Optical Downlink Modeling for LEO and MEO Satellites under Atmospheric Turbulence with a Quantum State Tomography Use Case

TL;DR

This paper models optical satellite-to-ground links considering atmospheric effects and turbulence, and introduces a quantum state tomography scheme for quantum communication verification from LEO and MEO satellites.

Contribution

It provides a detailed link budget model for satellite optical links including atmospheric turbulence and introduces a quantum state tomography method for onboard quantum resource verification.

Findings

Quantitative estimates of optical losses under typical conditions

A general method for transmittance calculation along slant paths

A quantum state tomography scheme for satellite-based quantum communication

Abstract

This paper presents a comprehensive analysis of the link budget for free-space optical systems involving Low Earth Orbit (LEO) and Medium Earth Orbit (MEO) satellites. We develop a detailed model of the satellite-to-ground channel that accounts for the primary physical processes affecting transmittance: atmospheric absorption and scattering, free-space diffraction, and turbulence-induced fluctuations. The study introduces a general method for computing transmittance along a slant path between a satellite and an optical ground station, incorporating zenith angle, slant range, and altitude-dependent attenuation. The proposed framework is intended to support the design and evaluation of space-based optical links and serves as a critical tool for defining technical specifications in satellite communication demonstrators and simulations. Numerical estimates are provided to illustrate the magnitude of losses under typical operational conditions, including the role of aperture averaging. In addition to the link budget analysis, we introduce a satellite-based quantum use case. We propose a scheme for quantum state tomography performed on states generated by an onboard photon source on an LEO or MEO satellite and transmitted to the optical ground station. This approach enables continuous verification of the quality of quantum resources that can be used to perform quantum protocols within quantum information networks.