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Phase‐Locked Homodyne Measurement of Quasiprobability Q Function and Detection of Information‐Carrying Weak‐Coherent States
Author(s) -
Garcia Edith,
Mendieta Francisco J.,
Lopez Josue A.,
Alvarez Eduardo,
Arvizu Arturo,
Gallion Philippe
Publication year - 2013
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.27844
Subject(s) - homodyne detection , direct conversion receiver , quantum key distribution , coherent states , continuous phase modulation , physics , electronic engineering , transmitter , local oscillator , computer science , quantum mechanics , engineering , telecommunications , quantum , phase noise , channel (broadcasting)
We present an eight‐port homodyne receiver implemented in free space technology for detection of weak coherent states that carry binary information. For transmitted power economy, we use suppressed‐carrier modulation, therefore, we have implemented an optical Costas‐loop‐type carrier synchronizer. We obtain the quasiprobability Q function from the in‐phase and quadrature observables that are simultaneously measured. Statistical results for the quadrature components are presented. We perform measurements for the bit error rate and the mutual information between transmitter–receiver. The results show that the proposed setup is suitable in quantum communications and continuous variable quantum key distribution systems. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2431–2437, 2013