Increasing the secret key rate of satellite-to-ground entanglement-based QKD assisted by adaptive optics

TL;DR

This paper demonstrates that adaptive optics can significantly improve the secret key rate in satellite-to-ground entanglement-based quantum key distribution during daytime by mitigating atmospheric turbulence effects.

Contribution

The study assesses the effectiveness of adaptive optics in enhancing entanglement-based QKD performance in turbulent daytime conditions for satellite-ground links.

Findings

Adaptive optics improves key rate by up to a few hundred bits per second.

Turbulence mitigation enhances fiber coupling of quantum signals.

Daytime satellite-to-ground entanglement-based QKD benefits from adaptive optics.

Abstract

Future quantum networks will be composed of both terrestrial links for metropolitan and continent-scale connections and space-based links for global coverage and infrastructure resilience. However, the propagation of quantum signals through the atmosphere is severely impacted by the effects of turbulence. This is even more the case for entanglement-based quantum communication protocols requiring two free-space channels to be considered simultaneously. In this work, we assess the advantage of turbulence mitigation by adaptive optics, in particular during daytime link operation, so as to increase the coupling of the received signal into an optical fiber. We show in particular that this improves the performance of entanglement-based quantum key distribution by up to a few hundred bits per second when compared with the uncorrected scenario