Germany tests hybrid quantum network across mobile and fiber links

Germany’s QuNET initiative has successfully demonstrated hybrid quantum key distribution (QKD) across both mobile and fiber optic communication channels, marking a major advancement toward secure digital communication networks. Supported by a €125 million investment from the German Federal Ministry for Research, Technology, and Space, the project involves leading institutions such as Fraunhofer IOF, Fraunhofer HHI, the Max Planck Institute, and others. Over the past four years, the consortium has completed several real-world tests, including quantum-secured video conferencing between federal agencies, secure data transmission over Berlin’s fiber network, and quantum communication with a research aircraft, showcasing the system’s robustness in complex and mobile environments. A key innovation of the project is the integration of diverse QKD protocols and link types—fiber, free-space optical links, and future satellite nodes—into a single functioning network, a feat not previously published worldwide. The team addressed challenges such as signal degradation in turbulent air by employing free-jet technology to enable mobile and