Quantum frequency converters are key enabling technologies in photonic quantum information science to bridge the gap between quantum emitters and telecom photons. Here, we report a coherent frequency converter scheme combining a fiber-coupled nonlinear optical Lithium Niobate waveguide with a fiber-pigtailed single-photon source based on semiconductor quantum dots. Single and indistinguishable photons are converted from 925.7 nm to the telecommunication C-band, with a 48.4% end-to-end efficiency and full preservation of single-photon purity and indistinguishability. The integration of the two fiber-based modules achieving top-level performance represents an important step toward the practical interconnection of future quantum information processing systems operating at different wavelengths.
@article{arxiv.2512.09390,
title = {Compact and efficient quantum frequency conversion of a fiber-pigtailed single-photon source},
author = {Mathis Cohen and Anthony Martin and Romain Dalidet and Florian Pastier and Marie Billard and Aristide Lemaitre and Valérian Giesz and Niccolo Somaschi and Sarah Thomas and Pascale Senellart-Mardon and Sébastien Tanzilli and Laurent Labonté},
journal= {arXiv preprint arXiv:2512.09390},
year = {2025}
}