The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 06, 1981
Filed:
Dec. 19, 1978
William E Richards, Silver Springs, MD (US);
Henry F Taylor, Newbury Park, CA (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
An electro-optical modulator/antenna operates in the tunable diffraction ting mode to vary the magnitude of the zero diffraction order and consequently transmits optical information. A relatively thin slab of lithium niobate or equivalent electro-optic material has its lateral surfaces optically polished and its C-axis, or optical axis, running parallel to the polished lateral surfaces. At least one set of interdigital metallic electrodes are deposited on the face or just within the lateral surfaces to form, among other things, a diffraction grating that is orthogonally disposed with respect to the C-axis. When a potential source is coupled to the interdigital electrodes, the electric fields between adjacent electrodes change the crystal's index of refraction in accordance with the linear transverse Pockel's effect. The thin crystal having the electrodes substantially covering at least one of its lateral surfaces, thusly presents a large aperture modulator/antenna capable of modulating incident optical energy over a wide angle of incidence, for example, up to plus and minus 45 degrees. Because of the thinness of the crystal, transmissivity is good and losses are reduced. The cooperation between the diffraction grating phenomenon and the Pockel's effect greatly reduces if not totally eliminates the possibility of arcing between adjacent electrodes as the zero diffraction order is modulated since the potentials creating the modulating electric fields between adjacent interdigital electrodes are greatly reduced in this mode of operation.