Single-mode coupling efficiencies of type-II spontaneous parametric down-conversion: Collinear, noncollinear, and beamlike phase matching

Abstract

We report a series of experimental studies on single-mode fiber coupling of entangled photon pairs in type-II spontaneous parametric down-conversion. We experimentally compare the single-mode coupling efficiencies for three different phase matching regimes of bulk type-II spontaneous parametric down-conversion: collinear, noncollinear, and beamlike. Our experiment shows that the beamlike scheme provides the best single-mode coupling efficiency.