QuNET & FuNK - Compact optical communication systems for quantum-safe information exchange between authorities

The threat of cyber attacks by future quantum computers requires new systems to secure communication, especially between national authorities and international organizations. To this end, the continuation of the QuNET project is developing optical communication systems that use quantum key distribution (QKD) as well as data transmission via free-space optical links and satellite radio. So-called fixed nodes are to ensure communication over distances of a few kilometers in the event that fiber optic networks are disrupted or unavailable. Mobile nomadic nodes will also be used to meet short-term communications requirements and for applications in the field. Optical signals are transmitted via telescopes. In addition to the QKD channel, a conventional communication link is to be provided via the same optical path, and a connection via satellite radio is to be made possible.

The goal of the development is compact and robust communication nodes with easy handling at a low price. The flexible design of the terminal and the resulting possibility to use other transmission protocols also expands the potential user base outside of government networks. In this subproject, the Fraunhofer IPMS and the Fraunhofer IOF are jointly working on the development of an eye-safe system for optical wireless communication for a distance of up to two km. In addition, a PAT (pointing acquisition tracking) system for link establishment between two nodes is to be developed, which can be used for optical wireless communication and free-beam QKD.

The task of Fraunhofer IPMS is to develop a suitable beam steering system for use in quantum technologies as well as for classical data transmission using Li Fi. At the end of the subproject, the subsystems developed by the Fraunhofer institutes, LiFi, PAT and QKD, will be integrated into a demonstrator together with the modules of the other project partners and the functionality of a quantum key transmission between any two nodes will be proven. The overall system is also to be finally demonstrated in key experiment 4 of the QuNET core project.