Optical properties of polymerized polyethylene layers deposited on glass substrates by PECVD technique at different radio frequency powers are studied through transmission and reflection spectra. Analysis of the experimental spectra by using conventional classic models which permit the determination of optical constants as the refractive index n, the dielectric permittivity \epsilon, the extinction k and absorption coefficients α which leads to the optical parameters characterizing the layers such as static refractive index ns,permittivity \epsilons, plasmon frequency ωp, carrier density to effective mass ratio N/m*e,optical conductivity σop, optical band gap Eg and dispersion diffusion energies E0 and Ed. These different values permit to select the suitable power for elaborate layers with performant properties for various applications in the field of communication, electrical isolation, and miniaturized optoelectronics and sensors devices. \textcopyright 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.