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

arXiv:2503.04399

A polychromatic continuous-variable quantum communication network enabled by optical frequency combs

Yuehan Xu, Qijun Zhang, Junpeng Zhang, Liao, Xiaojuan, Ziyi Shen, Xu Liu, Beibei Zhang, Zicong Tan, Zehao Zhou, Jisheng Dai, Xueqin Jiang, Pengcheng Huang, Tao Wang, Guihua Zeng

Published Mar 6, 2025• 1 citation
arXivHTMLPDF

Abstract

In classical communication, the introduction of polychromatic resources has rapidly boosted classical networks' rate and scale. Quantum communication is now at a similar critical stage in its development, and therefore, it is essential to investigate polychromatic quantum communication networks. In this letter, we report a polychromatic continuous-variable quantum communication network enabled by optical frequency combs. The multi-mode density matrices constituted by polychromatic quantum networks are studied. Considering the limited mode isolation, the maximum amount of information that eavesdroppers can obtain is recalculated, therefore, the total secret key rate is provided. We have also demonstrated that, compared to other multiplexing techniques, polychromatic quantum networks can theoretically achieve a secret key rate without decreasing with the increase in users. In the experiment, direct-transmission type and round-trip type quantum communication networks were built using optical frequency combs and dual-comb interference detection technology. The Gaussian-modulated continuous-variable quantum key distribution (CV-QKD) protocol has been validated, with a network capacity of 19 and a total secret key rate of 8.75 Gbps at a uniform distance of 5 km (asymptotic case), 0.82 Mbps at 120 km (finite-size effect), 89.10 Mbps at 40 km (compsable security), 13.66 Mbps at 40 km (compsable finite-size security). This implementation not only provides technical support for a high-speed multi-node quantum network, but also provides a solution for the future quantum Internet with continuous variables.

DOI
10.48550/arxiv.2503.04399

Related papers

Polychromatic continuous-variable quantum communication network enabled by optical frequency combs

Yuehan Xu, Qijun Zhang, Junpeng Zhang +11 more

Polychromatic resources have transformed classical communication networks by boosting rate and scalability; quantum communication networks are reaching a similar inflection point. Here, we report a polychromatic continuous-variable quantum communication network enabled by optical frequency combs. The multi-mode density matrices constituted by polychromatic quantum networks are studied. We incorporate finite mode isolation into the security analysis to bound Eve’s accessible information and compute the total network secret key rate. It is demonstrated that, compared to other multiplexing techniques, polychromatic quantum networks can theoretically achieve a secret key rate without decreasing with the increase in users. In the experiment, direct-transmission type and round-trip type quantum communication networks were built using optical frequency combs and dual-comb interference detection technology. The Gaussian-modulated continuous-variable quantum key distribution (CV-QKD) protocol has been validated, with a network capacity of 19 and a total secret key rate of 8.75 Gbps at a uniform distance of 5 km (asymptotic case), 0.82 Mbps at 120 km (finite-size effect), 89.10 Mbps at 40 km (composable security), 13.66 Mbps at 40 km (composable finite-size security). This implementation not only provides technical support for a high-speed multi-node quantum network, but also provides a solution for the future quantum Internet with continuous variables.

npj Quantum Information•Mar 7, 2026•1 citation

Large-scale continuous-variable quantum secret sharing with optical frequency comb

Qijun Zhang, Yuehan Xu, Tao Wang +3 more

Abstract Quantum secret sharing (QSS), as a fundamental cryptographic protocol for future quantum networks, continues to face significant challenges, particularly in the generation of multipartite entanglement and the degradation of entanglement fidelity during distribution, both of which severely limit its scalability. These persistent constraints motivate an alternative approach based on continuous-variable (CV) systems. We propose a CVQSS scheme based on an electro-optically modulated optical frequency comb. The scheme employs a single laser to generate multi-wavelength coherent states, enabling the efficient and flexible construction of secret sharing subnetworks. By incorporating a broadcast-based distribution mechanism, the architecture is scalable to 128 players. Experimental verification with 24 players over a 10 km fiber link demonstrates a secret sharing rate of 6.24 per player under asymptotic conditions and 1.27 Mbps per player under finite-size effects, and a 1.05MB image is secretly shared to six players. This work achieves information-theoretically secure QSS both within and across subnetworks, providing a solid technical foundation for the development of scalable and multifunctional quantum networks.

