Multichannel parallel continuous-variable quantum key distribution with Gaussian modulation

摘要

We propose a scheme for continuous-variable quantum key distribution (CV-QKD) using the subcarrier multiplexing technique which was employed in microwave photonics. This scheme allows distribution of N channels with independent Gaussian-modulated CV-QKD in parallel with one laser source and several phase modulators. We analyze the influence of nonlinear signal mixing and security in the asymptotic limit. Results indicate that by using this multiplexing technique, each channel will have a non-Gaussian extra source noise, resulting in slight shortening of the maximum transmission distance, while the total secret key rate can be considerably increased. This scheme could also be used for key distribution for multiple users, and combined with wavelength division multiplexing devices it has potential to be used for construction of a CV-QKD network.