Liquid-crystal planar-waveguide apparatus and method for fast control of polarization and other properties of light
First Claim
Patent Images
1. Polarization controller apparatus, comprising:
- a waveguide that is clad at least partially with at least a first liquid crystal cell and a second liquid crystal cell for guiding a light beam in a propagation vector through the waveguide, each of said cells being responsive to an applied voltage to have variable birefringence with a slow axis oriented parallel to the propagation vector and a fast axis oriented perpendicular to the slow axis; and
first means positioned between the first liquid crystal cell and the second liquid crystal cell for rotating eigenstates of polarization of the light beam.
1 Assignment
0 Petitions
Accused Products
Abstract
A polarization controller includes a plurality of liquid crystal cells positioned as cladding on a waveguide that propagates a beam of light so that the evanescent field extends into the liquid crystal cells, and a ½-wave birefringent retarder for rotating the eigenstates of polarization between the liquid crystal cells. For fast response, the evanescent field preferably extends only into the surface effect region of the liquid crystal cells, where directors in the liquid crystal respond faster to changes in voltages applied across the liquid crystal cells.
53 Citations
41 Claims
-
1. Polarization controller apparatus, comprising:
-
a waveguide that is clad at least partially with at least a first liquid crystal cell and a second liquid crystal cell for guiding a light beam in a propagation vector through the waveguide, each of said cells being responsive to an applied voltage to have variable birefringence with a slow axis oriented parallel to the propagation vector and a fast axis oriented perpendicular to the slow axis; and first means positioned between the first liquid crystal cell and the second liquid crystal cell for rotating eigenstates of polarization of the light beam. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
-
-
33. Polarization controller apparatus, comprising:
-
a waveguide, which is clad at least partially by a plurality of liquid crystal cells so that an evanescent field of a light beam propagated in the waveguide extends into the liquid crystal cells; a birefringent ½
-wave retarder positioned between adjacent ones of the liquid crystal cells and extending across the waveguide for rotating eigenstates of polarization of the light beam between the liquid crystal cells; andmeans for applying variable voltages across the liquid crystal cells for varying birefringence of the liquid crystal cells.
-
-
34. A method of controlling polarization of a light beam, comprising:
-
propagating the light beam in a waveguide that is at least partially clad with at least a first liquid crystal cell and a second liquid crystal cell in such a manner that the light beam'"'"'s evanescent field extends into the first and second liquid crystal cells; actuating the first liquid crystal cell to retard TM mode of the light in the evanescent field; rotating eigenstates of polarization of the light beam that emerges from the first liquid crystal cell; and actuating the second liquid crystal cell to retard TM mode of the light in the evanescent field. - View Dependent Claims (35, 36, 37, 38, 39, 40)
-
-
41. A method of controlling polarization of a light beam, comprising:
-
propagating the light beam through a waveguide that is clad at least partially by at least two liquid crystal cells in such a manner that an evanescent field of the light beam extends only into surface effect regions of the liquid crystal cells; rotating eigenstates of polarization between the liquid crystal cells; and applying voltages across the liquid crystal cells to vary birefringence of the liquid crystal cells as needed to produce a desired polarization in the light beam.
-
Specification