Switching network for information channels, preferably in the optical frequency range

Claim 1

An optical switching network for selectively interconnecting input channels and output channels through intermediary light beams, comprising an array of light modulators, each of said light modulators comprising a connection for an input channel, means for separately illuminating each of said light modulators with a beam of coherent radiation, each of said light modulators thereby providing a separate output beam of coherent radiation modulated by information on the corresponding channel, an array of photoelectric transducers, each of said photoelectric transducers comprising an output channel, an array of erasable holographic storage elements, means for directing the modulated light beams on to said holographic storage elements, scanning means for deflecting a beam of coherent reference radiation to a plurality of spaced locations, optical means comprising a separate optical element at each of said spaced locations for focussing said reference radiation on a single corresponding hologram of said array of holograms, and for broadening said beam of reference radiation between said separate optical elements and said array of holograms, mask means in the parth of the broadened beam of reference radiation for limiting the transmission path of said beam to a selected number of a plurality of possible transmission paths in the cross-sectional area of said broadened beam of reference radiation whereby the angle with which the coherent reference radiation impinges on said corresponding hologram is selected, the coherent reference radiation and the modulated light beams forming a hologram in said corresponding holographic storage element wherein the angle by which the coherent reference radiation impinged on said corresponding holographic storage element upon readout with said modulated light determines the direction of modulated light emanating from said corresponding holographic storage element, each of said photoelectric transducers being located in the path of the light from said holographic storage elements corresponding to a particular transmission path of said mask means.