Chip-to-chip optical interconnection using high refractive index couplers

Abstract

A method for establishing optical coupling between spatially separated first and second planar waveguides includes arranging an optical interconnect on the first planar waveguide. The optical interconnect has first and second end portions and an intermediate portion. Each of the end portions has an inverse taper. The second planar waveguide is arranged on the optical interconnect so that the second planar waveguide overlaps with one of the inverse tapered end portions but not the other inverse tapered end portion to thereby enable an adiabatic transition of an optical signal from the first planar waveguide to the second planar waveguide via the optical interconnect. The first and second planar waveguides have different refractive indices at an operating wavelength and the optical interconnect have a higher refractive index at the operating wavelength than the refractive indices of a core of the first planar waveguide and a core of the second planar waveguide.