A planar optical component having a relatively high refractive index waveguide that is capable of being coupled to a standard optical fiber or other standard optical waveguide having a relatively low refractive index waveguide exhibits reduced loss of signal as compared with conventional planar optical components having a high refractive index waveguides. The component includes a waveguide which includes a first waveguide segment having a core material with a first refractive index, and a transition waveguide segment between the first and second waveguide segments. The transition waveguide segment includes a core material with the first refractive index and a core material with the second refractive index. The first and second core materials have an interface that is sloped or tapered at an acute angle. |