Higher-order dispersion terms of a photonic crystal fiber with hexagonal holes

摘要

In the modeling of supercontinuum generation in photonic crystal fibers by ultrashort pulses, the knowledge of the higher-order dispersion terms of the fiber are necessary to achieve a good approximation between the simulated and experimental spectra. However, these parameters are usually not provided by the manufacturer. In this work, we present the numerical estimation of the higher-order dispersion terms for a nonlinear photonic crystal fiber with hexagonal holes. For the simulation, we chose a commercial fiber with a high nonlinear response (Blazephotonics NL-2.4-8). The fiber was designed with a small core diameter of 2.4 μm and a triangular pattern of air holes in the cladding with a pitch of 2.9 μm. Through the free software, MIT Photonic Bands, the structure of the fiber was modeled and the effective refractive index, as well as the dispersion terms curves are estimated. From our results, the zero-dispersion wavelength of the fiber resulted to be of 800 run and at this wavelength, the higher-order dispersion terms were: β_2=0, β_3=0.05 ps~3/km, β_4=-7.03×l0~(-5) ps~4/km, β_5=1.4×10~(-7) ps5/km, β_6=-4.163×10~(-10) ps~6/km, β_7=1.118×10~(-12) ps~7/km. The zero-dispersion wavelength and the dispersion slope estimated at this wavelength agree with the values reported by the manufacturer.