Elongating and breaking of nanoparticles during the drawing of optical fibers

Description

Optical fibers form the basis for a wide range of applications that have grown considerably in technological impact recently, such as telecommunications, sensors, and lasers. These applications rely on the remarkable qualities of silica glass; particularly its significant mechanical and chemical stability, high optical damage threshold, low cost, and very high transparency. However, silica also possess certain characteristics that are detrimental for the luminescence ions including low rare-earth dopant solubility and relatively high vibrational energies. To overcome these issues, the incorporation of rare-earth ions into nanoparticles, which are then doped into the silica, is investigated to tailor the spectroscopic properties through the control of their local chemical environment about the dopant. Such optical fibers are elaborated by a high temperature fiber drawing (2000°C) of nanoparticles-doped optical preforms. The drawing step is usually assumed to be a homothetic transformation of the preform. However, at this stage, the glass is heated to a temperature at which it softens and then flows. This can induce the transformation of heterogeneities such as nanoparticles. In this presentation, we highlight the elongation and even break up of oxide nanoparticles during the draw process. In particular, we will focus on the comparison between experimental results and numerical simulations in Molecular Dynamics. These phenomena allow new route to prepare optical fibers with new amplifying properties.

Abstract

International audience

Additional details