A pressure compensated hydrophone for measuring dynamic pressures is
disclosed. The hydrophone includes a compliant hollow mandrel with a
single optical fiber coiled around at least a portion of the mandrel. The
mandrel further includes at least one pressure relief valve for
compensating for changes in hydrostatic pressure. The pressure relief
valve includes a micro-hole, which allows hydrostatic pressures or low
frequency pressure events to couple into the interior of the mandrel to
provide compensation against such pressure. Higher frequencies pressure
events of interest do not couple through the micro-hole and therefore
only act only on the exterior of the mandrel, allowing for their
detection. Because (quasi) hydrostatic events are compensated for, the
mandrel may be made particularly compliant, rendering the singular fiber
optic coil particularly sensitive to the detection of the higher
frequency signals of interest.