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arXiv · 2506.15520

Time-bin encoded quantum key distribution over 120 km with a telecom quantum dot source

Jipeng Wang·Joscha Hanel·Zenghui Jiang·Raphael Joos·Michael Jetter·Eddy Patrick Rugeramigabo·Simone Luca Portalupi·Peter Michler·Xiao-Yu Cao·Hua-Lei Yin·Shan Lei·Jingzhong Yang·Michael Zopf·Fei Ding
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Abstract

Quantum key distribution (QKD) with deterministic single photon sources has been demonstrated over intercity fiber and free-space channels. The previous implementations relied mainly on polarization encoding schemes, which are susceptible to birefringence, polarization-mode dispersion and polarization-dependent loss in practical fiber networks. In contrast, time-bin encoding offers inherent robustness and has been widely adopted in mature QKD systems using weak coherent laser pulses. However, its feasibility in conjunction with a deterministic single-photon source has not yet been experimentally demonstrated. In this work, we construct a time-bin encoded QKD system employing a high-brightness quantum dot (QD) single-photon source operating at telecom wavelength. Our proof-of-concept experiment successfully demonstrates the possibility of secure key distribution over fiber link of 120 km, while maintaining extraordinary long-term stability over 6 hours of continuous operation. This work provides the first experimental validation of integrating a quantum dot single-photon source with time-bin encoding in a telecom-band QKD system. In addition, it demonstrates the highest secure key rate among the time-bin QKDs based on single-photon sources. This development signifies a substantial advancement in the establishment of a robust and scalable QKD network based on solid-state single-photon technology

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Jipeng Wang, Joscha Hanel, Zenghui Jiang, Raphael Joos, Michael Jetter, Eddy Patrick Rugeramigabo, Simone Luca Portalupi, Peter Michler, Xiao-Yu Cao, Hua-Lei Yin, Shan Lei, Jingzhong Yang, Michael Zopf, Fei Ding. 2026-02-26. Time-bin encoded quantum key distribution over 120 km with a telecom quantum dot source. https://doi.org/10.1038/s41377-026-02205-9

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