Study On Techniques To Expand Dynamic Range Of Fiber-Optic Hydrophone

Interferometric fiber-optic hydrophone based on fiber-optic technology is a new style fiber-optic sensor which can detect underwater acoustic signal. Compared with traditional piezoelectric hydrophone, fiber-optic hydrophone has many advantages such as high sensitivity, prodigious dynamic range and immunity to electromagnetic interference. Optic-fiber hydrophone had been one of the important investigative schemes for many countries modern nation defense construction.In this degree paper, the development status of fiber-optic hydrophone and the basic theories are reviewed. This paper analyses and research several typical scheme of signal detection technique. Some main factors affecting the dynamic range of the interferometric fiber-optic hydrophone are researched. The structure of the spectrum of the interferometric fiber-optic hydrophone's output signal are analyzed. And the limitary factors to dynamic range of the fiber-optic hydrophone which used PGC detection technology are detailedly researched. A group of simulation is done by inputting a group of different signals.The components of the fiber-optic hydrophone's dynamic range lower limits (background noise) are analyzed. And it was proved that the phase noise of the laser was the biggest components of the dynamic range lower limit. Through the study on the fiber-optic hydrophone, some effective ways to expand the dynamic range are put forward. The standard of choosing laser, the probe technology, phase demodulation technology and the structure of the demodulation circuit are lucubrated.