Comparison and analysis of the basic characteristics of photonic crystal fiber with three typical structures

The multi-pole method is used to analyse and compare the dispersion coefficient, dispersion slope, nonlinear coefficient, confinement loss of photonic crystal fibers of hexagonal, octagonal and decagonal structures with the same structure parameters. The photonic crystal fiber with hexagonal structure is more suited for study of dispersion compensation and high nonlinearity. The nonlinear coefficient of photonic crystal fiber with hexagonal structure is 0.37 m-1·W-1 at 0.8 μm. The photonic crystal fiber with decagonal structure is more suited for study of flat dispersion curve and low confinement loss.The confinement loss of photonic crystal fiber with decagonal structure is about 3000 orders of magnitude less than that with hexagonal structure around 0.8 μm.The dispersion of photonic crystal fibre with decagonal structure is less than 0.17 and larger than -0.07 ps/(km·nm) from 1.4 to 1.65 μm, resulting in nearly zero dispersion of photonic crystal fiber around 1.55 μm. The cladding structure of photonic crystal fiber is closer to the circular structure, the dispersion of which is much flatter, the nonlinear coefficient and the confinement loss of which are much lower.