Abstract
Ytterbium-thulium-codoped silica fiber is proposed and studied for the first time. We first established a novel model for Yb3+-Tm3+-codoped silica fiber amplifier based on the Yb3+ to Tm3+ energy transfer. Using appropriate fiber parameters and energy transfer parameters, we analyzed and solved the coupled rate equations. We have obtained improved gain results in comparison to silica fiber amplifiers doped with Tm3+ only. The results demonstrated that the ytterbium to thulium energy transfer process in the material is significant and beneficial. © 2005 Elsevier B.V. All rights reserved.