network. Overall, findings from the evaluations demonstrated the practicality of QKD coexisting on deployed fibre networks with end-to-end high speed encrypted data transmission across multiple extended fibre links and trusted nodes.

“Data security is the bedrock of our services at Orange, and we’re excited to reveal the successful outcomes of our collaboration with Toshiba,” stated Laurent Leboucher, Group CTO and SVP, Orange Innovation Networks.” Our last work demonstrates that quantum key distribution (QKD) 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 to our customers.”

“We’ve seen that many organizations are moving from merely evaluating the threat posed by quantum computing to taking action to protect themselves,” said Dr Andrew Shields, Head of the Toshiba Quantum Technology Division. “These lab evaluations have demonstrated that our QKD technology can be successfully deployed on real-life networks for real-life applications, today, without the need for further investment in new infrastructure. It’s been a pleasure to work with operators like Orange to test the viability of the QKD technology use in today’s networks, and we look forward to helping organizations protect their communications now and into the future.”

As part of the evaluations, Toshiba and Orange tested two different types of QKD technology within the end-to-end system. Two 67km sections used Toshiba’s Long-Distance (LD) 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.

The research paper provides experimental results and important considerations to have when organizations plan to implement QKD to protect their communications by demonstrating how it’s possible for high speed quantum secure data encryption to be deployed over multi-link fibre networks, coexisting with conventional data services utilizing the type of network infrastructure often used in metropolitan settings. To read the full research paper, please visit:

For more information on Toshiba’s QKD services and quantum technology offerings, please visit:


About Toshiba

Toshiba Corporation leads a global group of companies that combines knowledge and capabilities from almost 150 years of experience in a wide range of businesses—from energy and social infrastructure to electronic devices—with world-class capabilities in information processing, digital and AI technologies. These distinctive strengths support Toshiba in building infrastructure that everyone can enjoy, and a connected data society, and in achieving the Company’s ultimate goal, a future that realizes carbon neutrality and a circular economy. Guided by the Basic Commitment of the Toshiba Group, “Committed to People, Committed to the Future,” Toshiba contributes to society’s positive development with services and solutions that lead to a better world. The Group and its 110,000 employees worldwide secured annual sales of 3.4 trillion yen (US$25.1 billion) in fiscal year 2022.

Find out more about Toshiba at

About Orange 

Orange is one of the world’s leading telecommunications operators with revenues of 43.5 billion euros in 2022 and 137,000 employees worldwide at 30 September 2023, including 73,000 employees in France. The Group has a total customer base of 296 million customers worldwide at 30 September 2023, including 251 million mobile customers and 25 million fixed broadband customers. The Group is present in 26 countries. Orange is also a leading provider of global IT and telecommunication services to multinational companies under the brand Orange Business. In February 2023, the Group presented its strategic plan “Lead the Future”, built on a new business model and guided by responsibility and efficiency. “Lead the Future” capitalizes on network excellence to reinforce Orange’s leadership in service quality. 

Orange is listed on Euronext Paris (symbol ORA) and on the New York Stock Exchange (symbol ORAN). 

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Orange and any other Orange product or service names included in this material are trademarks of Orange or Orange Brand Services Limited. 

Contact Information:
George Pope, Nelson Bostock Unlimited
[email protected]  

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