Strong Einstein-Podolsky-Rosen entanglement from a single squeezed light source
- Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik der Leibniz Universitaet Hannover, Callinstrasse 38, D-30167 Hannover (Germany)
- Centre for Quantum Engineering and Space-Time Research - QUEST, Leibniz Universitaet Hannover, Welfengarten 1, D-30167 Hannover (Germany)
- Institut fuer Theoretische Physik der Leibniz Universitaet Hannover, Appelstrasse 2, D-30167 Hannover (Germany)
Einstein-Podolsky-Rosen (EPR) entanglement is a criterion that is more demanding than just certifying entanglement. We theoretically and experimentally analyze the low-resource generation of bipartite continuous-variable entanglement, as realized by mixing a squeezed mode with a vacuum mode at a balanced beam splitter, i.e., the generation of so-called vacuum-class entanglement. We find that in order to observe EPR entanglement the total optical loss must be smaller than 33.3 %. However, arbitrarily strong EPR entanglement is generally possible with this scheme. We realize continuous-wave squeezed light at 1550 nm with up to 9.9 dB of nonclassical noise reduction, which is the highest value at a telecom wavelength so far. Using two phase-controlled balanced homodyne detectors we observe an EPR covariance product of 0.502{+-}0.006<1, where 1 is the critical value. We discuss the feasibility of strong Gaussian entanglement and its application for quantum key distribution in a short-distance fiber network.
- OSTI ID:
- 21546746
- Journal Information:
- Physical Review. A, Journal Name: Physical Review. A Journal Issue: 5 Vol. 83; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
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