Abstract: A beam splitter and/or beam combiner is disclosed which in a splitting mode of operation receives an input beam of light and splits the beam into two orthogonally polarized parallel sub-beams of light. The device uses two wedges wherein at least one is birefringent or wherein both are birefringent such as a Wallaston prism, for splitting the input beam into two sub-beams wherein at least one diverges from the other, to provide two diverging beams. Only one or two small crystals are required to do this beam splitting. The two diverging beams are then made parallel by passing them through a prism, such as a roof prism, spaced from the beam splitting prism(s).