US Patent 7570849 Integrated circuit device having optically coupled layers

In an integrated circuit device comprising a vertical arrangement of integrated circuit layers, coupling of an optical signal between a first integrated circuit layer thereof and a second integrated circuit layer thereof is described. The optical signal is evanescently coupled between a photonic crystal defect waveguide and a photonic crystal defect cavity in the first integrated circuit layer and projectably coupled between the photonic crystal defect cavity and an optical aperture on the second integrated circuit layer.