A numerical analysis of a compact microring resonator that was defined on a yttrium-aluminum-garnet (YAG) thin film bonded on top of a SiO2 cladding layer and operated at the wavelengths of approximately 1.064 and 1.6 μm was performed. The single-mode conditions of YAG waveguides at different waveguide geometries and their propagation losses at different SiO2 cladding layer thicknesses were systematically analyzed. The key design parameters of the microring resonator, such as gap size and ring radius, were simulated based on the 2.5-dimensional variational finite-difference time-domain method. This study could be helpful in understanding the mechanism of microring resonators defined on YAG thin films and fabricating integrated microlaser sources on YAG-on-insulators.
