Free space quantum key distribution over 500 meters using electrically driven quantum dot single-photon sources—a proof of principle experiment
Markus Rau, Tobias Heindel, Sebastian Unsleber, Tristan Braun, Julian Fischer, Stefan Frick, Sebastian Nauerth, Christian Schneider, Gwenaëlle Vest, Stephan Reitzenstein, Martin Kamp, A. Forchel, Sven Höfling, Harald Weinfurter · New Journal of Physics · 2014
Highly efficient single-photon sources (SPS) can increase the secure key rate of quantum key distribution (QKD) systems compared to conventional attenuated laser systems. Here we report on a free space QKD test using an electrically driven quantum dot single-photon source (QD SPS) that does not require a separate laser setup for optical pumping and thus allows for a simple and compact SPS QKD system. We describe its implementation in our 500 m free space QKD system in downtown Munich. Emulating a BB84 protocol operating at a repetition rate of 125 MHz, we could achieve sifted key rates of 5–17 kHz with error ratios of 6–9% and -values of 0.39–0.76.