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 and untrusted nodes. Unlike conventional QKD networks that predominantly depend on either fiber-based or free-space optical (FSO) links, the testbed presented amalgamates 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.
@article{arxiv.2412.07473,
title = {Ad-hoc hybrid-heterogeneous metropolitan-range quantum key distribution network},
author = {Matthias Goy and Jan Krause and Ömer Bayraktar and Philippe Ancsin and Florian David and Thomas Dirmeier and Nico Doell and Jansen Dwan and Friederike Fohlmeister and Ronald Freund and Thorsten A. Goebel and Jonas Hilt and Kevin Jaksch and Oskar Kohout and Teresa Kopf and Andrej Krzic and Markus Leipe and Gerd Leuchs and Christoph Marquardt and Karen L. Mendez and Anja Milde and Sarika Mishra and Florian Moll and Karolina Paciorek and Natasa Pavlovic and Stefan Richter and Markus Rothe and René Rüddenklau and Gregor Sauer and Martin Schell and Jan Schreck and Andy Schreier and Sakshi Sharma and Simon Spier and Christopher Spiess and Fabian Steinlechner and Andreas Tünnermann and Hüseyin Vural and Nino Walenta and Stefan Weide},
journal= {arXiv preprint arXiv:2412.07473},
year = {2025}
}