Enhanced Acoustic Sensitivity in Polymeric Coated Fiber Bragg Grating

Abstract

In this work, a new fiber optic hydrophone based on the intensity modulation of the laser light in FBG (Fiber Bragg Grating) under the influence of the sound pressure is experimental proved. In order to increase the sensitivity, FBGs have been coated with proper materials characterized by elastic modulus much lower than the fiber one. The minimum detectable acoustic pressure has been found to be of the order of ~10Pa in the investigated frequency range, with excellent performances in terms of linear response and wide dynamic range. The experimental analysis also reveals that, by a proper design of the coating features, sensor bandwidth and sensitivity can be tailored for specific applications.

Keywords

• Fiber optics sensors
• Fiber Bragg Gratings
• Hydrophones