Freiburg 2024 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 37: Poster III

Q 37.45: Poster

Wednesday, March 13, 2024, 17:00–19:00, Tent B

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

Today's IT infrastructure is threatened e.g. by quantum computers implementing Shor's algorithm. Quantum key distribution (QKD) offers a method to make this infrastructure resilient against such future attacks. While various QKD setups have been tested relying on numerous different protocols, most systems do not consider scaling beyond more than two users. We report on a phase-time coding protocol based quantum key hub. The star-shaped layout of our network with an entangled photon pair source as a central untrusted node allows scaling to more than 100 users. We demonstrate the feasibility of a city-wide network by showing results from experiments with parties spatially distributed in separate buildings connected via field-deployed fiber. During a measurement our system is able to generate real-time secure keys, with one of two implemented error-correction algorithms. Furthermore, we demonstrate the plug-and-play flexibility and robustness of our setup allowing for different fiber distances, connected parties and long-time operation over several hours.

Keywords: Quantum Key Distribution; Network; Photon Pair Source; Time Bin Coding; Multi-User