Time-dependent radiation-induced attenuation changes in germanosilicate (~13wt%) optical fibers were measured under steady-state γ-ray and pulsed X-ray irradiation. For each type of irradiation, spectral attenuation measurements showed that permanent radiation-induced losses at 1.55μm were due to the infra-red absorption band of P1 centers. It was assumed that the kinetics of recovery, and an increase in attenuation measured in P co-doped fibers after pulsed X-ray irradiation, were governed by a charge re-trapping phenomenon from P oxygen hole centers to P1 centers. The P co-doped fiber characteristics after both types of irradiation were explained in terms of this mechanism. The results showed that the effect of P-related color centers increased when the P co-doped cladding (~0.3wt%) also contained Ge (~0.3wt%).

Properties of Phosphorus-Related Defects Induced by γ-Rays and Pulsed X-Ray Irradiation in Germanosilicate Optical Fibers. S.Girard, A.Boukenter, Y.Ouerdane, J.P.Meunier, J.Keurinck: Journal of Non-Crystalline Solids, 2003, 322[1-3], 78-83

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