Response of π-phase-shifted fiber Bragg grating to inhomogeneous strain fields caused by ultrasonic wave  

作　　者：AN Bingwen WU Xianmei LI Ziqi LI Feiran 

机构地区：[1]Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190 [2]University of Chinese Academy of Sciences,Beijing 100049

出　　处：《Chinese Journal of Acoustics》2024年第2期218-231,共14页声学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (11674351)。

摘　　要：Aiming at different sensing characteristics on waveform and amplitude of aπ-phase-shifted fiber Bragg grating under axially and vertically incident ultrasonic wave in water, a fiber Bragg grating ultrasonic sensing model is established based on transfer matrix method. Inhomogeneous strain fields along grating under axially and vertically incident ultrasonic wave are calculated, which helps analyze sensing characteristics of π-phase-shifted fiber Bragg grating under above two situations by using further wavelength shift results. Experiments are then performed to verify analytical results. Results show that the sensing characteristics of π-phase-shifted fiber Bragg grating are obviously affected by different inhomogeneous strain field distributions under two incident angles. Both sensing waveform and amplitude under vertically incident ultrasonic wave perform better than axially, and π phase shift plays a significant effect on sensing characteristics. With the increase of the distance between incident position and phase shift point, the response under vertically incident ultrasonic significantly declines. The research provides guidance for analyzing ultrasonic sensing mechanism of π-phase-shifted fiber Bragg grating.

关 键 词：FIBER shifted WAVE 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]