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:1310.2405 · Physical Review A

Multichannel parallel continuous-variable quantum key distribution with Gaussian modulation

Jian Fang, Peng Huang, Guihua Zeng

Published Feb 12, 2014• 49 citations
arXivHTMLPDF

Abstract

We propose a scheme for continuous-variable quantum key distribution (CV-QKD) using the subcarrier multiplexing technique which was employed in microwave photonics. This scheme allows distribution of $N$ channels with independent Gaussian-modulated CV-QKD in parallel with one laser source and several phase modulators. We analyze the influence of nonlinear signal mixing and security in the asymptotic limit. Results indicate that by using this multiplexing technique, each channel will have a non-Gaussian extra source noise, resulting in slight shortening of the maximum transmission distance, while the total secret key rate can be considerably increased. This scheme could also be used for key distribution for multiple users, and combined with wavelength division multiplexing devices it has potential to be used for construction of a CV-QKD network.

DOI
10.1103/physreva.89.022315

Related papers

Modulation noise model for multi-carrier Gaussian modulated continuous-variable quantum key distribution based on OFDM technology

Ting Ye, Heng Wang, Yan Pan +6 more

In this paper, a multi-carrier Gaussian modulated continuous variable quantum key distribution (CV-QKD) scheme has been proposed based on orthogonal frequency division multiplexing (OFDM) for distributing multiplexing independent secret keys encoded on N subcarriers within a single fiber channel. However, the performance of the system will be significantly influenced by the extra modulation noise in the multi-carrier quantum state preparation. Therefore, a modulation noise model is analyzed in more compact for multi-carrier Gaussian modulated CV-QKD system. Specifically, the gain imbalance and quadrature skew in IQ modulation and the third-order intermodulation effect in N subcarrier modulation are systematically analyzed in the OFDM-based multi-carrier CV-QKD with Gaussian modulation. That is, the IQ imbalance noise and the intermodulation noise are modeled as the modulation noise of the multi-carrier Gaussian modulated CV-QKD system. Moreover, the secure performances of the multi-carrier Gaussian modulated CVQKD are evaluated based on the proposed modulation noise model. Besides, the simulation results show the SKRs are greatly increased by N independent quantum state preparation, which indicates that the multi-carrier CV-QKD system gets rid of the asymptotic SKR limit of single-carrier CV-QKD system for future high-rate CV-QKD deployment in broadband access network.

SPIE Conference on Quantum and Nonlinear Optics•Oct 12, 2023•1 citation

High-performance multi-protocol continuous-variable quantum key distribution using one OFDM-based transceiver

Wang Heng, Yan Pan, Ting Ye +9 more

We experimentally demonstrated a high-performance multi-protocol continuous-variable quantum key distribution (CV-QKD) using one transceiver. The demonstrated multi-protocol CV-QKD system can simultaneously distribute 5 subcarriers with Gaussian, 4QAM, 16QAM, 64QAM, and 1024QAM modulation protocols based on orthogonal-frequency-division-multiplexing (OFDM) technology. Moreover, the modulation variance and probability distribution factor of 5 subcarriers are carefully optimized to maximize their respective SKRs. Besides, we innovatively design an effective OFDM-based DSP scheme and a precise dual-stage phase noise compensation scheme to realize a low excess noise for each subcarrier operating at a 2 GHz symbol rate. Thus, the multi-protocol CV-QKD achieves multiple SKRs of 48.79, 7.58, 23.67, 32.93, and 36.78 Mbps over a typical transmission distance of 50 km within a single transmission. Therefore, our work provides a practical solution to achieve highly efficient, interoperable, flexible, and secure QKDs for high-speed quantum secure communication.

Optics Letters•Jan 5, 2026•0 citations

Multicarrier Multiplexing Continuous-Variable Quantum Key Distribution at Terahertz Bands Under Indoor Environment and in Inter-Satellite Links Communication

Chengji Liu, Changhua Zhu, Xiao Liu +3 more

We propose a continuous-variable quantum key distribution (CVQKD) scheme at terahertz (THz) bands based on multicarrier multiplexing (MCM) technology. In this scheme, multiple Gaussian modulated subcarriers are coupled to transmit multipath superposed thermal Gaussian states. At the receiver, optical discrete Fourier transform (ODFT) is used to demultiplex the received subcarriers, and the keys can be generated in parallel by homodyne detection and post processing. We analyze the security of the scheme against the optimal collective Gaussian attack under indoor environment and in inter-satellite links respectively. Results indicate that by using MCM technology, each subchannel may be affected by crosstalk, resulting in slight shortening of the maximal transmission distance while the total secret key rate can be greatly increased. We also verify the feasibility of higher key rate and longer distance THz-QKD by using MCM technology in inter-satellite links communication. We expect this work will provide an efficient path to build a global quantum communication network.

