Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2607.21454

Rack-integrated quantum dot-based source of single and entangled photons at telecom C-band

Michal Vyvlecka, Raphael Joos, Benjamin Breiholz, Emma Marmasse, Anna Friederike Köhler, Ponraj Vijayan, Tobias Huber-Loyola, Sven Höfling, Michael Jetter, Simone Luca Portalupi, Peter Michler

quant-phcond-mat.otherphysics.opticsSubmitted Jul 23, 2026• Announced Jul 24, 2026• 0 citations
arXivHTMLPDF

Abstract

For quantum light sources in everyday telecommunication networks, quantum science needs to be fully transformed into quantum technology. The first necessary step to move outside a well-controlled lab environment requires the use of quantum light sources operating in the technologically relevant telecom O- and C-band. This can be provided using epitaxial quantum dots as deterministic sources of quantum light. Particularly intriguing is that emitters operating at telecom wavelengths are rapidly catching up with their short wavelength counterparts in terms of performances. Here, we make a decisive step forward in the development of quantum communication networks: a state-of-the-art source of quantum light, a semiconductor quantum dot (QD), with record coincidence rate for entangled photon emission in the telecom C-band, is operated inside an optimized rack-based setup. This setup includes a tunable pulsed laser for the QD excitation (from quasi- to fully resonant excitation), all optics for the excitation filtering, and QD signal coupling into single-mode fibers. Overall, the setup allows for above $50\%$ transmission for both exciton and biexciton photons. These results show that quantum dots-based telecom light sources can now be transported and integrated into existing fiber infrastructures, an important step to demonstrate the feasibility of the upcoming quantum internet.

Related papers

A Quantum Light Source for Quantum Information Applications in the Telecom C-Band

Anderson, Matthew

Semiconductor quantum dot (QD) quantum light sources have long been established as suitable candidates for many quantum information applications, due to the on-demand emission of highly pure and highly indistinguishable single and entangled photons. A key factor in the development of this technology is the operation over the standard telecommunication optical fibre network infrastructure, where the minimum absorption wavelength window is centred on the telecom C-band (1530 – 1565 nm). Initial experiments in this work demonstrated single-photon emission of a QD light source emitting directly in the telecom C-band, under both continuous wave (CW) and 1-GHz pulsed excitation regimes. The QDs were further characterised in terms of fine-structure splitting (FSS) and coherence time, in order to determine their suitability for quantum entanglement and interference-based applications. Long coherence times were observed in the majority of the QDs considered, allowing the demonstration of Hong-Ou-Mandel-type two-photon interference of subsequently emitted photons under CW excitation. The post-selected interference visibility was found to be limited by only the detector resolution and single-photon purity. A further demonstration of high-visibility interference under the same limitations was then made using QD photons and dissimilar photons from a laser, forming the basis of a fibre-based quantum relay. Working further towards a quantum relay, polarisation-entangled photon pairs in the telecom C-band were then generated using the radiative cascade of the biexciton, where a record high fidelity to the ©+ Bell state was observed under both CW and 1-GHz pulsed excitation regimes. While an anomalous effect of the FSS was observed in a majority of the studied QDs, a further characterisation of the FSS in terms of the QD polarisation eigenstates confirmed the emission of entangled photon pairs from such an anomalous-splitting QD. Finally, the work of this thesis was combined to demonstrate a proof-of-principle quantum relay using a QD light source in the telecom C-band. The relay was operated first under CW excitation where polarisation encoded laser input qubits were used and high-fidelity quantum teleportation was observed. In an effort to demonstrate a more technologically relevant application, the quantum relay was subsequently operated at 1 GHz in order to demonstrate the teleportation of initially time-bin encoded laser input qubits. A high mean teleportation fidelity was again observed, demonstrating the potential of this telecom C-band QD quantum light source in the future of long-distance quantum information applications.

