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

Conference on Lasers and Electro-Optics

Low-Loss Bragg-Reflection Waveguides for On-Chip Time-Bin Entanglement

Hannah Thiel, Marita Wagner, Bianca Nardi, Alexander Schlager, Robert J. Chapman, Stefan Frick, Gregor Weihs, Holger Suchomel, Martin Kamp, Sven Höfling, Christian Schneider, Lennart Jehle, Hauke Conradi, Moritz Kleinert, Norbert Keil

Published Jan 1, 2022• 0 citations
Publisher

Abstract

We fabricate low-loss AlGaAs Bragg-reflection waveguides for the creation of telecom wavelength photon pairs via parametric down-conversion. These photon pairs are used in a hybrid on-chip time-bin entanglement scheme.
DOI
10.1364/cleo_at.2022.jtu3b.47

Related papers

Semiconductor sources of photon pairs

Gregor Weihs, T. Günthner, Benedikt Pressl +5 more

We demonstrate efficient photon pair generation for quantum communication using an all-semiconductor approach. In an AlGaAs Bragg-reflection waveguide we employ spontaneous parametric down-conversion to produce photon pairs at telecommunication wavelengths. The various phase-matching solutions present in our device can be used to create timebin or polarization entanglement. This approach can to lead to a fully integrated photon pair source with the pump laser, active and passive optical devices all on a single semiconductor chip.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 29, 2013•0 citations

Invited Article: Time-bin entangled photon pairs from Bragg-reflection waveguides

H. Chen, S. Auchter, M. Prilmüller +9 more

Semiconductor Bragg-reflection waveguides are well-established sources of correlated photon pairs as well as promising candidates for building up integrated quantum optics devices. Here, we use such a source with optimized non-linearity for preparing time-bin entangled photons in the telecommunication wavelength range. By taking advantage of pulsed state preparation and efficient free-running single-photon detection, we drive our source at low pump powers, which results in a strong photon-pair correlation. The tomographic reconstruction of the state’s density matrix reveals that our source exhibits a high degree of entanglement. We extract a concurrence of 88.9(1.8)% and a fidelity of 94.2(9)% with respect to a Bell state.

arXiv:1804.11108•APL Photonics•Aug 1, 2018•25 citations

Fabrication of low-loss III-V Bragg-reflection waveguides for parametric down-conversion

Hannah Thiel, Marita Wagner, Bianca Nardi +8 more

Entangled photon pairs are an important resource for quantum cryptography schemes that go beyond point-to-point communication. Semiconductor Bragg-reflection waveguides are a promising photon-pair source due to mature fabrication, integrability, large transparency window in the telecom wavelength range, integration capabilities for electro-optical devices as well as a high second-order nonlinear coefficient. To increase performance we improved the fabrication of Bragg-reflection waveguides by employing fixed-beam-moving-stage optical lithography, low pressure and low chlorine concentration etching, and resist reflow. The reduction in sidewall roughness yields a low optical loss coefficient for telecom wavelength light of alpha_reflow = 0.08(6)mm^(-1). Owing to the decreased losses, we achieved a photon pair production rate of 8800(300)(mW*s*mm)^(-1) which is 15-fold higher than in previous samples.

arXiv:2309.00936•Sep 2, 2023•0 citations

AlGaAs Bragg Reflection Waveguides as Single and Entangled Photon Pair Source

Akriti Raj, Tobias Bauer, David Lindler +3 more

AlGaAs Bragg reflection waveguides are promising systems for the generation of single and entangled photons through the process of spontaneous parametric down-conversion (SPDC) [1]. We use a type II SPDC process where the downconverted photons are orthogonally polarized. The produced photons are inherently polarization-entangled eliminating the need for any additional entanglement setup. The material AlGaAs is our preferred choice as a nonlinear medium because it features a high nonlinear coefficient allowing for room temperature operation and has the advantage of being a non-birefringent material. Further, the material platform allows for the direct integration of a pump laser into the same chip.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 23, 2025•0 citations

Bragg reflection waveguide as a source of wavelength-multiplexed polarization-entangled photon pairs

Jiŕí Svozilík, Martin Hendrych, Juan P. Torres

We put forward a new highly efficient source of paired photons entangled in polarization with an ultra-large bandwidth. The photons are generated by means of a conveniently designed spontaneous parametric down-conversion process in a semiconductor type-II Bragg reflection waveguide. The proposed scheme aims at being a key element of an integrated source of polarization-entangled photon pairs highly suitable for its use in a multi-user quantum-key-distribution system.

