Silicon-plus photonics

Silicon photonics has become very popular because of their compatibility with mature CMOS technologies while it is still very difficult to realize various photonic functional devices for realizing large-scale photonic integration by utilizing the material system of pure silicon due to the intrinsic properties of silicon. An effective solution is to develop silicon-plus photonics by introducing other materials to complement the disadvantages of silicon. People have already tried to put various materials on silicon, e.g., metals, III-V semiconductors, group four materials (like Ge, Graphene, etc.), polymer, magnetic-optical materials, liquid crystals, etc. In this way, silicon-plus photonics becomes very powerful and useful for various applications of optical communications as well as optical sensing in the wavelength range from visible light to the mid-infrared light. In this paper, we give a review and discussion on the progresses and future development of silicon-plus photonics, including the structures, devices and applications.