An algorithm for evaluation of loss in lightguide fibers.

A curve-fitting algorithm for analyzing single-mode lightguide 1.2-1.6 micron spectral loss data is described. The algorithm dissects a composite long wavelength loss curve into its separate constituent profiles and then estimates the numerical values of the associated model parameters. The various mathematical models used to represent the individual loss functions are presented, and the results of a sample analysis are discussed. The algorithm, dubbed "ELLF," should prove to be a useful tool for WDM system design, excess loss studies, fiber design optimization, and for development/manufacturing diagnostics.