COST 218 evaluation of optical fiber lifetime models

More than 10 existing lifetime models for optical fibers, based on a power law to describe the stress-induced crack growth, are studied and compared. The number of models is reduced to only 1 basic model. This model is taking into account the effects of proof test. An alternative model, to be used when proof testing is performed on-line, is given as a worst-case limit of the basic model. A choice of 3 testing methods to obtain information about the weak-flaw distribution is given: dynamic-fatigue and variable screen-testing of long lengths or using the failure number during proof test. The models can also be used for titanium-doped fibers, but then a correction must be made for the compressive surface-stress. The lifetime models cannot be used for carbon-coated fibers and for fibers in water without further study.