This paper presents a comparison of synthesis techniques for SPE-OCDMA Encoders/decoders based on FBGs. The synthesis method studied relies on the Inverse Scattering method and Genetic Algorithm approach. The comparisons between approaches takes into considerations the accuracy of convergence, the algorithm complexity and the constraints imposed on the component behaviour and its fabrication method. We implement the algorithms of the two approaches numerically, leading to versatile tools of simulations. This study is illustrated by the design and simulations of several encoders/decoders.