© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

arXiv:2409.08982 · Nanophotonics

A fiber‐pigtailed quantum dot device generating indistinguishable photons at GHz clock‐rates

Lucas Rickert, Kinga Żołnacz, Daniel A. Vajner, Martin von Helversen, Sven Rodt, Stephan Reitzenstein, Hanqing Liu, Shulun Li, Haiqiao Ni, Paweł Wyborski, Grzegorz Sek, Anna Musiał, Zhichuan Niu, Tobias Heindel

Published Jan 3, 2025• 16 citations

Abstract

Abstract Solid‐state quantum light sources based on semiconductor quantum dots (QDs) are increasingly employed in photonic quantum information applications. Especially when moving towards real‐world scenarios outside shielded lab environments, the efficient and robust coupling of nanophotonic devices to single‐mode optical fibers offers substantial advantage by enabling “plug‐and‐play” operation. In this work we present a fiber‐pigtailed cavity‐enhanced source of flying qubits emitting single indistinguishable photons at clock‐rates exceeding 1 GHz. This is achieved by employing a fully deterministic technique for fiber‐pigtailing optimized QD‐devices based on hybrid circular Bragg grating (hCBG) micro‐cavities. The fabricated fiber‐pigtailed hCBGs feature emission lifetimes of ps, corresponding to a Purcell factor of ∼9, a suppression of multi‐photon emission events with g (2) (0) < 1 %, a photon‐indistinguishability % and a measured single‐photon coupling efficiency of 53 % in a high numerical aperture single‐mode fiber, corresponding to 1.2 Megaclicks per second at the single‐photon detectors under 80 MHz excitation clock‐rates. Furthermore, we show that high multi‐photon suppression and indistinguishability prevail for excitation clock‐rates exceeding 1 GHz. Our results show that Purcell‐enhanced fiber‐pigtailed quantum light sources based on hCBG cavities are a prime candidate for applications of quantum information science.

DOI: 10.1515/nanoph-2024-0519

Related papers

Efficient generation of indistinguishable single photons on-demand at telecom wavelengths

Je‐Hyung Kim, Tao Cai, Christopher J. K. Richardson +2 more

Highly efficient single photon sources are important building blocks for optical quantum information processing. For practical use and long-distance quantum communication, single photons should have fiber-compatible telecom wavelengths. In addition, most quantum communication applications require high degree of indistinguishability of single photons, such that they exhibit interference on a beam splitter. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem in particular at telecom wavelengths. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. To obtain the efficient single quantum dot emission, we employ the higher order mode in L3 photonic crystal cavity that shows a nearly Gaussian transverse mode profile and results in out-coupling efficiency exceeding 46 {\\%} and unusual bright single quantum dot emission exceeding 1.5 million counts per second at a detector. We also observe Purcell enhanced spontaneous emission rate as large as 4 and high linear polarization ratio of 0.96 for the coupled dots. Using this source, we generate high purity single photons at 1.3 ??m wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement.

Bulletin of the American Physical Society•Mar 17, 2016•0 citations

A diode nanocavity for fast, efficient and tunable emission of highly entangled photon pairs and Fourier-transform-limited single photons

Ievgen Brytavskyi, Thomas Oberleitner, Christian Weidinger +16 more

Deterministic sources of entangled photon pairs and indistinguishable photons are expected to play a key role in photonic quantum technologies. Semiconductor quantum dots are promising candidates due to their on-demand emission and compatibility with nanophotonic structures. However, current implementations face trade-offs between extraction efficiency, Purcell enhancement, as well as charge noise that causes blinking and degrades indistinguishability. Here we demonstrate a tunable nano-optoelectronic device based on a quantum dot embedded in a p-i-n diode circular-Bragg-grating-resonator and featuring extraction efficiencies up to 0.55(6) and Purcell-factor of $\sim$8. The device generates wavelength-tunable entangled photon pairs with suppressed blinking and raw (corrected) concurrence > 0.89 (0.91) over a range of 1.6 nm. The very same source also emits single, nearly Fourier-limited and highly indistinguishable photons with raw (corrected) $\mathcal{V}_{\text{HOM}}$ = 0.951(4) (0.988(6)). These results demonstrate a viable platform for semiconductor quantum photonics.

