title: Polarization-entangled photon-pair source obtained via type-II non-collinear SPDC process with PPKTP crystal.
abstract: We demonstrate a polarization-entangled photon-pair source obtained via a type-II non-collinear quasi-phase-matched spontaneous parametric down-conversion process with a 10-mm periodically poled KTiOPO4 crystal, which is as stable and wavelength-tunable as the well-known Sagnac configuration scheme. A brightness of 4.2 kHz/mW is detected and a concurrence of 0.975 is estimated using quantum state tomography. Without loss of entanglement and brightness, the photon-pair wavelengths are tunable through control of the crystal temperature. This improvement is achieved using the non-collinear configuration and a stable interferometric distinguishability compensator.
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Heonoh
authors.initials: H
authors.lastname: Kim
authors.forename: Myoungsik
authors.initials: M
authors.lastname: Cha
authors.forename: Han Seb
authors.initials: HS
authors.lastname: Moon