SAMOP 2023 – scientific programme

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QI: Fachverband Quanteninformation

QI 6: Poster I (joint session QI/Q)

QI 6.17: Poster

Monday, March 6, 2023, 16:30–19:00, Empore Lichthof

Towards a city-wide quantum key distribution network with a multi-user phase-time coding quantum key hub — •Maximilian Tippmann, Erik Fitzke, Till Dolejsky, Florian Niederschuh, and Thomas Walther — TU Darmstadt, Institute of Applied Physics, 64289 Darmstadt

Quantum key distribution (QKD) paves a way to make today's IT-infrastructure resilient against future attacks e.g. from quantum computers. Various QKD protocols and setups have been tested over the last decades. However, most experiments focus on two-user systems, thus not allowing an easy scaling to multiple users. Here, we report on a quantum key hub implementing the phase-time protocol with a central untrusted node for simultaneous pairwise key exchange, tested with four users, but readily scalable to more than 100 users. The central untrusted node consists of an entangled photon pair source, and provides high-flexibility, allowing plug-and-play reconfiguration of the connected parties. Furthermore, the setup has been tested with real-world deployed fiber demonstrating the practicability of our approach. Going towards a city-wide deployment, we look into setup specific issues, including post-processing and alignment of the setup, arising from the distribution of the communicating parties to a city-wide scale.