A Whispering-Gallery Timing Resonator with Torsion Trim

Whispering-gallery resonators confine light by total internal reflection around a polished rim, reaching quality factors that make them excellent frequency references and sensors. This paper designs a 5 mm magnesium fluoride resonator as the timing element of a compact reference, with a torsion-coupled trim to tune its frequency, and computes its principal figures. At a loaded quality factor of 2e8 the resonance linewidth is 967.07 kHz and the ring-down time is 0.16 microseconds. Thermal tuning over ten kelvin spans 19.34 GHz, within which the torsion trim provides fine, contactless adjustment. The design is simulated from stated material and geometry parameters; no resonator has been fabricated or characterised for this study.