Research Of The π/2 Phase Demodulation Technology Using In The Fiber-Optic Hydrophone Base On The Acousto-Optic Coupling On The Water Surface

As its high sensitivity, small size, good stability, wide dynamic range, etc, the fiber-optic hydrophone has been widely used in oil and gas exploration, seismic wave detection, marine fisheries, marine environmental testing of modern naval anti-submarine warfare and other aspects. There is a interferometric fiber-optic hydrophone based on acousto-optic coupling on the water surface, it can realize the detection of the underwater acoustic signals as all the hydrophone system up on the water surface. In his paper, we research on the special hydrophone, at the same time, an innovation demodulation method based on theπ/2 phase modulation is proposed.This paper mainly contains three parts. In the first part, we study on the principle of the interferometric fiber-optic hydrophone based on acousto-optic coupling on the water surface and explore about how to realize the detection of underwater acoustic information base on the acousto-optic coupling principle, finally the analysis of the noise of this hydrophone is presented. In the second part, we propose aπ/2 phase modulation method, and discuss this signal demodulation process for theory, and then, we take a matlab simulation to conducted test the feasibility of this demodulation method, at last, we analysis the influence of various factors on the demodulation result of this novel method by simulation too. In the last part, an experiment of the demodulation method based on theπ/2 phase modulation is taken on, the experiment result shows that this demodulation method can use for practical application.