Four-state discrimination beyond heterodyne detection
Christian R. Mueller, Mario A. Usuga, Christoffer Wittmann, Masahiro Takeoka, Christoph W. Marquardt, Ulrik L. Andersen, Gerd Leuchs · 2012
We propose and experimentally demonstrate a hybrid discrimination scheme for the quadrature phase shift keying protocol, which outperforms heterodyne detection for any signal power. The discrimination is composed of a quadrature measurement, feed forward and photon detection.