We investigate the dual generation of type-0 and type-II spontaneous parametric down conversions (SPDCs) within a single periodically poled rubidium-doped KTiOPO4 (PPRKTP) waveguide. By coupling a 45 degree linearly polarized pump laser into the waveguide, both SPDC processes are concurrently excited: the type-0 SPDC process is facilitated via third-order quasi-phase matching (QPM) utilizing the nonlinear coefficient d33 , while the type-II SPDC process employs first-order QPM with the nonlinear coefficient d24. This dual-SPDC scheme holds potential for applications in quantum communication protocols targeting the telecommunication wavelength.
@article{arxiv.2505.14269,
title = {Rubidium-Doped KTiOPO$_4$ Waveguides as a Dual-Type Photon Pair Source},
author = {Patrick Hendra and Josué R. León-Torres and Valerio Flavio Gili and Markus Gräfe},
journal= {arXiv preprint arXiv:2505.14269},
year = {2025}
}