Device for modulating light
AssigneeSiemens Aktiengesellschaft
InventorPeter Baues
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Abstract
A device for modulating light characterized by an electro-optical crystal which is either a solid crystal or a liquid crystal having an index of refraction greater than the index of refraction of the substrate on which the crystal is disposed and having a surface opposite the substrate covered with a dielectric material having an index of refraction less than the index of refraction of the crystal. A plurality of strip electrodes are disposed on the layer with adjacent electrodes connected to different terminals to form an interdigital electrode structure. When a modulating voltage is applied to the interdigital electrode structure, electrical fields are created between the electrode strips extending parallel to the direction of light propagation in the crystal to change the index of refraction to cause modulation of the light.
Claims10
A device for modulating polarized light comprising a substrate of material having an index of refraction n.sub.S ;
- an electro-optical crystal of a material having an index of refraction n.sub.K,O >n.sub.S disposed in an integrated manner on a surface of the substrate to form a waveguide, a layer of dielectric intermediary material having an index of refraction n.sub.Z <n.sub.K,O covering a surface of the electro-optical crystal which is opposite to the substrate;
- a plurality of electrode strips disposed on the layer to extend perpendicular to the direction of propagation of light in the waveguide with adjacent strips connected to different poles to form an interdigital electrode structure, each of said strips having a width equal to an integral multiple of .pi. of the propagation phase of the waveguide mode of the electro-optical crystal, and means for applying a voltage to said electrode strips whereby application of a modulation voltage to the interdigital structure creates electrical fields in the crystal extending parallel to the direction of propagation of the light in the crystal to create changes in the index of refraction of the crystal.
Dependencies are inferred from the claim text.