Ultra‐large mode area mid‐infrared fiber based on chalcogenide glasses extrusion

This is the authors' abstract. We don't add key points for this paper.

We have prepared an ultra‐large core, high numerical aperture (NA) chalcogenide (ChG) step‐index fiber (SIF) with a mode area of >43 600 μm 2 at the wavelength of 5.5 μm by an improved extrusion method. The fiber based on two ChG glasses with similar softening temperature has a core diameter of 339.0 μm and ultra‐thin cladding. The fiber exhibits a minimum loss of 1.75 dB/m at 9.74 μm and an optical loss of <5.0 dB/m from 5.3 to 10.8 μm. Broadband supercontinuum (SC) covering from 1.2 μm to 13.7 μm has been generated in a 17‐cm‐long ultra‐large mode area fiber with large core and high NA. All these show that, the fiber possesses the potential for high‐power infrared laser transmission.