FIRST PRINCIPLES STUDY OF OPTICAL PROPERTIES OF OXYGEN DEFICIENT CENTERS IN PURE AND GE-DOPED AMORPHOUS SILICA

Abstract : Generation mechanisms of radiation-induced point defects in amorphous silica (a-SiO2) have been widely studied due to its central role in most of the contemporary electronics and photonics technologies used in harsh environments. Point defects or color centers are generated at the microscopic scale through ionizing or/and “knock-on” processes. At the macroscopic scale, these defects are responsible for the degradation of electrical properties of microelectronic components and of optical properties of bulk or fiber waveguides. In this study, we focus on Oxygen Deficient Centers (ODC) and theirs effects in optical fibers. Several experimental techniques allow the determination of the nature and properties of point defects. Electron Spin Resonance (ESR) is used to determine the structural properties and concentrations of paramagnetic centers. Optical Absorption (OA) measurements point out the bands responsible for the radiation-induced attenuation increase of optical fibers. Luminescence measurements can also be used to identify the emitting point defects.