10-Mb/s Quantum Key Distribution
Zhiliang Yuan, Akira Murakami, Mamko Kujiraoka, Marco Lucamarini, Yoshimichi Tanizawa, Hideaki Sato, Andrew J. Shields, Alan Plews, Ririka Takahashi, Kazuaki Doi, Winci Tam, Andrew W. Sharpe, Alexander R. Dixon, Evan Lavelle, James F. Dynes · Journal of Lightwave Technology · 2018
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 postprocessing 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 an asymmetric Mach-Zehnder interferometer, and active stabilization of the interferometer phase and photon polarization. An efficient variant of the decoy-state BB84 protocol is implemented for the security analysis, with a large dataset size of 108bits 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 invention.