IEEE photonics journal•Jul 21, 2021•32 citations

Security analysis of orthogonal-frequency-division-multiplexing–based continuous-variable quantum key distribution with imperfect modulation

Hang Zhang, Yu Mao, Duan Huang +3 more

We introduce a reliable scheme for continuous-variable quantum key distribution (CV-QKD) by using orthogonal frequency division multiplexing (OFDM). As a spectrally efficient multiplexing technique, OFDM allows a large number of closely spaced orthogonal subcarrier signals used to carry data on several parallel data streams or channels. We place emphasis on modulator impairments which would inevitably arise in the OFDM system and analyze how these impairments affect the OFDM-based CV-QKD system. Moreover, we also evaluate the security in the asymptotic limit and the Pirandola-Laurenza-Ottaviani-Banchi upper bound. Results indicate that although the emergence of imperfect modulation would bring about a slight decrease in the secret key bit rate of each subcarrier, the multiplexing technique combined with CV-QKD results in a desirable improvement on the total secret key bit rate which can raise the numerical value about an order of magnitude.

Physical Review A•May 29, 2018•28 citations

Continuous-variable quantum key distribution with non-Gaussian operations

Liyun Hu, M. Al-Amri, Zeyang Liao +1 more

Continuous-variable quantum key distribution (CV-QKD) provides an effective way to obtain the high secret key rate, but is limited by practical techniques. To overcome this limitation, we investigate the performance of CV-QKD protocols when non-Gaussian operations are applied to both sides of the channels, including photon subtraction and addition, and photon catalysis. A comparison is also made between Gaussian modulation and non-Gaussian modulation. We show that the optimal transmission distance cannot be improved by non-Gaussian modulation at the sender's side, but it can be improved by single-photon catalysis at the receiver's side. For a given modulation variance that exceeds a certain threshold, the performance of the zero-photon catalysis at the sender's side is the best when compared with other non-Gaussian modulations (except single-photon catalysis at the receiver's side), and it can always reach the optimal distance. Our paper will provide a useful insight for the use of non-Gaussian modulation to other CV-QKD protocols.

Physical Review A•Jul 6, 2020•90 citations

Multirate and multiprotocol OFDM-based multicarrier continuous-variable quantum key distribution

Ting Ye, Qingsong Jia, Heng Wang +7 more

In this paper, we propose a multi-rate and multi-protocol CV-QKD scheme based on the orthogonal-frequencydivision- multiplexing (OFDM) technology. The proposed OFDM-based multi-carrier CVQKD scheme only requires one transmitter and one receiver to realize QKD with different modulation protocols and different key rates in one communication. More importantly, the multiple subcarriers with different modulation protocols have different excess noise tolerances in the same transmission channel, which can achieve the flexible QKD service even in long-distance and high-disturbance fiber channel. In order to verify the proposed scheme, 5 subcarriers with QPSK, 64QAM, 256QAM, 1024QAM and Gaussian modulation protocols are evaluated by the SDP and no-switch Gaussian security analysis method at different transmission distances. The simulation results show the proposed OFDM-based multi-carrier scheme allows various QKDs with different modulation protocols and different key rates in one communication. Moreover, according to the obtained 5 SKRs, we can choose the optimal modulation protocol of the subcarriers to meet different needs of quantum network operators. In addition, the scheme also can choose much more subcarriers and different symbol rates to flexibly achieve the QKD in different quantum secure communication scenarios. Therefore, the proposed scheme changes the modulation protocol, subcarrier number and symbol rate to achieve the interoperability, flexibility and compatibility.

