High-quality source of fiber-coupled polarization-entangled photons at 1.56 [mu]m

Abstract

This thesis describes the development of a high-quality source of single-mode fibercoupled polarization-entangled photon pairs based on a collinear spontaneous parametric down-conversion process in a bidirectionally pumped periodically-poled potassium titanyl phosphate (PPKTP) crystal inside a polarization Sagnac interferometer at communication wavelength (1.56 [mu]m). A two-photon quantum interference visibility of 97.1% was measured. In addition to the Sagnac source, a linear Mach-Zehnder source at 810 nm was built for the Interdisciplinary Quantum Information Science and Engineering (iQuISE) teaching laboratory, to allow students to observe fundamental quantum phenomena such as the Hong-Ou-Mandel (HOM) dip, the collapse of a Bell state due to measurement, or the Clauser-Horne-Shimony-Holt (CHSH) inequality violation in a single experimental setup. An HOM dip with a two-photon quantum interference visibility of 80% was demonstrated.