In one embodiment, a waveguide lens of the invention has a pair of planar waveguides, e.g., a single-mode waveguide connected to a multimode waveguide. The widths of the two waveguides and the length of the multimode waveguide are selected such that particular mode coupling between the waveguides and multimode interference (MMI) effects in the multimode waveguide cause the latter to output a converging beam of light similar to that produced by a conventional waveguide lens. Advantageously, waveguide lenses of the invention may be used to implement low-loss, low-crosstalk waveguide crossings and/or compact waveguide turns. In addition, waveguide lenses of the invention can be readily and cost-effectively incorporated into waveguide devices designated for large-scale production.