S An

High-rate, high-fidelity entanglement of qubits across an elementary quantum network

L J Stephenson, D P Nadlinger, B C Nichol, S An [1,2], P Drmota, T G Ballance, K Thirumalai, J F Goodwin, D M Lucas, C J Ballance

Abstract

We demonstrate remote entanglement of trapped-ion qubits via a quantum-optical fiber link with fidelity and rate approaching those of local operations. Two ${}^{88}$Sr${}^{+}$ qubits are entangled via the polarization degree of freedom of two photons which are coupled by high-numerical-aperture lenses into single-mode optical fibers and interfere on a beamsplitter. A novel geometry allows high-efficiency photon collection while maintaining unit fidelity for ion-photon entanglement. We generate remote Bell pairs with fidelity $F=0.940(5)$ at an average rate $182\,\mathrm{s}^{-1}$ (success probability $2.18\times10^{-4}$).