A light input is divided into a plurality of light outputs by a structure comprising a first beam splitter configured to divide the light input into a first part and a second part, a first polarization beam splitter configured to provide from the first part a first polarized part and a second polarized part, wherein the first polarized part is for providing a first output and the second polarized part for providing a second output, at least one polarization altering device configured to alter the polarization of light in the second part, and at least one second polarization beam splitter configured to receive light altered by respective at least one polarization altering device and provide therefrom at least one third polarized part for providing at least one third output. A light output can be generated based on similar principles in reverse.