Patent ID: 7359593

Claim:
An optical chip connectable to a waveguide having a spot size, the optical chip comprising: a substrate; an optical circuit on the substrate; and an optical mode transformer on the substrate and having an input for coupling to the waveguide, and an output coupled to the optical circuit, the optical mode transformer, comprising: a first waveguide layer having a first thickness and being constructed of a high contrast waveguide, the first waveguide layer coupled to the optical circuit; and a second waveguide layer, at least a portion of the second waveguide layer being contiguous with at least a portion of the first waveguide layer, the first and second waveguide layers together forming a composite waveguide having a mode matching section adjacent to the input of the optical mode transformer, the mode matching section having a spot size matching the spot size of the waveguide to capture light from the waveguide, and an adiabatic section in which the second waveguide layer is tapered, with a larger end of the second waveguide layer receiving light from the mode matching section and a mode size of propagating light in the second waveguide layer being reduced along the taper of the second waveguide layer to couple the propagating light into the first waveguide layer and to the optical circuit on the substrate.