Patent ID: 8045854

Claim:
A M×N wavelength selective switch (WSS) module comprising: M input ports each for inputting a light beam having K wavelength channel sub-beams, and N output ports for outputting a light beam, wherein K, M, N are integer numbers larger than unity; a wavelength dispersive element for spatially separating the wavelength channel sub-beams along M spaced apart lines of dispersion, wherein each said line of dispersion corresponds to a particular of the M input ports; a first director array comprising M rows of K directors for directing the wavelength channel sub-beams, wherein each of the M rows is disposed along a particular of the M lines of dispersion, and wherein in each of said M rows, one director is disposed to direct one wavelength channel sub-beam, in dependence upon a control signal applied to that director; an intermediate focal plane, for receiving the wavelength channel sub-beams; wherein the M input ports are optically coupled to the wavelength dispersive element, and the wavelength dispersive element is optically coupled to the first director array and to M locations on the intermediate focal plane, wherein each of said M locations corresponds to a particular of the M input ports, wherein each particular wavelength channel sub-beam has an angle of incidence onto said intermediate focal plane, depending upon a control signal applied to a corresponding director of the first director array, disposed to direct that particular wavelength channel sub-beam; a second director array comprising N directors for directing the wavelength channel sub-beams, wherein each director is optically coupled to a particular of N output ports, for selecting only one of the M input ports to be optically coupled to said particular of the N output ports, in dependence upon control signals applied to the corresponding director of the second director array; a switching coupler for optically coupling any particular wavelength channel sub-beam at any of said M locations on the intermediate focal plane to any one of the N directors of the second director array, depending upon the angle of incidence of that particular wavelength channel sub-beam onto the intermediate plane; whereby any one of the K wavelength channel sub-beams in a particular one of the M input ports is independently switchable into any particular one of the N output ports, in dependence upon control signals applied to corresponding directors of the first and the second director arrays, provided that wavelength channel sub-beams from only one of the M input ports are switchable into the particular one of the N output ports.