Optimization of W-type fibre in order to use it in bright soliton transmission

The goal of the optimization process is simultaneously maximization of the single-mode and the anomalous dispersion range in the vicinity of λ= 1.55 μm. Input data in the optimization process are the values of the coefficients appearing in the Sellmeier dispersive formula that determines the value of the refractive index of silica glass as a function of wavelength and the amount and the type of a dopant. Output data in the optimization process are values of the core and the first cladding radii. The optimization process consists in solving the eigenvalue equation of the fibre in order to determine the cut-off frequency of the fundamental and the second mode and to define the shape and the zeros of dispersive characteristic of the fundamental mode. Verification of the optimization process rely on the generation of bright soliton in such an optimized fibre in the vicinity of λ= 1.55 μm. For this purpose, nonlinear Schrödinger equation is solved numerically using the split-step Fourier method.