As i know the dispersion equation related to beta2 value, means if i have dispersion value at particular wavelength, then i can calculate beta2. We use this beta2 value to generate higher order dispersion coefficient like beta3, beta4 and so on..... by differentiating this beta2 value with respect to wavelength. and all these betas are used to generate supercontinuum spectrum. My doubt is while calculating higher order through curve fitting tool in MATLAB, all the values of betas are same as betas values which are calculated through differentiation ????