Telecom C-band single-photon sources with a semiconductor-dielectric microresonator

TL;DR

This paper reports a highly efficient, monolithically integrated single-photon source using a semiconductor-dielectric microresonator, advancing quantum communication technologies with record efficiency.

Contribution

Introduction of a novel semiconductor-dielectric microresonator design for single-photon generation with 11% efficiency, compatible with quantum key distribution.

Findings

Achieved 11% end-to-end efficiency in single-photon generation.

Enabled resonant excitation with π-pulses.

Demonstrated polarization control of emitted photons.

Abstract

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/SiO$_2$) Bragg reflectors. Compatibility of these materials in a monolithic source is achieved by depositing a small amount of Si/SiO$_2$ pairs on an incomplete micropillar made from a coherent heterostructure grown by molecular beam epitaxy. This design enables resonant excitation with $\pi$-pulses and generation of polarized photons with a record-breaking end-to-end efficiency of 11%.