Simulation of satellite and optical link dynamics in a quantum repeater constellation

TL;DR

This paper presents a comprehensive simulation of satellite-based quantum repeater networks, modeling dynamic satellite passes and atmospheric effects to optimize entanglement distribution for global quantum communication.

Contribution

It introduces a detailed simulation framework for satellite-ground quantum links considering satellite motion, atmospheric effects, and adaptive optics, advancing the design of quantum repeater constellations.

Findings

Optimal satellite altitude and inter-satellite distance improve entanglement rates.

Dynamic modeling reveals performance variations over satellite passes.

Analytical expressions for Bell state measurement errors enhance protocol accuracy.

Abstract

Quantum repeaters and satellite-based optical links are complementary technological approaches to overcome the exponential photon loss in optical fibers and thus allow quantum communication on a global scale. We analyze architectures which combine these approaches and use satellites as quantum repeater nodes to distribute entanglement to distant optical ground stations. Here we simulate dynamic, three-dimensional ground station passes, going beyond previous studies that typically consider static satellite links. For this, we numerically solve the equations of motion of the dynamic system consisting of three satellites in low Earth orbit. The model of the optical link takes into account atmospheric attenuation, single-mode fiber coupling, beam wandering and broadening, as well as adaptive optics effects. We derive analytical expressions for the Bell state measurement and associated error rates for quantum memory assisted communications, including retrieval efficiency and state coherence. We consider downlink and uplink architectures for continental and intercontinental connections and evaluate the impact of satellite altitude and inter-satellite distance on the expected entanglement swapping rate. Our simulation model enables us to design different orbital configurations for the satellite constellation and analyze the annual performance of the quantum repeater under realistic conditions.