Inverse analysis of surface degradation using optical fibers

The authors present a general method based on inverse analysis of light signals from a fiber-optic sensor for in situ detection of metal, film, or coating degradation. This method, which does not, in principle, depend on the geometry of the fiber-optic sensor, is based on analysis of reflected light intensity loss as opposed to reflected or transmitted intensity modulation. Following an inverse-analysis approach, the level and rate of intensity loss are correlated with levels and rates of surface degradation. This approach allows optimization of fiber-optic sensors for specific applications and different environments. Case study analyses using experimental data are used to demonstrate the fundamentals of various aspects of this method.