Nanophotonic quantum network nodes based on epitaxial rare-earth on silicon heterostructures

We present the development of nanophotonic quantum nodes based on an epitaxial Er³⁺:Y2O3 (yttria) on silicon platform. Heterostructure photonic cavities with ultra-small mode volumes couple to individual erbium qubits at the telecom wavelength. We measure silicon cavities with fabrication-limited Qcav~400,000 and develop yttria nanofabricaton processes.