Ultra-broadband modulation instability gain characteristics in As₂S₃ and As₂Se₃ chalcogenide glass photonic crystal fiber

Based on the designed As₂Se₃ and As₂S₃ chalcogenide glass photonic crystal fiber (PCF) and the scalar nonlinear Schrödinger equation, the effects of pump power and wavelength on modulation instability (MI) gain are comprehensively studied in the abnormal dispersion regime of chalcogenide glass PCF. Owing to high Raman effect and high nonlinearity, ultra-broadband MI gain is obtained in chalcogenide glass PCF. By choosing the appropriate pump parameter, the MI gain bandwidth reaches 2738 nm for the As₂Se₃ glass PCF in the abnormal-dispersion region, while it is 1961 nm for the As₂S₃ glass PCF.