Microbend loss fiber optic direction and amplitude sensors for underwater applications

Dual purpose fiber optic microbend loss sensors have been developed for measurement of underwater acousticwave amplitudes and for detection of the direction of wave propagation. Three different construction schemes for cylindrical sensing elements are considered. The dual purpose hydrophones have been characterized for frequencies ranging from 15 to 75 kHz. They exhibit sensitivities in the range of -175 to -200 dB r e:1 V/uPa and directionality sensitivity limited by geometrical construction. 1990 Acoustical Society of America