Design of spontaneous parametric down-conversion in integrated hybrid SixNy-PPLN waveguides

High-efficient and high-purity photon sources are highly desired for quantum information processing. We report the design of a chip-scale hybrid SixNy and thin film periodically-poled lithium niobate waveguide for generating high-purity type-II spontaneous parametric down-conversion (SPDC) photons in the telecommunication band. The modeled second harmonic generation efficiency of 225% W-1 . cm(-2) is obtained at 1560nm. Joint spectral analysis is performed to estimate the frequency correlation of SPDC photons, yielding intrinsic purity with up to 95.17%. The generation rate of these high-purity photon pairs is estimated to be 2.87 x 10(7) pairs/s/mW within the bandwidth of SPDC. Our chip-scale hybrid waveguide design has the potential for large-scale on-chip quantum information processing and integrated photon-efficient quantum key distribution through highdimensional time-energy encoding. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.