Mechanism and Suppression Technology of Mandrel Fiber Hydrophone Resonance Characteristics

The mandrel frame is the most commonly used sensitizing structure for scalar fiber hydrophones, and its material properties and structure directly affect hydrophone performance. The finite element simulation model of a hydrophone is established based on the principle of acoustic-structure interaction. Additionally, the influences of the material and structure on hydrophone sensitivity and the working bandwidth are analyzed in detail. The results show that the sensitivity and bandwidth of the hydrophone restrict each other, and the inner mandrel resonance exerts the main limitation on the bandwidth. Increasing the inner mandrel thickness and reducing the inner mandrel radius can widen the working bandwidth while maintaining sensitivity. The accuracy of the model is verified by via experiments in a lake.