Long Distance Continuous-Variable Quantum Key Distribution with a Gaussian Modulation

Paul Jouguet (1, 2) , Kunz-Jacques Sébastien (1) , Leverrier Anthony (3)

1 SeQureNet
2 LTCI - Laboratoire Traitement et Communication de l'Information
3 The Institute of Photonic Sciences

We designed high-efficiency error correcting codes allowing to extract an errorless secret key in a continuous-variable quantum key distribution protocol using a Gaussian modulation of coherent states and a homodyne detection. These codes are available for a wide range of signal-to-noise ratios on an AWGN channel with a binary modulation and can be combined with a multidimensional reconciliation method proven secure against arbitrary collective attacks. This improved reconciliation procedure considerably extends the secure range of a continuous-variable quantum key distribution with a Gaussian modulation, giving a secret key rate of about 10^{-3} bit per pulse at a distance of 120 km for reasonable physical parameters.

Domaines: Physique Quantique [quant-ph]

Paul Jouguet, Kunz-Jacques Sébastien, Leverrier Anthony. Long Distance Continuous-Variable Quantum Key Distribution with a Gaussian Modulation. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2011, 84 (6), pp.062317. ⟨10.1103/PhysRevA.84.062317⟩. ⟨hal-00663594⟩