To achieve high rejection ratios with a nulling interferometer, the beams to be combined have to be as equal as possible, especially concerning the transverse field distribution. This requires highly symmetric beam recombination stages as well as modal wavefront filtering. Usually co-axial beam recombination employing beam splitters is used, ideally in highly symmetrizing double-pass configurations. Considering that a single-mode waveguide is required anyway for spatial wavefront filtering, it seems reasonable to incorporate the functionalities of beam recombination and modal filtering in a single device. If the beams to be combined are injected multi-axially into the single-mode waveguide, co-axial beam recombination is obtained within the waveguide. We show that such beam recombination stages may outperform conventional symmetric co-axial realizations with respect to optical throughput and system complexity.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.