Patent ID: 8094979

Claim:
An optical switch, comprising: a plurality of light inputs; a plurality of light outputs; a polarization beam splitter, configured to split light beams received through the input into separate first and second polarization components; a plurality of semi-transparent mirrors and polarization rotators arranged to allow controllable deflection of the first and second polarization components from the beam splitter to a selected one of the light outputs, wherein based on defining: for each of the semi-transparent mirrors through which the first polarization component may pass in the arrangement, a first respective plane as the plane formed by the directions of the possible paths of the first polarization component exiting the semi-transparent mirror in the arrangement, and for each of the semi-transparent mirrors through which the second polarization component may pass in the arrangement, a second respective plane as the plane formed by the directions of the possible paths of the second polarization component exiting the semi-transparent mirror in the arrangement, the one or more first respective planes of most of the semi-transparent mirrors do not coincide with second respective planes; and a controller adapted to control the beam rotators in order that the semi-transparent mirrors deflect beams from desired inputs to desired outputs, wherein the semi-transparent mirrors and polarization rotators are arranged such that the separate polarization components each pass through at least one separately controlled polarization rotator through which the other polarization component does not pass.