quant-pharXiv:2607.11494•Jul 14, 2026•0 citations

Plug‐and‐Play Fiber‐Coupled Quantum Dot Single‐Photon Source via Photonic Wire Bonding

Marco De Gregorio, Shangxuan Yu, Donald M. Witt +9 more

Abstract The collection of single‐photon emission from a quantum dot (QD) in a Bragg waveguide through a photonic wire bond (PWB) via free‐space resonant frequency pumping at 1.6 K is demonstrated. The in‐fiber single photons show a small multiphoton contribution, quantified by a low second order photon autocorrelation value of (background‐corrected) or (raw data). The decay time of the QD is measured to be ps. The PWB obviates the need for in‐cryostat alignment of the single‐photon source with an optical fiber and thus offers a route to scalable integration of quantum photonic devices in a cryogenic environment. Uniquely, the approach combines the QD‐waveguide technique, enabling resonant driving of individual QDs without the need for cross‐polarization filtering, and the PWB for deterministic, alignment‐free coupling of single‐photon sources to optical fibers.

Advanced Quantum Technologies•Nov 2, 2023•11 citations

A bright on-demand source of indistinguishable single photons at telecom wavelengths

Je‐Hyung Kim, Tao Cai, Christopher J. K. Richardson +2 more

Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. In many applications these photons must also be indistinguishable such that they exhibit interference on a beamsplitter, which implements effective photon-photon interactions. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. The cavity enhances the quantum dot emission, resulting in a nearly Gaussian transverse mode profile with high out-coupling efficiency exceeding 46%, leading to detected photon count rates that would exceed 1.5 million counts per second. We also observe Purcell enhanced spontaneous emission rate as large as 4. Using this source, we generate linearly polarized, high purity single photons at telecom-wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement. Our results provide a promising approach to generate on-demand indistinguishable single photons at telecom wavelength for applications in quantum networking and quantum communication.

•Nov 17, 2015•0 citations

Gigahertz-clocked Generation of Highly Indistinguishable Photons at C-band Wavelengths

Robert Behrends, Lucas Rickert, Nils D. Kewitz +9 more

High-performance single-photon sources at telecom C-band wavelentghs are key building blocks for applications in long-distance quantum communication. Here, we report the generation of highly indistinguishable, single photons at a clock-rate of 2.5 GHz. This is achieved by coherently driving the biexciton transition ($T_1^\mathrm{XX}=64(1)\,$ps) of a semiconductor quantum dot embedded in a microcavity with strong asymmetric Purcell enhancement. Employing pulsed two-photon resonant excitation, strong multiphoton suppression with $g^{(2)}(0) < 4\%$ and high two-photon-interference visibility of $V_\mathrm{raw}> 85\%$ is observed. The observed photon indistinguishability is close to the theoretical limit expected for the photonically engineered radiative cascade and matches values obtained at lower repetition rates. Our results show a substantial advancement towards interference-based quantum information protocols at unprecedented data rates in the telecom C-Band.

cond-mat.mes-hallCross-listedarXiv:2603.26651•Mar 30, 2026•0 citations

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

Shi-Wen Xu, Yuming Wei, Rongbin Su +7 more

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.

Photonics Research•Jun 6, 2022•30 citations

Abstract Solid‐state quantum light sources based on semiconductor quantum dots (QDs) are increasingly employed in photonic quantum information applications. Especially when moving towards real‐world scenarios outside shielded lab environments, the efficient and robust coupling of nanophotonic devices to single‐mode optical fibers offers substantial advantage by enabling “plug‐and‐play” operation. In this work we present a fiber‐pigtailed cavity‐enhanced source of flying qubits emitting single indistinguishable photons at clock‐rates exceeding 1 GHz. This is achieved by employing a fully deterministic technique for fiber‐pigtailing optimized QD‐devices based on hybrid circular Bragg grating (hCBG) micro‐cavities. The fabricated fiber‐pigtailed hCBGs feature emission lifetimes of ps, corresponding to a Purcell factor of ∼9, a suppression of multi‐photon emission events with g (2) (0) < 1 %, a photon‐indistinguishability % and a measured single‐photon coupling efficiency of 53 % in a high numerical aperture single‐mode fiber, corresponding to 1.2 Megaclicks per second at the single‐photon detectors under 80 MHz excitation clock‐rates. Furthermore, we show that high multi‐photon suppression and indistinguishability prevail for excitation clock‐rates exceeding 1 GHz. Our results show that Purcell‐enhanced fiber‐pigtailed quantum light sources based on hCBG cavities are a prime candidate for applications of quantum information science.

