M x N WAVELENGTH SELECTIVE SWITCH (WSS)

An M×N wavelength-selective switch (WSS) comprising:

• M input ports for launching M input beams, wherein each of the M input beams includes K sub-beams at K wavelength bands, and wherein M and K are integers greater than 1;
• N output ports for outputting K selected sub-beams at the K wavelength bands, wherein N is an integer greater than 1;
• a wavelength-dispersing system, disposed to receive the M input beams from the M input ports, for dispersing the M input beams into the M×K sub-beams;
• a redirecting system including at least one relaying element having optical power, wherein the redirecting system is disposed to receive the M×K sub-beams from the wavelength-dispersing system, and is for redirecting the M×K sub-beams;
• a first switching array of K first reflecting elements, disposed to receive the M×K sub-beams from the redirecting system, for selecting the K selected sub-beams from the M×K sub-beams;
• wherein each of the K first reflecting elements is associated with one wavelength band of the K wavelength bands, is disposed to receive the M sub-beams at that wavelength band, and is for selecting one sub-beam from the M sub-beams at that wavelength band;
• wherein the redirecting system is also disposed to receive the M×K sub-beams from the first switching array, and is also for passing the K selected sub-beams while blocking the (M−1)×K non-selected sub-beams, and for re-imaging only the K selected sub-beams by means of the at least one relaying element;
• a second switching array of K second reflecting elements, disposed to receive the K selected sub-beams from the redirecting system, for routing the K selected sub-beams to the N output ports;
• wherein each of the K second reflecting elements is associated with one wavelength band of the K wavelength bands, is disposed to receive the selected sub-beam at that wavelength band, and is for routing the selected sub-beam at that wavelength band to one output port of the N output ports;
• wherein the redirecting system is also disposed to receive the K selected sub-beams from the second switching array, and is also for redirecting the K selected sub-beams;
• wherein the wavelength-dispersing system is also disposed to receive the K selected sub-beams from the redirecting system, and is also for combining any selected sub-beams that are routed to a same output port of the N output ports;
• and
• wherein the N output ports are disposed to receive the K selected sub-beams from the wavelength-dispersing system.