For a single-mode optical fiber, the only source of dispersion is due to group-velocity dispersion (GVD), or intramodal dispersion where the dispersion is the result of g. In the geometrical-optics description such a broadening was attributed to different paths followed by different rays. Dispersion causes signal distortion, while losses reduce signal strength. Engineers tackle these problems through clever. In this paper, the dispersion characteristics of two standard single-mode optical fibers (SMFs), fabricated with silica and poly (methyl methacrylate) (PMMA) are studied in telecommunication spectral regions.