Quantum-safe metro network with low-latency reconfigurable quantum key distribution

Xinke Tang, Adrian Wonfor, Rupesh Kumar, Richard V. Penty, Ian H. White

Research output: Contribution to journalArticlepeer-review

18 Citations (SciVal)


This paper reports a practical quantum-safe metro network, integrating optically-switched QKD systems with high speed reconfigurability to protect classical network traffic. Quantum signals are routed by millisecond optical switches and secure keys are shared between any two endpoints or network nodes via low-latency reconfigurable connections. Efficient quantum encryption topologies between different end-users are also presented. We show experimentally the feasibility of a rapidly reconfigured QKD transmission system between multiple users in the proposed network. Classical data and control signals coexist with the quantum signals in the same fibre. Proof-of-concept experiments are conducted over effective transmission distances of 30 km, 31.7 km, 33.1 km, and 44.6 km. Software controlled QKD transmission is established between four different transmitters (Alice) and one receiver (Bob) with a switching time of a few milliseconds. The quantum bit error rates for the four paths are proportional to the channel losses with values between 2.6% and 4.1%. Optimization of the reconciliation and clock distribution architecture is predicted to result in a maximum key generation delay of 20 s, far shorter than previously demonstrated.

Original languageEnglish
Article number8466887
Pages (from-to)5230-5236
Number of pages7
JournalJournal of Lightwave Technology
Issue number22
Early online date17 Sept 2018
Publication statusPublished - 15 Nov 2018


  • Metropolitan area networks
  • optical switches
  • quantum key distribution
  • quantum network
  • reconfigurable architectures

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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