M X N WSS with reduced optics size

A wavelength selective switch module comprising:

• a first plurality of ports;
• a first beam relayer including first and second elements having optical power, the first beam relayer for forcing light beams launched from or to the first plurality of ports to intersect at a common point, the first and second elements having optical power disposed such that light transmitted from the first plurality of ports is substantially focused at a first plane, the common point optically disposed between the first and second elements having optical power, the common point spatially separated from the first plane;
• a wavelength dispersive element for spatially separating a multiplexed beam of light into a plurality of wavelength channel sub-beams;
• a first switching array including a first plurality of switching elements, each switching element in the first switching array for redirecting a different wavelength channel sub-beam transmitted from the wavelength dispersive element at a predetermined angle;
• a second beam relayer for relaying light between the first plane, the wavelength dispersive element, and the first switching array, the second beam relayer including at least one element having optical power;
• and
• a second switching array including a second plurality of switching elements, each switching element in the second switching array for redirecting light to or from a second other plurality of ports;
• wherein the second switching array is disposed about the common point such that light propagating in a first propagating direction towards the first plane circumvents the switching elements in the second switching array, whereas light propagating in a second opposite propagating direction is redirected by the switching elements in the second switching array in dependence upon an angle at which it was redirected away from the first switching array.