Abstract
We demonstrate two approaches for unbalanced interferometers as time-bin qubit analyzers for quantum communication, robust against mode distortions and polarization effects as expected from free-space quantum communication systems including wavefront deformations, path fluctuations, pointing errors, and optical elements. Despite strong spatial and temporal distortions of the optical mode of a time-bin qubit, entangled with a separate polarization qubit, we verify entanglement using the Negative Partial Transpose, with the measured visibility of up to 0.85±0.01. The robustness of the analyzers is further demonstrated for various angles of incidence up to 0.2. The output of the interferometers is coupled into multimode fiber yielding a high system throughput of 0.74. Therefore, these analyzers are suitable and efficient for quantum communication over multimode optical channels.
Original language | English |
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Article number | 043847 |
Journal | Physical Review A |
Volume | 97 |
Issue number | 4 |
DOIs | |
State | Published - Apr 19 2018 |
Externally published | Yes |
Funding
The authors would like to thank Jacob Koenig, Rolf Horn, Evan Meyer-Scott, and Patrick Coles for useful discussions, and Martin Laforest for lending us the Hamamatsu EM-CCD camera. We gratefully acknowledge supports through the Office of Naval Research (ONR), the Canada Foundation for Innovation (CFI), the Ontario Research Fund (ORF), the Canadian Institute for Advanced Research (CIFAR), the Natural Sciences and Engineering Research Council of Canada (NSERC), and Industry Canada.