arXiv:1207.4218•Optics Express•Jun 20, 2012•14 citations

Nonlinear Quantum Photonics With AlGaAs Bragg-Reflection Waveguides

Félicien Appas, Othmane Meskine, Aristide Lemaître +4 more

Integrated photonics is playing a key role in the development of quantum technologies covering applications ranging from quantum communication to computing and from simulations to sensing. In this context, material platforms enabling the chip-scale integration of quantum components are a key issue on the way towards real-world and large-scale technological implementations. In this paper, we review our last achievements on AlGaAs Bragg reflection waveguides emitting nonclassical states of light by spontaneous parametric down conversion. The choice of this platform combines the advantages of a mature fabrication technology, room temperature operation, emission in the telecom C-Band and compliance with electrical injection. We demonstrate the ability of these devices to generate a large variety of quantum states spanning from biphoton frequency combs to broadband polarization entanglement enabling promising applications in quantum processing as well as flexible quantum networks.

Journal of Lightwave Technology•Oct 13, 2022•26 citations
We demonstrate efficient photon pair generation for quantum communication using an all-semiconductor approach. In an AlGaAs Bragg-reflection waveguide we employ spontaneous parametric down-conversion to produce photon pairs at telecommunication wavelengths. The various phase-matching solutions present in our device can be used to create timebin or polarization entanglement. This approach can to lead to a fully integrated photon pair source with the pump laser, active and passive optical devices all on a single semiconductor chip.
Semiconductor Bragg-reflection waveguides are well-established sources of correlated photon pairs as well as promising candidates for building up integrated quantum optics devices. Here, we use such a source with optimized non-linearity for preparing time-bin entangled photons in the telecommunication wavelength range. By taking advantage of pulsed state preparation and efficient free-running single-photon detection, we drive our source at low pump powers, which results in a strong photon-pair correlation. The tomographic reconstruction of the state’s density matrix reveals that our source exhibits a high degree of entanglement. We extract a concurrence of 88.9(1.8)% and a fidelity of 94.2(9)% with respect to a Bell state.
Entangled photon pairs are an important resource for quantum cryptography schemes that go beyond point-to-point communication. Semiconductor Bragg-reflection waveguides are a promising photon-pair source due to mature fabrication, integrability, large transparency window in the telecom wavelength range, integration capabilities for electro-optical devices as well as a high second-order nonlinear coefficient. To increase performance we improved the fabrication of Bragg-reflection waveguides by employing fixed-beam-moving-stage optical lithography, low pressure and low chlorine concentration etching, and resist reflow. The reduction in sidewall roughness yields a low optical loss coefficient for telecom wavelength light of alpha_reflow = 0.08(6)mm^(-1). Owing to the decreased losses, we achieved a photon pair production rate of 8800(300)(mW*s*mm)^(-1) which is 15-fold higher than in previous samples.
AlGaAs Bragg reflection waveguides are promising systems for the generation of single and entangled photons through the process of spontaneous parametric down-conversion (SPDC) [1]. We use a type II SPDC process where the downconverted photons are orthogonally polarized. The produced photons are inherently polarization-entangled eliminating the need for any additional entanglement setup. The material AlGaAs is our preferred choice as a nonlinear medium because it features a high nonlinear coefficient allowing for room temperature operation and has the advantage of being a non-birefringent material. Further, the material platform allows for the direct integration of a pump laser into the same chip.
Integrated photonics is playing a key role in the development of quantum technologies covering applications ranging from quantum communication to computing and from simulations to sensing. In this context, material platforms enabling the chip-scale integration of quantum components are a key issue on the way towards real-world and large-scale technological implementations. In this paper, we review our last achievements on AlGaAs Bragg reflection waveguides emitting nonclassical states of light by spontaneous parametric down conversion. The choice of this platform combines the advantages of a mature fabrication technology, room temperature operation, emission in the telecom C-Band and compliance with electrical injection. We demonstrate the ability of these devices to generate a large variety of quantum states spanning from biphoton frequency combs to broadband polarization entanglement enabling promising applications in quantum processing as well as flexible quantum networks.