Photon Counting and Super Homodyne Detection of Weak QPSK Signals for   Quantum Key Distribution
  We compare the principles and experimental results of two different QPSK signal detection configurations, photon counting and super homodyning, for applications in fiber-optic Quantum Key Distribution (QKD) systems operating at telecom wavelength, using the BB84 protocol. 
Q. XU, M.B. Costa e Silva, S. Agnolini, P. Gallion, F.J. Mendieta