Multiplexed ion-ion entanglement over $1.2$ kilometer fibers

TL;DR

This paper demonstrates a multiplexing technique that significantly speeds up entanglement generation between remote trapped-ion quantum nodes over long fiber links, achieving high fidelity and scalability for quantum networks.

Contribution

First demonstration of multiplexing-enhanced heralded entanglement between remote ion traps over long-distance fibers, enabling faster and scalable quantum network links.

Findings

Achieved 4.59-fold speedup in entanglement generation

Attained 95.9% entanglement fidelity over 1.2 km fiber

System is scalable to multiple quantum network nodes

Abstract

Quantum networks and quantum repeaters represent the promising avenues for building large-scale quantum information systems, serving as foundational infrastructure for distributed quantum computing, long-distance quantum communication, and networked quantum sensing. A critical step in realizing a functional quantum network is the efficient and high-fidelity establishment of heralded entanglement between remote quantum nodes. Multiplexing offers a powerful strategy to accelerate remote entanglement distribution, particularly over long optical fibers. Here, we demonstrate the first multiplexing-enhanced heralded entanglement between two trapped-ion quantum network nodes. By multiplexing $10$ temporal photonic modes, we achieve a 4.59-fold speedup in ion-ion entanglement generation and attain an entanglement fidelity of $95.9\pm1.5\%$ over $1.2$ km of fiber. Employing a dual-type architecture, our system is readily scalable to multiple nodes, thereby establishing a key building block for future large-scale quantum networks.