We report generation of near-infrared photon pairs in fundamental spatial modes via type-II spontaneous parametric down-conversion in a periodically poled potassium titanyl phosphate (KTiOPO4) nonlinear waveguide supporting multiple transverse modes. This demonstrates experimentally a versatile scheme for controlling the spatial characteristics of the produced nonclassical light based on exploitation of intermodal dispersion. The down-converted photons are characterized by the measurement of the beam quality factors in the heralded regime.
@article{arxiv.1110.5064,
title = {Dispersion-based control of modal characteristics for parametric down-conversion in a multimode waveguide},
author = {Michal Karpinski and Czeslaw Radzewicz and Konrad Banaszek},
journal= {arXiv preprint arXiv:1110.5064},
year = {2013}
}