Efficient design of spatially symmetric Bragg gratings for add/drop multiplexers

A simple and fast numerical procedure is presented for designing spatially symmetric Bragg gratings with no need for iteratively solving the coupled mode equations. Using a unique relation between the phase and the amplitude of the reflection spectra valid for spatially symmetric gratings, the grating spectra are suitably optimized to fit given specifications. At the end of the design process an inverse-scattering algorithm determines the spatial structure of the corresponding Bragg grating. This method is particularly useful for the design of add/drop multiplexers, where symmetry can be a crucial prerequisite.