Design optimization for bright electrically-driven quantum dot single-photon sources emitting in telecom O-band

Abstract

A combination of advanced light engineering concepts enables a substantial improvement in photon extraction efficiency of micro–cavity–based single–photon sources in the telecom O–band at ∼1.3 µm. We employ a broadband bottom distributed Bragg reflector (DBR) and a top DBR formed in a dielectric micropillar with an additional circular Bragg grating in the lateral plane. This device design includes a doped layer in pin–configuration to allow for electric carrier injection. It provides broadband (∼8–10 nm) emission enhancement with an overall photon–extraction efficiency of ∼83% into the upper hemisphere and photon–extraction efficiency of ∼79% within numerical aperture NA=0.7. The efficiency of photon coupling to a single–mode fiber reaches 11% for SMF28 fiber (with NA=0.12), exceeds 22% for 980HP fiber (with NA=0.2) and reaches ∼40% for HNA fiber (with NA=0.42) as demonstrated by 3D finite–difference time–domain modeling.

Performance of the nanopost single-photon source: beyond the single-mode model

“…Such a device has been investigated numerically 83 , however, without a clear improvement in the performance. It has also been investigated for a halfmicropillar SPS in the telecom O-band 84 , where improvements were possible for the collection efficiency, but without reaching the performance of state-of-the-art numerically optimized SPS micropillars 17 . Cylindrical dielectric DBRs around the micropillar SPS have also been realized experimentally 85 , where the offresonance SE rate was decreased compared to the bulk SE rate indicating that Γ B had been suppressed.…”

Fiber-coupled quantum light sources based on solid-state quantum emitters

“…Another step, which is still in the future for fiber-coupled sources, could be the implementation of an electrical excitation [86,92], which would make the required infrastructure much more compact. A modified CBG design is shown in figure 4, which enables electrical driving of the quantum light source by electrical carrier injection due to an integrated p-i-n layer structure [88,93,94].…”

High-Performance Single-Photon Sources at Telecom Wavelength Based on Broadband Hybrid Circular Bragg Gratings

“…Hybrid circular Bragg gratings (CBGs) have recently emerged as a promising alternative to those platforms thanks to the presence of a backside gold mirror, which eliminates the loss of photons into the substrate as well as the issue of a fragile free-standing membrane that affects the original suspended version. − The first experiments with hybrid CBGs showed the ability to provide a moderate Purcell enhancement of both the exciton and the biexciton transitions as well as high extraction efficiency in a wide range of wavelengths, , leading to count rates >10 MHz. , However, they focused on the spectral region between 780 and 880 nm, which prevents their integration with the standard optical fiber infrastructure due to strong attenuation (>1 dB/km) at those wavelengths. Despite the publication of various design studies − and the demonstration of a device operating in the O-band, similar results at telecom wavelength have not been achieved yet and the degree of reproducibility remains an open question.…”