Abstract

It has been well known that the optical absorption band at 5eV exists in Ge doped a-SiO₂. Some origins of photosensitivity are proposed [1] and undoubtedly one of them is related to the origin of 5eV band [2]. Two kinds of different defects have responsibility on the absorption band at 5eV, one is a neutral oxygen vacancy (NOV) peaking at 5.06eV and the other is a Ge lone pair center (GLPC) at 5.14eV [3]. Hosono et al. reported that the NOV was photochemically converted into Ge E' center [2]. Recently, a maximum refractive-index change A of 1% has been reported in hydrogen-loaded germsnosilicate fibers. In this article, photochemical reactions in H₂ loaded Ge-doped a-SiO₂ were examined [4].

© 1995 Optical Society of America