Theoretical analysis of the membrane parameters of the fiber optic microphone

In the membrane displacement equation of fiber optic microphone, there are, beside the pressure, two kinds of parameters: membrane parameters and damping mechanism parameters. The first kind, which consists of the membrane radius, surface density and border tension, has an effect on the sensitivity and the acoustic frequency band (sonic and ultrasonic), whereas the second kind has almost no effect. The theoretical analysis of these parameters shows that some ultrasonic frequencies can cover a band close to 100 kHz, for a radius of 0.1 mm, with the increase of the sensitivity. This analysis provides a general approach useful to design a fiber optic microphone for a particular application.