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European Conference on Optical Communication

Experimental Demonstration of $47 \times 800 \text{Gbps}$ Classical Communication and QKD Coexistence Over 101.6 Km HCF

Tianqi Dou, Weiwen Kong, Lei Zhang, Song Wei Gao, Lipeng Feng, Zhenhua Li, Yuheng Xie, Wenpeng Gao, Peizhe Han, Peng Li, Zihan Dong, Nan Lu, Jianjun Tang

Published Sep 28, 2025• 0 citations
Publisher

Abstract

We experimentally demonstrate 37.6 Tbps ($47 \times 800 \text{Gbps}$) classical optical communication and quantum key distribution coexisting over a 101.6 km hollow-core fiber, achieving a record capacity and distance to the best of our knowledge. Sustained secure key rate can be maintained at around 5 kbps. ©2025 The Author(s)

DOI
10.1109/ecoc66593.2025.11263383

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We experimentally demonstrate 37.6 Tbps (47×800Gbps47 \times 800 \text{Gbps}47×800Gbps) classical optical communication and quantum key distribution coexisting over a 101.6 km hollow-core fiber, achieving a record capacity and distance to the best of our knowledge. Sustained secure key rate can be maintained at around 5 kbps. ©2025 The Author(s)
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The integration of quantum key distribution (QKD) with classical optical networks has emerged as a pivotal strategy for building secure communication infrastructures. However, achieving their coexistence in silica-core fibers faces inherent limitations due to nonlinear interference, particularly under high classical signal power. In this paper, we experimentally demonstrate the coexistence of classical optical transport networks and QKD over 101.6 km of hollow-core fiber (HCF) with classical power exceeding 20 dBm for the first time to the best of our knowledge. Through systematic theoretical analysis, we characterize HCF’s transmission loss and nonlinear noise generation mechanisms, revealing its unique compatibility with high-power classical–quantum coexistence compared to conventional fibers. To address spectral interference from HCF’s absorption peaks and nonlinear effects, we propose a spectrally optimized multi-stage allocation (SOMA) scheme that coordinates low-loss channel selection and noise suppression. Experimental validation shows that, under the SOMA scheme, coexisting classical signals achieve 19 dBm in single-wavelength configuration and 21 dBm in multi-wavelength configuration, while maintaining a secure key rate above 10 kbps. This breakthrough establishes HCF as a viable platform for simultaneous high-capacity classical communication and quantum-secured data transmission, overcoming critical power limitations of existing fiber-based coexistence systems.
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