A planar lens (30) which comprises a slab waveguide (36) and an optical waveguide (33), preferably formed in unitar fashion, wherein the slab waveguide has a curved end face (37) to focus light into or out of the optical waveguide, an wherein at least one additional lens (32) is included within the slab waveguide. The additional lens is either converging or diverging. The additional lens may match the acceptance angle of the optical waveguide to the curved end face of the slab waveguide. Alternatively it may improve the tolerance of the planar lens to design or assembly errors and/or temperature variations. Preferably, the planar lenses are composed of a photo-patternable polymer, and the additional lenses are composed of air.