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arXiv · 2603.20718

Frequency-Division Multiplexed CV-QKD System

Jaehyeok Han·Donghyeok Lee·Minseok Ryu·Syed Assad·Yong-Su Kim·Sunghyun Bae
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Abstract

We propose a frequency-division multiplexed (FDM) continuous-variable quantum key distribution (CV-QKD) system with enhanced spectral efficiency through optimized channel spacing of low-symbol-rate signals. A four-channel 10-Mbaud FDM-CV-QKD system was experimentally demonstrated using Gaussian modulation, a transmitted local oscillator, and homodyne detection. Despite the inter-channel interference, under a finite-size scenario (m=1.25x10^6), the system achieved a 3.6-fold back-to-back secret key rate gain and outperformed the single-channel frequency-upconverted signal up to 26.8 km.

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Jaehyeok Han, Donghyeok Lee, Minseok Ryu, Syed Assad, Yong-Su Kim, Sunghyun Bae. 2026-03-21. Frequency-Division Multiplexed CV-QKD System. https://arxiv.org/abs/2603.20718

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