Radiation Damage of Germanium-Doped Silica Glasses: Spectral Simplification by Photo- and Thermal Bleaching, Spectral Identification and Microwave Saturation Characteristics

摘要

In recent years research on SiO2-GeO2 glasses has been intensified because of the potential use of this material in low attenuation optical waveguides for communication. To date, research efforts to develop extremely low-loss as well as radiation-tolerant optical waveguides using germanium-doped silica glass has focused on identifying the paramagnetic defect centers produced by ionizing radiation and by fabrication processes. These studies have been extremely useful for not only characterizing the radiation response of optical-waveguide glasses but also for understanding the mechanisms of color center formation and for developing means to minimize their formation. Friebele identified four germanium-related defects in gamma-irradiated germanium-doped silica using electro-spin resonance (ESR) spectroscopy. Since the spectra were complex due to overlapping resonances, detailed spectral simulations were required to determine the g tensor components for each defect center. Further studies of their spectral assignment have not progressed since this original work. Reprint