Simple approximate formula for forecast of the lifetime of optical fibers of a cable communication line

The article is devoted to predicting optical cable communication lines’ lifetime, determined by optical fibers’ lifetime in a cable. Based on the well-known formulas for calculating the reliability indicators of optical fibers, taking into account the high requirements for the reliability of cable networks and the ranges of changes in the parameters of the destruction of silica optical fibers, the simple approximate formulas were obtained for calculating the lifetime of a cable of communication lines with a given probability. The formulas are obtained for a constant load on the cable fibers and their random nature. Estimates of the errors of the proposed formulas are given. Calculations show that the errors in the area of interest for the reliability of communication lines compared to the known more rigorous formulas do not exceed fractions of a percent, which allows us to recommend the obtained approximations for use.