Si is the irreplaceable substrate materials of microclectronics because it is never used up and the process is mature. Developing the SOC chips of the optical network with Si based materials is an improtant approach to overcome the above mentione difficulties. Si has an indirect gap and it is a kind material of cubic inversionsymmetry, it does not have excellent natural optical characeristics. Artificial modification is the basic approach to break the intrinsic limitation of Si based materials. The combination of gap engineering, nanoengineering,localization engineering, photon engineering and phonon engineering is expected to realize Si based all optical wavelnegth converter,high-speed all optical switch and even Si based laser,which will be the important base for the developing of the SOC chips in the integrated optical netowrk and the opening of the novel subject of Si based integrated photonics.