Quantum displacement receiver for M-ary phase-shift-keyed coherent states
Shuro Izumi, Masahiro Takeoka, Mikio Fujiwara, Nicola Dalla Pozza, Antonio Assalini, Kazuhiro Ema, Masahide Sasaki · AIP conference proceedings · 2014
We propose quantum receivers for 3- and 4-ary phase-shift-keyed (PSK) coherent state signals to overcome the standard quantum limit (SQL). Our receiver, consisting of a displacement operation and on-off detectors with or without feedforward, provides an error probability performance beyond the SQL. We show feedforward operations can tolerate the requirement for the detector specifications.