Angled sidewalls in silicon slot waveguides: conformal filling and mode properties

Effect of angled sidewalls on the filling and properties of silicon slot waveguides is discussed. We demonstrate complete filling of slot waveguide structures with oxide material systems using the atomic layer deposition technique and discuss use of various slot filling materials. Properties of the optical modes in angled-sidewall slot waveguides are studied. Enhanced vertical confinement is obtained with certain waveguide parameters. The reduced effective mode area enhances e.g. nonlinear effects in the waveguide. We discuss the use of atomic layer deposition in realization of filled slot waveguides optimized for all-optical functionalities.