Temperature Effects on Optical Resonances in Single-Mode Circular Ring and Squircular Resonators

Optical dielectric microresonators have been extensively studied due to their potential applications in optical sensing and measurements, and as optical interconnects. Although sensitive to temperature variations, the effect on temperature on their performance is often overlooked. In the present study the sensitivity of resonance to temperature arising from thermal expansion or contraction based change in physical path length, and minute changes in dielectric material and surrounding refractive indices is examined. The multiphysics finite element approach used in this study combines the heat transfer in solids with solid mechanics to understand the micro-level deformation of optical resonator due to thermal heating. This is coupled with electromagnetic frequency domain analysis of Maxwell’s equations with temperature dependent refractive indices to quantify the change in resonant frequency. It is found that the temperature induced change in refractive index of the resonator material primarily drives the change in resonant frequency.