Influence of molecular hydrogen diffusion on concentration and distribution of hydroxyl groups in silica fibers

To study the hydroxyl [OH]-group contamination mechanisms in silica-based optical fibers, the transmission spectra of substrate tubes and fiber preforms made from various types of silica glasses ["Suprasil F-300," KS-4V, and KUVI] are measured by the method of infrared Fourier spectroscopy in a wavelength region of 2-5 μm. Due to the intensity of the fundamental OH stretching vibration band, the absorption coefficient, concentration, and a distribution profile of OH groups across the aforesaid samples are calculated.