ALD high-k layer grating couplers for single and double slot on-chip SOI photonics

► State of the art grating couplers for horizontal single and double slot waveguides. ► One mask, fully etched structure for high yield applications. ► Atomic layer deposited (ALD) high-k dielectrics forming the low refractive index slot in the waveguides. ► Optical characterization of the ALD high-k materials by spectroscopic ellipsometry. ► An 18.5% measured efficiency for single slot horizontal waveguides.