Implementing a temperature-resistant fiber hydrophone sensor using FBG

摘要

A new type of fiber acoustic sensor (hydrophone) is exhibited here with two fiber Bragg gratings (FBG) and a unique demodulation method. Almost all former FBG sensors had separated detecting and demodulating components while this FBG hydrophone has an idiomatic structure for both detecting and demodulating method, it utilizes a couple of same cascaded FBGs, as well as a barrel shaped structure. The physical form of the hydrophone helps us to overcome the effects of temperature noises and it will even help us for localization purposes in future works. We successfully reached more than 0.5nm/MPa sensitivity which is appropriate for environments with less than 200dB pressure.