Optical time delay apparatus
First Claim
1. An apparatus responsive to a beam of light from source for providing selectable delay times of said light beam between said source and utilization means, said apparatus comprising:
- means for selectively altering the polarization of said light beam;
means for providing a plurality of optical paths between said source and said utilization means, said paths having different lengths; and
means responsive to the polarization of said light beam for directing said light beam along one of said plurality of paths.
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Accused Products
Abstract
An optical time delay unit for use in an optical phased array beam-steering system includes a switchable polarization rotator in conjunction with Brewster plates and mirrors to form electrically-selectable optical paths of different lengths. The switchable polarization rotator is aligned with the optical beam and is responsive to a control signal for varying the polarization of light passing therethrough. The Brewster plates receive the light passing through the first polarization rotator and are transmissive to a first polarization and reflective of a second. The transmissive and reflective paths are of different lengths, and are recombined at a second Brewster plate. The original polarization may be restored by a second polarization rotator. A plurality of time delay units may be cascaded to permit selection from among many paths of various lengths. In a preferred embodiment, the polarization rotators include liquid crystal cells having nematic phase molecules. Optically-transparent electrodes are formed on the cell windows by an ion implantation process. A planar phased array beam-forming system comprises a plurality of time delay units, illustratively arranged in a 2-by-2 configuration, wherein each unit is illuminated by a corresponding sector of a single light beam.
39 Citations
48 Claims
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1. An apparatus responsive to a beam of light from source for providing selectable delay times of said light beam between said source and utilization means, said apparatus comprising:
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means for selectively altering the polarization of said light beam; means for providing a plurality of optical paths between said source and said utilization means, said paths having different lengths; and means responsive to the polarization of said light beam for directing said light beam along one of said plurality of paths. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus for providing an output beam of light having a selectable time delay, said apparatus comprising:
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source means for generating a beam of substantially collimated light of predetermined polarization; means for selectively altering the polarization of said light beam from said source; means for providing a plurality of optical paths between said source means and said output beam, said paths having different lengths; and means responsive to the polarization of said light beam from said polarization altering means for directing said light beam along one of said plurality of paths. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A phased array optical beamforming system comprising:
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source means for generating a beam of substantially collimated light of predetermined polarization; and a plurality of means for providing selectable delay times of said light beam, each of said plurality of providing means being responsive to a distinct sector of the cross-section of said light beam, said providing means recombining said selectably delayed cross-sectional sectors of said light beam into an output beam, each of said plurality of providing means comprising; (i) means for selectively altering the polarization of the corresponding sector of said light beam; (ii) means for providing a plurality of optical paths between said source means and said output beam, said paths having different lengths; and (iii) means responsive to the polarization of light in the corresponding sector for directing the corresponding sector of said light beam along one of said plurality of paths. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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Specification