Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE Communications Letters

Parameter Optimization of Quantum Key Distribution in Quantum-Classical WDM-SDM Coexistence Systems

Yaoxian Gao, Yongmei Sun, Yuefeng Ji

Published Dec 24, 2025• 0 citations
Publisher

Abstract

In quantum-classical coexistence systems, classical noise and system loss can significantly affect the performance of quantum key distribution (QKD), while the fixed-parameter QKD (FPQ) cannot adapt to varying conditions. In this paper, we propose a local search algorithm (LSA) for QKD to optimize the parameters in wavelength division multiplexing (WDM) and space division multiplexing (SDM) systems. Simulation results show that LSA can achieve 99.9% performance of the exhaustive search algorithm, while significantly reducing computational complexity. Moreover, LSA improves QKD performance by 31.9% over standard single mode fiber and 24.5% over multicore fiber in quantum-classical coexistence systems.

DOI
10.1109/lcomm.2025.3648306

Related papers

A Core and Wavelength Allocation Scheme for Synergistic Transmission of Classical and Quantum Signals

Xueqin Ren, Yongmei Sun, Weiwen Kong +1 more

Wavelength division multiplexing (WDM) and space division multiplexing (SDM) can be used to implement coexistence of the classical and quantum signals. But some noises are introduced due to the SDM/WDM techniques, such as Raman, Four-wave mixing and inter-core crosstalk noises, which will restrict the performance of the quantum key distribution system (QKD). In this paper, we consider that the classical optical communication system is also affected by such noises. So, in order to improve the performance of the coexistence system based on WDM and SDM, we propose a dual optimized core and wavelength allocation (DOCWA) scheme to realize the synergistic transmission of classical and quantum signals over multi-core fiber. Experiments verify that the proposed scheme can suppress noise photons on classical and quantum channels up to 152.71% and 167.28% compared to the quantum equal frequency spacing scheme, respectively.

Asia Communications and Photonics Conference•Nov 5, 2022•2 citations

Parameters optimization based on neural network of practical wavelength division multiplexed decoy-state quantum key distribution

Jiahao Li, Lei Shi, Tianxiu Li +3 more

The integration of quantum key distribution (QKD) devices with the existing optical fiber networks is of great significance in reducing the deployment costs and saving fiber resources. Wavelength division multiplexing (WDM) is expected to be a desirable approach to fulfill this ultimate task. In this paper, we analyze the dominant noises in WDM-based QKD system and optimize the key parameters based on a modified model with 200 GHz channel spacing. Then, an appropriate decoy-state method is adopted to estimate the system performance considering statistical fluctuations. Finally, a three-layer artificial neural network is used to train and predict the optimal mean photon numbers within different situations. Our work provides a useful method for the parameters optimization of WDM-QKD system and accelerates the practical development of QKD that coexists with the current backbone fiber infrastructure.

Modern Physics Letters B•Sep 16, 2021•4 citations

Improving Parameter Optimization in Decoy-State Quantum Key Distribution

Zijian Li, Kejin Wei

Quantum key distribution (QKD) enables two remote users to share a string of key bits with information-theoretical security. Parameter optimization is a crucial step in achieving optimal performance in practical QKD systems. In general, such optimization is implemented using a local search algorithm (LSA). However, LSAs inevitably fail to find out the optimal values when the searched key rate function is nonconvex or has a discontinuity of first-order derivatives and a narrow parameter search space. This paper proposes a genetic algorithm-based method to overcome the limitations of LSAs for QKD parameter optimization. We tested the proposed method with various types of common QKD protocols and found that it has very high parameter optimization performance for QKD with a time consumption comparable to that using a standard LSA. We expect our method to be a valuable optimization tool for quantum information processing tasks.

