An interdisciplinary team of researchers and companies in Germany has demonstrated the integration of quantum key distribution (QKD) with Li-Fi technology for the first time. The demonstration was carried out as part of the BMBF-funded project “QuINSiDa” and showcased at the PMRExpo exhibition in Köln, Germany.
While QKD produces ultra-secure keys used for encrypting data, it relies on an optical line of sight connection to work – the very principle underlying Li‑Fi – making them a natural match. This fusion unlocks innovative applications that combine ultra‑high data security with the speed and efficiency of LED‑based Li‑Fi. Key applications include local quantum networks (Q‑LANs) for campuses, as well as fixed‑to‑mobile connections for airports, planes, shipyards, ships, and critical infrastructure.
Technological details
Developed by consortium partners, the key technologies include:
Li-Fi (Light Fidelity): is a wireless communication technology that utilizes light to transmit data, providing high-speed data transfer, enhanced security, and minimized interference. It is specifically designed for environments where radio frequency communication is restricted or where secure data exchange is essential. The Fraunhofer Institute IPMS in Dresden is designing these systems and provides both sender and receiver within the project.
QKD and KMS: KEEQuant GmbH in Fürth is developing a continuous‑variable quantum key distribution (CV‑QKD) system. Built on standard coherent communication fiber optics, it leverages Heisenberg’s uncertainty principle for quantum security, operates at room temperature, and fits in a standard 19″ rack. An accompanying Key Management System supplies encryption keys to applications. The project focuses on seamless system integration and protocols tailored for campus networks.
Networking Monitoring: Monitoring systems combined with meaningful dashboards are crucial for many reasons. In addition to visualizing a general overview, it is also helpful to get deep insights into the status of individual devices or the overall health of the network. QKD applications and devices are not yet widely available, especially in a fibreless version. As part of the QuINSiDa project, KeeQuant has been working on the interfaces to the QKD and KMS systems as well as to the Li-Fi and PAT systems. For the QKD connection, we have built on the ETSI QKD standards. The PMR-Expo dashboard provided by Infosim® shows a logical representation of the demo with status indicators of each device. In addition, the relevant metrics, such as key rate and error rate, were visualized as time series.
Integrating these technologies enabled a two‑node demonstration in which the classical communication channel between CV‑QKD devices - typically connected by cable - was replaced by a wireless Li‑Fi link.
BESCom GmbH, investigating these use cases, predicts that mobile high‑security data communication will play a crucial role in the future of both mobile and optical networks.
The optical fiber linking the quantum components of the two QKD systems will later be replaced by a telescope developed by Fraunhofer IPMS, enabling a fully wireless system. Moreover, project partners plan to integrate an encrypted link (Telco Tech GmbH) and an entanglement‑based QKD system (Fraunhofer IOF, Jena), laying a robust foundation for future experiments and products targeting high‑security campus networks and fixed‑to‑mobile scenarios. Further updates on the project will be communicated through the communication channels of the involved partners.
Funding acknowledgement
This project was funded by the Federal Ministry of Education and Research (BMBF) Germany under project number 16KISQ082K.
Fraunhofer Institute for Photonic Microsystems
