Working together to secure future communication systems
Current communication systems could be vulnerable from future technologies such as powerful quantum computers, capable of hacking current encryption protocols. To address this, researchers are working to develop communications networks built on quantum computing to ensure their stability and security. Combining expertise from both sides of the Atlantic will help to speed up deployment of this technology in both the U.S. and the EU. “Quantum communication is a future-proof technology, enabling secure communication independent of future technological developments and inventions,” explains Qurope project coordinator Klaus Jöns(opens in new window) from Paderborn University(opens in new window) in Germany. These future-proof communication networks could also revolutionize the transmission of data and usher in an era of quantum-based internet. “A quantum network can connect quantum devices, enabling exchange of quantum information between novel sensors or computers,” notes Jöns. “Without quantum communication, future quantum devices will be isolated lone warriors, missing the connectivity their classical counterparts build on.”
Need for network infrastructure
Qurope, a transatlantic consortium of scientists from Europe, the United Kingdom and the United States, sought to advance quantum networks by developing new hybrid quantum repeater architecture. Some quantum information can be lost as photons travel through optical fibers as they travel. Quantum repeaters overcome these losses by splitting up the distance between communicators. The consortium was able to test quantum memory systems, thanks to access to quantum-network infrastructure developed by U.S. partners. “The collaboration was crucial to focus on the larger picture,” adds Jöns. “We need a compatible worldwide quantum network infrastructure, and the team at Stony Brook University in the U.S. around Eden Figueroa(opens in new window) has set up a quantum network. We learned a lot from the classical infrastructure they used to set up this network, such as using White Rabbit architecture(opens in new window) as a synchronization mechanism for quantum networks.”
Real-world quantum applications
The project’s new quantum repeater system was based on two innovative technologies pioneered through the project: quantum-entangled photon pairs, with tunable wavelengths and on-demand operation; and broadband ‘quantum memories’, which were designed to store and retrieve entangled photons. Through the project, the team worked on a second-generation quantum repeater architecture, based on two-photon measurements. This two-photon architecture requires on-demand entangled photon pair sources and absorptive quantum memories. “Two-photon architectures promise much higher qubit rates compared to single photon protocols, if we can interface its different technology efficiently,” explains Jöns. The researchers tested both building blocks individually and interfaced them in the laboratory, before testing the system in real-world applications for quantum key distribution via fiber networks and free-space links. “We have teleported quantum bits using two independent quantum light sources over fiber networks and free-space links. Our consortium has been the first to achieve this with semiconductor quantum dots,” notes Jöns.
Rolling out quantum network tech
The collaboration and determination of the researchers have opened a pathway toward large-scale implementation of efficient and secure quantum communication. Based on the successful results of the Qurope project, several partners have started follow-up EU projects to advance the technology readiness level of the quantum repeater system. “We have also joined a company(opens in new window) building quantum network hardware with other researchers to roll out quantum network technology,” says Jöns.