OPTICAL FIBER BRAGG GRATING COATING REMOVAL DETECTION

摘要

An optical corrosion sensor employs an optical fiber Bragg grating (20) embedded within an optical fiber (18). The grating (20) has a coating (40) made of a material, such as aluminum, which corrodes or can otherwise be removed. The coating (40) exerts forces (46) radially inward around and along the grating (20) so as to cause the wavelength bandwidth of the grating reflectivity profile to become broader and to be shifted relative to its uncoated condition. Also, the forces on the grating (20) are reduced when the coating corrodes, thereby causing the wavelength bandwidth and shift of the reflectivity profile of the grating to narrow and to return to its uncoated condition.