A new technique to characterize localized linear elastic constitutive behavior within a Fiber Optic Sensor (FOS) embedded parallel to reinforcing fibers has been developed. A unit cell model has been developed with stresses anywhere within the unit cell formulated as a function of sensor strains. A slicing approach has been implemented within the unit cell to determine effective stresses within each slice of the unit cell. Different layers of the FOS are modeled using individual slices to model the stresses within a given slice. Numerical results are presented for SMF-28 FOS. The accuracy of the developed slicing based micromechanics approach has been validated by comparisons with results obtained using an established micromechanics analysis code based on the Generalized Method of Cells and a general purpose finite element technique. Effective unit cell stress results from all three models show close correlation to one another. In addition, convergence of normal stresses was also investigated with increasing volume fraction of surrounding reinforcing carbon fibers.