Quantum dots stand out as the most advanced and versatile light-matter interface available today. Their ability to deliver high-quality, high-rate, and pure photons has set benchmarks that far surpass other emitters. Yet, a critical frontier has remained elusive: achieving these exceptional capabilities at telecom wavelengths, bridging the gap to fiber-optic infrastructure and scalable silicon photonics. Overcoming this challenge demands high quality quantum materials and devices which, despite extensive efforts, have not been realized yet. Here, we demonstrate waveguide-integrated quantum dots and realize a fully quantum-coherent photon-emitter interface operating in the original telecommunication band. The quality is assessed by recording transform-limited linewidths only 8 % broader than the inverse lifetime and bright 41.7 MHz emission rate under 80 MHz π-pulse excitation, unlocking the full potential of quantum dots for scalable quantum networks.
@article{arxiv.2510.09251,
title = {A quantum-coherent photon--emitter interface in the original telecom band},
author = {Marcus Albrechtsen and Severin Krüger and Juan Loredo and Lucio Stefan and Zhe Liu and Yu Meng and Lukas L. Niekamp and Bianca F. Seyschab and Nikolai Spitzer and Richard J. Warburton and Peter Lodahl and Arne Ludwig and Leonardo Midolo},
journal= {arXiv preprint arXiv:2510.09251},
year = {2025}
}