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:2604.06869

Telecom C-band single-photon sources with a semiconductor-dielectric microresonator

Yuriy Serov, Aidar Galimov, Sergey Sorokin, Nikolai Maleev, Marina Kulagina, Yuriy Zadiranov, Grigorii Klimko, Maxim Rakhlin, Alexey Veretennikov, Gleb Veyshtort, Olga Lakuntsova, Yuliya Salii, Daria Berezina, Sergey Troshkov, Demid Kirilenko, Alexey Blokhin, Alexei Vasil'ev, Alexander Kuzmenkov, Mikhail Bobrov, Irina Sedova, Tatiana V. Shubina, Alexey A. Toropov

cond-mat.mes-hallphysics.opticsquant-phSubmitted Apr 8, 2026• Announced Apr 9, 2026
arXivHTMLPDF

Abstract

Secure communications with quantum key distribution over fiber-optic links is one of the few recognized applications of quantum physics at the level of individual quanta -- single C-band photons. Currently, the widely used sources of such photons are highly attenuated laser pulses, featured by a low probability of single photon occurrence. Here, we present an efficient source with an InAs/GaAs quantum dot on a metamorphic buffer layer inside a micropillar-shaped microcavity. The key innovation is the use of different semiconductor and dielectric materials to form the lower (GaAs/AlGaAs) and upper (Si/SiO$_2$) Bragg reflectors. Compatibility of these materials in a monolithic source is achieved by depositing a small amount of Si/SiO$_2$ pairs on an incomplete micropillar made from a coherent heterostructure grown by molecular beam epitaxy. This design enables resonant excitation with $π$-pulses and generation of polarized photons with a record-breaking end-to-end efficiency of 11%.

Related papers

Source of Indistinguishable Single Photons Based on Epitaxial InAs/GaAs Quantum Dots for Integration in Quantum Computing Schemes

A. I. Galimov, Maxim V. Rakhlin, Grigorii V. Klimko +5 more

The characteristics of single photons emitted by columnar microstructures based on epitaxial microcavity heterostructures with distributed Bragg reflectors, which include self-organized InAs/GaAs quantum dots and have a comparatively low Q factor in the range of 2000–3000, have been studied. It has been shown that a state with a given spin configuration—exciton with a certain polarization or trion—can be initialized in a single quantum dot under the coherent resonant linearly polarized optical pumping by a π pulse. The measurement of two-photon interference by the Hong–Ou–Mandel scheme has demonstrated that the degree of indistinguishability of successively emitted single photons is 97 and 93% at a time delay of 2 and 250 ns, respectively. Prospects of application of such sources in optical quantum computing schemes have been discussed.

Journal of Experimental and Theoretical Physics Letters•Feb 1, 2021•16 citations

On-Demand Generation of Entangled Photon Pairs in the Telecom C-Band with InAs Quantum Dots

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

High Resolution Image Download MS PowerPoint Slide Entangled photons are an integral part in quantum optics experiments and a key resource in quantum imaging, quantum communication, and photonic quantum information processing. Making this resource available on-demand has been an ongoing scientific challenge with enormous progress in recent years. Of particular interest is the potential to transmit quantum information over long distances, making photons the only reliable flying qubit. Entangled photons at the telecom C-band could be directly launched into single-mode optical fibers, enabling worldwide quantum communication via existing telecommunication infrastructure. However, the on-demand generation of entangled photons at this desired wavelength window has been elusive. Here, we show a photon pair generation efficiency of 69.9 ± 3.6% in the telecom C-band by an InAs/GaAs semiconductor quantum dot on a metamorphic buffer layer. Using a robust phonon-assisted two-photon excitation scheme we measure a maximum concurrence of 91.4 ± 3.8% and a peak fidelity to the Φ + state of 95.2 ± 1.1%, verifying on-demand generation of strongly entangled photon pairs and marking an important milestone for interfacing quantum light sources with our classical fiber networks.

ACS Photonics•Jul 15, 2021•88 citations

InP-based single-photon sources operating at telecom C-band with increased extraction efficiency

Anna Musiał, Monika Mikulicz, Paweł Mrowiński +7 more

In this work, we demonstrate a triggered single-photon source operating at the telecom C-band with photon extraction efficiency exceeding any reported values in this range. The non-classical light emission with low probability of the multiphoton events is realized with single InAs quantum dots (QDs) grown by molecular beam epitaxy and embedded directly in an InP matrix. Low QD spatial density on the order of 5 × 108 cm−2 to ∼2 × 109 cm−2 and symmetric shape of these nanostructures together with spectral range of emission make them relevant for quantum communication applications. The engineering of extraction efficiency is realized by combining a bottom distributed Bragg reflector consisting of 25 pairs of InP/In0.53Ga0.37Al0.1 As layers and cylindrical photonic confinement structures. Realization of such a technologically non-demanding approach even in a non-deterministic fashion results in photon extraction efficiency of (13.3 ± 2) % into 0.4 numerical aperture detection optics at approximately 1560 nm emission wavelength, i.e., close to the center of the telecom C-band.

