Comparative study of supercontinuum spectra generated by As2S3 chalcogenide photonic crystal fibers with different lattice types

Three distinct configurations of As₂S₃ chalcogenide photonic crystal fibers (PCFs) were designed to investigate supercontinuum generation (SCG). The optical properties of PCFs with the circular lattice (CL), square lattice (SL), and hexagonal lattice (HL) were comprehensively analyzed to choose the optimal fiber for SCG. This investigation facilitated the identification of three superior structures, specifically designated as #CF, #SF, and #HF, respectively. These structures are unified by operating within an all-normal dispersion regime, each presenting a lattice constant of 1.0 μm and a filling factor of 0.35. These fibers were subjected to a peak power of 4.0 kW and a pulse duration of 270 fs, culminating in an expansive supercontinuum range. Notably, the SC range extended from 2.0 to 6.5 μm for #CF, from 2.0 to 8.3 μm for #SF, and from 1.9 to 6.6 μm for #HF. The SL-PCF exhibited the broadest supercontinuum, attributed to its protracted flat dispersion band. Furthermore, compared to previously reported all-normal dispersion PCFs, the spectral range facilitated by this peak power was significantly augmented. These optical fibers promise to provide supercontinuum spectra with broad bandwidth for practical applications in sensing and gas detection.