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Development of broadband supercontinuum sources has been studied since decades for its high application potential in various fields like spectroscopy, medical science and others. First experiments were made with silica but the results shown the need to find new materials for supercontinuum generation in the IR wavelength range. Two types of materials have been found interesting for supercontinuum generation: chalcogenide and tellurite glasses. These materials have a high non-linear refractive index and a good transmission in infrared which provides a high potential for applications. Bulks tellurite glasses transmit until 5µm while bulks chalcogenide glasses transmit until 12-20µm depending on their composition. We report here the synthesis of low-OH step-index tellurite fibers and their linear and non-linear characterization. The synthesis is firstly realized by build-in-casting in a glovebox which allows to get a large-core preform(∅clad/∅core 2) and a large core corresponding fiber(∅core 60µm). Then, the rod-in-tube technique allows, from the jacketing of the stretched initial preform, to get a small-core preform and subsequently a small core fiber (∅core 3.5µm). The minimum of losses of the large-core fiber is below 1dB/m, the IR transmission wavelength exceeds 4 µm on several meters of fibers and reaches more than 5 µm on small samples (several centimeters long). We have developed core-clad composition with a large refractive index difference (∆n=0.132) which provides a high confinement in our step-index fibers. We discuss the supercontinuum generation in these fibers exploiting numerical simulations based on the generalized nonlinear Schrödinger equation and then we present the supercontinuum experimental results obtained between 1 and 5µm. Most of pollutant and greenhouse gases emitted by human activity, including methane, carbon dioxide and nitrous oxide, absorbs in the mid-IR. The spectroscopic experiments realized on the gases through supercontinuum generation between 1 and 5 µm are presented.
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