Direct spectral characterization of a quantum photon-pair source usually involves cumbersome, costly, and time-consuming detection issues. In this study, we experimentally characterize the spectral properties of a type-II phase-matched spontaneous parametric down-conversion (SPDC) source based on a titanium-diffused periodically poled lithium niobate (Ti:PPLN) waveguide. The characterization of the spectral information of the generated cross-polarized photon pairs is of importance for the use of such sources in applications including quantum information and communication. We demonstrate that the joint spectral intensity of the cross-polarized photon-pair source can be fully reconstructed using the quantum-classical correspondence through classical sum-frequency generation (SFG) measurements. This technique, which uses a much less complex detection system for visible light, opens the possibility of fast monitoring and control of the quantum state of (polarization-correlated) photon-pair sources to facilitate the realization of a stable and high-usability quantum source.
@article{arxiv.2007.00880,
title = {Spectral mapping of polarization-correlated photon-pair sources using quantum-classical correspondence},
author = {Hung-Pin Chung and Pawan Kumar and Kai Wang and Olivier Bernard and Chinmay Shirpurkar and Wen-Chiuan Su and Thomas Pertsch and Andrey A. Sukhorukov and Yen-Hung Chen and Frank Setzpfandt},
journal= {arXiv preprint arXiv:2007.00880},
year = {2020}
}