PhotoniX•Jul 14, 2026•0 citations

OFDM-based quantum key distribution access network reaching Nyquist limits

Yuehan Xu, Xiaojuan Liao, Qijun Zhang +3 more

Quantum key distribution (QKD) can theoretically accomplish unconditionally secure communication with the support of quantum mechanics. The point-to-point QKD system has already been well developed, and the focus of advanced research has shifted more toward QKD networks. However, it is still unclear how to achieve the maximum secret key rate within the limited physical bandwidth in QKD networks. In this paper, we propose an orthogonal frequency division multiplexing continuous-variable QKD access network (CV-QAN), which improves the bandwidth utilization efficiency to the Nyquist limit. Specifically, each quantum network unit prepares a carrier-modulated Gaussian-modulated coherent state so that they become orthogonal in the frequency domain when received by the quantum line terminal. Crosstalk arising from the multi-path effect among multi-mode quantum states was effectively suppressed through the implementation of a cyclic prefix. In this theory, we have demonstrated the feasibility of this scheme through the continuous-mode Gaussian information theory. In this experiment, we conducted a local local oscillator (LLO) CV-QAN experiment within the existing passive optical network architecture. The network capacity of CV-QAN is 7, and the secret key rate of each user reaches 4.06 and 0.87 Mbps at 25 km in the asymptotic case and the finite-size effect, respectively. This achievement has established an efficient and simple QAN based on digital signal processing, laying the foundation for the practicality and commercialization of large-scale quantum networks.

Optica•Sep 29, 2025•3 citations

Continuous-variable quantum key distribution network based on untrusted entanglement states of optical frequency combs

Hai Zhong, Qianqian Hu, Zhiyue Zuo +3 more

Continuous-variable quantum key distribution (CVQKD) offers high key rates and compatibility with classical optical communications. Developing scalable and efficient CVQKD networks will facilitate the deployment of large-scale quantum communication networks. This paper proposes a CVQKD network based on the untrusted entanglement states of an optical frequency comb. The scheme generates Einstein-Podolsky-Rosen states with a frequency comb structure via a type-II optical parametric oscillator. By employing the entanglement-in-the-middle scheme, a source-untrusted fully connected CVQKD network capable of distributing secret keys simultaneously can be formed. We analyze the security of the system in the asymptotic and finite-size cases. Simulation results show that with careful control of system loss and noise, the proposed scheme is feasible for deploying a short-distance fully connected CVQKD network. Loss will be the main factor limiting system performance. The proposed scheme offers a new perspective for a multi-user fully connected CVQKD network.

Optics Express•Apr 20, 2026•0 citations

Continuous-variable quantum key distribution network based on entangled states of optical frequency combs

Hai Zhong, Qianqian Hu, Zhiyue Zuo +3 more

Continuous-variable quantum key distribution (CVQKD) features a high key rate and compatibility with classical optical communication. Developing expandable and efficient CVQKD networks will promote the deployment of large-scale quantum communication networks in the future. This paper proposes a CVQKD network based on the entangled states of an optical frequency comb. This scheme generates Einstein-Podolsky-Rosen entangled states with a frequency comb structure through the process of a type-II optical parametric oscillator. By combining with the scheme of entanglement in the middle, a fully connected CVQKD network capable of distributing secret keys simultaneously can be formed. We analyze the security of the system in the asymptotic case. Simulation results show that under commendable controlling of system loss and noise, the proposed scheme is feasible for deploying a short-distance fully connected CVQKD network. Loss will be the main factor limiting the system's performance. The proposed scheme provides new ideas for a multi-user fully connected CVQKD network.

quant-pharXiv:2512.24718•Jan 1, 2026•0 citations

Experimental demonstration of high-rate discrete-modulated continuous-variable quantum key distribution system

