Fiber Optic Pressure Sensor Research Articles

Design of rubber mandrel fiber optic hydrophones

The response of a fiber optic pressure sensor consisting of a long fiber waveguide wrapped azimuthally on a rubber cylinder has been analyzed. The response of the rubber cylinder includes forced waves and free bar waves. The sensitivity of the hydrophone depends on the trace wavenumber of the incident pressure field and therefore is strongly affected by the frequency and the angle of incidence of the sound wave. In addition the temperature of the environment and the frequency of the pressure field affect dynamic properties of the rubber cylinder. Axial stiffeners stabilize the properties of the hydrophone and also reduce the influence of the trace wavenumber of the incident acoustic wave. Two types of design work well, either one with stiffening sufficient to produce a slightly subsonic bar wave, or one with stiffening sufficient to produce a bar wave speed of about four times the speed of sound.