Gigahertz quantum signatures compatible with telecommunication technologies

Matthew Thornton, Callum Croal, Imran Khan, 3 Christoph Marquardt, 3 Gerd Leuchs, 3 and Natalia Korolkova School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, Scotland Max Planck Institute for the Science of Light, Staudstraße 2, Erlangen, Germany Institute of Optics, Information and Photonics, University of Erlangen-Nuremberg, Staudtstraße 7/B2, Erlangen, Germany