Optics Express

Nearly degenerate wavelength-multiplexed polarization entanglement by cascaded optical nonlinearities in a PPLN ridge waveguide device

Shin Arahira, Hitoshi Murai

Published Mar 22, 2013• 21 citations

Abstract

In this paper we report the generation of wavelength-multiplexed polarization-entangled photon pairs in the 1.5-μm communication wavelength band by using cascaded optical second nonlinearities (sum-frequency generation and subsequent spontaneous parametric down-conversion, c-SFG/SPDC) in a periodically poled LiNbO(3) ridge waveguide device. The c-SFG/SPDC method makes it possible to fully use the broad spectral bandwidth of SPDC in nearly frequency-degenerate conditions, and can provide more than 50 pairs of wavelength channels for the entangled photon pairs in the 1.5-μm wavelength band, using only standard optical resources in the telecom field. Visibilities higher than 98% were clearly observed in two-photon interference fringes for all the wavelength channels under investigation (eight pairs). We further performed a detailed experimental investigation of the cross-talk characteristics and the impact of detuning the pump wavelengths.

DOI: 10.1364/oe.21.007841

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