Fabrication of nanoimprinted curved feature for focusing grating coupler using hydrogen silsesquioxane mold

The nanoimprinted curved features for focusing grating coupler have been fabricated with hydrogen silsesquioxane mold. The minimum gap between the nanoimprinted curved features is 85 nm and the whole device size is 1 mm × 1 mm. The mold without anti-stiction coating did not cause the failure during separation process. The implemented optical device using nanoimprinted curved features have very small spot size and good output coupling efficient of 347 nm and 28.2%, respectively.