Continuous Variable Quantum Communications

Research Lead: Romain Alléaume
PhD Student: Raphaël Aymeric

This research theme investigates research topics positioned at the frontier between quantum communications and classical coherent optical communications. It is in particular centered on the design of Continuous-Variable Quantum Key Distribution (CV-QKD) systems and their integration in modern optical networks.

The high-level objective of our work is to enable simultaneous transmission of Classical and QKD signals. In collaboration with our colleagues Cedric Ware and Yves Jaouen, from the Optical Telecommunication group of Télécom Paris, we perform experimental quantum communications demonstrations over a state-of-the art (40 Gb/s) optical coherent communication platform (cf figure).

We specifically tackle novel questions in the context of quantum communications, such as the use of DSP-based noise-control techniques and the convergence of classical and quantum communication systems design. This enables us to improve our ability to deploy quantum communications over a shared fiber in presence of intense classical WDM signals [2,3], but also to operate classical and quantum communications with shared hardware [1], paving the way for a seamless integration of quantum communications into modern optical networks.

This work is supported by the European Quantum Technology Flagship project CIVIQ.

[1] A. Marie, R. Alléaume, Self-coherent phase reference sharing for continuous-variable quantum key distribution, Phys. Rev. A 95, 012316, (2017)
[2] R. Kumar, H. Qin, R. Alléaume, Coexistence of continuous variable QKD with intense DWDM classical channels, New Journal of Physics, 17(4), 043027. (2015)
[3] A. Amari, P. Ciblat and Y. Jaouën, Inter-subcarrier Nonlinear Interference Canceler for Long-Haul Nyquist- WDM Transmission J. Photon. Technol. Lett., PTL-28, 2760-2763, (2016)