arXiv:2102.00450•Applied Physics Letters•May 31, 2021•36 citations

Coherent control and high purity single-photon emission from telecom quantum dots on metamorphic InGaAs

Beatrice Costa, Bianca Scaparra, Hubert Riedl +5 more

Semiconductor quantum dots emitting in the telecommunication O- and C-bands are promising candidates as single-photon sources for fiber-based quantum communication. In this work, we show how coherent quasi-resonant and phonon-assisted excitation help reveal the intrinsic optical properties of InAs quantum dots embedded in relaxed InGaAs matrices on top of metamorphic InGaAs layers for achieving emission in the telecom bands. By systematically comparing excitation schemes, we separate excitation-induced effects from intrinsic emitter properties. This allows us to observe linewidths as narrow as 21 $μ$eV, the disappearance of slow decay channels, and single-photon purity reaching second-order autocorrelation values in the order of $10^{-2}$. Photoluminescence excitation reveals higher excited states, enabling coherent control of trion transitions and the observation of Rabi-like oscillations in both telecom bands. These results confirm the promising potential of these quantum dots for applications in quantum technologies.

cond-mat.mes-hallCross-listedarXiv:2610.38060•Oct 29, 2026

On-demand generation of entangled photons in the telecom C-band

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

Fiber-based quantum networks require on-demand sources of entangled photons in the telecom C-band for long distance information transfer. Historically, the field of in-fiber entanglement distribution has been dominated by photons provided via spontaneous processes. In recent years, semiconductor quantum dots have emerged as strong competitors in terms of generating single and entangled photons due to their promise of deterministic qubit generation in the NIR wavelength region. Here, we show the on-demand generation of polarization entangled photons in the telecom C-band based on InAs/GaAs quantum dots grown via metal-organic vapor-phase epitaxy. By employing a robust phonon-assisted two-photon excitation scheme, we are able to generate pairs of entangled photons with a concurrence of 91.4 ± 3.8 % and a maximum fidelity to the Bell state Φ+ of 95.2 ± 1.1 %.

Quantum Nanophotonic Materials, Devices, and Systems•Aug 20, 2020•5 citations

Strain-free, symmetrical, InGaAs quantum dots as single photon emitters in the telecomC-band

Rabbia Tahir, Paweł Wyborski, Artur Tuktamyshev +4 more

Non-classical photon sources made of semiconductor quantum dots (QDs) emitting in the telecommunication C-band are crucial components for low-loss, long-distance photonic quantum communication networks. Here we designed and fabricated strain--free In$_{0.7}$Ga$_{0.3}$As/In$_{0.7}$Al$_{0.3}$As QDs grown on GaAs(111)A substrates working as single-photon emitters in the 1550 nm window. The QDs were grown via local droplet etching method in a molecular beam epitaxy environment, employing a thin In$_{0.7}$Al$_{0.3}$As metamorphic buffer layer with the same lattice constant of the QD material, thus allowing for a completely strain--free self-assembly of the QDs. The QDs exhibit a C$_{3v}$ symmetry with a ground state emission in the 1400--1600 nm range. The exciton lifetimes of $\approx$ 1.3--1.9 ns and linewidths as low as $\approx$ 300 $μ$eV show the good quality of the fabricated QDs. Second-order autocorrelation measurements under pulsed excitation confirmed the single-photon purity of the emitters, yielding a $g^{(2)}(0)$ value of $0.141 \pm 0.027$

