This work is concerned with graphene-based optical modulators including Mach-Zehnder and waveguide modulator for 1310 and 1550 nm operating wavelengths with square and rectangular modulator cross-section shapes using COMSOL Multiphysics, Lumerical, and MATLAB software for computational analysis. It also investigates the Graphene's Optoelectronic properties and Mathematically modeling it to establish fitting simulation environment.