Abstract: The present invention uses a light-pipe for beam splitting, combining, hybrid space-wavelength multiplexing, hybrid space-wavelength demultiplexing, dense wavelength division multiplexing, and dense wavelength division demultiplexing. A light-pipe has a first end where light enters the light-pipe and a second end where the light exits the light-pipe. The light-pipe is a polygonal rod or a hollow reflective cavity. To perform beam splitting, light enters the first end of the light-pipe and reflects off of the side surfaces inside the light-pipe producing additional light beams. By placing an imaging lens at the output end of the light-pipe, all of the virtual images (n-1) of the additional light beams and the original light entering the light-pipe become the object of the imaging lens. As a result, the light-pipe acts as a 1-to-n splitter.