Open AccessLong-distance distribution of time-bin entangled photon pairs over 100 km using frequency up-conversion detectors
Author(s) -
Toshimori Honjo,
Hiroki Takesue,
H. Kamada,
Y. Nishida,
O. Tadanaga,
Masaki Asobe,
Kyo Inoue
Publication year - 2007
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.15.013957
Subject(s) - physics , optics , spontaneous parametric down conversion , photon , bin , lithium niobate , coincidence counting , photon entanglement , quantum key distribution , detector , coincidence , quantum entanglement , quantum mechanics , quantum , computer science , medicine , alternative medicine , algorithm , pathology
We report an experimental demonstration of the distribution of time-bin entangled photon pairs over 100 km of optical fiber. In our experiment, 1.5-mum non-degenerated time-bin entangled photon pairs were generated with a periodically poled lithium niobate (PPLN) waveguide by using the parametric down conversion process. Combining this approach with ultra-low-loss filters to eliminate the pump light and separate signal and idler photons, we obtained an efficient entangled photon pair source. To detect the photons, we used single-photon detectors based on frequency up-conversion. These detectors operated in a non-gated mode so that we could use a pulse stream of time correlated entangled photon pairs at a high repetition frequency (1 GHz). Using these elements, we distributed time-bin entangled photon pairs over 100 km of dispersion shifted fiber and performed a two-photon interference experiment. We obtained a coincidence fringe of 81.6% visibility without subtracting any background noise, such as accidental coincidence or dark count, which was good enough to violate Bell's inequality. Thus, we successfully distributed time-bin entangled photon pairs over 100 km.