SPIE Conference on Quantum and Nonlinear Optics•Oct 11, 2024•0 citations
We propose a scheme for continuous-variable quantum key distribution (CV-QKD) using the subcarrier multiplexing technique which was employed in microwave photonics. This scheme allows distribution of NNN channels with independent Gaussian-modulated CV-QKD in parallel with one laser source and several phase modulators. We analyze the influence of nonlinear signal mixing and security in the asymptotic limit. Results indicate that by using this multiplexing technique, each channel will have a non-Gaussian extra source noise, resulting in slight shortening of the maximum transmission distance, while the total secret key rate can be considerably increased. This scheme could also be used for key distribution for multiple users, and combined with wavelength division multiplexing devices it has potential to be used for construction of a CV-QKD network.
In this paper, a multi-carrier Gaussian modulated continuous variable quantum key distribution (CV-QKD) scheme has been proposed based on orthogonal frequency division multiplexing (OFDM) for distributing multiplexing independent secret keys encoded on N subcarriers within a single fiber channel. However, the performance of the system will be significantly influenced by the extra modulation noise in the multi-carrier quantum state preparation. Therefore, a modulation noise model is analyzed in more compact for multi-carrier Gaussian modulated CV-QKD system. Specifically, the gain imbalance and quadrature skew in IQ modulation and the third-order intermodulation effect in N subcarrier modulation are systematically analyzed in the OFDM-based multi-carrier CV-QKD with Gaussian modulation. That is, the IQ imbalance noise and the intermodulation noise are modeled as the modulation noise of the multi-carrier Gaussian modulated CV-QKD system. Moreover, the secure performances of the multi-carrier Gaussian modulated CVQKD are evaluated based on the proposed modulation noise model. Besides, the simulation results show the SKRs are greatly increased by N independent quantum state preparation, which indicates that the multi-carrier CV-QKD system gets rid of the asymptotic SKR limit of single-carrier CV-QKD system for future high-rate CV-QKD deployment in broadband access network.
We experimentally demonstrated a high-performance multi-protocol continuous-variable quantum key distribution (CV-QKD) using one transceiver. The demonstrated multi-protocol CV-QKD system can simultaneously distribute 5 subcarriers with Gaussian, 4QAM, 16QAM, 64QAM, and 1024QAM modulation protocols based on orthogonal-frequency-division-multiplexing (OFDM) technology. Moreover, the modulation variance and probability distribution factor of 5 subcarriers are carefully optimized to maximize their respective SKRs. Besides, we innovatively design an effective OFDM-based DSP scheme and a precise dual-stage phase noise compensation scheme to realize a low excess noise for each subcarrier operating at a 2 GHz symbol rate. Thus, the multi-protocol CV-QKD achieves multiple SKRs of 48.79, 7.58, 23.67, 32.93, and 36.78 Mbps over a typical transmission distance of 50 km within a single transmission. Therefore, our work provides a practical solution to achieve highly efficient, interoperable, flexible, and secure QKDs for high-speed quantum secure communication.
We propose a continuous-variable quantum key distribution (CVQKD) scheme at terahertz (THz) bands based on multicarrier multiplexing (MCM) technology. In this scheme, multiple Gaussian modulated subcarriers are coupled to transmit multipath superposed thermal Gaussian states. At the receiver, optical discrete Fourier transform (ODFT) is used to demultiplex the received subcarriers, and the keys can be generated in parallel by homodyne detection and post processing. We analyze the security of the scheme against the optimal collective Gaussian attack under indoor environment and in inter-satellite links respectively. Results indicate that by using MCM technology, each subchannel may be affected by crosstalk, resulting in slight shortening of the maximal transmission distance while the total secret key rate can be greatly increased. We also verify the feasibility of higher key rate and longer distance THz-QKD by using MCM technology in inter-satellite links communication. We expect this work will provide an efficient path to build a global quantum communication network.
We introduce a reliable scheme for continuous-variable quantum key distribution (CV-QKD) by using orthogonal frequency division multiplexing (OFDM). As a spectrally efficient multiplexing technique, OFDM allows a large number of closely spaced orthogonal subcarrier signals used to carry data on several parallel data streams or channels. We place emphasis on modulator impairments which would inevitably arise in the OFDM system and analyze how these impairments affect the OFDM-based CV-QKD system. Moreover, we also evaluate the security in the asymptotic limit and the Pirandola-Laurenza-Ottaviani-Banchi upper bound. Results indicate that although the emergence of imperfect modulation would bring about a slight decrease in the secret key bit rate of each subcarrier, the multiplexing technique combined with CV-QKD results in a desirable improvement on the total secret key bit rate which can raise the numerical value about an order of magnitude.
Continuous-variable quantum key distribution (CV-QKD) provides an effective way to obtain the high secret key rate, but is limited by practical techniques. To overcome this limitation, we investigate the performance of CV-QKD protocols when non-Gaussian operations are applied to both sides of the channels, including photon subtraction and addition, and photon catalysis. A comparison is also made between Gaussian modulation and non-Gaussian modulation. We show that the optimal transmission distance cannot be improved by non-Gaussian modulation at the sender's side, but it can be improved by single-photon catalysis at the receiver's side. For a given modulation variance that exceeds a certain threshold, the performance of the zero-photon catalysis at the sender's side is the best when compared with other non-Gaussian modulations (except single-photon catalysis at the receiver's side), and it can always reach the optimal distance. Our paper will provide a useful insight for the use of non-Gaussian modulation to other CV-QKD protocols.
In this paper, we propose a multi-rate and multi-protocol CV-QKD scheme based on the orthogonal-frequencydivision- multiplexing (OFDM) technology. The proposed OFDM-based multi-carrier CVQKD scheme only requires one transmitter and one receiver to realize QKD with different modulation protocols and different key rates in one communication. More importantly, the multiple subcarriers with different modulation protocols have different excess noise tolerances in the same transmission channel, which can achieve the flexible QKD service even in long-distance and high-disturbance fiber channel. In order to verify the proposed scheme, 5 subcarriers with QPSK, 64QAM, 256QAM, 1024QAM and Gaussian modulation protocols are evaluated by the SDP and no-switch Gaussian security analysis method at different transmission distances. The simulation results show the proposed OFDM-based multi-carrier scheme allows various QKDs with different modulation protocols and different key rates in one communication. Moreover, according to the obtained 5 SKRs, we can choose the optimal modulation protocol of the subcarriers to meet different needs of quantum network operators. In addition, the scheme also can choose much more subcarriers and different symbol rates to flexibly achieve the QKD in different quantum secure communication scenarios. Therefore, the proposed scheme changes the modulation protocol, subcarrier number and symbol rate to achieve the interoperability, flexibility and compatibility.