Optical Sensor for Steel Corrosion Monitoring Based on Etched Fiber Bragg Grating Sputtered With Iron Film

An optical sensor for steel corrosion monitoring based on etched fiber Bragg grating (FBG) sputtered with iron film is developed. The sensor is fabricated by magnetron sputtering an iron film on an etched FBG, and tested in sodium chloride solution. The chemical composition, structure, and morphology of film are investigated by energy dispersive X-ray analysis, X-ray diffraction, scanning electron microscope, and so on. The central wavelength shift and peak power of the FBG are analyzed with a spectral meter. The experimental results show that the wavelength shift and spectral chirp are related to the corrosion of iron film, and the sensor is able to monitor the status of iron in the corrosion process.