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:2203.14621 · Journal of Lightwave Technology

DV-QKD Coexistence With 1.6 Tbps Classical Channels Over Hollow Core Fibre

Obada Alia, R. S. Tessinari, Sima Bahrani, Thomas D. Bradley, Hesham Sakr, Kerrianne Harrington, John Hayes, Yong Chen, Periklis Petropoulos, David John Richardson, Francesco Poletti, George Theodore Kanellos, Reza Nejabati, Dimitra E. Simeonidou

Published Jun 3, 2022• 0 citations
arXivHTMLPDF

Abstract

The feasibility of coexisting a quantum channel with carrier-grade classical optical channels over Hollow Core Nested Antiresonant Nodeless Fibre (HC-NANF) is experimentally explored for the first time in terms of achievable quantum bit error rate (QBER), secret key rate (SKR) as well as classical signal bit error rates (BER). A coexistence transmission of 1.6 Tbps is achieved for the classical channels simultaneously with a quantum channel over a 2 km-long HC-NANF with a total coexistence power of 0 dBm. To find the best and worst wavelength position for the classical channels, we simulated different classical channels bands with different spacing between the quantum and classical channels considering the crosstalk generated from both Raman scattering and four-wave-mixing (FWM) on the quantum channel. Following our simulation, we numerically estimate the best (Raman spectrum dip) and worst locations (Raman spectrum peak) of the classical channel with respect to its impact on the performance on the quantum channel in terms of SKR and QBER. We further implemented a testbed to experimentally test both single-mode fibre (SMF) and HC-NANF in the best and worst-case scenarios. In the best-case scenario, the spacing between quantum and classical is 200 GHz (1.6 nm) with 50 GHz (0.4 nm) spacing between each classical channel. The SKR was preserved without any noticeable changes when coexisting the quantum channel with eight classical channels at 0 dBm total coexistence power in HC-NANF compared to a significant drop of 73% when using SMF at$-$24 dBm total coexistence power which is 250 times lower than the power used in HC-NANF. In the worst-case scenario using the same powers, and with 1 THz (8 nm) spacing between quantum and classical channels, the SKR dropped 10% using the HC-NANF, whereas in the SMF the SKR plummeted to zero.

DOI
10.1109/jlt.2022.3180232

Related papers

Coexistence analysis of classical channels with DV-QKD over hollow core nested antiresonant nodeless fibre (HC-NANF)

Obada Alia, R. S. Tessinari, Sima Bahrani +12 more

Quantum Key Distribution (QKD) technology has been considered as the ultimate physical layer security due to its dependencies on the physical laws of physics to generate quantum keys. However, for QKD to become functional for practical scenarios, it must be integrated with the classical optical networking infrastructure. Coping with optical nonlinearity from the classical represents a major challenge for QKD systems. In this paper, we take the advantage of the ultra-low nonlinearity of Hollow Core Nested Antiresonant Nodeless Fibre (HC-NANF) to demonstrate the coexistence of discrete-variable quantum key distribution channel with carrier-grade classical optical channels over a 2 km HC-NANF.

Quantum Computing, Communication, and Simulation•Feb 17, 2022•0 citations

1.6 Tbps Classical Channel Coexistence With DV-QKD Over Hollow Core Nested Antiresonant Nodeless Fibre (HC-NANF)

Obada Alia, R. S. Tessinari, Thomas D. Bradley +10 more

We demonstrate for the first time the coexistence of a quantum-channel and 8×200 Gpbs 16-QAM optical channels with launching powers as high as -9dBm/channel in a 2 km HC-NANF. Comparative analysis with single-mode fibre reveals that the quantum-channel could not be sustained at such power-levels.

arXiv:2106.14560•European Conference on Optical Communication•Sep 13, 2021•11 citations

Coexistence of entanglement-based quantum channels with DWDM classical channels over hollow core fibre in a four node quantum communication network

