In this paper, with dispersion engineering, two waveguides with silicon core and SiO2 cladding are proposed to generation the supercontinuum spectrum and optical frequency combs. By injecting a pulse with a peak power of 800 (W) and a pulse duration of 50 (fs), the output supercontinuum spectrum is obtained from a wavelength of 1100 (nm) to 4000 (nm). Also, by applying a maximum power of 1 KW and a pulse width of 100 (fs), optical frequency combs based on a supercontinuum with a broadband frequency combs have been obtained. Our proposed structure has good potential for engineering and achieving flatness dispersion which there are two zero dispersion wavelengths at 1890 (nm) and 2850 (nm). This flat dispersion can be very useful to achieve the desired output spectrum. Due to the materials used and the flat structure of the proposed waveguides, these waveguides can be used for integrated optical circuits as well as applications in optical communications, spectroscopy, and sensors.