Compact and efficient silicon nanowire to slot waveguide coupler

We propose a Y-branch coupler to efficiently transfer light from a silicon nanowire waveguide to a slot waveguide. The coupler is 500 nm long and functions with greater than 90 % efficiency over a 200 nm bandwidth when operated either in air or solvent. Its versatility makes it a good candidate for photonic circuits with applications including sensing, nonlinear optics and information processing.