Improved theoretical estimation of mechanical reliability of optical fibers

We propose an enhanced theory that can be commonly applied to fiber reliability evaluations under various stress and failure probability levels, under prolonged stress and in stressed fiber distribution conditions. In the theory, the inert strength distribution of fibers is composed of two types of Weibull distributions with different slope parameters. We included proof-test conditions that adhere to Mitsunaga's theory in the calculations. New parameters that express the high-strength distribution can be obtained from the tensile strength data using a theoretical equation. We analyzed the static fatigue characteristics under uniform bending and two-point bending using this theory. The experimental results agreed well with the calculated results for bent fibers. We believe that the theory will play a vital role in the design of optical fiber cords for sharp-bending uses and in the minimization of various optical packages.