Modeling and optimization of grating coupler for slab waveguide

In the following paper, designing, modeling and optimizing an optical coupler based on titanium dioxide TiO₂ is described. A rectangular diffraction grating integrated with a TiO₂ waveguide is modeled. The optimized parameter is the coupling efficiency. The following parameters are also considered: coupler length, grating period, and grating etching depth. Critical values of grating filling factor preventing the coupling of light into the structure are determined. Finally, parameters of a structure showing the best coupling efficiency are presented.