Study On Corrosion Acoustic Emission Sensor Based On Orthogonally Polarized Dual-frequency DBR Laser

With the development of the optical fiber sensing technology,the acoustic emission detecting technology based on optical fiber is widely used in many fields including structural health monitoring and non-destructive testing.The project aims to launch online monitoring for Q235 metal corrosion by using acoustic emission.A corrosion acoustic emission sensor with high sensitivity is proposed on foundation of the orthogonally polarized DBR fiber laser.The main contents are as follows:Aiming at the design optimization of the DBR fiber laser,the sensing principle and theoretical model are analyzed.And the influence of the cavity parameter on the performance of the corrosion acoustic emission sensor is revealed.The mechanical model of the DBR fiber laser is discussed under the condition of simulating acoustic field.The experimental results of the acoustic emission sensor based on DBR fiber laser have proved the effectiveness of the proposed method.Wavelet transform is used as a tool for decomposition and reconstruction of signals for noise suppression.Hilbert transform is applied for frequency demodulation and thus provides indication of specific corrosion period of the Q235 steel plate.