Deployed trusted-node quantum key distribution over 300 km with a multi-core fiber access link

• URL: http://arxiv.org/abs/2606.06107v1
• Date: Thu, 04 Jun 2026 12:53:46 GMT
• Title: Deployed trusted-node quantum key distribution over 300 km with a multi-core fiber access link
• Abstract summary: Quantum key distribution (QKD) is increasingly considered for deployment in realistic communication networks.<n>Here, we demonstrate trusted-node QKD between Linkping University and the Stockholm hub of the Swedish national quantum communication infrastructure.
• Score: 4.8015208893445385
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Quantum key distribution (QKD) is increasingly considered for deployment in realistic communication networks, where long distances, heterogeneous fiber infrastructure, and coexistence with classical traffic present substantial challenges. Here, we demonstrate trusted-node QKD between Linköping University and the Stockholm hub of the Swedish national quantum communication infrastructure over 270 km of deployed single-mode fiber, extended by a 33 km multi-core fiber (MCF) segment emulating a metropolitan access link, for a total distance of 303 km. The two sub-links use commercial QKD systems whose receivers are interfaced with external superconducting nanowire single-photon detectors, enabling operation at losses beyond those supported by standard internal gated-mode detectors. We operate the link while actively switching the QKD channel between two MCF cores, with co-propagating Ethernet traffic and injected broadband optical noise in the other cores. The results demonstrate the integration of commercial QKD into demanding, dynamically reconfigurable fiber infrastructure relevant to future hybrid quantum-classical networks. Finally, using the generated secret keys, we illustrate how limited and time-varying QKD throughput affects one-time-pad-protected image transmission: image fidelity depends strongly on the available QKD-generated key budget and the choice of compression algorithm, highlighting application-level challenges for QKD-based encryption in realistic scenarios.

Related papers

• Secure Medical Data Transmission Using Quantum Key Distribution and Post-Quantum Cryptography in Real-World Fiber Networks [28.447055318796842]
  Quantum key distribution (QKD) and post-quantum cryptography (PQC) offer complementary security guarantees.<n>We demonstrate a field-deployed quantum-secure network integrating entanglement-based QKD with end-to-end PQC over 140 km of installed fiber in Thuringia, Germany.<n>The generated keys secured a telemedicine proof-of-concept without modifying existing medical systems.
  arXiv  Detail & Related papers  (2026-08-19T12:46:33Z)
• Deploying and validating a metropolitan QKD secure network: architecture and field performance [76.02413102965598]
  Quantum Key Distribution provides information-theoretic security for key establishment.<n>A metropolitan-scale quantum-secure network between data centers in Milan is reported.<n>Results establish the technical and operational readiness of metropolitan QKD networks for production deployment.
  arXiv  Detail & Related papers  (2026-07-13T15:51:26Z)
• Multi-node quantum key distribution network using existing underground optical fibre infrastructure [0.0]
  This work demonstrates the first quantum communication network in Cyprus via the deployment of a multi-node quantum network.<n>Results obtained reveal consistent key generation rates across all nodes, confirming reliable operation in a real-world environment.
  arXiv  Detail & Related papers  (2025-12-02T12:30:12Z)
• Coexistence of continuous-variable quantum key distribution and classical data over 120-km fiber [0.0]
  We show the longest quantum-distance continuous QKD over 120 km (20 dB loss) in the finite-size regime, and over 100 km (17 dB loss) in the finite-size regime.<n>Our results set a record fiber distance for CV-QKD, showing its potential for cost-effective, large-scale deployment in existing network infrastructure.
  arXiv  Detail & Related papers  (2025-02-24T18:14:09Z)
• Time-bin encoding quantum key distribution in free-space horizontal links during nighttime and daytime [36.136619420474766]
  We demonstrate the viability of a time-bin encoded QKD protocol operating in the C-band through horizontal turbulent free-space channels.<n>The results encourage further exploration of the interoperability between free-space and fiber-based infrastructures.
  arXiv  Detail & Related papers  (2025-01-15T16:01:58Z)
• Practical hybrid PQC-QKD protocols with enhanced security and performance [44.8840598334124]
  We develop hybrid protocols by which QKD and PQC inter-operate within a joint quantum-classical network. In particular, we consider different hybrid designs that may offer enhanced speed and/or security over the individual performance of either approach.
  arXiv  Detail & Related papers  (2024-11-02T00:02:01Z)
• Metropolitan quantum key distribution using a GaN-based room-temperature telecommunication single-photon source [54.32714639668751]
  Single-photon sources (SPS) hold the potential to enhance the performance of quantum key distribution (QKD) We have successfully demonstrated QKD using a room-temperature SPS at telecommunication wavelength.
  arXiv  Detail & Related papers  (2024-09-27T07:35:51Z)
• Single-emitter quantum key distribution over 175 km of fiber with optimised finite key rates [45.82374977939355]
  We perform fibre-based quantum key distribution with a quantum dot frequency-converted to telecom wavelength. We demonstrate positive key rates up to 175 km in the regime. This result represents major progress towards the feasibility of long-distance single-emitter QKD networks.
  arXiv  Detail & Related papers  (2022-09-07T18:03:36Z)
• Towards fully-fledged quantum and classical communication over deployed fiber with up-conversion module [47.187609203210705]
  We propose and demonstrate a new method, based on up-conversion assisted receiver, for co-propagating classical light and QKD signals. Our proposal exhibits higher tolerance for noise in comparison to the standard receiver, thus enabling the distribution of secret keys in the condition of 4 dB-higher classical power.
  arXiv  Detail & Related papers  (2021-06-09T13:52:27Z)
• Path-encoded high-dimensional quantum communication over a 2 km multicore fiber [50.591267188664666]
  We demonstrate the reliable transmission over a 2 km long multicore fiber of path-encoded high-dimensional quantum states. A stable interferometric detection is guaranteed, allowing for low error rates and the generation of 6.3 Mbit/s of secret key rate.
  arXiv  Detail & Related papers  (2021-03-10T11:02:45Z)
• Twin-Field Quantum Key Distribution over 511 km Optical Fiber Linking two Distant Metropolitans [21.87659562677264]
  We complete a twin field QKD (TF-QKD) and distribute secure keys without any trusted repeater over a 511 km long haul fiber trunk. Our secure key rate is around 3 orders of magnitudes greater than what is expected if the previous QKD field test system over the same length were applied. The efficient quantum-state transmission and stable single-photon interference over such a long distance deployed fiber paves the way to large-scale fiber quantum networks.
  arXiv  Detail & Related papers  (2021-01-31T11:25:00Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.