Directing optical beam
First Claim
1. A method of directing a beam of optical radiation toward a selected location, and modulating the intensity thereof at the location, comprisingdirecting the beam over a path that includes a Bragg grating, andselectively modifying the angle between the direction at which the beam enters the Bragg grating and a direction of Bragg incidence of the grating.
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Accused Products
Abstract
Methods and apparatus for directing a beam of optical radiation toward a selected location and modulating the intensity thereof at the location by directing the beam over a path that includes a Bragg grating, and selectively modifying the angle between the direction at which the beam enters the Bragg grating and a direction of Bragg incidence of the grating by applying an electric or acoustic field to change the index of refraction in a portion of the path. An electric field may be applied either by interdigital electrodes at the grating, to change the Bragg angle thereof, or by electrodes at different angles across an earlier portion of the path, to change the direction at which the beam enters the grating. An acoustic field may be applied in an analogous manner. Useful for modulating and switching in planar wave guides and bulk material.
45 Citations
23 Claims
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1. A method of directing a beam of optical radiation toward a selected location, and modulating the intensity thereof at the location, comprising
directing the beam over a path that includes a Bragg grating, and selectively modifying the angle between the direction at which the beam enters the Bragg grating and a direction of Bragg incidence of the grating.
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7. Apparatus for directing a beam of optical radiation toward a selected location, and modulating the intensity thereof at the location, comprising
means for directing the beam over a path that includes a Bragg grating, and means for selectively modifying the angle between the direction at which the beam enters the Bragg grating and a direction of Bragg incidence of the grating.
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22. Apparatus for changing the Bragg angle in a phase grating comprising a material that changes its index of refraction in response to changes in an electric field, comprising a plurality of spaced electrodes adjacent thereto and and means for applying different electric potentials to the electrodes to provide an electric field at the grating and thus to change the average index of refraction therein.
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23. Apparatus for changing the direction of a beam of light in a portion of its path in a planar optical waveguide comprising a material that changes its index of refraction in response to changes in an electric field, comprising a pair of spaced elongate electrodes overlying the path and extending over the path in different directions, and means for applying a different electric potential to each electrode to provide an electric field across the path and thus to change the index of refraction in the portion of the path between the electrodes.
Specification