Organic axial stretching DFB fiber laser hydrophones: Theoretical and experimental study of eccentricity

For the structure of the organic material axial stretching distributed feedback (DFB) fiber laser hydrophones, both ends are sensitized by the organic material perfusion molding. During encapsulation, when the DFB laser fiber is not precisely fixed to the central axis of the sleeve, the fiber will produce eccentricity after the organic matters are solidified. Therefore, the theoretical model of eccentricity was established in this paper, and the influence of eccentricities on frequency response characteristics of hydrophones was analyzed with the finite element method, and the experimental verification was carried out. Simulation and experimental results indicated that this eccentricity will reduce the sensitivity of DFB fiber laser hydrophones about 2 dB and increase the frequency response fluctuation about 3 dB, which is the key factor to be controlled in the packaging process.