Heat treatment and fiber drawing effect on the matrix structure and fluorescence lifetime of Er- and Tm-doped silica optical fibers

Abstract

We investigate the influence of the optical fiber fabrication process on the fluorescence lifetime of Er 3+ and Tm 3+ ions. Optical fiber preforms were prepared using the MCVD method combined with Al 2 O 3 nanoparticle doping. The preforms were subjected to various fabrication processes, such as preform elongation, fiber drawing, and heat treatment. The matrix structure of the preforms and fibers was studied by XRD and TEM. The fluorescence lifetime was measured. The fabrication processes caused the dissolution of the doped Al 2 O 3 nanoparticles and a significant decrease of fluorescence lifetime of Tm 3+ ions, from 875 µs in the preform down to 610 µs in the fiber, whereas no significant effect was observed for Er 3+ ions, with fluorescence lifetime in the 9.6–10.2 ms range.