The QTF-Backbone: Proposal for a Nationwide Optical Fibre Backbone in Germany for Quantum Technology and Time and Frequency Metrology

Authors:Tara Cubel Liebisch, Peter Kaufmann, Harald Schnatz, Susanne Naegele-Jackson, Jochen Kronjäger, Klaus Blaum, Stefan Kück, Dieter Meschede, Stephan Schiller, Laura Agazzi, Soroosh Alighanbari, Joachim Ankerhold, Georgy V. Astakhov, Stefanie Barz, Ingo Baumann, Rainer Baumgart, Christoph Becher, Hendrik Bekker, Oliver Benson, Paolo Bianco, Ronald Bieber, Immanuel Bloch, Ulrike Blumröder, Rainer Bockholt, Johannes Bouman, Claus Braxmaier, Enrico Brehm, Dagmar Bruss, Dmitry Budker, Hans-Joachim Bungartz, Erik Busley, José R. Crespo López-Urrutia, Cornelia Denz, Christian Deppe, Guido Dietl, Fei Ding, Thomas Eickermann, Florian Elsen, Wolfgang Ertmer, Stefan Filipp, Marc Fischer, Jakob Flury, Thomas Fröhlich, Johann Furthner, Ilia Gerhardt, Kay Uwe Giering, Christoph Glingener, Helmut Grießer, Rüdiger Grimm, Christian Grimm, Andreas Gritsch, Fritz Hack, Theodor Hänsch, Thomas Halfmann, Andreas Hanemann, Daniel Harlacher, Niklas Hegemann, Tobias Heindel, Robert Heinkelmann, Luis Hellmich, Thomas Hildmann, David Hock, Sven Höfling, Bruno Höft, Harald Hofmann, Peter Holleczek, Ronald Holzwarth, Wolfgang Hommel, Thomas Hühn, Urs Hugentobler, David Hunger, Nils Huntemann, Cigdem Issever, Fedor Jelezko, Klaus Jöns, Tim Johann, Philippe Jousset, Bernd Jungbluth, Franz Kärtner, Jonas Kankel, Heike Kaufmann, Dmitry Khabi, Thomas Kissinger, Carsten Klempt, Thomas Klügel, Ann-Kathrin Kniggendorf, Jan Kodet, Uwe Konrad, Joachim Kopp, Michael Kramer, Stefan Kremling, Michael Krist, Markus Krutzik, Sascha Kwasniok, Yvonne Leifels, Gerd Leuchs, Christian Lisdat, Yuri Litvinov, Manfred Lochter, Peter van Loock

et al. (69 additional authors not shown)

Abstract:The recent breakthroughs in the distribution of quantum information and high-precision time and frequency (T&F) signals over long-haul optical fibre networks have transformative potential for physically secure communications, resilience of timing infrastructure (such as that supporting Global Navigation Satellite Systems (GNSS)) and fundamental physics. To date, these capabilities remain confined to isolated testbeds, with quantum and T&F signals accessible, for example in Germany, to only a few institutions. In this white paper we propose the QTF Backbone: a dedicated national fibre-optic infrastructure in Germany for the networked distribution of Quantum and T&F signals using dark fibres and specialised hardware. The QTF Backbone is planned as a four-phase deployment over ten years to ensure scalable, sustainable access for research institutions and industry. The concept builds on successful demonstrations of time and frequency distribution at high Technology Readiness Levels (TRLs) across Europe, including PTB-MPQ links in Germany, REFIMEVE in France, and the Italian LIFT network. The QTF Backbone will enable transformative Research and Development (R&D), support a nationwide QTF ecosystem, and ensure the transition from innovation to deployment. As a national and European hub, it will position Germany and Europe at the forefront of quantum networking, as well as T&F transfer.

60 pages, 7 figures This version of the article has been accepted for publication, after peer review (when applicable) but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: this https URL

Instrumentation and Detectors (physics.ins-det); Atomic Physics (physics.atom-ph); Geophysics (physics.geo-ph); Quantum Physics (quant-ph)

arXiv:2506.03998 [physics.ins-det]

(or arXiv:2506.03998v3 [physics.ins-det] for this version)

Liebisch, T.C., Kaufmann, P., Schnatz, H. et al. The QTF Backbone: proposal for a nationwide optical fibre backbone in Germany for quantum technology and time and frequency metrology. Eur. Phys. J. Spec. Top. 235, 3353-3387 (2026)

https://doi.org/10.1140/epjs/s11734-026-02451-3 DOI(s) linking to related resources