Ultrabroad coherent comb-like optical spectra spanning several octaves are essential for the field of attoscience. Generation and guidance of a three-octave spectral comb, spanning wavelengths from 325 to 2300 nanometers has been demonstrated in a hydrogen-filled hollow-core photonic crystal fiber. Here, numerical simulations with JCMsuite are used for designing and understanding Kagome lattice HCPCF cladding modes.
F. Couny, et al. Generation and Photonic Guidance of Multi-Octave Optical-Frequency Combs. Science 318, 1118 (2007).