Radiation-induced transmission loss in Low Water Peak Single Mode (LWPSM) fiber has been investigated. Formation
and conversion processes of defect centers also have been proposed using electron spin resonance in the fiber irradiated
with gamma rays. When the irradiation dose is low, Germanium electron center (GEC) and self-trapped hole center
(STH) occur. With the increase of dose, E’ centers (Si and Ge) and nonbridge oxygen hole centers (NBOHCs) generate.
With the help of thermal-bleaching or photo-bleaching, the radiation-induced loss of pre-irradiation optical fiber can be
reduced effectively. The obtain results also have been analyzed in detail.
Infrared spectra of optical fiber cladding materials have been investigated by the irradiating treatment, and the
quenching and annealing process with different temperature. The results show that, with the method of quenching firstly,
the 1100 cm-1 peak in the IR spectrum of cladding materials changes dramatically, which may attribute to the quenching
process, corrected the fictive temperature and induced structural disorder. And then, the irradiation process induces
defects. Finally annealing process can make the material become more stable, but the intensity and shape of 1100 cm-1
peak no change remarkably. This result shows that annealing process repaired the structural disorder induced by
quenching process and the defects induced by irradiated.