Optical switching device comprising:a) first elementary switching module which in turn comprises i) a crystalline element without internal planes of separation and which is capable of rotating the plane of polarization of a polarized optical signal by a predetermined angle under the action of an optical control beam, and ii) a polarization analyzer capable of selecting, according to a predetermined plane, the said polarized optical signal issuing from the said crystalline element, b) first means for supplying the said polarized optical signal to the said elementary switching module, and c) second means for supplying the said optical control beam to the said elementary switching module, in which the said first and second means route at least two different polarized optical signals and at least one optical control beam in the said crystalline element such that the said at least one control beam is substantially collinear with and superimposed on the said at least two polarized optical signals.