Step-index fibre from metal halide chalcogenide glasses

The GeS2-Ga2S3 vitreous matrix can incorporate metal halides in its network allowing the properties of the glasses to be adjusted following the composition. In this work, different systems containing either CsCl, CsI, CdCl2, or CdI2 are investigated in order to determine the compositions having the most suitable properties for drawing a step-index fibre. Indeed, transition glass temperatures and optical parameters such as the optical band-gap, the linear and nonlinear refractive indexes are given. The preforms were prepared using the rod-in-tube technique and multimode step-index fibres were successfully drawn. This initial work led from these glass families, which also show both the possibility to be rare-earth doped and to be permanently photo-written by a femtosecond laser, paves the way to a future mid-IR laser fibre. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement