Design study of a guided-wave optical microphone with a diaphragm

Our guided-wave optical microphone consists of a diaphragm and a single-mode optical waveguide on the diaphragm. Since sensitivity and frequency response are strongly dependent on waveguide position and diaphragm dimensions, designing the microphone is relatively complicated without a design guideline. In this report, a convenient and helpful chart diagram when designing the microphone is proposed based on theoretical and experimental results on dependences of sensitivity and resonance frequency on diaphragm dimensions. In addition, since damping of diaphragm vibration is also vital in obtaining a broader flat frequency response, squeeze-film air damping is discussed.