An investigation of the pressure-to-acceleration responsivity ratio of fiber-optic mandrel hydrophones

The acceleration responsivity of the fiber-optic air-backed mandrel hydrophone is studied. This responsivity may be a significant noise source in high vibration environments. The pressure-to-acceleration responsivity ratio is therefore a figure of merit for the hydrophone. It is shown that an ideal hydrophone with a sufficiently rigid support cylinder should not show any first-order acceleration responsivity. The dominant contribution to any first-order acceleration responsivity is the deformation of the support cylinder due to acceleration. The responses are evaluated both theoretically and experimentally. This treatment gives a set of guidelines which should be followed in order to maximize the pressure-to-acceleration responsivity ratio. It is also theoretically and experimentally demonstrated that the axial acceleration responsivity can be significantly reduced by symmetrical elicitation of the hydrophone.