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:
May. 05, 1992
Filed:
Mar. 29, 1991
Jayantilal S Patel, Red Bank, NJ (US);
Bell Communications Research, Inc., Livingston, NJ (US);
Abstract
A tunable dual-polarization liquid-crystal etalon filter, in which a Fabry-Perot cavity is set up between two end reflectors, preferably interference mirrors. A nematic liquid crystal fills a substantial portion of the Fabry-Perot cavity. The alignment layer adjacent to one end of the cavity is dividend into two portions, both of which are homogeneous but which are buffed in orthogonal directions so that they align the liquid crystal parallel to their surfaces but at orthogonal directions to each other. The other alignment layer is homeotropic so that it aligns the liquid crystal perpendicularly to its surface. Electrodes incorporated with each mirror apply a voltage across the liquid crystal so as to change the dielectric constant and thus the effective cavity length for radiation polarized along the alignment direction of the respective homogeneous portion. Because of the orthogonal buffing of the two homogeneous portions, they operate in equal amounts upon the two orthogonal polarizations. An input beam is divided between the two homogeneous portions. Preferably, both substrates upon which the filter is built are birefringent, e.g., calcite, so as to act as a polarization beam splitter and a recombiner.