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

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This paper reports a practical quantum-safe metro network, integrating optically-switched QKD systems with high speed reconfigurablility 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 30km, 31.7km, 33.1km and 44.6km. 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 (QBER) 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 20s, far shorter than previously demonstrated



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

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Journal of Lightwave Technology

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Institute of Electrical and Electronics Engineers (IEEE)
EPSRC (via University of York) (EP/M013472/1 R16690)
EPSRC (via University of York) (EP/M013472/1)