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New Journal of Physics

Ad-hoc hybrid-heterogeneous metropolitan-range quantum key distribution network

Matthias Goy, Jan Krause, Ömer Bayraktar, Philippe Ancsin, Florian X. David, Thomas Dirmeier, Nico Doell, Jansen Dwan, Friederike Fohlmeister, Ronald E. Freund, Thorsten A. Goebel, Jonas Hilt, Kevin Jaksch, Oskar Kohout, Teresa Kopf, Andrej Kržič, Markus Leipe, Gerd Leuchs, Christoph Marquardt, Karen Lozano-Mendez, Anja Milde, Sarika Mishra, Florian Moll, Karolina Paciorek, Natasa Pavlovic Tucakovic, Stefan Richter, Marcel Rothe, René Rüddenklau, Gregor Sauer, Martin A. Schell, Jan Schreck, Andy Schreier, Sakshi Sharma, Simon Spier, Christopher Spiess, Fabian Steinlechner, Andreas Tünnermann, Hüseyin Avni Vural, Nino Walenta, Stefan Weide

Published Oct 28, 2025• 6 citations

Abstract

Abstract This paper presents the development and implementation of a versatile ad-hoc metropolitan-range quantum key distribution (QKD) network. The approach presented integrates various types of physical channels and QKD protocols, and a mix of trusted nodes and intermodal coupling. Unlike conventional QKD networks that predominantly depend on either fiber-based or free-space optical (FSO) links, the testbed presented incorporates FSO and fiber-based links, thereby overcoming some inherent limitations. Various network deployment strategies have been considered, including permanent infrastructure and provisional ad-hoc links to eradicate coverage gaps. Furthermore, the ability to rapidly establish a network using portable FSO terminals and to investigate diverse link topologies is demonstrated. The study also showcases the successful establishment of a quantum-secured link to a cloud server.

DOI: 10.1088/1367-2630/ae1864

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