Yan Pan, Heng 恒 Wang 王, Yun Feng Shao +5 more

A high-rate continuous-variable quantum key distribution (CV-QKD) system based on high-order discrete modulation is experimentally investigated. With the help of the novel system scheme, effective digital signal processing (DSP) algorithms and advanced analytical security proof methods, the transmission results of 5.059 km, 10.314 km, 24.490 km, and 50.592 km are achieved for 1 GBaud optimized quantum signals. Correspondingly, the asymptotic secret key rates (SKRs) are 292.185 Mbps, 156.246 Mbps, 50.491 Mbps, and 7.495 Mbps for discrete Gaussian (DG) 64QAM, and 328.297 Mbps, 176.089 Mbps, 51.304 Mbps, and 9.193 Mbps for DG 256QAM, respectively. Under the same parameters, the achieved SKRs of DG 256QAM is almost same as ideal Gaussian modulation. In this case, the demonstrated high-rate discrete-modulated CV-QKD system has the application potential for high-speed security communication under tens of kilometers.

arXiv:2203.08470•Optics Letters•Jun 10, 2022•95 citations
In classical communication, the introduction of polychromatic resources has rapidly boosted classical networks' rate and scale. Quantum communication is now at a similar critical stage in its development, and therefore, it is essential to investigate polychromatic quantum communication networks. In this letter, we report a polychromatic continuous-variable quantum communication network enabled by optical frequency combs. The multi-mode density matrices constituted by polychromatic quantum networks are studied. Considering the limited mode isolation, the maximum amount of information that eavesdroppers can obtain is recalculated, therefore, the total secret key rate is provided. We have also demonstrated that, compared to other multiplexing techniques, polychromatic quantum networks can theoretically achieve a secret key rate without decreasing with the increase in users. In the experiment, direct-transmission type and round-trip type quantum communication networks were built using optical frequency combs and dual-comb interference detection technology. The Gaussian-modulated continuous-variable quantum key distribution (CV-QKD) protocol has been validated, with a network capacity of 19 and a total secret key rate of 8.75 Gbps at a uniform distance of 5 km (asymptotic case), 0.82 Mbps at 120 km (finite-size effect), 89.10 Mbps at 40 km (compsable security), 13.66 Mbps at 40 km (compsable finite-size security). This implementation not only provides technical support for a high-speed multi-node quantum network, but also provides a solution for the future quantum Internet with continuous variables.
Polychromatic resources have transformed classical communication networks by boosting rate and scalability; quantum communication networks are reaching a similar inflection point. Here, we report a polychromatic continuous-variable quantum communication network enabled by optical frequency combs. The multi-mode density matrices constituted by polychromatic quantum networks are studied. We incorporate finite mode isolation into the security analysis to bound Eve’s accessible information and compute the total network secret key rate. It is demonstrated that, compared to other multiplexing techniques, polychromatic quantum networks can theoretically achieve a secret key rate without decreasing with the increase in users. In the experiment, direct-transmission type and round-trip type quantum communication networks were built using optical frequency combs and dual-comb interference detection technology. The Gaussian-modulated continuous-variable quantum key distribution (CV-QKD) protocol has been validated, with a network capacity of 19 and a total secret key rate of 8.75 Gbps at a uniform distance of 5 km (asymptotic case), 0.82 Mbps at 120 km (finite-size effect), 89.10 Mbps at 40 km (composable security), 13.66 Mbps at 40 km (composable finite-size security). This implementation not only provides technical support for a high-speed multi-node quantum network, but also provides a solution for the future quantum Internet with continuous variables.
Abstract Quantum secret sharing (QSS), as a fundamental cryptographic protocol for future quantum networks, continues to face significant challenges, particularly in the generation of multipartite entanglement and the degradation of entanglement fidelity during distribution, both of which severely limit its scalability. These persistent constraints motivate an alternative approach based on continuous-variable (CV) systems. We propose a CVQSS scheme based on an electro-optically modulated optical frequency comb. The scheme employs a single laser to generate multi-wavelength coherent states, enabling the efficient and flexible construction of secret sharing subnetworks. By incorporating a broadcast-based distribution mechanism, the architecture is scalable to 128 players. Experimental verification with 24 players over a 10 km fiber link demonstrates a secret sharing rate of 6.24 per player under asymptotic conditions and 1.27 Mbps per player under finite-size effects, and a 1.05MB image is secretly shared to six players. This work achieves information-theoretically secure QSS both within and across subnetworks, providing a solid technical foundation for the development of scalable and multifunctional quantum networks.