Highly efficient single photon sources are important building blocks for optical quantum information processing. For practical use and long-distance quantum communication, single photons should have fiber-compatible telecom wavelengths. In addition, most quantum communication applications require high degree of indistinguishability of single photons, such that they exhibit interference on a beam splitter. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem in particular at telecom wavelengths. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. To obtain the efficient single quantum dot emission, we employ the higher order mode in L3 photonic crystal cavity that shows a nearly Gaussian transverse mode profile and results in out-coupling efficiency exceeding 46 {\\%} and unusual bright single quantum dot emission exceeding 1.5 million counts per second at a detector. We also observe Purcell enhanced spontaneous emission rate as large as 4 and high linear polarization ratio of 0.96 for the coupled dots. Using this source, we generate high purity single photons at 1.3 ??m wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement.

Deterministic sources of entangled photon pairs and indistinguishable photons are expected to play a key role in photonic quantum technologies. Semiconductor quantum dots are promising candidates due to their on-demand emission and compatibility with nanophotonic structures. However, current implementations face trade-offs between extraction efficiency, Purcell enhancement, as well as charge noise that causes blinking and degrades indistinguishability. Here we demonstrate a tunable nano-optoelectronic device based on a quantum dot embedded in a p-i-n diode circular-Bragg-grating-resonator and featuring extraction efficiencies up to 0.55(6) and Purcell-factor of $\sim$8. The device generates wavelength-tunable entangled photon pairs with suppressed blinking and raw (corrected) concurrence > 0.89 (0.91) over a range of 1.6 nm. The very same source also emits single, nearly Fourier-limited and highly indistinguishable photons with raw (corrected)

\mathcal{V}_{\text{HOM}}

= 0.951(4) (0.988(6)). These results demonstrate a viable platform for semiconductor quantum photonics.

Abstract The collection of single‐photon emission from a quantum dot (QD) in a Bragg waveguide through a photonic wire bond (PWB) via free‐space resonant frequency pumping at 1.6 K is demonstrated. The in‐fiber single photons show a small multiphoton contribution, quantified by a low second order photon autocorrelation value of (background‐corrected) or (raw data). The decay time of the QD is measured to be ps. The PWB obviates the need for in‐cryostat alignment of the single‐photon source with an optical fiber and thus offers a route to scalable integration of quantum photonic devices in a cryogenic environment. Uniquely, the approach combines the QD‐waveguide technique, enabling resonant driving of individual QDs without the need for cross‐polarization filtering, and the PWB for deterministic, alignment‐free coupling of single‐photon sources to optical fibers.

Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. In many applications these photons must also be indistinguishable such that they exhibit interference on a beamsplitter, which implements effective photon-photon interactions. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. The cavity enhances the quantum dot emission, resulting in a nearly Gaussian transverse mode profile with high out-coupling efficiency exceeding 46%, leading to detected photon count rates that would exceed 1.5 million counts per second. We also observe Purcell enhanced spontaneous emission rate as large as 4. Using this source, we generate linearly polarized, high purity single photons at telecom-wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement. Our results provide a promising approach to generate on-demand indistinguishable single photons at telecom wavelength for applications in quantum networking and quantum communication.

High-performance single-photon sources at telecom C-band wavelentghs are key building blocks for applications in long-distance quantum communication. Here, we report the generation of highly indistinguishable, single photons at a clock-rate of 2.5 GHz. This is achieved by coherently driving the biexciton transition (

T_1^\mathrm{XX}=64(1)\,

ps) of a semiconductor quantum dot embedded in a microcavity with strong asymmetric Purcell enhancement. Employing pulsed two-photon resonant excitation, strong multiphoton suppression with

g^{(2)}(0) < 4\%

and high two-photon-interference visibility of

V_\mathrm{raw}> 85\%

is observed. The observed photon indistinguishability is close to the theoretical limit expected for the photonically engineered radiative cascade and matches values obtained at lower repetition rates. Our results show a substantial advancement towards interference-based quantum information protocols at unprecedented data rates in the telecom C-Band.

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.