Photonics on a silicon chip could enable a platform for monolithic integration of optics and microelectronics for applications of optical interconnects in which high data streams are required in a small footprint. In this talk I will review the challenges and achievement in the field of silicon photonics. Using highly confined photonic structures one can enhance the electro-optical and non-linearities properties of Silicon and enable ultra-compact and low power photonic components with very low loss. We have recently demonstrated several active components including GHz electro-optic low power switches and modulators, all-optical amplifiers and wavelength converters on silicon.