Quantum teleportation over a field-deployed hollow-core fibre network

Research Overview

Quantum teleportation is a cornerstone of the future quantum internet, but its practical deployment is often hindered by the noise and instability of standard solid-core fibre (SCF) networks. In conventional fibres, intense classical data traffic generates spontaneous Raman scattering, which introduces noise that degrades the fidelity of quantum states. This study explores the use of hollow-core fibre (HCF) as a superior medium for quantum-classical coexistence, leveraging its air-guided structure to minimize light-matter interactions.

Experimental Approach

The researchers utilized a field-deployed metropolitan HCF network in Chengdu, connecting three distinct nodes. Alice prepared time-bin encoded photonic qubits, while Bob generated entangled photon pairs. These signals were transmitted through HCF links to a central node (Charlie) for a Bell-state measurement (BSM). To test the network's robustness, the team co-propagated classical data traffic alongside the quantum signals, reaching launch powers of up to 160 mW.

Key Findings

The HCF network exhibited remarkable performance, with Raman noise levels approximately three orders of magnitude lower than those found in standard solid-core fibres. The links maintained passive polarization and timing stability over seven hours without the need for active compensation. Even under high-power classical interference, the system achieved an average teleportation fidelity of 86.2%, and a single-photon fidelity of 90.4%, both of which significantly exceed the classical limit of 2/3. These results confirm that HCF is a viable, plug-and-play infrastructure for scalable quantum networks.

This work bridges the gap between theoretical quantum networking and real-world implementation. By demonstrating that quantum and classical signals can coexist in existing HCF infrastructure without complex active stabilization, the study provides a practical, scalable pathway for integrating quantum communication into current telecommunications frameworks.