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arXiv · 2604.23422

Stark-tunable O-band single-photon sources based on deterministically fabricated quantum dot--circular Bragg gratings on silicon

Sarthak Tripathi·Kartik Gaur·Priyabrata Mudi·Peter Ludewig·Alexander Kosarev·Kerstin Volz·Imad Limame·Stephan Reitzenstein
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Abstract

Semiconductor quantum dots (QDs) offer outstanding quantum-optical properties, making them highly attractive for quantum information technologies. However, combining wide-range electrical tunability, efficient photon extraction, elevated-temperature operation, monolithic silicon integration, and telecom-wavelength compatibility remains a major challenge. Here, we demonstrate electrically contacted circular Bragg grating (eCBG) resonators incorporating InGaAs QDs directly grown on silicon, enabling bright single-photon emission in the telecom O-band. Deterministic electron-beam lithography and a ridge-based vertical p--i--n diode architecture enable precise device integration and electrical control of individual emitters. The QD--eCBGs exhibit a quantum-confined Stark shift of approximately 16 nm (11 meV) at 4 K, representing a record for QDs embedded in nanophotonic structures at telecom wavelengths. This is achieved alongside a photon extraction efficiency of $(21.7 \pm 3.0)\%$ into the first lens, while maintaining excellent radiative properties and high single-photon purity, with $g^{(2)}(0)=0.0078 \pm 0.0012$ below saturation and $g^{(2)}(0)=0.0183 \pm 0.0021$ at saturation under pulsed excitation. Robust antibunching persists up to 77 K, with $g^{(2)}(0)=0.0663 \pm 0.0056$, enabling operation with liquid-nitrogen or compact Stirling cryocoolers. Furthermore, spatially separated QD--eCBGs can be electrically tuned into spectral resonance without degrading photon statistics. These results establish a silicon-compatible, electrically addressable telecom O-band quantum light platform combining wide spectral tunability, high single-photon purity, and elevated-temperature operation, providing a scalable route toward practical photonic quantum networks.

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Sarthak Tripathi, Kartik Gaur, Priyabrata Mudi, Peter Ludewig, Alexander Kosarev, Kerstin Volz, Imad Limame, Stephan Reitzenstein. 2026-04-25. Stark-tunable O-band single-photon sources based on deterministically fabricated quantum dot--circular Bragg gratings on silicon. https://arxiv.org/abs/2604.23422

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