M. J. Clark, Obada Alia, Sima Bahrani +10 more

We experimentally demonstrate the coexistence of three entanglement-based quantum channels with carrier-grade classical optical channels over 11.5 km hollow core nested antiresonant nodeless fibre, in a four user quantum network. A transmission of 800 Gbps is achieved with four classical channels simultaneously with three quantum channels all operating in the C-band with a separation of 1.2 nm, with aggregated coexistence power of -3 dBm. We established quantum key distribution in the four-node full-mesh quantum network with Bell state fidelity of up to 90.0 ± 0.8%. The secret key rate for all the links in the network are passively preserved over 55 hours of experimental time.

arXiv:2508.00072•npj Quantum Information•Nov 19, 2025•4 citations

11.2 Tb/s Classical Channel Coexistence With DV-QKD Over a 7-Core Multicore Fiber

E. Hugues-Salas, Obada Alia, Rui Wang +4 more

The feasibility of transmitting discrete-variable quantum key distribution channels with carrier-grade classical optical channels over multicore fibers is experimentally explored in terms of achievable quantum bit error rates, secret key rates as well as classical signal bit error rates. A coexistence transmission record of 11.2 Tb/s is achieved for the classical channels simultaneously with a DV-QKD channel over a 1 km-long 7-core multicore fiber. Coexistence over the same multicore fiber core is identified as a dominant factor for the performance of the quantum channel requiring optical bandpass filtering of 17 nm for the quantum channel to avoid the effect of Raman noise. Also, counter-propagation of classical channels and quantum channels probe more tolerance to noise proliferation than co-propagation. In addition, the performance of the quantum channel is maintained when more than three cores are used for the classical channels. Furthermore, by adding a second DV-QKD channel in the multicore fiber, the simultaneous transmission of classical channels as well as the generation of quantum-secured keys of two QKD channels is achieved with an operational range of 10 dB of launched power into the MCF.

Journal of Lightwave Technology•May 27, 2020•53 citations

Entanglement-based quantum key distribution with data in hollow-core fiber

Yue Luo, Sheng Liu, Yun-Ru Fan +11 more

The coexistence of quantum information and classical signals in a single fiber is essential for future quantum networks that leverage the well-established optical fiber infrastructure. Although multiplexing technologies can separate quantum and classical signals, pure silica core fibers (PSCFs) remain fundamentally limited by the high nonlinearity, which generates substantial Raman scattering and four-wave mixing noise. Hollow-core fibers (HCFs), guiding light predominantly in air, offer an attractive solution with intrinsically ultra-low nonlinearity and strongly suppressed nonlinear noise. In this work, we demonstrate the entanglement-based key coexisting with data over an 18-km HCF link. We achieve time-encoded high-dimensional quantum key distribution (HD-QKD) carrying 0 dBm of bidirectional received power, corresponding to a theoretical data capacity of up to 2.3 Tbps. During 24 hours of continuous operation, an average secret key rate (SKR) of 10.56 kbps is obtained. Theoretical analysis further predicts SKRs above 135 kbps over transmission distances exceeding 200 km using state-of-the-art low-loss HCFs. These results show significantly improved performance compared with PSCF-based systems and highlight the potential of HCFs for scalable quantum-classical coexistence compatible with the architectures of established fiber-optic networks.

quant-pharXiv:2607.25331•Jul 29, 2026•0 citations

Experimental coexistence of quantum key distribution and high-power classical communication over 101.6 km hollow-core fiber

Weiwen Kong, Tianqi Dou, Lei Zhang +8 more

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.

