Bonn 2025 – wissenschaftliches Programm
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QI: Fachverband Quanteninformation
QI 37: Poster – Quantum Information Technologies (joint session Q/QI)
QI 37.10: Poster
Donnerstag, 13. März 2025, 17:00–19:00, Tent
AlGaAs Bragg Reflection Waveguides as Single and Entangled Photon Pair Source — •Akriti Raj1, Tobias Bauer1, David Lindler1, Quankui Yang2, Thorsten Passow2, and Christoph Becher1 — 1Universität des Saarlandes, FR Physik, Campus E2.6, 66123 Saarbrücken — 2Fraunhofer-Institut für Angewandte Festkörperphysik IAF, Tullastr. 72, 79108 Freiburg
True single and entangled photon pair sources are crucial elements for applications in quantum technologies. Such sources may be realized by AlGaAs Bragg reflection waveguides, generating correlated single photon pairs through the process of spontaneous parametric down conversion (SPDC) [1]. The material AlGaAs is our preferred choice as the nonlinear medium because it features a high nonlinear coefficient, allows for room temperature operation and has the advantage of being a non-birefringent material. By using a type II SPDC process where the downconverted photons are orthogonally polarised to each other, the produced photons are inherently polarisation entangled eliminating the need for any additional entanglement setup [2]. We here present photon generation rates of 4 × 107 pairs/s/mW from these waveguides. The purity of the produced single photons is quantified by measuring the heralded g(2)(0) = 0.0017 at ≈ 0.28 mW pump power. The photons show 91.9% entanglement fidelity with the |ψ +> Bell state and 90% purity. We thus realize a room temperature entangled pair photon source at 1546 nm that is already coupled in a standard single-mode telecom fiber for further applications. [1] F. Appas et al., J. Light. Technol. 40 (2022). [2] R. T. Horn et al., Sci. Rep. 3.1 (2013).
Keywords: SPDC; Entanglement; AlGaAs; Heralding