•Nov 1, 2020•0 citations

Network Integration and Coherent Operation of Telecom Entangled Light Sources Based on Semiconductor Quantum Dots

Jan Huwer, Jon Heffernan, D. A. Ritchie +9 more

Quantum light sources based on single-photon emitters are a core technology, which is expected to enable a multitude of emerging quantum-photonic applications with superior performance. As the development of sources is approaching a certain level of maturity, the important next step for quantum-network related applications is to distribute the generated photons in the most practical way. However, so far these remained within research facilities or were only transmitted over short specially installed fiber. In this regard, operation of the sources at standard telecom wavelengths such that existing classical communication infrastructure can be used, seems the most desirable solution.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2019•0 citations

Evaluating a Stand-Alone Quantum-Dot Single-Photon Source for Quantum Key Distribution at Telecom Wavelengths

Timm Kupko, Lucas Rickert, Felix Urban +12 more

Deterministic solid-state quantum light sources are key building blocks in photonic quantum technologies. While several proof-of-principle experiments of quantum communication using such sources have been realized, all of them required bulky setups. Here, we evaluate for the first time the performance of a compact and stand-alone fiber-coupled single-photon source emitting in the telecom O-band ($1321\,$nm) for its application in quantum key distribution (QKD). For this purpose, we developed a compact 19'' rack module including a deterministically fiber-coupled quantum dot single-photon source integrated into a Stirling cryocooler, a pulsed diode laser for driving the quantum dot, and a fiber-based spectral filter. We further employed this compact quantum light source in a QKD testbed designed for polarization coding via the BB84 protocol resulting in $g^{(2)}(0) = 0.10\pm0.01$ and a raw key rate of up to $(4.72\pm0.13)\,$kHz using an external laser for excitation. In this setting we investigate the achievable performance expected in full implementations of QKD. Using 2D temporal filtering on receiver side, we evaluate optimal parameter settings for different QKD transmission scenarios taking also finite key size effects into account. Using optimized parameter sets for the temporal acceptance time window, we predict a maximal tolerable loss of $23.19\,$dB. Finally, we compare our results to previous QKD systems using quantum dot single-photon sources. Our study represents an important step forward in the development of fiber-based quantum-secured communication networks exploiting sub-Poissonian quantum light sources.

•May 7, 2021•1 citation

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

A stable wavelength-tunable triggered source of single photons and cascaded photon pairs at the telecom C-band

Katharina D. Zeuner, Matthias Paul, Thomas Lettner +8 more

The implementation of fiber-based long-range quantum communication requires tunable sources of single photons at the telecom C-band. Stable and easy-to-implement wavelength-tunability of individual sources is crucial to (i) bring remote sources into resonance, (ii) define a wavelength standard, and (iii) ensure scalability to operate a quantum repeater. So far, the most promising sources for true, telecom single photons are semiconductor quantum dots, due to their ability to deterministically and reliably emit single and entangled photons. However, the required wavelength-tunability is hard to attain. Here, we show a stable wavelength-tunable quantum light source by integrating strain-released InAs quantum dots on piezoelectric substrates. We present triggered single-photon emission at 1.55 μm with a multi-photon emission probability as low as 0.097, as well as photon pair emission from the radiative biexciton–exciton cascade. We achieve a tuning range of 0.25 nm which will allow us to spectrally overlap remote quantum dots or tuning distant quantum dots into resonance with quantum memories. This opens up realistic avenues for the implementation of photonic quantum information processing applications at telecom wavelengths.

arXiv:1801.01518•Applied Physics Letters•Apr 23, 2018•32 citations

On-demand generation of entangled photon pairs in the telecom C-band for fiber-based quantum networks

