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arXiv · 2607.23413

Highly integrated quantum key distribution transmitter enabled by silicon photonics

Rende Liu·Yan-Lin Tang·Cheng-Guang Dong·Yan Ma·Guo-Qing Liu·Zhi-Lin Xie·Shuai Li·Mi Zou·Hao Liang·Shi-biao Tang
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Abstract

Quantum key distribution (QKD) provides information-theoretic security independent of computational assumptions, yet the bulk and cost of current systems hinder large-scale deployment. Although integrated photonic technologies have enabled highly integrated QKD chips, practical QKD transmitters are still predominantly implemented as rack-mounted systems. Here, we demonstrate a highly integrated standalone QKD transmitter that integrates all essential functionalities required for practical QKD operation within a compact platform built around a silicon photonic encoding chip. The transmitter occupies only $167 \times 56 \times 21~\mathrm{mm}^3$ ($\sim 0.2~\mathrm{dm}^3$), comparable in size to a half-height, half-width PCIe card and more than 30 times smaller in volume than a conventional 1U rack-mounted system. Paired with a conventional discrete-component receiver, it achieves a secure key rate of 219.1 kbps over 51.3 km of standard single-mode fiber, with performance comparable to that of conventional discrete-component implementations. This work bridges the gap between photonic chip integration and deployable QKD hardware, marking an important step toward transitioning QKD transmitters from conventional rack-mounted equipment to compact board-level platforms.

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Rende Liu, Yan-Lin Tang, Cheng-Guang Dong, Yan Ma, Guo-Qing Liu, Zhi-Lin Xie, Shuai Li, Mi Zou, Hao Liang, Shi-biao Tang. 2026-07-26. Highly integrated quantum key distribution transmitter enabled by silicon photonics. https://arxiv.org/abs/2607.23413

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