Telecom quantum dots on GaAs substrates as integration-ready high performance single-photon sources

TL;DR

This paper reports on the development and optical characterization of telecom-band quantum dots on GaAs substrates, demonstrating their potential as high-performance, integration-ready single-photon sources for quantum communication.

Contribution

It introduces a new heterostructure of MBE-grown quantum dots emitting in telecom bands with improved optical properties suitable for photonic device integration.

Findings

Linewidths as low as 50 μeV

Fine structure splittings near 10 μeV

g^{(2)}(0) values as low as 0.08

Abstract

The development of deterministic single photon sources emitting in the telecommunication bands is a key challenge for quantum communication and photonic quantum computing. Here, we investigate the optical properties and single-photon emission of molecular beam epitaxy grown semiconductor quantum dots emitting in the telecom O- and C- bands. The quantum dots are embedded in a InGaAs matrix with fixed indium content grown on top of a compositionally graded InGaAs buffer. This structure allows for the future implementation of electrically contacted nanocavities to enable high-quality and bright QD emission. In detailed optical characterizations we observe linewidths as low as $ 50 \mu$eV, close to the spectrometer resolution limit, low fine structure splittings close to $ 10 \mu$eV, and $g^{(2)} (0)$ values as low as $0.08$. These results advance the current performance metrics for MBE-grown quantum dots on GaAs substrates emitting in the telecom bands and showcase the potential of the presented heterostructures for further integration into photonic devices.