Numerical demonstration of widely tunable femtosecond soliton generation in chalcogenide microstructured fibers

We numerically investigated widely tunable femtosecond solitons spanning from 4.1 to 7.2 mu m in designed chalcogenide fibers with Iwo rings of air holes. The core was made of Ge15Sb15Se70 glass and the cladding glass was composed of Ge20As15S65. By using a 4.1 mu m fiber laser with a pulse width of 100 fs as the pump light and 1 m long chalcogenide microstructured fibers as the nonlinear media, widely tunable femtosecond solitons spanning from 4.1 to 7.2 mu m were observed, and the pulse width of these tunable Raman solitons remained below 150 fs. The efficiencies of the mid-infrared soliton could be up to over 80%, ranging from 4.1-6.8 mu m. Through ntunerical simulations, we also observed red-shifted dispersive waves varying from 10.2 to 8.9 mu m. Our simulated results show that the designed chalcogenide microstructured fibers are promising nonlinear media for generating tunable mid-infrared light sources.