Pressure compensated fiber laser hydrophone: Modeling and experimentation

Abstract

A pressure compensated metal diaphragm based fiber laser hydrophone configuration that can provide good sensitivity, large bandwidth, and sea state zero noise floor is proposed in this paper. A simplified theoretical model of the proposed sensor configuration is developed in which the acoustic elements of the sensor configuration are modeled using a four-pole acoustic transfer matrix and the structural elements are modeled as second order single degree of freedom elements. This model is then used to optimize the design parameters of the sensor system to achieve the performance objectives. An axisymmetric finite element analysis of the sensor configuration is also carried out to validate the results from the simplified theoretical model. Prototype sensors were fabricated and hydrostatic testing in a pressure vessel validated the static pressure compensation performance of the sensor. Frequency dependent sensitivity of the sensor system was measured through acoustic testing in a water tank. The prototype sensor gave a flat frequency response up to 5 kHz and experimental results compared well with theoretical predictions. The sensor has an acceleration rejection figure on the order of 0 dB ref 1 m/s(2) Pa and the pressure compensation approach worked reasonably well up to a hydrostatic pressures equivalent to a depth of 50 m.

分布反馈式光纤激光水听器探头封装及应用研究进展

“…12 Application of the DFB fiber laser hydrophone. (a) Batch packaging of physical drawings; (b) orientation history map of the hydrophone array to the target [26] 0100002 [30][31][32] 综 述 [33] 图 16 DFB 光纤激光微地震仪的结构。 (a)DFB 光纤激光水听器； (b)DFB 光纤激光加速度计 ［35］ Fig. 16 Structure of the DFB fiber laser microseismometer.…”