Broad and flat supercontinuum source (ranging from wavelengths 2.5 μm to 8 μm) using honeycomb microstructured fiber

Applications such as frequency comb generation and spectroscopy can greatly benefit from the mid-infrared (mid-IR) supercontinuum (SC) generation. The goal of this work is to achieve mid-IR SC using a honeycomb-structured chalcogenide Ge_11.5As₂₄Se_64.5 photonic crystal fiber (PCF). Quantitative computations were carried out with an ultrashort laser serving as the pump source. To create a wide and effective SC, the geometrical and pump pulse characteristics were both optimized. The resulting spectrum has a wavelength range of 2.5 to 8 microns. Our approach, with careful material selection and geometrical parameter optimization, produces a flat and extended spectrum up to 8 microns, whereas previous research in the literature has difficulty extending SC beyond 5 microns. Furthermore, our approach requires half the PCF length that was previously necessary.