Highly coherent supercontinuum generation in a photonic crystal fiber based on GeSe₂–As₂Se₃–PbSe chalcogenide in the mid-infrared region

We numerically demonstrated highly coherent mid-infrared (IR) super-continuum (SC) generation using all-normal dispersion (AND) GeSe 2 −As 2 Se 3 −PbSe chalcogenide photonic crystal fiber (PCF). The structural parameters of this PCF were optimized to obtain an ultra-flat-AND region and high nonlinearity characteristics using the full-vectorial finite difference method with the perfectly matched layer boundary conditions to calculate the linear properties of the fiber. We show that, pumping a light source at 9.8 µm pump wavelength with an input pulse energy of 3.5 nJ and pulse width of 200 fs, corresponding to the peak power of 17.5 kW, into a 10-cm-long fiber, an ultra-flat-coherent mid-IR SC extended from 2851.8 nm to 13538.8 nm (bandwidth of 10687 nm) is obtained. This ultra-wide and flattened spectrum has excellent stability and coherence properties that can be used for mid-IR applications such as biological imaging, optical coherence tomography, and frequency metrology.