Characterization of Mid-Infrared Silicon-on-Sapphire Microring Resonators With Thermal Tuning

Microring resonators on silicon-on-sapphire (SOS) were characterized at 2.75 mu m wavelength. We obtained a Q factor of 11400 +/- 800. The thermo-optic coefficient of epitaxial silicon of SOS wafer was measured to be 2.11 +/- 0.08 x 10(-4) K-1. We also describe a characterization technique to measure the Q of microring resonators using a fixed wavelength source. By only varying the temperature of the device, it is possible to measure the Q of a mid-infrared (mid-IR) microresonator. The proposed method provides an alternative method of Q measurement for microring resonators in mid-IR, where tunable lasers may not be easily available. The technique was used to determine the Q of SOS microring resonators at 2.75 mu m wavelength.