Theoretical study of coherent supercontinuum generation in chalcohalide glass photonic crystal fiber

Medjouri A. and Abed Djamel

Volume  219, Pages  165-178, (2020)

Optik

https://doi.org/10.1016/j.ijleo.2020.165178

Abstract

Mid-infrared supercontinuum (SC) generation in normally dispersive photonic crystal fiber (PCF) made of GeS₂-Ga₂S₃-CsI chalcohalide glass, is theoretically investigated. The finite difference method is employed to compute and optimize the different linear and nonlinear parameters of the fundamental guided mode. Simulation results indicate that the all-normal regime of dispersion over the entire wavelength range is achieved by properly reducing the diameter of the core neighboring air holes. The pulse propagation within the core of the proposed PCF and the SC generation process are accurately modelled and optimized, by numerically solving the generalized nonlinear Schrodinger equation. Both of Self Phase Modulation (SPM) and Optical Wave Breaking (OWB) effects are identified as the dominant nonlinear mechanisms involved in the pulse spectral broadening process. By launching at 3 μm, a 3 nJ energy and 50 fs duration input pulse into 15 mm long PCF, a broadband and highly coherent mid-infrared SC spectrum spanning the spectral region from 1.45 μm to 5.95 μm at 20 dB, is successfully generated.