aqora

Coexistence of O-band polarization-entangled photons with C-band classical channels in a dynamically reconfigurable metropolitan fiber network

Thomas Rieser, Hsuan-Hao Lu, Hsuan‐Hao Lu +6 more

We present polarization entanglement distribution over an operator-owned, metropolitan-scale fiber network, employing standard wavelength-division multiplexing components to achieve coexistence of O-band photons and C-band classical light. First, we demonstrate dynamic path switching by alternating between 15-km and 30-km deployed fiber loops, enabled by automated polarization compensation achieving sub-second recovery and time-averaged CHSH S -values exceeding 2.65 over 21 hours. We then assess the impact of co-propagating 100-Gbit/s C-band classical signals by varying launch powers up to 6 dBm. Finally, by combining path switching and classical co-propagation, we achieve stable entanglement distribution over 30 km of deployed fiber, validating the feasibility of hybrid quantum–classical transmission and paving the way for entanglement-based quantum networking on existing metropolitan infrastructure.We present polarization entanglement distribution over an operator-owned, metropolitan-scale fiber network, employing standard wavelength-division multiplexing components to achieve coexistence of O-band photons and C-band classical light. First, we demonstrate dynamic path switching by alternating between 15-km and 30-km deployed fiber loops, enabled by automated polarization compensation achieving sub-second recovery and time-averaged CHSH S -values exceeding 2.65 over 21 hours. We then assess the impact of co-propagating 100-Gbit/s C-band classical signals by varying launch powers up to 6 dBm. Finally, by combining path switching and classical co-propagation, we achieve stable entanglement distribution over 30 km of deployed fiber, validating the feasibility of hybrid quantum–classical transmission and paving the way for entanglement-based quantum networking on existing metropolitan infrastructure.

Optics LettersOct 8, 20260 citations

Disentanglement induced by combined effects of polarization mode dispersion and polarization-dependent loss in optical fibers

Yiwen Liu

Optical and Quantum ElectronicsJun 10, 20233 citations

100-km Entanglement Distribution with Co-existing Quantum and Classical Signals in a Single Fiber

Anouar Rahmouni, Paulina S. Kuo, Ya-Shian Li-Baboud +11 more

We demonstrate metropolitan-scale polarization entanglement distribution with co-existing quantum and WR-PTP classical synchronization signals in the same single-core fiber. We achieved high-fidelity entanglement between nodes separated by 100 km of optical fiber.

Quantum 2.0 Conference and ExhibitionJan 1, 20240 citations

Study of multiple degrees of freedom entanglement in optical fiber

H.M. Zhang, Chao Zhao

arXiv:2404.11073Indian Journal of PhysicsAug 28, 20241 citation

Passive Synchronization of Nonlocal Franson Interferometry for Fiber-Based Quantum Networks Using Co-propagating Classical Clock Signals

Xiao Xiang, Runai Quan, Yuting Liu +7 more

We demonstrate a robust, high-visibility nonlocal Franson interferometry for fiber-based quantum networks by co-propagating a classical Radio-over-Fiber clock signal with energy-time entangled photon pairs in the same fiber. Utilizing cross-band allocation (O-band for classical, L-band for quantum signals), the spontaneous Raman scattering noise photons are effectively suppressed. At the same time, their environmental delay fluctuations remain highly correlated for common-mode noise cancellation, achieving a passive synchronization with picoseconds precision. Over 50 km of single-mode fiber, this co-propagation enables nonlocal quantum interference with a visibility of (88.35\pm3.62)%, without relying on external dedicated timing infrastructure. This work provides a practical, scalable synchronization solution for metropolitan-scale entanglement-based quantum networks.We demonstrate a robust, high-visibility nonlocal Franson interferometry for fiber-based quantum networks by co-propagating a classical Radio-over-Fiber clock signal with energy-time entangled photon pairs in the same fiber. Utilizing cross-band allocation (O-band for classical, L-band for quantum signals), the spontaneous Raman scattering noise photons are effectively suppressed. At the same time, their environmental delay fluctuations remain highly correlated for common-mode noise cancellation, achieving a passive synchronization with picoseconds precision. Over 50 km of single-mode fiber, this co-propagation enables nonlocal quantum interference with a visibility of (88.35\pm3.62)%, without relying on external dedicated timing infrastructure. This work provides a practical, scalable synchronization solution for metropolitan-scale entanglement-based quantum networks.

quant-pharXiv:2602.21483Feb 26, 20260 citations

High-brightness fiber-coupled source of polarization-entangled photon pairs spanning the telecom C- and L-bands

Vikash Kumar Yadav, Vivek Venkataraman, Joyee Ghosh

Optics & Laser TechnologyFeb 29, 20249 citations

Characterization of polarization entanglement distribution in fiber co-propagating with classical C-band signal

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