In the previous chapters, we have provided the coupled-mode theory that determines the significant parameters for fiber Bragg gratings (FBG) and related them to the spectral properties. To calculate reflection, transmission, delay, and dispersion characteristics of the FBG, the coupled-mode equations must be solved [1–3]. There are several techniques can be used for this purpose. These techniques differ in the complexity, accuracy, and speed of computation [1, 2]. Therefore, the requirements from the designer make a compromise between them for optimum choice.