High-Q aluminum oxide microring resonators operating at 460 nm

Aluminum oxide offers an excellent platform for integrated photonics in the visible and ultraviolet ranges, combining low propagation losses, high index contrast with silica, and strong compatibility with rare earth dopants. This work reports a comprehensive study of 460 nm microring resonators in various configurations. The reported devices, obtained through a commercial multi-project wafer service, exhibit a record intrinsic quality factor of 3.6 × 10⁵ on the aluminum oxide platform. Thermal tuning of the resonances is achieved via integrated metallic heaters, with a tuning efficiency of 1.63 pm/mW over a 500 pm range. These results demonstrate fully integrated photonic functionalities in the visible range, opening new prospects for sensing, spectroscopy, and quantum photonic applications.