Damping ratio in a glass-based guided-wave optical microphone without a damping structure

In a guided-wave optical microphone with a diaphragm as the vibration plate, damping diaphragm vibration is very significant. In this study, a glass-based guided-wave optical microphone without a damping structure was experimentally examined to evaluate the damping ratio as the first phase in the optimization of damping. The damping ratio and resonance frequency were evaluated to be 0.009 and 3.5kHz, respectively, for a fabricated microphone with a diaphragm of 20 mm × 20 mm × 0.15 mm.