Experimental investigations on stability and noise issues of Michelson interferometer based fiber optic hydrophones

Interferometric fiber optic hydrophones are projected as potential sensors for underwater security. The performance of all-fiber Michelson interferometer suitable for both fiber laser and fiber mandrel based hydrophones was analyzed in this work. Structural and optical scheme for the hydrophones are found to have crucial role in determining the stability and hence the noise of the hydrophone. Experiments were carried out to study the role of mirror vibrations and back-scattering from the fiber routings on the performance stability of the interferometer configuration. Results show that the mirrors are very sensitive to vibrations, thereby affecting the noise floor of the hydrophone. Attempts were made to reduce these noise effects to make Michelson interferometer more stable and achieved high performance.