Quantum Engineering•Feb 4, 2022•42 citations

Practical security of wavelength-multiplexed decoy-state quantum key distribution

Liang-Yuan Zhao, Qianjun Wu, Hong-Kang Qiu +2 more

Wavelength division multiplexing (WDM) of quantum key distribution (QKD) with classical optical channels has been proven to be feasible experimentally. In this paper, we will analyze the practical security of WDM-QKD theoretically. Specifically, we first establish the noise model of classical signals. Then, the influence of classical noises on the performance of decoy-state WDM-QKD is studied with a finite-key security analysis. For numerical simulations, the effect of classical noise-reduction methods for different experimental settings is given. The secret key rate and maximum transmission distance of WDM-QKD is simulated with various sent number of quantum pulses or transmitted power of classical signals. Furthermore, the performance of two kinds of decoy-state WDM-QKD is compared, which shows that the optimal decoy-state protocol for WDM-QKD is related to the sent number of quantum pulses. Since WDM-QKD is desired to reduce the cost of QKD networks and since experiments have already been carried out, our work can not only close the gap between theory and practice, but also be used to optimize the experimental parameters and improve its performance.

Physical Review A•Feb 26, 2021•15 citations

Finite-key analysis based on neural network of practical wavelength division multiplexed decoy-state quantum key distribution

Jiahao Li, Lei Shi, Junhui Wang +2 more

The integration of quantum key distribution (QKD) devices with the existing optical fiber networks is of great significance in reducing the deployment costs and saving fiber resources. Wavelength division multiplexing (WDM) is expected to be a desirable approach to fulfill this ultimate task. In this paper, we analyze the dominant noises in WDM-based QKD system and optimize the key parameters based on a modified model with 200 GHz channel spacing. Then, an appropriate decoy-state method is adopted to estimate the system performance considering statistical fluctuations. Finally, a three-layer artificial neural network is used to train and predict the optimal mean photon numbers within different situations. Our work provides a useful method for the parameters optimization of WDM-QKD system and accelerates the practical development of QKD that coexists with the current backbone fiber infrastructure.

AOPC 2021: Optical Sensing and Imaging Technology•Nov 24, 2021•2 citations

Continuous Variable Quantum Key Distribution Coexisting with Classical Channels

Masab Iqbal, Michela Svaluto Moreolo, Arturo Villegas +2 more

Quantum Key Distribution (QKD) offers a secure method for generating cryptographic keys crucial for 6G future networks. It relies on quantum mechanics principles to guarantee protection against potential threats from quantum computers. However, QKD signal is fragile and can be easily degraded by external noise sources. Therefore, integrating QKD into existing networks poses a challenge, as it must seamlessly coexist with classical channels, in optical fiber links utilizing wavelength division multiplexing (WDM). Continuous-variable QKD (CV-QKD), which leverages optical coherent technology, is seen as a promising solution for this integration within current telecom infrastructure. Additionally, Software-Defined Networking (SDN) presents opportunities for enhancing efficiency and facilitating dynamic management in coexistence scenarios. This paper reports key noise sources that degrade CV-QKD performance in coexistence and the parameters contributing to these noise sources such as classical channel (CC) power, separation between CC and quantum channel (QC) and position of QC. We also report strategies for effectively managing coexistence scenarios using SDN. We focus on the coexistence of CVQKD in presence of classical channels spaced according a 100 GHz ITU-T grid over a 10 km link length, providing guidelines to optimize the performance.

