GeSe4 glass fibres with low optical losses in the mid-IR

Abstract This study proposes the realisation of low-loss fibres in the Ge–Se system. Ge–Se chalcogenide fibres are transparent in the near and middle infrared and show a high non linear refractive index. So, such fibres are of high interest for new optical applications like all optical telecommunication provided that optical losses be sufficiently low. To decrease the optical losses of fibres, several GeSe4 glasses have been prepared with different chemical and physical purification steps and thorough distillation of selenium under dynamic vacuum. The lowest the optical losses of GeSe4 fibre are lower than 0.5 dB/m between 1.7 and 7.5 μm except at 4.5 μm where losses are equal to 2.8 dB/m because of Se–H absorption.