Quantum key distribution (QKD) can theoretically accomplish unconditionally secure communication with the support of quantum mechanics. The point-to-point QKD system has already been well developed, and the focus of advanced research has shifted more toward QKD networks. However, it is still unclear how to achieve the maximum secret key rate within the limited physical bandwidth in QKD networks. In this paper, we propose an orthogonal frequency division multiplexing continuous-variable QKD access network (CV-QAN), which improves the bandwidth utilization efficiency to the Nyquist limit. Specifically, each quantum network unit prepares a carrier-modulated Gaussian-modulated coherent state so that they become orthogonal in the frequency domain when received by the quantum line terminal. Crosstalk arising from the multi-path effect among multi-mode quantum states was effectively suppressed through the implementation of a cyclic prefix. In this theory, we have demonstrated the feasibility of this scheme through the continuous-mode Gaussian information theory. In this experiment, we conducted a local local oscillator (LLO) CV-QAN experiment within the existing passive optical network architecture. The network capacity of CV-QAN is 7, and the secret key rate of each user reaches 4.06 and 0.87 Mbps at 25 km in the asymptotic case and the finite-size effect, respectively. This achievement has established an efficient and simple QAN based on digital signal processing, laying the foundation for the practicality and commercialization of large-scale quantum networks.
Continuous-variable quantum key distribution (CVQKD) offers high key rates and compatibility with classical optical communications. Developing scalable and efficient CVQKD networks will facilitate the deployment of large-scale quantum communication networks. This paper proposes a CVQKD network based on the untrusted entanglement states of an optical frequency comb. The scheme generates Einstein-Podolsky-Rosen states with a frequency comb structure via a type-II optical parametric oscillator. By employing the entanglement-in-the-middle scheme, a source-untrusted fully connected CVQKD network capable of distributing secret keys simultaneously can be formed. We analyze the security of the system in the asymptotic and finite-size cases. Simulation results show that with careful control of system loss and noise, the proposed scheme is feasible for deploying a short-distance fully connected CVQKD network. Loss will be the main factor limiting system performance. The proposed scheme offers a new perspective for a multi-user fully connected CVQKD network.
Continuous-variable quantum key distribution (CVQKD) features a high key rate and compatibility with classical optical communication. Developing expandable and efficient CVQKD networks will promote the deployment of large-scale quantum communication networks in the future. This paper proposes a CVQKD network based on the entangled states of an optical frequency comb. This scheme generates Einstein-Podolsky-Rosen entangled states with a frequency comb structure through the process of a type-II optical parametric oscillator. By combining with the scheme of entanglement in the middle, a fully connected CVQKD network capable of distributing secret keys simultaneously can be formed. We analyze the security of the system in the asymptotic case. Simulation results show that under commendable controlling of system loss and noise, the proposed scheme is feasible for deploying a short-distance fully connected CVQKD network. Loss will be the main factor limiting the system's performance. The proposed scheme provides new ideas for a multi-user fully connected CVQKD network.
A high-rate continuous-variable quantum key distribution (CV-QKD) system based on high-order discrete modulation is experimentally investigated. With the help of the novel system scheme, effective digital signal processing (DSP) algorithms and advanced analytical security proof methods, the transmission results of 5.059 km, 10.314 km, 24.490 km, and 50.592 km are achieved for 1 GBaud optimized quantum signals. Correspondingly, the asymptotic secret key rates (SKRs) are 292.185 Mbps, 156.246 Mbps, 50.491 Mbps, and 7.495 Mbps for discrete Gaussian (DG) 64QAM, and 328.297 Mbps, 176.089 Mbps, 51.304 Mbps, and 9.193 Mbps for DG 256QAM, respectively. Under the same parameters, the achieved SKRs of DG 256QAM is almost same as ideal Gaussian modulation. In this case, the demonstrated high-rate discrete-modulated CV-QKD system has the application potential for high-speed security communication under tens of kilometers.