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Conference on Lasers and Electro-Optics

Cougate-Franson interferometry for testing nonlocality of time-energy entangled biphotons

Changchen Chen, Jeffrey H. Shapiro, Franco N. C. Wong

Published Jan 1, 2021• 0 citations
Publisher

Abstract

We report the first experimental demonstration of a conjugate-Franson interferometer, i.e., a nonlocal interferometer that can certify time-energy entanglement. Our measured 96% visibility tightly bounds the temporal correlation of biphotons generated by spontaneous parametric down-conversion.
DOI
10.1364/cleo_qels.2021.fm3m.5

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Energy and time entangled photons at a wavelength of 1310 nm are produced by parametric down-conversion in a KNbO3{\mathrm{KNbO}}_{3}KNbO3​ crystal and are sent into all-fiber interferometers using a telecommunications fiber network. The two interferometers of this Franson-type test of the Bell inequality are located 10.9 km apart from one another. Two-photon fringe visibilities of up to 81.6% are obtained. These strong nonlocal correlations support the nonlocal predictions of quantum mechanics and provide evidence that entanglement between photons can be maintained over long distances.
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