https://doi.org/10.1140/epjqt/s40507-025-00408-4
Research
Experimental measurement-device-independent quantum key distribution with flawed state-preparation over 300 km
1
Henan Key Laboratory of Quantum Information and Cryptography, IEU, 450001, Zhengzhou, China
2
State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Key Lab of Navigation and Location Services, Department of Electronic Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China
a
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b
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Received:
27
April
2025
Accepted:
12
August
2025
Published online:
25
August
2025
Quantum key distribution (QKD) promises theoretically secure communication. However, it encounters challenges in implementation security and performance due to inevitable device imperfections. Since the proposal of measurement-device-independent (MDI) QKD, the critical step toward practical security is to secure QKD with imperfect sources. The source imperfections manifest as state-preparation uncertainty (SPU) in various aspects, e.g., encoding uncertainty, intensity fluctuation, and imperfect vacuum states. Here, we perform an MDI-QKD experiment and achieve both high practical security and superior performance. We address the general form of SPU and guarantee a tight estimation of the secret key rate based on the operator dominance method. We achieve secure key distribution over 303.37 km, which not only represents the farthest distance in experiments involving SPU but also considers the most SPU scenarios. Our experimental results represent a significant step toward promoting practical and secure quantum communication.
Key words: Quantum key distribution / State-preparation uncertainty / Measurement-device-independent
© The Author(s) 2025
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