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Q: Fachverband Quantenoptik und Photonik

Q 59: QuanTour V – Protocols

Q 59.2: Talk

Thursday, March 5, 2026, 15:00–15:15, P 7

GHz-clocked Single-photon Quantum Key Distribution in the Telecom C-band — •Mareike Lach¹, Koray Kaymazlar¹, Robert B. Behrends¹, Lucas Rickert¹, Martin von Helversen¹, Jochen Kaupp², Yorick Raum², Tobias Huber Loyola^2,3, Sven Höfling², Andreas Pfenning², and Tobias Heindel⁴ — ¹Institute of Physics and Astronomy, Technische Univeristät Berlin — ²Technische Physik, Physikalisches Institut and Würzburg-Dresden Cluster of Excellence — ³Karlsruher Institut für Technologie, Institute of Photonics and Quantum Electronics — ⁴Department for Quantum Technology, Univeristät Münster

High speed operation is one of the most desired properties for implementations of quantum key distribution (QKD). This requires however the generation and state-preparation of photonic qubits at high speed. Here, we report on a QKD system based on the BB84 protocol that operates at GHz clock-rates using a highly Purcell-enhanced single-photons source emitting in the telecom C-band. We use a laser with a repetition rate of 2.5 GHz to pump the quantum dot source and prepare the polarization states fot the protocol using a customized fiber-based electro-optic modulator (EOM) controlled by an arbitrary waveform generator (AWG) using the trigger output of the pump laser as common clock. Our results show that our system performs the BB84 protocol succesfully with a quantum bit error ratio (QBER) around 5 % at these unprecendeted high clock-rates.

Keywords: Quantum Dot; Single Photons; BB84; QKD