Fiber-optic accelerometer with hydrophone applications

A fiber-optic linear accelerometer based on intensity modulation produced by lateral displacement of a cantilevered fiber has been fabricated and tested. The model reported on is constructed with multimode fiber and has a displacement sensitivity of 6.4 x 10(-13) m. The device has general application as a linear accelerometer with the inherent advantages of remote optical fiber sensing. Particular attention is given to sono-buoy hydrophone applications in which the present model has a sensitivity limit corresponding to 75 dB relative to 1 microPa at 1 kHz. Means for substantially improving the accelerometer's sensitivity as a hydrophone are discussed.