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arXiv · 2508.08722

Continuous-variable quantum key distribution over 50.4 km fiber using integrated silicon photonic transmitter and receiver

Shuaishuai Liu·Yanxiang Jia·Yuqi Shi·Yizhuo Hou·Pu Wang·Yu Zhang·Shiwei Yang·Zhenguo Lu·Xuyang Wang·Yongmin Li
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Abstract

Quantum key distribution (QKD) is the fastest-growing and relatively mature technology in the field of quantum information, enabling information-theoretically secure key distribution between two remote users. Although QKD based on off-the-shelf telecom components has been validated in both laboratory and field tests, its high cost and large volume remain major obstacles to large-scale deployment. Photonic integration, featured by its compact size and low cost, offers an effective approach to addressing the above challenges faced by QKD. Here, we implement a high-performance, integrated local local oscillator continuous-variable (CV) QKD system based on an integrated silicon photonic transmitter and receiver. By employing a high-speed silicon photonic integrated in-phase and quadrature modulator, a low-noise and high bandwidth silicon photonic integrated heterodyne detector, and digital signal processing, our CV-QKD system achieves a symbol rate of up to 1.5625 GBaud. Furthermore, the system achieves asymptotic secret key rates of 31.05 and 5.05 Mbps over 25.8 and 50.4 km standard single-mode fiber, respectively, using an 8-phase-shift keying discrete modulation. Our integrated CV-QKD system with high symbol rate and long transmission distance pays the way for the quantum secure communication network at metropolitan area.

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Shuaishuai Liu, Yanxiang Jia, Yuqi Shi, Yizhuo Hou, Pu Wang, Yu Zhang, Shiwei Yang, Zhenguo Lu, Xuyang Wang, Yongmin Li. 2025-08-12. Continuous-variable quantum key distribution over 50.4 km fiber using integrated silicon photonic transmitter and receiver. https://doi.org/10.1364/prj.561085

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