Design of a New Taper for Light Coupling Between a Ridge Waveguide

We propose the design of a new taper to improve light coupling between a photonic-crystal-based W1 waveguide and a ridge waveguide of similar width. The taper design is directly deduced from band structure calculations and allows an adiabatic mode conversion. The comparison between light propagation from the ridge waveguide through the W1 waveguide and through the taper, respectively, shows good improvement of the coupling efficiency