Fiber-optic Hydrophone Primitive Characteristics And The Research Of Detection Method Based On PGC

There are abundant resources in the ocean. Many countries, especially major powers have made a huge investment on the ocean. As the world's most populous country, china started late in the marine development and its technology was relatively backward. Fiber-optic hydrophone can effectively pick up acoustic signals of the ocean and it is essential for marine oil-gas development and marine military applications. In a variety of fiber-optic hydrophone, phase interferometric fiber-optic hydrophone with the most research and application has a large dynamic range, frequency bandwidth, sensitivity characteristics. Phase generated carrier modulation and demodulation technology as a signal demodulation method is widely used for the interferometric fiber-optic hydrophone. Therefore, the studies on the interferometric fiber-optic hydrophone element and the detection method based on the phase generated carrier modulation and demodulation technology in this paper have important meaning.Interferometric fiber-optic hydrophone element characteristics and improved method based on Phase generated carrier were studied in this paper, includes the following two aspects:On the one hand, the element characteristics of mandrel hydrophone based on Michelson interferometer structure and with the air cavity was studied using the theory of elasticity. The impact of element materials and geometry on the sensitivity of the phase shift was analyzed. Then, the sensitivity, resonant frequency, frequency response and directivity characteristics of the fiber-optic hydrophone element was analyzed using the finite element method in the paper.On the other hand, an improved method based on phase generated carrier modulation and demodulation technology has been proposed, the result of the improved PGC demodulation method and the minimum sampling frequency were analyzed, and the problems in the new program was better solved. The simulation model of improved PGC method was established using MATLAB based on the theoretical analysis, the impact of threshold size on the demodulation results, system dynamic range, system frequency response and linearity of the system were studied by simulation. The simulation results verify the correctness of the improved method.