Acoustic sensor development at NRL

Abstract

The development of fiber optic acoustic sensors at the Naval Research Laboratory will be reviewed. The talk will describe the fundamentals of the design and operation of fiber optic sensors. The major area of this talk will be the transduction mechanism of acoustic energy to optical phase shift. Methods to detect the phase shifts and to provide a linear voltage output will only be briefly discussed. The frequency regimes to be covered range from a few tens of Hz to MHz. In the low-frequency regime (up to several kHz), where the pressure is hydrostatic, the role of the material moduli of fiber coatings and bulk mandrels will be considered. A number of sensor designs for operation in the higher-frequency regimes, where inertial effects do not permit direct axial strain terms to play a major role, will also be described.