By: Aya Zaki, American University in Cairo
The proposed modulator consists of two non-identical hybrid plasmonic waveguides (HPW) vertically coupled through an ultra-thin metal spacer. Each HPW has three main layers in a metal-oxide-semiconductor structure. The lower HPW employs an additional layer of conducting oxide that acts as the active material for electro-optical modulation. A detailed analysis is performed to study the supported modes in the on and off states of the modulator. It is established that the low loss symmetric super-mode guided by the modulator is easily excited by butt coupling to a standard silicon waveguide. The switching mechanism proposed is based on breaking the symmetry of the waveguide and introducing losses resulting in a high extinction ratio while keeping the insertion loss ultra-low.