Fully integrated continuous-variable quantum key distribution with composable security over 100 km
Abstract
Quantum key distribution (QKD) guarantees information-theoretic security by the laws of physics, but deployment at scale requires compact, manufacturable photonic terminals. Continuous-variable QKD (CV-QKD) is well suited for this transition through telecom-compatible, room-temperature coherent detection. However, unifying full on-chip core terminal integration, room-temperature operation, high loss tolerance, and composable end-to-end security in long-distance QKD remains a key bottleneck. Here we report a fully integrated CV-QKD platform in which two hybrid III--V/Si3N4 integrated lasers, a silicon transmitter, and a silicon coherent receiver implement the core terminal functions, operating with a local local oscillator (LLO) over fibre links of 25--150 km. A Bayesian machine-learning algorithm maintains robust phase lock throughout the long records required for composable security, consistently outperforming the conventional unscented Kalman filter, while rate-matched multidimensional reconciliation approaches the Shannon limit. The system certifies a composable finite-size secret-key rate of 29.3 kbps at 100 km from a 140-billion-symbol block, with 12.9 kbps at 125 km under finite-size analysis and 9.17 kbps at 150 km under asymptotic analysis. By establishing the longest finite-size and asymptotic reaches and the highest secret-key rate per symbol reported for integrated CV-QKD, this work advances the development of practical chip-based quantum networks.
Related
- Wavelength-shifting attack on a chip-based continuous-variable quantum key distribution system
- Coherent receiver for Continuous-Variable Quantum Key Distribution using a 3 × 3 beam splitter and single-ended photodetectors
- Continuous variable quantum key distribution through a fading channel with minimal information leakage
- Deterministic Minimum-Leakage Continuous-Variable Quantum Key Distribution with Phase-Conjugated Twin Beams
- Multiplexing of Continuous-Variable and Discrete-Variable Quantum Key Distribution Systems over Fibered and Free-Space Channels
BibTeX
@misc{xu2026fully,
title = {{Fully integrated continuous-variable quantum key distribution with composable security over 100 km}},
author = {Yankai Xu and Xinhang Li and Tao Wang and Jisheng Dai and Xueqin Jiang and Yuyao Guo and Peng Huang and Linjie Zhou and Guihua Zeng},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.29200},
eprint = {2608.29200},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.29200},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Fully integrated continuous-variable quantum key distribution with composable security over 100 km
AU - Yankai Xu
AU - Xinhang Li
AU - Tao Wang
AU - Jisheng Dai
AU - Xueqin Jiang
AU - Yuyao Guo
AU - Peng Huang
AU - Linjie Zhou
AU - Guihua Zeng
PY - 2026
DA - 2026/08/29
PB - arXiv
DO - 10.48550/arxiv.2608.29200
UR - https://arxiv.org/abs/2608.29200
AB - Quantum key distribution (QKD) guarantees information-theoretic security by the laws of physics, but deployment at scale requires compact, manufacturable photonic terminals. Continuous-variable QKD (CV-QKD) is well suited for this transition through telecom-compatible, room-temperature coherent detection. However, unifying full on-chip core terminal integration, room-temperature operation, high loss tolerance, and composable end-to-end security in long-distance QKD remains a key bottleneck. Here we report a fully integrated CV-QKD platform in which two hybrid III--V/Si_3N_4 integrated lasers, a silicon transmitter, and a silicon coherent receiver implement the core terminal functions, operating with a local local oscillator (LLO) over fibre links of 25--150 km. A Bayesian machine-learning algorithm maintains robust phase lock throughout the long records required for composable security, consistently outperforming the conventional unscented Kalman filter, while rate-matched multidimensional reconciliation approaches the Shannon limit. The system certifies a composable finite-size secret-key rate of 29.3 kbps at 100 km from a 140-billion-symbol block, with 12.9 kbps at 125 km under finite-size analysis and 9.17 kbps at 150 km under asymptotic analysis. By establishing the longest finite-size and asymptotic reaches and the highest secret-key rate per symbol reported for integrated CV-QKD, this work advances the development of practical chip-based quantum networks.
ER -