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M-ary state phase-shift keying discrimination below the homodyne limit



Francisco E. Becerra Chavez, Jingyun Fan, Gerald Baumgartner, Sergey V. Polyakov, Julius Goldhar, Jonathan Kosloski, Alan L. Migdall


We investigate a strategy for M-ary discrimination of nonorthogonal phase states with error rates below the homodyne limit. This strategy uses feed forward to update a reference field and Signal nulling for the state discrimination. We experimentally analyze the receiver performance using postprocessing and a Bayesian strategy to emulate the feed-forward process. This analysis demonstrates that for a moderate system detection efficiency, it is possible to surpass the homodyne error limit for quadrature phase-shift keying (QPSK) signals using feed forward.
Physical Review A


state discrimination, quantum information, quantum communication, single photon, quantum mechanics, single photon detection


Becerra, F. , Fan, J. , Baumgartner, G. , Polyakov, S. , Goldhar, J. , Kosloski, J. and Migdall, A. (2011), M-ary state phase-shift keying discrimination below the homodyne limit, Physical Review A, [online], (Accessed April 21, 2024)
Created December 22, 2011, Updated February 19, 2017