Interface loss, diffraction loss, and physical sizes of arrayed-waveguide (AWG) devices, such as AWG routers, are reduced via use of an array of asymmetric waveguide couplers that is inserted between arrayed waveguides. The asymmetric waveguide couplers operate to couple leaked optical power back to the arrayed waveguides. A lenslet matrix may also be used to pre-channel portions of an optical wavefront. The lenslet matrix includes lenslet columns that are aligned with gaps between the arrayed waveguides, such that the portions of the optical wavefront are directed towards the arrayed waveguides rather than towards the gaps.