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QuaNTUM: A Modular Quantum Communication Testbed for Scalable Fiber and Satellite Integration

Julien Chénedé, Tjorben Matthes, Josefine Krause, Asli Cakan, Tobias Vogl

Abstract

Secure communication is essential for modern society, from financial transactions to critical infrastructure. As classical encryption faces threats from advancing computational power, quantum communication provides a fundamentally secure alternative based on physical laws. We present QuaNTUM (Quantum Network at the Technical University of Munich), a modular and extensible quantum communication testbed enabling scalable experiments across fiber-based campus networks and satellite-ground links. The terrestrial network connects research institutions in Garching near Munich via single-mode fibers in a star topology with polarization-maintaining components, multiplexers, and time-synchronized analysis modules. Active polarization control and real-time feedback support stable qubit transmission for high-fidelity quantum key distribution and entanglement distribution. A key feature is the integration of deterministic solid-state single-photon sources, including defects in hexagonal boron nitride and excited erbium atoms, with initial deployments on small satellites to bridge terrestrial and free-space channels. As an open-access platform, QuaNTUM enables protocol development, device benchmarking, and hybrid network research, providing a foundation for scalable quantum communication and future global quantum networks.

QuaNTUM: A Modular Quantum Communication Testbed for Scalable Fiber and Satellite Integration

Abstract

Secure communication is essential for modern society, from financial transactions to critical infrastructure. As classical encryption faces threats from advancing computational power, quantum communication provides a fundamentally secure alternative based on physical laws. We present QuaNTUM (Quantum Network at the Technical University of Munich), a modular and extensible quantum communication testbed enabling scalable experiments across fiber-based campus networks and satellite-ground links. The terrestrial network connects research institutions in Garching near Munich via single-mode fibers in a star topology with polarization-maintaining components, multiplexers, and time-synchronized analysis modules. Active polarization control and real-time feedback support stable qubit transmission for high-fidelity quantum key distribution and entanglement distribution. A key feature is the integration of deterministic solid-state single-photon sources, including defects in hexagonal boron nitride and excited erbium atoms, with initial deployments on small satellites to bridge terrestrial and free-space channels. As an open-access platform, QuaNTUM enables protocol development, device benchmarking, and hybrid network research, providing a foundation for scalable quantum communication and future global quantum networks.
Paper Structure (10 sections, 2 figures, 1 table)

This paper contains 10 sections, 2 figures, 1 table.

Table of Contents

  1. Introduction
  2. QuaNTUM Testbed Architecture
  3. Fiber‐Optic Backbone
  4. Timing and Control
  5. Entanglement and QKD Layers
  6. Single‐Photon Emitters in hBN
  7. Deterministic Fabrication
  8. Optical Performance
  9. Integrated photonics
  10. Conclusion

Figures (2)

  • Figure 1: Topology of the QuaNTUM testbed on the Garching campus near Munich: star‐shaped fiber connections using SMF-28 ultra fibers, 780-HP and 1060-XP between the department of physics (TUM‐PH), Electrical Engineering (TUM‐EE), the Max Planck Institute of Quantum Optics (MPQ), the Leibniz Supercomputing Centre (LRZ), the Walter Schottky Institut (WSI), the Walther-Meißner-Institut (WMI) and with the central node in School of Computation, Information and Technology (TUM-MI). An additional special cable with only SMF-28 ultra fibers is connecting directly ZQE and TUM-PH (dotted-line). -- For geographic reference, see the map: https://v.bayern.de/N74hf -- ©Bayerische Vermessungsverwaltung 2025
  • Figure 2: Room-temperature photoluminescence spectrum of a single hBN emitter fabricated by localized electron irradiation, featuring peak emission near 575 nm (orange line). Comparison with a non-irradiated hBN (blue line). Laser excitation at 530 nm and long-pass filter at 550 nm.