International Conference on Transparent Optical Networks•Jul 14, 2024•6 citations
In quantum-classical coexistence systems, classical noise and system loss can significantly affect the performance of quantum key distribution (QKD), while the fixed-parameter QKD (FPQ) cannot adapt to varying conditions. In this paper, we propose a local search algorithm (LSA) for QKD to optimize the parameters in wavelength division multiplexing (WDM) and space division multiplexing (SDM) systems. Simulation results show that LSA can achieve 99.9% performance of the exhaustive search algorithm, while significantly reducing computational complexity. Moreover, LSA improves QKD performance by 31.9% over standard single mode fiber and 24.5% over multicore fiber in quantum-classical coexistence systems.
Wavelength division multiplexing (WDM) and space division multiplexing (SDM) can be used to implement coexistence of the classical and quantum signals. But some noises are introduced due to the SDM/WDM techniques, such as Raman, Four-wave mixing and inter-core crosstalk noises, which will restrict the performance of the quantum key distribution system (QKD). In this paper, we consider that the classical optical communication system is also affected by such noises. So, in order to improve the performance of the coexistence system based on WDM and SDM, we propose a dual optimized core and wavelength allocation (DOCWA) scheme to realize the synergistic transmission of classical and quantum signals over multi-core fiber. Experiments verify that the proposed scheme can suppress noise photons on classical and quantum channels up to 152.71% and 167.28% compared to the quantum equal frequency spacing scheme, respectively.
The integration of quantum key distribution (QKD) devices with the existing optical fiber networks is of great significance in reducing the deployment costs and saving fiber resources. Wavelength division multiplexing (WDM) is expected to be a desirable approach to fulfill this ultimate task. In this paper, we analyze the dominant noises in WDM-based QKD system and optimize the key parameters based on a modified model with 200 GHz channel spacing. Then, an appropriate decoy-state method is adopted to estimate the system performance considering statistical fluctuations. Finally, a three-layer artificial neural network is used to train and predict the optimal mean photon numbers within different situations. Our work provides a useful method for the parameters optimization of WDM-QKD system and accelerates the practical development of QKD that coexists with the current backbone fiber infrastructure.
Quantum key distribution (QKD) enables two remote users to share a string of key bits with information-theoretical security. Parameter optimization is a crucial step in achieving optimal performance in practical QKD systems. In general, such optimization is implemented using a local search algorithm (LSA). However, LSAs inevitably fail to find out the optimal values when the searched key rate function is nonconvex or has a discontinuity of first-order derivatives and a narrow parameter search space. This paper proposes a genetic algorithm-based method to overcome the limitations of LSAs for QKD parameter optimization. We tested the proposed method with various types of common QKD protocols and found that it has very high parameter optimization performance for QKD with a time consumption comparable to that using a standard LSA. We expect our method to be a valuable optimization tool for quantum information processing tasks.
Wavelength division multiplexing (WDM) of quantum key distribution (QKD) with classical optical channels has been proven to be feasible experimentally. In this paper, we will analyze the practical security of WDM-QKD theoretically. Specifically, we first establish the noise model of classical signals. Then, the influence of classical noises on the performance of decoy-state WDM-QKD is studied with a finite-key security analysis. For numerical simulations, the effect of classical noise-reduction methods for different experimental settings is given. The secret key rate and maximum transmission distance of WDM-QKD is simulated with various sent number of quantum pulses or transmitted power of classical signals. Furthermore, the performance of two kinds of decoy-state WDM-QKD is compared, which shows that the optimal decoy-state protocol for WDM-QKD is related to the sent number of quantum pulses. Since WDM-QKD is desired to reduce the cost of QKD networks and since experiments have already been carried out, our work can not only close the gap between theory and practice, but also be used to optimize the experimental parameters and improve its performance.
The integration of quantum key distribution (QKD) devices with the existing optical fiber networks is of great significance in reducing the deployment costs and saving fiber resources. Wavelength division multiplexing (WDM) is expected to be a desirable approach to fulfill this ultimate task. In this paper, we analyze the dominant noises in WDM-based QKD system and optimize the key parameters based on a modified model with 200 GHz channel spacing. Then, an appropriate decoy-state method is adopted to estimate the system performance considering statistical fluctuations. Finally, a three-layer artificial neural network is used to train and predict the optimal mean photon numbers within different situations. Our work provides a useful method for the parameters optimization of WDM-QKD system and accelerates the practical development of QKD that coexists with the current backbone fiber infrastructure.
Quantum Key Distribution (QKD) offers a secure method for generating cryptographic keys crucial for 6G future networks. It relies on quantum mechanics principles to guarantee protection against potential threats from quantum computers. However, QKD signal is fragile and can be easily degraded by external noise sources. Therefore, integrating QKD into existing networks poses a challenge, as it must seamlessly coexist with classical channels, in optical fiber links utilizing wavelength division multiplexing (WDM). Continuous-variable QKD (CV-QKD), which leverages optical coherent technology, is seen as a promising solution for this integration within current telecom infrastructure. Additionally, Software-Defined Networking (SDN) presents opportunities for enhancing efficiency and facilitating dynamic management in coexistence scenarios. This paper reports key noise sources that degrade CV-QKD performance in coexistence and the parameters contributing to these noise sources such as classical channel (CC) power, separation between CC and quantum channel (QC) and position of QC. We also report strategies for effectively managing coexistence scenarios using SDN. We focus on the coexistence of CVQKD in presence of classical channels spaced according a 100 GHz ITU-T grid over a 10 km link length, providing guidelines to optimize the performance.