Free-space quantum links under diverse weather conditions

TL;DR

This study investigates how diverse weather conditions like rain and haze affect the transmission of nonclassical light in free-space quantum communication links, combining theoretical modeling with experimental validation.

Contribution

The paper generalizes existing atmospheric light transmission theory to include diverse weather effects and analyzes their impact on quantum light transmission.

Findings

Rain causes additional deterministic losses.

Haze induces beam deformations.

Quantum entanglement transmission is affected by weather conditions.

Abstract

Free-space optical communication links are promising channels for establishing secure quantum communication. Here we study the transmission of nonclassical light through a turbulent atmospheric link under diverse weather conditions, including rain or haze. To include these effects, the theory of light transmission through atmospheric links in the elliptic-beam approximation presented by Vasylyev et al. [D. Vasylyev et al., Phys. Rev. Lett. 117, 090501 (2016); arXiv:1604.01373] is further generalized.It is demonstrated, with good agreement between theory and experiment, that low-intensity rain merely contributes additional deterministic losses, whereas haze also introduces additional beam deformations of the transmitted light. Based on these results, we study theoretically the transmission of quadrature squeezing and Gaussian entanglement under these weather conditions.