High frequency response of fiber-optic planar acoustic sensors

The frequency response of planar interferometric fiber-optic acoustic hydrophones is considered. It is shown that such sensors formed from materials whose impedance closely matches that of the fluid generally have acoustically induced acceleration effects which tend to decrease the high-frequency response for the normal incidence case. Planar sensor configurations are identified which reduce this effect, and measurements on one such configuration are presented to confirm this. Since this is achieved by reducing the response of the sensor to normal acceleration, this fiber sensor design should also be useful for other applications requiring a low acceleration response