Patent ID: 6931180

Claim:
A coupling device for optically coupling an optical fiber to a planar waveguide comprising: an optical waveguiding structure comprising a segmented guiding portion and a tapered guiding portion, each disposed in a lower refractive index cladding region between the fiber and the planar waveguide; the segmented guiding portion comprising a series of spaced apart segments of lower refractive index material, the segments having longitudinal cross sections substantially equal to the cross section of the fiber core and successive segments having increasing axial thicknesses to present to light from the fiber an effective refractive index increasingly approximating that of the planar waveguide as the light approaches the waveguide; and the tapered guiding portion having a longitudinal cross section adjacent the segmented guiding portion substantially equal to the adjacent segment longitudinal cross sectional area and, between the segmented guiding portion and then planar waveguide core, a tapered region tapering the cross sectional area to approximate that of the waveguide core at an axial position adjacent the waveguide core.