We study theoretically the generation of photon pairs with controlled spectral correlations via the four-wave mixing (FWM) process in graded-index multimode optical fibers (GIMFs). We show that the quantum correlations of the generated photons in GIMFs can be preserved over a wide spectral range for a tunable pump source. Therefore, GIMFs can be utilized as quantum-state-preserving tunable sources of photons. In particular, we have shown that it is possible to generate factorable two-photon states, which allow for heralding of single-photon pure-state photons without the need for spectral post filtering. We also elaborate on the possibility of simultaneously generating correlated and uncorrelated photon pairs in the same optical fiber.
@article{arxiv.1711.01021,
title = {Photon Pair Generation with Tailored Frequency Correlations in Graded-Index Multimode Optical Fibers},
author = {Hamed Pourbeyram and Arash Mafi},
journal= {arXiv preprint arXiv:1711.01021},
year = {2018}
}