Patent ID: 6785442
Filing Date: 2004-08-31
Classification: H04Q

Abstract:
A selective routing device adapted to operate on a wavelength division multiplexed (WDM) optical signal, said WDM optical signal comprising a plurality of component signals at respective different wavelengths, the selective routing device being adapted to route said component signals selectively and comprising:diffraction means, said diffraction means being adapted to receive optical signals and produce therefrom diffracted optical signals corresponding to a plurality of orders of diffraction including an mth order of diffraction, diffracted optical signals of consecutive orders of diffraction being spaced apart from each other by a spacing (D); first input means for making said WDM optical signal incident on said diffraction means whereby to cause a first diffracted optical signal, corresponding to an mth order of diffraction, to be produced by the diffraction means, said first diffracted optical signal comprising a plurality of first component signals at respective different wavelengths and at respective first locations, adjacent first locations being spatially separated from one another by a separation (a); selection means for selecting, from among said plurality of first component signals, one or more second component signals at respective different wavelengths, the remaining first component signal(s) constituting third component signal(s); second input means for making said one or more second component signals incident on said diffraction means, said second input means being adapted to present said one or more second component signals to said diffraction means at respective second locations, said second locations being spatially separated from one another and offset from said first locations, said second locations being selected to cause production of a second diffracted optical signal comprising said one or more second component signals wavelength division multiplexed together; and a main output for outputting said second diffracted optical signal; wherein said second diffracted optical signal does not correspond to the mth order of diffraction.