Demonstration of green and UV wavelength high Q aluminum nitride on sapphire microring resonators integrated with microheaters

We demonstrate a high Q aluminum nitride (AlN) on sapphire microring resonators at green (532 nm) and ultraviolet (UV) (369.5 nm), which are two important wavelengths for sensing and quantum information processing. The quality factors (Q) of these resonators are characterized using integrated microheaters and based on thermo-optic resonance sweeping around those wavelengths for which tunable lasers are typically less available. We measure a record of high intrinsic Q of 147 000 with a propagation loss of 7.3 dB/cm at 532 nm wavelength, and an intrinsic Q of 25 500 with a propagation loss of 60.4 dB/cm at UV 369.5 nm wavelength. We also investigate the thermal crosstalk between the adjacent resonators when temperature change is applied by the microheater of one of the resonators on the same chip. A large thermal crosstalk and resonance shift are observed on other microring resonators even at millimeter(s) distance away from a microheater. This study provides further insight on the functionalities and capabilities of this promising integrated photonic platform for the ultraviolet (UV) and visible range.