Thermoluminescence characterization of traps involved in the photodarkening of ytterbium-doped silica fibers

Description

Photodarkening mechanisms of ytterbium-doped silica optical fibers are still not elucidated though hardening routes have been proposed. Most basic questions are still under debate about the assignment of the darkening excitation bands into the UV range, the nature of absorbing centers (photoionized centers or trapped carriers?), or of traps accepting photo-released carriers (electron or hole traps?). We used thermoluminescence measurements to characterize traps populated by different radiation types. It is notably demonstrated that photodarkening involves silica hole traps. The popular idea that color centers are formed upon carrier trapping is not consistent with our observations.

Abstract

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