Katharina D. Zeuner, Klaus D. Jöns, Lucas Schweickert +9 more

On-demand sources of entangled photons for the transmission of quantum information in the telecom C-band are required to realize fiber-based quantum networks. So far, non-deterministic sources of quantum states of light were used for long distance entanglement distribution in this lowest loss wavelength range. However, they are fundamentally limited in either efficiency or security due to their Poissonian emission statistics. Here, we show on-demand generation of entangled photon pairs in the telecom C-band by an InAs/GaAs semiconductor quantum dot. Using a robust phonon-assisted excitation scheme we measure a concurrence of $91.4\,\%$ and a fidelity of $95.2\,\%$ to $Φ^+$. On-demand generation of polarization entangled photons will enable secure quantum communication in fiber-based networks. Furthermore, applying this excitation scheme to several remote quantum dots tuned into resonance will enable first on-demand entanglement distribution over large distances for scalable real-life quantum applications.

arXiv:1912.04782•Dec 10, 2019•4 citations
For quantum light sources in everyday telecommunication networks, quantum science needs to be fully transformed into quantum technology. The first necessary step to move outside a well-controlled lab environment requires the use of quantum light sources operating in the technologically relevant telecom O- and C-band. This can be provided using epitaxial quantum dots as deterministic sources of quantum light. Particularly intriguing is that emitters operating at telecom wavelengths are rapidly catching up with their short wavelength counterparts in terms of performances. Here, we make a decisive step forward in the development of quantum communication networks: a state-of-the-art source of quantum light, a semiconductor quantum dot (QD), with record coincidence rate for entangled photon emission in the telecom C-band, is operated inside an optimized rack-based setup. This setup includes a tunable pulsed laser for the QD excitation (from quasi- to fully resonant excitation), all optics for the excitation filtering, and QD signal coupling into single-mode fibers. Overall, the setup allows for above 50%50\%50% transmission for both exciton and biexciton photons. These results show that quantum dots-based telecom light sources can now be transported and integrated into existing fiber infrastructures, an important step to demonstrate the feasibility of the upcoming quantum internet.
Semiconductor quantum dot (QD) quantum light sources have long been established as suitable candidates for many quantum information applications, due to the on-demand emission of highly pure and highly indistinguishable single and entangled photons. A key factor in the development of this technology is the operation over the standard telecommunication optical fibre network infrastructure, where the minimum absorption wavelength window is centred on the telecom C-band (1530 – 1565 nm). Initial experiments in this work demonstrated single-photon emission of a QD light source emitting directly in the telecom C-band, under both continuous wave (CW) and 1-GHz pulsed excitation regimes. The QDs were further characterised in terms of fine-structure splitting (FSS) and coherence time, in order to determine their suitability for quantum entanglement and interference-based applications. Long coherence times were observed in the majority of the QDs considered, allowing the demonstration of Hong-Ou-Mandel-type two-photon interference of subsequently emitted photons under CW excitation. The post-selected interference visibility was found to be limited by only the detector resolution and single-photon purity. A further demonstration of high-visibility interference under the same limitations was then made using QD photons and dissimilar photons from a laser, forming the basis of a fibre-based quantum relay. Working further towards a quantum relay, polarisation-entangled photon pairs in the telecom C-band were then generated using the radiative cascade of the biexciton, where a record high fidelity to the ©+ Bell state was observed under both CW and 1-GHz pulsed excitation regimes. While an anomalous effect of the FSS was observed in a majority of the studied QDs, a further characterisation of the FSS in terms of the QD polarisation eigenstates confirmed the emission of entangled photon pairs from such an anomalous-splitting QD. Finally, the work of this thesis was combined to demonstrate a proof-of-principle quantum relay using a QD light source in the telecom C-band. The relay was operated first under CW excitation where polarisation encoded laser input qubits were used and high-fidelity quantum teleportation was observed. In an effort to demonstrate a more technologically relevant application, the quantum relay was subsequently operated at 1 GHz in order to demonstrate the teleportation of initially time-bin encoded laser input qubits. A high mean teleportation fidelity was again observed, demonstrating the potential of this telecom C-band QD quantum light source in the future of long-distance quantum information applications.
