Phased array beam controller using integrated electro-optic circuits
First Claim
1. An apparatus for controlling a phased array antenna which includes a plurality of antenna elements, comprising:
- an electro-optic substrate;
a plurality of waveguides formed in said substrate, each of said waveguides being capable of simultaneously propagating light signals with orthogonal polarizations;
an input waveguide for inputting into each one of said plurality of waveguides a pair of co-propagating polarized light signals having orthogonal polarizations and offset frequencies;
a plurality of electrodes on said substrate configured to phase shift the signals traveling through each of said plurality of waveguides by a different amount in response to applied voltages, thereby creating phase shifted polarized signals; and
means for combining the phase shifted polarized signals within each one of said plurality of waveguides and propagating said combined signal to one of said plurality of antenna elements.
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Abstract
A photonic device for controlling phased array beam direction includes an electro-optic substrate; a plurality of waveguides formed in the substrate, each of which is capable of simultaneously propagating light signals with orthogonal polarizations; an input waveguide for inputting into each one of the plurality of waveguides a pair of copropagating polarized light signals having orthogonal polarizations and different frequencies; a plurality of electrodes on the substrate configured to phase shift the signals traveling through each waveguide by a different amount in response to applied voltages, thereby creating phase shifted polarized signals; and means for combining the phase shifted polarized signals within each one of the waveguides and propagating these combined signal to an antenna element. The basic operating principle of the invention is based on the differential phase shift between optical waves of orthogonal polarizations traveling in an electro-optic optical waveguide. This differential phase shift is directly proportional to the voltage applied to a control electrode and to the length of that electrode. If the two optical waves are slightly offset in optical frequency, they produce a beat frequency when photodetected whose phase shift equals the optical differential phase shift. An array of such phase shifters forms the basis for the photonic beam controller of the invention.
71 Citations
23 Claims
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1. An apparatus for controlling a phased array antenna which includes a plurality of antenna elements, comprising:
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an electro-optic substrate; a plurality of waveguides formed in said substrate, each of said waveguides being capable of simultaneously propagating light signals with orthogonal polarizations; an input waveguide for inputting into each one of said plurality of waveguides a pair of co-propagating polarized light signals having orthogonal polarizations and offset frequencies; a plurality of electrodes on said substrate configured to phase shift the signals traveling through each of said plurality of waveguides by a different amount in response to applied voltages, thereby creating phase shifted polarized signals; and means for combining the phase shifted polarized signals within each one of said plurality of waveguides and propagating said combined signal to one of said plurality of antenna elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 23)
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10. An apparatus for controlling beam steering of a two dimensional phased array having N rows and M columns of antenna elements comprising:
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an electro-optic substrate; at least N waveguides formed in said substrate, each of said at least N waveguides being capable of simultaneously propagating light signals with orthogonal polarizations; an input waveguide for inputting into each one of said at least N waveguides a pair of co-propagating polarized light signals having orthogonal polarizations and offset frequencies; a first plurality of electrodes on said substrate configured to phase shift the signals traveling through each of said at least N waveguides by a different amount in response to a first set of applied voltages, thereby creating a first set of phase shifted polarized signals; at least (N×
M) waveguides, each of said at least (N×
M) waveguides being capable of simultaneously propagating light signals with orthogonal polarizations;waveguide splitters formed in said substrate for splitting the first set of phase shifted polarized signals from said at least N waveguides into said at least (N×
M) waveguides;a second plurality of electrodes on said substrate configured to phase shift the signals traveling through each of said at least (N×
M) waveguides by a different amount in response to a second set of applied voltages, thereby creating a second set of phase shifted polarized signals; andmeans for combining the phase shifted polarized signals within each one of said at least (N×
M) waveguides and propagating said combined signals to an antenna element. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification