We present an integrated source of polarization entangled photon pairs in the telecom regime, which is based on type II-phasematched parametric down-conversion (PDC) in a Ti-indiffused waveguide in periodically poled lithium niobate. The domain grating -- consisting of an interlaced bi-periodic structure -- is engineered to provide simultaneous phase-matching of two PDC processes, and enables the direct generation of non-degenerate, polarization entangled photon pairs with a brightness of B=7×103 pairs/(s mW GHz). The spatial separation of the photon pairs is accomplished by a fiber-optical multiplexer facilitating a high compactness of the overall source. Visibilities exceeding 95% and a violation of the Bell inequality with S=2.57±0.06 could be demonstrated.
@article{arxiv.1307.7939,
title = {Post-selection free, integrated optical source of non-degenerate, polarization entangled photon pairs},
author = {Harald Herrmann and Xu Yang and Abu Thomas and Andreas Poppe and Wolfgang Sohler and Christine Silberhorn},
journal= {arXiv preprint arXiv:1307.7939},
year = {2015}
}