Bright single-photon sources in the telecom band by deterministically coupling single quantum dots to a hybrid circular Bragg resonator

High-performance solid-state quantum sources in the telecom band are of paramount importance for long-distance quantum communications and the quantum Internet by taking advantage of a low-loss optical fiber network. Here, we demonstrate bright telecom-wavelength single-photon sources based on In(Ga)As/GaAs quantum dots (QDs) deterministically coupled to hybrid circular Bragg resonators (h-CBRs) by using a wide-field fluorescence imaging technique. The QD emissions are redshifted toward the telecom O-band by using an ultra-low InAs growth rate and an InGaAs strain reducing layer. Single-photon emissions under both continuous wave (CW) and pulsed operations are demonstrated, showing high brightness with count rates of 1.14 MHz and 0.34 MHz under saturation powers and single-photon purities of g((2))(0) = 0.11 +/- 0.02 (CW) and g((2))(0) = 0.087 +/- 0.003 (pulsed) at low excitation powers. A Purcell factor of 4.2 with a collection efficiency of 11.2% +/- 1% at the first lens is extracted, suggesting efficient coupling between the QD and h-CBR. Our work contributes to the development of highly efficient single-photon sources in the telecom band for fiber-based quantum communication and future distributed quantum networks. (C) 2022 Chinese Laser Press

Automated summary

This paper demonstrates bright telecom-wavelength single-photon sources based on quantum dots coupled to hybrid circular Bragg resonators. The emissions are redshifted to the telecom O-band using an ultra-low growth rate and a strain reducing layer. Single-photon emissions under both continuous wave and pulsed operations are achieved, showing high brightness and purities.