Modulation efficiency optimization of a depletion-type silicon optical modulator utilizing a nano waveguide

A nano size single-mode waveguide for a silicon optical modulator was designed using the effective index method (EIM). The width of the waveguide was 350 nm for single-mode operation and the calculated optical confinement was 95.9%. The waveguide was fabricated on silicon-on-insulator (SOI) using e-beam lithography. The measured optical characteristics of the waveguide showed a propagation loss and optical confinement of 4.46dB/cm and 95.19%, respectively. A silicon optical modulator utilizing this waveguide was estimated to have 9.3 V mm modulation efficiency.