Reliability Assessment of Optical Fibers and Fiber Gratings

The topic of reliability of UV-induced fiber gratings is reviewed. Approaches to assess and predict changes in optical properties of fiber gratings due to thermal decay of refractive index modulation are presented and compared. The mastercurve/demarcation energy diagram approach is shown to be a powerful and general method for the purpose. The process of thermal stabilization to obtain gratings with superior stability is delineated. It is shown that the mastercurve approach could be used to analyze other reliability problems such as in predicting hydrogen-induced losses in fibers.