Discretely modulated continuous-variable quantum key distribution without phase compensation
Phys. Rev. A 113, 022602 – Published 3 February, 2026
DOI: https://doi.org/10.1103/fqh1-hz8j
Abstract
Continuous-variable quantum key distribution, which can use coherent states, shows great compatibility with classical optical communications, enabling high secret key rates over a metropolitan area. However, conventional continuous-variable quantum key distribution implementations require phase compensation mechanisms that introduce operational complexity. Here, we propose a unidimensional discrete-modulated continuous-variable quantum key distribution protocol by using the variance extremum search method that eliminates the need for phase compensation. This protocol ensures security through semidefinite programming and can be expanded. Simulation results demonstrate that, under typical excess noise conditions, this protocol achieves transmission distances exceeding 200 km at the asymptotic limit and can achieve a distance of over 75 km under finite-size effects using only a few constellation points. This innovation streamlines the experimental setup and holds promise for enhancing the practicality and promoting the future deployment of continuous-variable quantum key distribution.
