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.
@article{arxiv.1807.04484,
title = {10~Mb/s quantum key distribution},
author = {Z. L. Yuan and A. Plews and R. Takahashi and K. Doi and W. Tam and A. W. Sharpe and A. R. Dixon and E. Lavelle and J. F. Dynes and A. Murakami and M. Kujiraoka and M. Lucamarini and Y. Tanizawa and H. Sato and A. J. Shields},
journal= {arXiv preprint arXiv:1807.04484},
year = {2018}
}