Secure communications with quantum key distribution over fiber-optic links is one of the few recognized applications of quantum physics at the level of individual quanta -- single C-band photons. Currently, the widely used sources of such photons are highly attenuated laser pulses, featured by a low probability of single photon occurrence. Here, we present an efficient source with an InAs/GaAs quantum dot on a metamorphic buffer layer inside a micropillar-shaped microcavity. The key innovation is the use of different semiconductor and dielectric materials to form the lower (GaAs/AlGaAs) and upper (Si/SiO2) Bragg reflectors. Compatibility of these materials in a monolithic source is achieved by depositing a small amount of Si/SiO2 pairs on an incomplete micropillar made from a coherent heterostructure grown by molecular beam epitaxy. This design enables resonant excitation with π-pulses and generation of polarized photons with a record-breaking end-to-end efficiency of 11%.
@article{arxiv.2604.06869,
title = {Telecom C-band single-photon sources with a semiconductor-dielectric microresonator},
author = {Yuriy Serov and Aidar Galimov and Sergey Sorokin and Nikolai Maleev and Marina Kulagina and Yuriy Zadiranov and Grigorii Klimko and Maxim Rakhlin and Alexey Veretennikov and Gleb Veyshtort and Olga Lakuntsova and Yuliya Salii and Daria Berezina and Sergey Troshkov and Demid Kirilenko and Alexey Blokhin and Alexei Vasil'ev and Alexander Kuzmenkov and Mikhail Bobrov and Irina Sedova and Tatiana V. Shubina and Alexey A. Toropov},
journal= {arXiv preprint arXiv:2604.06869},
year = {2026}
}