Measurement and Modeling of Low-Wavelength Losses in Silica Fibers and Their Impact at Communication Wavelengths

Using the cutback technique, the attenuation of four different silica step-index fibers is measured in the very wide wavelength range of 190-1700 nm. The measured spectra are deconvolved into components describing Rayleigh scattering, infrared losses, Urbach edge, anomalous loss, and different localized absorptions using a least squares fit. The evaluated Urbach edge is compared against results based on measurements on bulk glass samples and good agreement between the two is found. Furthermore, the Urbach edge is found to contribute significantly to the overall attenuation at communication wavelengths for two of the four fibers investigated.