Controlling excess noise in fiber optics continuous variables quantum key distribution

Jérôme Lodewyck (1, 2) , Thierry Debuisschert (1) , Rosa Tualle-Brouri (2) , Philippe Grangier (2)

1 Thales Research and Technology [Palaiseau]
2 Laboratoire Charles Fabry de l'Institut d'Optique / Optique quantique

We describe a continuous variables coherent states quantum key distribution system working at 1550 nm, and entirely made of standard fiber optics and telecom components, such as integrated-optics modulators, couplers and fast InGaAs photodiodes. The setup is composed of an emitter randomly modulating a coherent state in the complex plane with a doubly Gaussian distribution, and a receiver based on a shot noise limited time-resolved homodyne detector. By using a reverse reconciliation protocol, the device can transfer a raw key rate up to 1 Mb/s, with a proven security against Gaussian or non-Gaussian attacks. The dependence of the secret information rate of the present fiber set-up is studied as a function of the line transmission and excess noise.

Domaines: Physique Quantique [quant-ph]

Jérôme Lodewyck, Thierry Debuisschert, Rosa Tualle-Brouri, Philippe Grangier. Controlling excess noise in fiber optics continuous variables quantum key distribution. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2005, 72, pp.050303(R). ⟨10.1103/PhysRevA.72.050303⟩. ⟨hal-00509172⟩