Narrow magneto-optical transitions of erbium implanted into silicon carbide-on-insulator

Solid-state spin-photon interfaces operating in the near-telecom and telecom bands are a key resource for long-distance quantum communication and scalable quantum networks. However, their optical transitions often suffer from spectral diffusion that hampers the generation of coherent spin-photon entanglement. Here we demonstrate narrow magneto-optical transitions of erbium dopants implanted into thin-film silicon carbide (SiC)-on-insulator, a viable platform for industrially scalable quantum networks. Using high-resolution resonant spectroscopy and spectral hole burning at cryogenic temperatures, we reveal sub-megahertz homogeneous linewidths and identify two lattice sites that best stabilise the emitters. We further characterise their optical lifetimes and magneto-optical response, establishing erbium-doped SiC-on-insulator as a robust and scalable platform for on-chip quantum networks. Solid-state spin-photon interfaces in the telecom bands are crucial for scalable quantum networks but are hindered by spectral diffusion. Here, the authors demonstrate narrow magneto-optical transitions of erbium in SiC-on-insulator, achieving sub-megahertz linewidths and stable emitters, paving the way for robust, scalable on-chip quantum communication.