Defect centers in a germanium-doped silica-core optical fiber

The radiation‐induced defect centers in a low‐loss Corning germanium‐doped optical fiber have been studied. In addition to silicon E′ centers, four germanium‐related centers, corresponding to electrons trapped at the site of oxygen vacancies in s p3 orbitals of germanium ions with zero to three next‐nearest‐neighbor germaniums, were observed. A model which assumes Gaussian distributions in the excited‐state energy‐level splittings has been successfully used to computer simulate the ESR spectrum of the irradiated fiber.