Design of Silicon-Based Slot Waveguide Configurations for Optimum Nonlinear Performance

Two different silicon slot waveguide configurations are thoroughly analyzed to achieve the optimum nonlinear performance. In the slot region, a complementary metal-oxide-semiconductor-compatible material made by silicon nanocrystals embedded in silica (SiO₂) has been considered. This material has demonstrated very promising characteristics for nonlinear applications. The optimum parameters for each configuration are first designed to achieve maximum field confinement in the slot region. Minimum effective areas around 0.1 mum ² are obtained for both configurations. The influence on the field confinement of the variation of the refractive index in the slot region and the variation of the sidewall angle is investigated. In the former, it is shown that the variation of the refractive index in the slot region has a small effect on both slot waveguide configurations. However, the influence of the sidewall angle on the field confinement depends on the configuration chosen