Progress towards a quantum network of ⁴⁰Ca⁺ ions trapped in a surface-electrode trap with an integrated fiber-based optical cavity

Although there has been significant progress towards creating useful quantum computers, no practical way to generate the remote entanglement that is required to share quantum information has been demonstrated. Entanglement shared over a quantum network could enable increased quantum computational power, bolster communication security, and enhance the performance of quantum sensors. One quantum networking framework utilizes nodes comprised of trapped ions as local memory qubits, interconnected with telecom-wavelength photonic flying qubits. Trapped ions are a favorable stationary qubit due to their long coherence times, precise controllability, and easily configurable interactions, while telecom-wavelength photons make ideal non-stationary qubits because of their low optical fiber transmission losses. Here we report on our progress to more efficiently and robustly combine telecom-wavelength photonic qubits with trapped ion qubits by trapping ⁴⁰Ca⁺ ions in a fiber Fabry-Perot optical cavity that is integrated into a surface-electrode trap. In this way, we hope to create high-fidelity, high-rate entanglement between ions and difference frequency generated 1550 nm wavelength photons for long-distance entanglement distribution.