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arXiv · 2105.04733

High-dimensional coherent one-way quantum key distribution

Kfir Sulimany·Guy Pelc·Rom Dudkiewicz·Simcha Korenblit·Hagai S. Eisenberg·Yaron Bromberg·Michael Ben-Or
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Abstract

High-dimensional quantum key distribution (QKD) offers secure communication, with secure key rates that surpass those achievable by QKD protocols utilizing two-dimensional encoding. However, existing high-dimensional QKD protocols require additional experimental resources, such as multiport interferometers and multiple detectors, thus raising the cost of practical high-dimensional systems and limiting their use. Here, we present and analyze a novel protocol for arbitrary-dimensional QKD, that requires only the hardware of a standard two-dimensional system. We provide security proofs against individual attacks and coherent attacks, setting an upper and lower bound on the secure key rates. Then, we test the new high-dimensional protocol in a standard two-dimensional QKD system over a 40 km fiber link. The new protocol yields a two-fold enhancement of the secure key rate compared to the standard two-dimensional coherent one-way protocol, without introducing any hardware modifications to the system. This work, therefore, holds great potential to enhance the performance of already deployed time-bin QKD systems through a software update alone. Furthermore, its applications extend across different encoding schemes of QKD qudits.

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quant-phcs.CRcs.ITmath.ITphysics.optics

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Kfir Sulimany, Guy Pelc, Rom Dudkiewicz, Simcha Korenblit, Hagai S. Eisenberg, Yaron Bromberg, Michael Ben-Or. 2021-05-11. High-dimensional coherent one-way quantum key distribution. https://doi.org/10.1038/s41534-025-00965-7

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