Nanosilicon photonics

Silicon photonics is no more an emerging field of research and technology but a present reality with commercial products available on the market, where low dimensional silicon (nanosilicon or nano-Si) can play a fundamental role. After a review of the field, the optical properties of silicon reduced to nanometric dimensions are introduced. The use of nano-Si, in the form of Si nanocrystals, in the main building blocks of silicon photonics (waveguides, modulators, sources and detectors) is reviewed and discussed. Recent advances of nano-Si devices such as waveguides, optical resonators (linear, rings and disks) are treated. Large emphasis is dedicated to the visible optical gain properties of nano-Si and to the sensitization effect on Er ions to achieve infrared light amplifications. The possibility of electrical injection in the light emitting diodes is presented as well as the recent development addressed to exploit nano-Si for solar cells. In addition, nonlinear optical effects which will enable fast all-optical switches are described.