Mainz 2026 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 81: Quantum Communication, Networks, Repeaters, & QKD III

Q 81.6: Talk

Friday, March 6, 2026, 15:45–16:00, P 10

QKD via Nanosatellites - Qube 2 Mission Hardware and Update — •Moritz Birkhold for the QUBE 2 Konsortium collaboration — Ludwig Maximilian University (LMU) — Munich Center for Quantum Science and Technology (MCQST)

Since the first proposal of the BB84 protocol in 1984, Quantum Key Distribution (QKD) has progressed from laboratory demonstrations to large-scale deployed fiber-based networks of 2000+ km in China. However, the limited reach of terrestrial links continues to motivate the development of space-based QKD to achieve global coverage. As a first step towards this goal, the QUBE-1 pathfinder mission, launched in 2024 with compact optical payloads but without full QKD capability, has enabled initial quantum experiments in orbit.

Building on the technologies and experience gained from these, the successor mission QUBE-2 now will introduce several major upgrades to enable full QKD operation from a nanosatellite platform. The optical terminal now includes an enlarged 8 cm aperture, improving link performance, while the fully re-engineered optical assembly is hermetically sealable and more reproducible. The QKD electronics supports repetition rates up to 200 MHz, incorporates decoy-state capability, and can perform all required post-processing tasks. Ground validation demonstrated key exchange with QBER < 0.5%. The payloads have successfully passed testing, are already integrated with the satellite bus and prepared for launch in 2026.

Keywords: QKD; Quantum Key Distribution; BB84; Satellite-based Quantum communication