Spontaneous parametric downconversion is an essential technique in quantum optics experiments. In this paper, various quasi-phase-matching processes in several typical periodically polarized nonlinear materials are analyzed and calculated. Furthermore, a general method for realizing multiple types of quasi-phase-matching in a monolithic material is presented. Finally, a novel design to prepare multiple entangled photon pairs based on the Sagnac interferometer is discussed. This technology can be applied to tiny optical paths in the telecom C band, saving both cost and space.
@article{arxiv.2207.04758,
title = {Telecom-band Multi-Type Spontaneous Parametric Downconversion in Periodically Polarized Nonlinear Materials},
author = {Xi-Yu Liu and Ya-Fei Yu and Zheng-Jun Wei and Tian-Ming Zhao and Jin-Dong Wang},
journal= {arXiv preprint arXiv:2207.04758},
year = {2022}
}