Strength of screen tested optical waveguide fibers

When an optical waveguide fiber is screen tested (stressed), flaws in the fiber enlarge so that it becomes weaker (fatigue). This paper develops a model that quantitatively evaluates the strength loss in terms of the way this is conventionally measured. The model utilizes conventional fracture mechanics and flaw growth theory which provides a reasonable representation of most fatigue data. While severe weakening can occur for some of the fibers, experimental detection of this effect requires measurement of failure probabilities less than 10−2.