Quantum key distribution system clocked at 2 GHz
  An improved quantum key distribution test system operating at clock rates of up to 2GHz using a specially adapted commercially available silicon single photon avalanche diode is presented. The use of improved detectors has improved the fibre-based test system performance in terms of transmission distance and quantum bit error rate. 
K. J. Gordon, V. Fernandez, G. S. Buller, I. Rech, S. D. Cova, and P.   D. Townsend