Ultrabright Entanglement Based Quantum Key Distribution over a 404 km Optical Fiber
Entangled photons are crucial resources for quantum information processing. Here, we present an ultrabright polarization-entangled photon source based on a periodically poled lithium niobate waveguide designed for practical quantum communication networks. Using a 780 nm pump laser, the source achieves a pair generation rate of 2.4×10^{10} pairs/s/mW. Remarkably, the entangled photons are bright enough to be detected by a power meter, reaching a power of 17.9 nW under a pump power of 3.2 mW. We demonstrate the practicality of the source by conducting quantum key distribution experiments over long-distance fiber links. Wavelength-division multiplexing was employed to enhance the key generation, and nonlocal dispersion compensation was implemented to ensure precise timing coincidence measurements across a broad spectral range. By utilizing nine pairs of wavelength channels, the system achieved the applicable secure key rates of up to 440.80 bits/s over 200 km with a 62 dB loss and extended the maximum secure key generation distance to 404 km. These results demonstrate the potential of wavelength-multiplexed polarization-entangled photon sources for high-speed, long-distance quantum communication, positioning them as key components for future large-scale quantum networks.
Authors
- Juan Yin (ORCID: https://orcid.org/0000-0002-9909-6211)
- Cheng-Zhi Peng (ORCID: https://orcid.org/0000-0002-4753-5243)
- Yuhuai Li (ORCID: https://orcid.org/0000-0002-6146-8083)
- Feihu Xu
- Lixing You (ORCID: https://orcid.org/0000-0001-7304-0474)
- Hui-Nan Wu (ORCID: https://orcid.org/0000-0002-1755-5331)
- Jian-Wei Pan (ORCID: https://orcid.org/0000-0002-6100-5142)
- Quan Yao
- Guang-Bing Li
- Yuan Cao (ORCID: https://orcid.org/0000-0002-0354-2855)
- Bo Li (ORCID: https://orcid.org/0000-0001-8417-7927)
- Qiang Zhang
- Xiu-Ping Xie
- Sophie Zhuang (ORCID: https://orcid.org/0009-0009-4293-514X)
- Ming-Yang Zheng (ORCID: https://orcid.org/0009-0005-9061-8852)
- Yanshan Zeng
- Hao Qin
Institutions
- University of Science and Technology of China (CN)
- Hefei National Center for Physical Sciences at Nanoscale (CN)
- Jinan Institute of Quantum Technology (CN)
- Shanghai Institute of Microsystem and Information Technology (CN)
- Beijing Academy of Quantum Information Sciences (CN)
Publication Details
- Journal
- Physical Review Letters
- Published
- 2025-06-09
- DOI
- https://doi.org/10.1103/physrevlett.134.230801
- Citations
- 14
- Primary Topic
- Quantum Information and Cryptography
- Type
- article
- Field-Weighted Citation Impact
- 34.73
Funders
- National Natural Science Foundation of China
- Chinese Academy of Sciences
- Science and Technology Commission of Shanghai Municipality
- Youth Innovation Promotion Association of the Chinese Academy of Sciences
- Natural Science Foundation of Shandong Province
- Key Technology Research and Development Program of Shandong
- National Key Research and Development Program of China
- Youth Innovation Promotion Association