A New Type of Etched Fiber Grating Hydrophone

We propose a new type of fiber hydrophone composed an etched Bragg grating and special packaging structure for detecting acoustic waves in the low-frequency band under water. The operating mechanism is based on mechanical vibration from induced vibrating stress pressure. pressure pushes silicone rubber thin film, causing its then stretching grating, thus resulting wavelength shift which overlapped with tunable laser. variation light intensity transferred to electrical signal by using photodetector. From experimental results, we can determine that smaller diameter, higher sensitivity frequency response. In order confirm this FBG has ability work high-frequency waves, standard piezoelectric are experimentally compared same test conditions range 4 10 kHz. According better responsivity than conventional hydrophone. Due unique sensing design, wide-band be useful long-term continuous monitoring waves.