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Proceedings Paper

Continuous operation of four-state continuous-variable quantum key distribution system
Author(s): Takuto Matsubara; Motoharu Ono; Yusuke Oguri; Tsubasa Ichikawa; Takuya Hirano; Kenta Kasai; Ryutaroh Matsumoto; Toyohiro Tsurumaru
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Paper Abstract

We report on the development of continuous-variable quantum key distribution (CV-QKD) system that are based on discrete quadrature amplitude modulation (QAM) and homodyne detection of coherent states of light. We use a pulsed light source whose wavelength is 1550 nm and repetition rate is 10 MHz. The CV-QKD system can continuously generate secret key which is secure against entangling cloner attack. Key generation rate is 50 kbps when the quantum channel is a 10 km optical fiber. The CV-QKD system we have developed utilizes the four-state and post-selection protocol [T. Hirano, et al., Phys. Rev. A 68, 042331 (2003).]; Alice randomly sends one of four states {|±α⟩,|±𝑖α⟩}, and Bob randomly performs x- or p- measurement by homodyne detection. A commercially available balanced receiver is used to realize shot-noise-limited pulsed homodyne detection. GPU cards are used to accelerate the software-based post-processing. We use a non-binary LDPC code for error correction (reverse reconciliation) and the Toeplitz matrix multiplication for privacy amplification.

Paper Details

Date Published: 24 October 2016
PDF: 6 pages
Proc. SPIE 9996, Quantum Information Science and Technology II, 99960S (24 October 2016); doi: 10.1117/12.2241766
Show Author Affiliations
Takuto Matsubara, Gakushuin Univ. (Japan)
Motoharu Ono, Gakushuin Univ. (Japan)
Yusuke Oguri, Gakushuin Univ. (Japan)
Tsubasa Ichikawa, Gakushuin Univ. (Japan)
Takuya Hirano, Gakushuin Univ. (Japan)
Kenta Kasai, Tokyo Institute of Technology (Japan)
Ryutaroh Matsumoto, Tokyo Institute of Technology (Japan)
Toyohiro Tsurumaru, Mitsubishi Electric Corp. (Japan)

Published in SPIE Proceedings Vol. 9996:
Quantum Information Science and Technology II
Mark T. Gruneisen; Miloslav Dusek; John G. Rarity, Editor(s)

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