The communications and computing industries are challenged to fasten and enlarge information exchange. The electrical chip routing challenges in the computer industry have driven the interest for silicon photonics. The idea is to integrate photonic circuits into a standard microelectronics process. In this paper we will review the status of the field and report on our progresses. In Trento we are using nanocrystalline silicon to change the dimensionality of silicon so that very fascinating and new optical properties of the material appear. In particular, light emission starts to be a very efficient process in nanostructured silicon and light emitting diodes with high efficiency have been fabricated. We will discuss some of the main research lines. These cover a wide spectral range spanning from visible to infrared. Light sources, modulators, waveguides, logical gates are a few examples of the various photonic devices which have been developed based on silicon nanocrystals.