New chalcogenide fibres

Chalcogenide glasses are known for their large transparency in the mid-infrared and their high linear refractive index (>;2). They present also a high non-linear coefficient (n₂), 100 to 1000 times larger than for silica, depending on the composition. An original way to obtain single-mode fibres is to design micro structured optical fibres (MOFs). In addition, these fibres present unique optical properties thanks to the high degree of freedom for designing the geometrical structure [1,2]. Microstructured optical fibres (MOFs) are traditionally prepared using the stack and draw technique. In order to avoid the interfaces problems observed in chalcogenide glasses [3], we have developed a new casting method to prepare the chalcogenide perform [4]. This method allows optical losses as low as 0.4 dB/m at 1.55 μm and less than 0.05 dB/m in the mid IR [5]. Our group has prepared various chalcogenide MOFs operating in the IR range in order to associate the high non-linear properties of these glasses and the original MOF properties. For example, small core fibres have been drawn to enhance the non linearities for telecom applications such as signal regeneration [6] and generation of supercontinuum sources [5, 7]. On the contrary, for military applications in the 3-5 and the 8-12 μm windows, large effective mode area and single mode fibres[8] are requested to permit the propagation of high-power Gaussian laser beams. In a other hand, infrared MOFs can be used for gas sensing like CO₂ detection for example [9].