ABSTRACT
Waveguide modulator design and fabrication gives an excellent impression of how rapidly silicon-based photonic components have evolved systematically within the last decades. Firstly, waveguides based on silicon nitride/silicon oxide allowed miniaturization up to tenths of microns. Later, silicon/silicon oxide waveguides could be miniaturized to the submicron regime due to their high refractive index contrast. The modulator is the core device applied in optical cross-connect (OXC) and optical add-drop multiplexing systems; it has great application prospects in the domains of computer and optical communication. The silicon electro-optic modulator based on the plasma dispersion effect is usually composed of two parts: an electrical structure and an optical structure. To change the carrier concentration distribution, many different electrical structures can be used to achieve the injection, accumulation, depletion, and inversion of free carrier, so the refractive index (or absorption coefficient) can be changed correspondingly.
