Single mode fiber dislocation Mach-Zehnder interfero- meter cascaded with fiber Bragg grating for monitoring metal electrochemical corrosion

Abstract:

An optical fiber sensor composed of a dislocation Mach-Zehnder interferometer (MZI) cascaded with a fiber Bragg grating (FBG) is proposed, and it is used to monitor the electrochemical corrosion of metals in experiments. The dislocation interferometer is composed of two segments of single-mode fiber (SMF) and one segment of dislocation SMF. The contact surface is increased between the fiber and the environment, which helps to improve the interference sensitivity. The relationship between the dislocation amount and the refractive index sensitivity of the interferometer is discussed through simulation. In the experiment, the sensitivity of the interferometer reaches more than 10 000 nm/RIU, and the monitoring of metal electrochemical corrosion is also realized in 3.5% NaCl solution. The proposed measurement scheme has the advantages of small structure, low cost and high sensitivity. It has good prospects in chemical reaction monitoring.