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Q: Fachverband Quantenoptik und Photonik
Q 58: Quantum Communication II: Implementations (joint session QI/Q)
Q 58.1: Vortrag
Donnerstag, 13. März 2025, 14:30–14:45, HS IX
Darmstadt quantum local area network (DaQLAN) — •Maximilian Tippmann1, Florian Niederschuh1, Maximilian Mengler1, Erik Fitzke2, Oleg Nikiforov2, and Thomas Walther1 — 1TU Darmstadt, Institute of Applied Physics, 64289 Darmstadt — 2Deutsche Telekom Technik GmbH, Darmstadt, Deutschland
Quantum computers can threaten today's IT infrastructure e.g. by implementing Shor's algorithm. Quantum key distribution (QKD) enables users to share a random secret, thus offering resilience against such attacks by choosing other cryptographic primitives. Many QKD systems based on various protocols have been tested. Often, these protocols are susceptible to drifts in the properties of the transmission link (e.g. changing polarization) and do not offer scalability to more than two users, hence, they are not ideal for real-world applications. We present a city-wide field test of our star-shaped QKD network enabling scalability to more than 100 users. A central untrusted node acts as a photon pair source. The phase-time coding protocol makes our setup independent of polarization drifts in the transmission links. We show results with four parties all being placed at different locations within the city and connected via field-deployed fibers exchanging pairwise keys. Our system features a complete post-processing allowing to generate real-time secure keys. Additionally, we demonstrate the plug-and-play flexibility of our network by showcasing various operation modes and combinations of receiver pairs.
Keywords: Quantum Key Distribution; Network; Photon Pair Source; Time Bin Coding; Multi-user