Numerical Calculations of Fiber Bragg Gratings with Intensity-Dependent Refractive Index

Modified discrete transfer matrix and transmission line models were applied to nonlinear refractive index fiber Bragg gratings (FBG). The methods were validated against analytical solutions for Kerr-type uniform FBG, evaluating accuracy, convergence, and computational time. Spectral reflectivity, bistability, index distribution, and group delay were computed for various FBG types, with results discussed for each grating, particularly regarding reflectivity and bistability.