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Optical Engineering • Open Access

Modeling satellite-Earth quantum channel downlinks with adaptive-optics coupling to single-mode fibers
Author(s): Mark T. Gruneisen; Michael B. Flanagan; Brett A. Sickmiller

Paper Abstract

The efficient coupling of photons from a free-space quantum channel into a single-mode optical fiber (SMF) has important implications for quantum network concepts involving SMF interfaces to quantum detectors, atomic systems, integrated photonics, and direct coupling to a fiber network. Propagation through atmospheric turbulence, however, leads to wavefront errors that degrade mode matching with SMFs. In a free-space quantum channel, this leads to photon losses in proportion to the severity of the aberration. This is particularly problematic for satellite-Earth quantum channels, where atmospheric turbulence can lead to significant wavefront errors. This report considers propagation from low-Earth orbit to a terrestrial ground station and evaluates the efficiency with which photons couple either through a circular field stop or into an SMF situated in the focal plane of the optical receiver. The effects of atmospheric turbulence on the quantum channel are calculated numerically and quantified through the quantum bit error rate and secure key generation rates in a decoy-state BB84 protocol. Numerical simulations include the statistical nature of Kolmogorov turbulence, sky radiance, and an adaptive-optics system under closed-loop control.

Paper Details

Date Published: 27 December 2017
PDF: 17 pages
Opt. Eng. 56(12) 126111 doi: 10.1117/1.OE.56.12.126111
Published in: Optical Engineering Volume 56, Issue 12
Show Author Affiliations
Mark T. Gruneisen, Air Force Research Lab. (United States)
Michael B. Flanagan, Leidos, Inc. (United States)
Brett A. Sickmiller, Leidos, Inc. (United States)

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