Quantum light sources based on single-photon emitters are a core technology, which is expected to enable a multitude of emerging quantum-photonic applications with superior performance. As the development of sources is approaching a certain level of maturity, the important next step for quantum-network related applications is to distribute the generated photons in the most practical way. However, so far these remained within research facilities or were only transmitted over short specially installed fiber. In this regard, operation of the sources at standard telecom wavelengths such that existing classical communication infrastructure can be used, seems the most desirable solution.
Deterministic solid-state quantum light sources are key building blocks in photonic quantum technologies. While several proof-of-principle experiments of quantum communication using such sources have been realized, all of them required bulky setups. Here, we evaluate for the first time the performance of a compact and stand-alone fiber-coupled single-photon source emitting in the telecom O-band (1321 1321\,1321nm) for its application in quantum key distribution (QKD). For this purpose, we developed a compact 19'' rack module including a deterministically fiber-coupled quantum dot single-photon source integrated into a Stirling cryocooler, a pulsed diode laser for driving the quantum dot, and a fiber-based spectral filter. We further employed this compact quantum light source in a QKD testbed designed for polarization coding via the BB84 protocol resulting in g(2)(0)=0.10±0.01g^{(2)}(0) = 0.10\pm0.01g(2)(0)=0.10±0.01 and a raw key rate of up to (4.72±0.13) (4.72\pm0.13)\,(4.72±0.13)kHz using an external laser for excitation. In this setting we investigate the achievable performance expected in full implementations of QKD. Using 2D temporal filtering on receiver side, we evaluate optimal parameter settings for different QKD transmission scenarios taking also finite key size effects into account. Using optimized parameter sets for the temporal acceptance time window, we predict a maximal tolerable loss of 23.19 23.19\,23.19dB. Finally, we compare our results to previous QKD systems using quantum dot single-photon sources. Our study represents an important step forward in the development of fiber-based quantum-secured communication networks exploiting sub-Poissonian quantum light sources.
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.
The implementation of fiber-based long-range quantum communication requires tunable sources of single photons at the telecom C-band. Stable and easy-to-implement wavelength-tunability of individual sources is crucial to (i) bring remote sources into resonance, (ii) define a wavelength standard, and (iii) ensure scalability to operate a quantum repeater. So far, the most promising sources for true, telecom single photons are semiconductor quantum dots, due to their ability to deterministically and reliably emit single and entangled photons. However, the required wavelength-tunability is hard to attain. Here, we show a stable wavelength-tunable quantum light source by integrating strain-released InAs quantum dots on piezoelectric substrates. We present triggered single-photon emission at 1.55 μm with a multi-photon emission probability as low as 0.097, as well as photon pair emission from the radiative biexciton–exciton cascade. We achieve a tuning range of 0.25 nm which will allow us to spectrally overlap remote quantum dots or tuning distant quantum dots into resonance with quantum memories. This opens up realistic avenues for the implementation of photonic quantum information processing applications at telecom wavelengths.
On-demand sources of entangled photons for the transmission of quantum information in the telecom C-band are required to realize fiber-based quantum networks. So far, non-deterministic sources of quantum states of light were used for long distance entanglement distribution in this lowest loss wavelength range. However, they are fundamentally limited in either efficiency or security due to their Poissonian emission statistics. Here, we show on-demand generation of entangled photon pairs in the telecom C-band by an InAs/GaAs semiconductor quantum dot. Using a robust phonon-assisted excitation scheme we measure a concurrence of 91.4 %91.4\,\%91.4% and a fidelity of 95.2 %95.2\,\%95.2% to Φ+Φ^+Φ+. On-demand generation of polarization entangled photons will enable secure quantum communication in fiber-based networks. Furthermore, applying this excitation scheme to several remote quantum dots tuned into resonance will enable first on-demand entanglement distribution over large distances for scalable real-life quantum applications.