Quantum frequency conversion serves a key role in the realization of hybrid quantum networks by interfacing between wavelength-incompatible platforms. Here we present the first quantum frequency converter connecting visible and telecom domains on a silicon nitride (SiN) chip, using Bragg-scattering four-wave mixing to upconvert heralded single photons from 1260 to 698 nm, which covers a 192 THz span. We examine the noise sources in SiN and devise approaches to suppress noise photons at the source and target frequencies to enable measurements at the single-photon level. We demonstrate an on-chip conversion efficiency of 5% in photon flux and describe design modifications that can be implemented to significantly improve it. Our results pave the way for the implementation of CMOS-compatible devices in quantum networks.
@article{arxiv.2505.10338,
title = {Telecom-to-Visible Quantum Frequency Converter on a Silicon Nitride Chip},
author = {Sidarth Raghunathan and Richard Oliver and Yun Zhao and Karl McNulty and Chaitali Joshi and Michal Lipson and Alexander L. Gaeta},
journal= {arXiv preprint arXiv:2505.10338},
year = {2025}
}