Design and numerical characterization of a high-performance VO2-based optical modulator are proposed. The modulation is achieved by the phase transition of VO2 in a Bragg grating which can be formed by the selective VO2 deposition on a silicon strip waveguide. The interplay of the Bragg reflection and the inherent loss of the metal phase VO2 is used to increase the extinction ratio (ER) while the similarity of the refractive indices of the silicon and insulator phase VO2 resulted in a low insertion loss (IL). ER and IL of the modulator are 34.5 dB and 3.4 dB, respectively, at the wavelength of 1.55 µm, and they are, respectively, above 33 dB and below 3.5 dB across the entire optical C-band. The ER can be improved to 110 dB at the expense of an increased IL of 7.3 dB. The energy consumption and the modulation speed are estimated by considering different VO2 triggering schemes, and it is shown that the energy consumption of 91.7fJ/bit and the speed of 14 THz can be achieved with the proper VO2 stimulation. Furthermore, the robustness of the device performance to fabrication errors is studied by simulating the effect of the variation in different geometrical parameters.