Towards Telecommunication-Band Quantum Networking with an Atom-Cavity Platform

Long-range quantum networking enables a broad range of applications in quantum information science, such as secure communication and distributed quantum sensing. We report progress towards telecommunication-band quantum networking with individually trapped ⁸⁷Rb atoms, leveraging their 5P_3/2 to 4D_5/2 transition at 1530 nm. First, we demonstrate cascaded emission, generating a pair of single photons at 780 nm and 1530 nm, verified by cross-correlation measurements. Second, to serve as an efficient photonic interface, we fabricate dual-wavelength microcavities. These are formed between a laser-ablated fiber and a microfabricated silicon mirror, achieving cooperativities of 240 and 170 at 780 nm and 1530 nm, respectively. Such advancements lay the groundwork for scalable, long-range quantum networking and integration with silicon nanophotonics for multiplexing and on-chip entanglement routing.