Briefly, in accordance with one more embodiments, a substrate guided relay comprises a slab guide having an absorbing edge at a first end of the slab guide. An input coupler is disposed on a surface of the slab guide at an angle with respect to a first edge of the slab guide. An output coupler is disposed on the surface at a second end of the slab guide. Light rays that enter the slab guide toward the first end are absorbed by the absorbing edge, and light rays that enter the slab guide toward the output coupler exit the slab guide via the output coupler. The absorbing edge on the first edge of the slab guide allows the input coupler to be placed on the slab guide without regard to alignment of the input coupler with the first end of the slab guide.