We have prepared an ultra‐large core, high numerical aperture (NA) chalcogenide (ChG) step‐index fiber (SIF) with a mode area of >43 600 μm² 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.

中文翻译：

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基于硫族化物玻璃挤压的超大模面积中红外光纤

我们已经制备的超大的芯，高数值孔径（NA）硫属化物（CHG）阶跃折射率光纤（SIF）具有> 43600μm的模式区域²由一种改进的挤压方法在为5.5μm的波长。基于两个具有相似软化温度的ChG玻璃的光纤，纤芯直径为339.0μm，并且包层超薄。光纤在9.74μm处的最小损耗为1.75 dB / m，从5.3到10.8μm的光损耗为<5.0 dB / m。在具有大纤芯和高NA的17厘米长超大模面积光纤中产生了覆盖范围从1.2μm到13.7μm的宽带超连续谱（SC）。所有这些表明，光纤具有大功率红外激光传输的潜力。