2018/07/12 by Z. L. Yuan, A. Plews, R. Takahashi +12 · 2 citations
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1109/jlt.2018.2843136
published as IEEE/OSA Journal of Lightwave Technology 36, 3427 (2018) · 7 pages, 8 figures, 1 table
arxiv created 2018/07/12 · arxiv updated 2018/07/13
We report the first quantum key distribution (QKD) systems capable of delivering sustainable, real-time secure keys continuously at rates exceeding 10 Mb/s. To achieve such rates, we developed high speed post-processing modules, achieving maximum data throughputs of 60 MC/s, 55 Mb/s, and 108 Mb/s for standalone operation of sifting, error correction and privacy amplification modules, respectively. The photonic layer of the QKD systems features high-speed single photon detectors based on self-differencing InGaAs avalanche photodiodes, phase encoding using asymmetric Mach-Zehnder interferometer, and active stabilization of the interferometer phase and photon polarisation. An efficient variant of the decoy-state BB84 protocol is implemented for security analysis, with a large dataset size of 108 bits selected to mitigate finite-size effects. Over a 2 dB channel, a record secure key rate of 13.72 Mb/s has been achieved averaged over 4.4 days of operation. We confirm the robustness and long-term stability on a second QKD system continuously running for 1 month without any user intervention.