Quantum 2025 – wissenschaftliches Programm
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TUE: Tuesday Contributed Sessions
TUE 2: Quantum Networks: Technologies
TUE 2.6: Vortrag
Dienstag, 9. September 2025, 15:30–15:45, ZHG002
Evaluating Cavity-enhanced Telecom-wavelength Quantum Dot Single-photon Sources for Quantum Cryptography — •Robert Behrends1, Koray Kaymazlar1, Mareike Lach1, Martin v. Helversen1, Pratim Saha1, Daniel Vajner1, Jochen Knaupp2, Yorick Reum2, Tobias Huber-Loyola2, Sven Höfling2, Andreas Pfenning2, and Tobias Heindel1 — 1Institute of Physics and Astronomy, Technische Univeristät Berlin, 10623 Berlin, Germany — 2Technische Physik, Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
Great advances are made in the fabrication of telecom-wavelength quantum light sources based on semiconductor quantum dots (QDs)[1]. Yet, further progress is needed towards practical applications. Here, we evaluate QD-based single-photon sources for applications in quantum cryptography in the telecom C-band. Exploiting cavity-enhanced devices with embedded InAs/InAlGaAs QDs, we achieve emitter lifetimes of 500 ps and g(2)(0)=0.044 under pulsed quasi-resonant excitation. Employed in a quantum cryptography testbed, we investigate dynamic polarization-state encoding using a customized fiber-coupled electro-optic modulator in single-pass configuration, which is controlled by an arbitrary waveform generator. The random preparation of four polarization states with low loss and low quantum bit error ratio thereby is crucial for applications in quantum key distribution and beyond[2].
[1] Holewa et al., Nanophotonics, 10.1515/nanoph-2024-0747 (2025)
[2] Vajner et al., arXiv:2412.14993 (2024)
Keywords: Quantum Communication; Quantum Key Distribution; Quantum Dots