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Physical Review A

Quantum analysis of polarization entanglement degradation induced by multiple-photon-pair generation

R. A. Brewster, Gerald Baumgartner, Yanne K. Chembo

Published Aug 11, 2021• 15 citations
Publisher

Abstract

The formation of multiple photon pairs in spontaneous parametric down-conversion leads to a degradation of polarization entanglement quality. The authors characterize this quality and perform all-quantum calculations that agree with known results for two different Bell-state-generation methods.
DOI
10.1103/physreva.104.022411

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Quantum computation and quantum communication require sources of entangled photons, especially from low-cost diode lasers. This study considered a polarization entangled photons pulse source produced via a spontaneous parametric down-conversion process in the type-I phase-matching of two nonlinear crystals, incorporating a continuous wave laser diode operating in pulse mode as a pump. The generated photons were measured based on visibility as a function of the pump frequency and collection apertures. A polarization correlation between photon pairs of approximately 93% and a Bell parameter S value of 2.56 ± 0.05 were obtained using the source described here.
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