Modeling daytime sky access for a satellite quantum key distribution downlink
Mark T. Gruneisen, Michael Flanagan, Brett A. Sickmiller, James P. Black, Kurt E. Stoltenberg, Alexander W. Duchane · Optics Express · 2015
Daytime sky radiance can lead to quantum-bit-error rates (QBER) sufficiently high to preclude quantum key distribution over satellite-to-Earth downlinks. For circular orbits, sky radiance and propagation losses are both pointing-angle-dependent quantities. This dependence makes it possible to map the sky as a function of the QBER in certain protocols. Sky radiance distributions are generated by libRadtran software with aerosol values representative of summer and winter. Hemispherical maps of the QBER are created for orbit altitudes of 400 and 800 km. Sunrise-to-sunset simulations are presented for a system with commercial optical components and compared to a case employing an atomic-line spectral filter.