Journal of Optical Communications and Networking•Aug 27, 2025•1 citation
The feasibility of coexisting a quantum channel with carrier-grade classical optical channels over Hollow Core Nested Antiresonant Nodeless Fibre (HC-NANF) is experimentally explored for the first time in terms of achievable quantum bit error rate (QBER), secret key rate (SKR) as well as classical signal bit error rates (BER). A coexistence transmission of 1.6 Tbps is achieved for the classical channels simultaneously with a quantum channel over a 2 km-long HC-NANF with a total coexistence power of 0 dBm. To find the best and worst wavelength position for the classical channels, we simulated different classical channels bands with different spacing between the quantum and classical channels considering the crosstalk generated from both Raman scattering and four-wave-mixing (FWM) on the quantum channel. Following our simulation, we numerically estimate the best (Raman spectrum dip) and worst locations (Raman spectrum peak) of the classical channel with respect to its impact on the performance on the quantum channel in terms of SKR and QBER. We further implemented a testbed to experimentally test both single-mode fibre (SMF) and HC-NANF in the best and worst-case scenarios. In the best-case scenario, the spacing between quantum and classical is 200 GHz (1.6 nm) with 50 GHz (0.4 nm) spacing between each classical channel. The SKR was preserved without any noticeable changes when coexisting the quantum channel with eight classical channels at 0 dBm total coexistence power in HC-NANF compared to a significant drop of 73% when using SMF at−-−24 dBm total coexistence power which is 250 times lower than the power used in HC-NANF. In the worst-case scenario using the same powers, and with 1 THz (8 nm) spacing between quantum and classical channels, the SKR dropped 10% using the HC-NANF, whereas in the SMF the SKR plummeted to zero.
Quantum Key Distribution (QKD) technology has been considered as the ultimate physical layer security due to its dependencies on the physical laws of physics to generate quantum keys. However, for QKD to become functional for practical scenarios, it must be integrated with the classical optical networking infrastructure. Coping with optical nonlinearity from the classical represents a major challenge for QKD systems. In this paper, we take the advantage of the ultra-low nonlinearity of Hollow Core Nested Antiresonant Nodeless Fibre (HC-NANF) to demonstrate the coexistence of discrete-variable quantum key distribution channel with carrier-grade classical optical channels over a 2 km HC-NANF.
We experimentally demonstrate the coexistence of three entanglement-based quantum channels with carrier-grade classical optical channels over 11.5 km hollow core nested antiresonant nodeless fibre, in a four user quantum network. A transmission of 800 Gbps is achieved with four classical channels simultaneously with three quantum channels all operating in the C-band with a separation of 1.2 nm, with aggregated coexistence power of -3 dBm. We established quantum key distribution in the four-node full-mesh quantum network with Bell state fidelity of up to 90.0 ± 0.8%. The secret key rate for all the links in the network are passively preserved over 55 hours of experimental time.
The feasibility of transmitting discrete-variable quantum key distribution channels with carrier-grade classical optical channels over multicore fibers is experimentally explored in terms of achievable quantum bit error rates, secret key rates as well as classical signal bit error rates. A coexistence transmission record of 11.2 Tb/s is achieved for the classical channels simultaneously with a DV-QKD channel over a 1 km-long 7-core multicore fiber. Coexistence over the same multicore fiber core is identified as a dominant factor for the performance of the quantum channel requiring optical bandpass filtering of 17 nm for the quantum channel to avoid the effect of Raman noise. Also, counter-propagation of classical channels and quantum channels probe more tolerance to noise proliferation than co-propagation. In addition, the performance of the quantum channel is maintained when more than three cores are used for the classical channels. Furthermore, by adding a second DV-QKD channel in the multicore fiber, the simultaneous transmission of classical channels as well as the generation of quantum-secured keys of two QKD channels is achieved with an operational range of 10 dB of launched power into the MCF.
The coexistence of quantum information and classical signals in a single fiber is essential for future quantum networks that leverage the well-established optical fiber infrastructure. Although multiplexing technologies can separate quantum and classical signals, pure silica core fibers (PSCFs) remain fundamentally limited by the high nonlinearity, which generates substantial Raman scattering and four-wave mixing noise. Hollow-core fibers (HCFs), guiding light predominantly in air, offer an attractive solution with intrinsically ultra-low nonlinearity and strongly suppressed nonlinear noise. In this work, we demonstrate the entanglement-based key coexisting with data over an 18-km HCF link. We achieve time-encoded high-dimensional quantum key distribution (HD-QKD) carrying 0 dBm of bidirectional received power, corresponding to a theoretical data capacity of up to 2.3 Tbps. During 24 hours of continuous operation, an average secret key rate (SKR) of 10.56 kbps is obtained. Theoretical analysis further predicts SKRs above 135 kbps over transmission distances exceeding 200 km using state-of-the-art low-loss HCFs. These results show significantly improved performance compared with PSCF-based systems and highlight the potential of HCFs for scalable quantum-classical coexistence compatible with the architectures of established fiber-optic networks.
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.