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Theses

Détection Optique Homodyne: application à la cryptographie quantique

Abstract : Nowadays the information security and privacy of the telecommunications Networks are based on the classical cryptography, which relies on the fragile mathematical assumptions. The quantum key distribution (QKD) is presently the only known way to distribute keys with unconditional security. This thesis aims to apply a multidisciplinary versatile approach to fill the gap between the fundamental physical limits and the experimental system implementations, in terms of speed, reliability and robustness. First of all, we proposed a BB84 protocol implementation using coherent phase states. The homodyne receiver was designed to compensate the phase and polarization fluctuations in the interferometers, as well as in the rest of the propagation channel. Then we established an experimental one-way QKD system operating at 1550 nm Telecom wavelength in a single mode fiber link, with QPSK modulation. Both the photon counting detection (PC) and the balanced homodyne detection (BHD) schemes have been implemented. Finally, we conducted theoretical and experimental comparisons of these two receivers. The BHD receiver has been improved with a dual-threshold post-decision. The implementation of such a process accepts non-conclusive measurements, and reduced key generation efficiency, but its permanence remains still better than the PC receiver at 1550 nm. We also proved that this system is robust under most common potential attacks.
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https://pastel.archives-ouvertes.fr/pastel-00005580
Contributor : Ecole Télécom Paristech <>
Submitted on : Monday, October 18, 2010 - 8:13:45 PM
Last modification on : Friday, July 31, 2020 - 10:44:05 AM
Long-term archiving on: : Thursday, December 1, 2016 - 5:44:20 AM

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  • HAL Id : pastel-00005580, version 1

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Qing Xu. Détection Optique Homodyne: application à la cryptographie quantique. domain_other. Télécom ParisTech, 2009. Français. ⟨pastel-00005580⟩

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