Optical wireless quantum security: Li-Fi and QKD in one system
The QuINSiDa project has demonstrated an optical free beam system in the laboratory that combines Li-Fi with continuous and discrete variable quantum key distribution (CV-/DV-QKD) in a common architecture
In addition to QKD transmission, the setup integrates encryption, key management system (KMS) and monitoring and is aimed at use in real high-security networks without fiber optic or radio infrastructure. Communication takes place via an optical line of sight, addressing applications in critical infrastructures, industrial campuses, maritime networks, aviation, automotive environments as well as temporary and mobile networks.
Technically, the system uses CV-QKD at 1550 nm, DV-QKD at 810 nm and Li-Fi in the 850-940 nm range. Wavelength separation and optical filtering enable parallel operation without any significant mutual interference. The QKD data is post-processed via the Li-Fi connection, which serves as the only classic channel. A pointing/acquisition/tracking subsystem stabilizes the free beam path, supported by Li-Fi based endpoint localization and feedback. Network management and telemetry, for example via gNMI, are integrated into QKD, Li-Fi and PAT components. Fraunhofer IPMS develops and integrates the Li-Fi and free-beam modules and is working on a telescope setup that will replace fiber optic connections between QKD components and enable a fully wireless QKD-over-Li-Fi scenario.
