Exploring Satellite Quantum Key Distribution under Atmospheric Constraints

TL;DR

This paper develops a numerical simulation framework to evaluate the performance and security of satellite quantum key distribution links affected by atmospheric turbulence and losses, aiding the design of secure global quantum communication.

Contribution

It introduces a comprehensive simulation method incorporating atmospheric turbulence models and static losses to assess quantum key distribution performance under realistic conditions.

Findings

Quantifies link budget and secure key rates over various distances.

Demonstrates impact of atmospheric turbulence on QKD security.

Provides a tool for optimizing satellite-based quantum communication links.

Abstract

Satellite Quantum Key Distribution creates a pathway for secure global communication with a level of security that is peerless. However, ground-to-satellite Quantum Key Distribution links are degraded due to the atmospheric turbulence. This paper gives a numerical framework using angular spectrum propagation, Hufnagel-Valley model of turbulence and Von Karman phase screens and takes into account the static losses introduced due to the absorption of the beam by the different elements and compounds in the atmosphere like O2, CO2 and H2O. This simulation propagates a Gaussian beam step by step through the atmosphere, where we incorporate the phase distortions using phase screens based on standard Cn2 profiles which take into account losses such as scintillation and beam wander. We simulate the BB84 protocol with decoy states for added security. The results of the simulation quantify the expected link budget and Secure key rates over a range of distances to measure the viability of Free Space Optical Quantum Key Distribution links at different distances.