quant-pharXiv:2605.17332•May 19, 2026
Secure communications with quantum key distribution over fiber-optic links is one of the few recognized applications of quantum physics at the level of individual quanta -- single C-band photons. Currently, the widely used sources of such photons are highly attenuated laser pulses, featured by a low probability of single photon occurrence. Here, we present an efficient source with an InAs/GaAs quantum dot on a metamorphic buffer layer inside a micropillar-shaped microcavity. The key innovation is the use of different semiconductor and dielectric materials to form the lower (GaAs/AlGaAs) and upper (Si/SiO2_22​) Bragg reflectors. Compatibility of these materials in a monolithic source is achieved by depositing a small amount of Si/SiO2_22​ pairs on an incomplete micropillar made from a coherent heterostructure grown by molecular beam epitaxy. This design enables resonant excitation with πππ-pulses and generation of polarized photons with a record-breaking end-to-end efficiency of 11%.
The characteristics of single photons emitted by columnar microstructures based on epitaxial microcavity heterostructures with distributed Bragg reflectors, which include self-organized InAs/GaAs quantum dots and have a comparatively low Q factor in the range of 2000–3000, have been studied. It has been shown that a state with a given spin configuration—exciton with a certain polarization or trion—can be initialized in a single quantum dot under the coherent resonant linearly polarized optical pumping by a π pulse. The measurement of two-photon interference by the Hong–Ou–Mandel scheme has demonstrated that the degree of indistinguishability of successively emitted single photons is 97 and 93% at a time delay of 2 and 250 ns, respectively. Prospects of application of such sources in optical quantum computing schemes have been discussed.
High Resolution Image Download MS PowerPoint Slide Entangled photons are an integral part in quantum optics experiments and a key resource in quantum imaging, quantum communication, and photonic quantum information processing. Making this resource available on-demand has been an ongoing scientific challenge with enormous progress in recent years. Of particular interest is the potential to transmit quantum information over long distances, making photons the only reliable flying qubit. Entangled photons at the telecom C-band could be directly launched into single-mode optical fibers, enabling worldwide quantum communication via existing telecommunication infrastructure. However, the on-demand generation of entangled photons at this desired wavelength window has been elusive. Here, we show a photon pair generation efficiency of 69.9 ± 3.6% in the telecom C-band by an InAs/GaAs semiconductor quantum dot on a metamorphic buffer layer. Using a robust phonon-assisted two-photon excitation scheme we measure a maximum concurrence of 91.4 ± 3.8% and a peak fidelity to the Φ + state of 95.2 ± 1.1%, verifying on-demand generation of strongly entangled photon pairs and marking an important milestone for interfacing quantum light sources with our classical fiber networks.
In this work, we demonstrate a triggered single-photon source operating at the telecom C-band with photon extraction efficiency exceeding any reported values in this range. The non-classical light emission with low probability of the multiphoton events is realized with single InAs quantum dots (QDs) grown by molecular beam epitaxy and embedded directly in an InP matrix. Low QD spatial density on the order of 5 × 108 cm−2 to ∼2 × 109 cm−2 and symmetric shape of these nanostructures together with spectral range of emission make them relevant for quantum communication applications. The engineering of extraction efficiency is realized by combining a bottom distributed Bragg reflector consisting of 25 pairs of InP/In0.53Ga0.37Al0.1 As layers and cylindrical photonic confinement structures. Realization of such a technologically non-demanding approach even in a non-deterministic fashion results in photon extraction efficiency of (13.3 ± 2) % into 0.4 numerical aperture detection optics at approximately 1560 nm emission wavelength, i.e., close to the center of the telecom C-band.
Semiconductor quantum dots emitting in the telecommunication O- and C-bands are promising candidates as single-photon sources for fiber-based quantum communication. In this work, we show how coherent quasi-resonant and phonon-assisted excitation help reveal the intrinsic optical properties of InAs quantum dots embedded in relaxed InGaAs matrices on top of metamorphic InGaAs layers for achieving emission in the telecom bands. By systematically comparing excitation schemes, we separate excitation-induced effects from intrinsic emitter properties. This allows us to observe linewidths as narrow as 21 μμμeV, the disappearance of slow decay channels, and single-photon purity reaching second-order autocorrelation values in the order of 10−210^{-2}10−2. Photoluminescence excitation reveals higher excited states, enabling coherent control of trion transitions and the observation of Rabi-like oscillations in both telecom bands. These results confirm the promising potential of these quantum dots for applications in quantum technologies.
Fiber-based quantum networks require on-demand sources of entangled photons in the telecom C-band for long distance information transfer. Historically, the field of in-fiber entanglement distribution has been dominated by photons provided via spontaneous processes. In recent years, semiconductor quantum dots have emerged as strong competitors in terms of generating single and entangled photons due to their promise of deterministic qubit generation in the NIR wavelength region. Here, we show the on-demand generation of polarization entangled photons in the telecom C-band based on InAs/GaAs quantum dots grown via metal-organic vapor-phase epitaxy. By employing a robust phonon-assisted two-photon excitation scheme, we are able to generate pairs of entangled photons with a concurrence of 91.4 ± 3.8 % and a maximum fidelity to the Bell state Φ+ of 95.2 ± 1.1 %.
Non-classical photon sources made of semiconductor quantum dots (QDs) emitting in the telecommunication C-band are crucial components for low-loss, long-distance photonic quantum communication networks. Here we designed and fabricated strain--free In0.7_{0.7}0.7​Ga0.3_{0.3}0.3​As/In0.7_{0.7}0.7​Al0.3_{0.3}0.3​As QDs grown on GaAs(111)A substrates working as single-photon emitters in the 1550 nm window. The QDs were grown via local droplet etching method in a molecular beam epitaxy environment, employing a thin In0.7_{0.7}0.7​Al0.3_{0.3}0.3​As metamorphic buffer layer with the same lattice constant of the QD material, thus allowing for a completely strain--free self-assembly of the QDs. The QDs exhibit a C3v_{3v}3v​ symmetry with a ground state emission in the 1400--1600 nm range. The exciton lifetimes of ≈\approx≈ 1.3--1.9 ns and linewidths as low as ≈\approx≈ 300 μμμeV show the good quality of the fabricated QDs. Second-order autocorrelation measurements under pulsed excitation confirmed the single-photon purity of the emitters, yielding a g(2)(0)g^{(2)}(0)g(2)(0) value of 0.141±0.0270.141 \pm 0.0270.141±0.027