Engineering the optical response of nanostructured silicon

The preceding miniaturization in microelectronics connected with the application of optical signals for information transfer demands siliconbased optical devices. Almost all the various photonic devices integrated on silicon wafer: e.g. silicon based optical waveguides, splitters, couplers, modulators, photonic crystals, detectors, etc. have already been demonstrated. These advances are based on welldeveloped silicon technology such as lithography, selective etching and silicon oxidation. This chapter describes another approach of engineering different silicon-based optical devices: it is based on indepth and in-plane nanostructuring of silicon wafers. In-depth variation of the refractive index is performed via porosification of silicon wafers aiming to achieve the desired spectral response of these devices while in-plane nanostructuring results in their polarization-dependent optical properties.