Mid-infrared flattened supercontinuum generation in all-normal dispersion tellurium chalcogenide fiber

We have prepared a well-structured tellurium chalcogenide (ChG) fiber with a specialized double cladding structure by an improved extrusion method, and experimentally demonstrated an ultra-flat mid-infrared (MIR) supercontinuum (SC) generation in such a fiber. The step-index fiber had an optical loss of <1 dB/m in a range from 7.4 to 9.7 mu m with a minimum loss of 0.69 dB/m at 7.87 mu m. Simulation showed that an all-normal dispersion profile can be realized in this double cladding tellurium fiber. An ultra-flat MIR SC spectrum (similar to 3.2-12.1 mu m at -10 dB, similar to 2-14 mu m at -30 dB) was generated from a 22-cm long fiber pumped with a femtosecond laser at 5 mu m (similar to 150 fs, 1 kHz). Then the degree of coherence was calculated out based on a simulation, showing that a high coherent MIR SC (from 2.9 to 13.1 mu m) can be generated in this double-cladding tellurium fiber. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement