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arXiv:1907.06472 · Journal of the Optical Society of America B

Continuous variable quantum key distribution with multi-mode signals for noisy detectors

Rupesh Kumar, Xinke Tang, A. Wonfor, Richard V. Penty, Ian H. White

Published Feb 20, 2019• 14 citations
arXivHTMLPDF

Abstract

This paper proposes a multi-mode Gaussian modulated continuous variable quantum key distribution (CV-QKD) scheme able to operate at high bandwidth despite using conventional noisy, coherent detectors. We demonstrate enhancement in shot-noise sensitivity as well as reduction in the electronic noise variance of the coherent receiver of the multi-mode CV-QKD system. A proof-of-concept simulation is presented using multiple modes; this demonstrates an increase in signal-to-noise ratio and secure key rate at various transmission distances with increasing signal modes.

DOI
10.1364/josab.36.00b109

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Abstract One of the difficulties in the application of quantum communication is the fragility of its encoded quantum states. Conventional quantum key distribution (QKD) requires strict filtering operations at the receiver. Any ambient light entering the system can significantly increase the bit error rate and even render the system inoperable. We present a continuous-variable quantum key distribution (CV-QKD) system that can function effectively during the day or even on rainy days without complex filtering operations. The Gaussian modulated coherent state continuous-variable quantum key distribution (GMCS CV-QKD) system demonstrates robustness, maintaining a secure key rate (SKR) of more than 100 kbps when operating at a frequency of 10 MHz, which lays the foundation for low-cost, highly robust free-space quantum communication.