I will expose a Computational analysis method for a design of a strain fiber optic sensor. I will use three different software programs. The first program will be MAPLE for the develop of the numerical and symbolic computations, the second program will be ANSYS for the structural analysis and the third one will be OPTIFIBER for the analysis of electromagnetic modes in the optic fiber. The design strategy is to translate the deformations of structures in changes in the refractive index of the optic fiber and the subsequent modification of the electromagnetic modes of the fiber. This strategy will be presented in detail from a computational mathematic point of view. Is hoped that this design method proposed be useful for engineers working with optic fiber.