Experimental study on the Gaussian-modulated coherent-state quantum key distribution over standard telecommunication fibers

By Bing Qi, Leilei Huang, Li Qian, Hoi-Kwong Lo. 2007

197 citations recorded by the source corpus.

In this paper, we present a fully fiber-based one-way quantum-key-distribution (QKD) system implementing the Gaussian-modulated coherent-state (GMCS) protocol. The system employs a double Mach-Zehnder interferometer (MZI) configuration in which the weak quantum signal and the strong local oscillator (LO) go through the same fiber between Alice and Bob, and are separated into two paths inside Bob's terminal. To suppress the LO leakage into the signal path, which is an important contribution to the excess noise, we implemented a scheme combining polarization and frequency multiplexing, achieving an extinction ratio of 70 dB. To further minimize the system excess noise due to phase drift of the double MZI, we propose that, instead of employing phase feedback control, one simply let Alice remap her data by performing a rotation operation. We further present noise analysis both theoretically and experimentally. Our calculation shows that the combined polarization and frequency multiplexing scheme can achieve better stability in practice than the time-multiplexing scheme, because it allows one to use matched fiber lengths for the signal and the LO paths on both sides of the double MZI, greatly reducing the phase instability caused by unmatched fiber lengths. Our experimental noise analysis quantifies the three main contributions tomore » the excess noise, which will be instructive to future studies of the GMCS QKD systems. Finally, we demonstrate, under the ''realistic model'' in which Eve cannot control the system within Bob's terminal, a secure key rate of 0.3bit/pulse over a 5 km fiber link. This key rate is about two orders of magnitude higher than that of a practical Bennett-Brassard 1984 protocol QKD system.« less

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/f0c6e7268d8d931426b458c2afc4b308d60fe581

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Citations in the corpus

Advances in quantum cryptography (2019, unknown): “[465] B.”
Distributing Secret Keys with Quantum Continuous Variables: Principle, Security and Implementations (2015, background): “These implementations, together with a few others [56–59], were suited for securing communications in metropolitan area size networks (involving distances up to 25 km) with high-speed requirements.”
Phase-Matching Quantum Key Distribution (2018, background): “Note that similar ideas of phase postcompensation and phase calibration have already been adopted in some continuous-variable QKD protocols, such as the Gaussianmodulated coherent-state protocol [30,31] and the self-”
Continuous‐Variable Quantum Key Distribution with Gaussian Modulation—The Theory of Practical Implementations (2017, background): “By now, many experimental demonstrations underlined the feasibility of CV-QKD with coherent states [14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25].”
The security of practical quantum key distribution (2008, background): “A possible solution consists in including the calibration of the devices in the protocol itself; the price to pay seems to be a complication of the setup (Qi et al., 2007).”
Self-referenced continuous-variable quantum key distribution protocol (2015, methodology): “[16] Bing Qi, Lei-Lei Huang, Li Qian, and Hoi-Kwong Lo, “Experimental study on the Gaussian-modulated coherent-state quantum key distribution over standard telecommunication fibers,” Phys.”
Secure quantum key distribution with realistic devices (2020, background): “…Detection Detector Theory 2005 Trojan horse (Gisin et al., 2006; Vakhitov et al., 2001) Source&Detection Backflection light Theory 2006 Time shift (Qi et al., 2007a; Zhao et al., 2008) Detection Detector Experiment∗ 2007 Time side-channel (Lamas-Linares and Kurtsiefer, 2007) Detection Timing…”