Abstract: An interferometer returns parallel beams that are subject to walk-off caused by reflector misalignment for an additional pass through the interferometer optics and thereby eliminates beam walk-off. A return reflector can be a plane mirror that directs returning beams to retrace paths through the interferometer optics to combine and exit along the axis of the input beam. Separation optics can separate the combined beam from the input beam. Alternatively, a return reflector such as an isosceles prism or a trapezoidal prism reflects and offsets returning beams so that the combined beam is offset from the input beam. The return reflector more generally responds to a shift in incident beam position with a matching shift of the reflected beam in contrast to a retroreflector, which shifts a reflected beam in a direction opposite to the shift in the incident beam.