Until now, most quantum telecommunication systems were based on dedicated fiber optic networks, which limited their flexibility and application possibilities. QuINSiDa has now developed an integrated optical wireless quantum security setup in the lab that combines free-space continuous and discrete-variable QKD (CV-/DV-QKD) with Li-Fi and enhances it with encryption including key management (KMS) and monitoring. The system operates via line-of-sight and enables quantum-safe key distribution for applications in civil critical infrastructures (e.g. maritime networking), industrial campuses, aviation, automotive environments, temporary secure networks and connections between fixed and mobile endpoints. The design allows convenient deployment and monitoring of the system while remaining compatible with existing security workflows. With this development, Germany is moving closer to a future scenario in which quantum-safe communication is increasingly used for mobile security applications that can be deployed anywhere optical wireless connections are possible. This brings quantum-safe encryption to real-world operating environments and provides a powerful tool for protecting critical infrastructures.
Focus of Fraunhofer IPMS work in the project
In the QuINSiDa project, the Fraunhofer Institute for Photonic Microsystems IPMS is responsible in particular for the development and integration of Li-Fi-based optical wireless communication. Li-Fi (Light Fidelity) is a wireless communication technology that uses light for data transmission and enables high-speed data transmission, improved security and minimal interference. It was developed specifically for environments where radio communication is limited or where secure data exchange is essential. In the QuINSiDa project, the institute provides the optical transmitter and receiver systems and combines them with quantum key distribution (QKD) to enable wireless quantum-safe data transmission. The basis for this is Fraunhofer IPMS’s more than 15 years of experience in the development of optical-wireless Li-Fi systems and the integration of optoelectronic components. In addition, Fraunhofer IPMS is working on an optical free-beam system based on a telescope structure, which will replace the previously used fiber optic connection between the QKD components and thus pave the way for a completely wireless QKD-over-Li-Fi system.
Technical highlights
The breakthrough was achieved in an approach based on a combination of Li-Fi and QKD that enables a line-of-sight connection. Li-Fi and QKD are integrated in the same optical wireless environment:
- Continuous-variable QKD at 1550 nm
- Discrete-variable QKD at 810 nm
- Li-Fi in the 850-940 nm range
Wavelength separation and optical filtering allow all three systems to operate simultaneously without causing mutual interference. The QKD data is post-processed via the Li-Fi connection instead of using a dedicated channel. The Li-Fi link is therefore the only channel required for traditional communication.
Maintaining a stable free-space optical link requires precise alignment, which the QuINSiDa system achieves using a pointing/acquisition/tracking (PAT) subsystem. Li-Fi supports the identification/localization of the endpoints and provides a feedback channel, allowing the PAT to acquire and maintain the alignment for the quantum link. An interface concept was implemented in the project in which both CV-QKD and DV-QKD were used and all signal properties relevant for QKD are retained. The control and telemetry of the PAT are fully integrated into the overall communication flow. At the same time, network management workflows and telemetry (e.g. via a gNMI-based approach) are adapted to QKD/Li-Fi/PAT components. The result is an end-to-end system that goes beyond a pure laboratory demonstration and is designed for real-life applications in areas with increased security requirements.
Consortium
QuINSiDa was carried out by a consortium of six partners: KEEQuant GmbH (coordination; CV-QKD, integration of key management), Fraunhofer Institute for Photonic Microsystems IPMS (Li-Fi and free beam interconnect components; PAT), Fraunhofer Institute for Applied Optics and Precision Engineering IOF (contribution to DV-QKD), Infosim GmbH & Co. KG (integration of monitoring and network management systems), TELCO TECH GmbH (integration of encryption) and BESCom Elektronik GmbH (use cases, transfer and dissemination).
– – – – – –
Further links
👉 www.ipms.fraunhofer.de
Photo: AI-generated
