Two-photon interference from an InAs/InAlGaAs quantum dot (QD) emitting in the telecom C-band with a raw two-photon interference visibility of VHOM=(71.9±0.2) % is demonstrated. This is achieved by a two-fold approach: an improvement of the molecular beam epitaxial growth for better QDs, and integration of the QDs into an optical circular Bragg grating resonator for a Purcell enhancement of the radiative decay rate. The quantum optical properties of the fabricated device are studied by means of time-correlated single-photon counting under quasi-resonant excitation of the charged exciton line. A reduced lifetime of T1=(257.5±0.2) ps is found corresponding to a Purcell factor of FP≧(4.7±0.5). Pronounced anti-bunching of the second-order autocorrelation function at zero time delay g(2)(0)=(0.0307±0.0004) confirms the single-photon emission character. The two-photon interference is demonstrated with an unbalanced Mach-Zehnder interferometer in Hong-Ou-Mandel configuration. We discuss strategies how to further improve the indistinguishability, and provide a survey of the state-of-the art.
@article{arxiv.2501.15970,
title = {Two-Photon Interference from an InAs Quantum Dot emitting in the Telecom C-Band},
author = {Jaewon Kim and Jochen Kaupp and Yorick Reum and Giora Peniakov and Johannes Michl and Felix Kohr and Monika Emmerling and Martin Kamp and Yong-Hoon Cho and Tobias Huber-Loyola and Sven Höfling and Andreas T. Pfenning},
journal= {arXiv preprint arXiv:2501.15970},
year = {2025}
}