Multi-element true time delay shifter for microwave beamsteering and beamforming

• US 5,663,736 A
• Filed: 12/19/1994
• Issued: 09/02/1997
• Est. Priority Date: 12/19/1994
• Status: Expired due to Fees

• Current Assignee: Rockwell International Corporation
• Original Assignee: Rockwell International Corporation
• Inventors: Hong, John H., Webb, Lance L.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): PHAN, DAO LINDA
• Application Number:
  US08/359,268
• Time in Patent Office: 988 Days
• Field of Search: 342/375, 359/298, 359/39, 359/42, 324/76.37, 324/76.35, 250/227.12, 250/201.9
• US Class Current: 342/375
• CPC Class Codes: H01Q 3/2676 Optically controlled phased array
• CPC Class Codes: H01Q 3/2682 Time delay steered arrays
• CPC Class Codes: H01Q 3/46 Active lenses or reflecting arrays

Abstract

In a broad aspect the present invention comprises a multiple element, multi-throw electronic switch for a fiber optical cable network. The multiple element, multi-throw electronic switch includes a bulk media optical deflector angularly controllable by selectable electronic steering signals. At least one multiple element, multi-throw electronic switch is use to construct a true time delay shifter using rows of a plurality of columns of a plurality of beamsteering optical fiber delay lines, all with a specified antenna scanning coherence center.

Distributed beamsteering is performed by selecting from the composite array, subarrays for which a common steering direction cosine can be applied to that subarray. The distributed beamforming is performed by combining elements beamsteered with a common antenna scanning coherence center from an electronically small core fibers with limited available modes into larger core multimode fibers. The distributed beamsteering and distributed beamforming is iterated until all antenna elements in the composite array have been beamsteered into an array with the identical specified antenna scanning coherence center.

The bulk media optical deflector angularly controllable by selectable electronic steering signals has the additional advantage that a plurality of squint-free antenna beamsteering commands can be simultaneously implemented providing a frequency-independent means of antenna beam shaping which necessary for a frequency-independent monopulse processing capability.

Claims

1. A multi-throw electronic switch for a fiber optical cable network, comprising:

a) a bulk media optical deflector comprising a Bragg cell angularly controllable by selectable electronic steering signals, said bulk media optical deflector having a first side for receiving an input optical signal, said input signal being collimated to a degree necessary for Bragg deflection and for being re-imagable, and a second side for transmitting at least one collimated electronically selectable output optical signal;

b) first positioning means for precision positioning of a primary optical fiber positioned near said first side of said bulk media optical deflector;

c) collimating means positioned between said first positioning means and said first side of said bulk media optical deflector for receiving said input optical signal, collimating said input optical signal and directing said input optical signal to said first side of said bulk media optical deflector;

,

d) second positioning means for precision positioning of a column of a plurality of secondary optical fibers positioned near said second side of said bulk media optical deflector;

e) imaging means positioned between said second side of said bulk media optical deflector and said second positioning means for receiving said at least one output optical signal from said bulk media optical deflector, imaging said output signal and directing said output optical signal to said secondary optical fibers; and

,

f) means for providing said selectable electronic steering signals, wherein selecting a desired electronic steering signal provides selection of a desired set of said second optical fibers.

2. A multi-element, multi-throw electronic switch for a fiber optical cable network, comprising:

a single bulk media optical deflector angularly controllable by selectable electronic steering signals, said bulk media optical deflector having a first side for receiving a plurality of input optical signals, said plurality of input signals being collimated to a degree necessary for Bragg deflection and for being re-imagable, and a second side for transmitting at least one collimated electronically selectable output optical signal;

b) first positioning means for precision positioning of a plurality of primary optical fibers positioned near said first side of said bulk media optical deflector;

c) collimating means positioned between said first positioning means and said first side of said bulk media optical deflector for receiving said plurality of input optical signals, collimating said plurality of input optical signals and directing said plurality of input optical signals to said first side of said bulk media optical deflector,

d) second positioning means for precision positioning of a plurality of columns of a plurality of secondary optical fibers positioned near said second side of said bulk media optical deflector;

e) imaging means positioned between said second side of said bulk media optical deflector and said second positioning means for receiving said at least one output optical signal from said bulk media optical deflector, imaging said output signal and directing said output optical signal to said secondary optical fibers; and

,

f) means for providing said selectable electronic steering signals, wherein selecting a desired electronic steering signal provides selection of a desired set of said secondary optical fibers.

3. A true time-delay (TTD) shifter, comprising:

a pair of back-to-back multi-throw electronic switches, each switch comprising;

a) a single bulk media optical deflector angularly controllable by selectable electronic steering signals, said bulk media optical deflector having a first side for receiving an input optical signal, said input signal being collimated to a degree necessary for Bragg deflection and for being re-imagable, and a second side for transmitting at least one collimated electronically selectable output optical signal;

b) first positioning means for precision positioning of a primary optical fiber positioned near said first side of said bulk media optical deflector;

c) collimating means positioned between said first positioning means and said first side of said bulk media optical deflector for receiving said input optical signal, collimating said input optical signals and directing said input optical signals to said first side of said bulk media optical deflector;

d) second positioning means for precision positioning of a column of a plurality of secondary optical fibers positioned near said second side of said bulk media optical deflector;

e) imaging means positioned between said second side of said bulk media optical deflector and said second positioning means for receiving said at least one output optical signal from said bulk media optical deflector, imaging said output signal and directing said output optical signal to said secondary optical fibers; and

,

f) means for providing said selectable electronic steering signals, wherein selecting a desired electronic steering signal provides selection of a desired set of said secondary optical fibers; and

beamsteering optical fiber delay lines for connecting said switches, said delay lines being connected on each said column of said plurality of secondary optical fibers.

4. A multi-element, true time-delay (TTD) shifter, comprising:

a pair of back-to-back, multi-element multi-throw electronic switches, each switch comprising;

a) a single bulk media optical deflector angularly controllable by selectable electronic steering signals, said bulk media optical deflector having a first side for receiving an input optical signal, said input signal being collimated to a degree necessary for Bragg deflection and for being re-imagable, and a second side for transmitting at least one collimated electronically selectable output optical signal;

b) first positioning means for precision positioning of a row of a plurality of primary optical fibers positioned near said first side of said bulk media optical deflector;

c) collimating means positioned between said first positioning means and said first side of said bulk media optical deflector for receiving said plurality of input optical signals, collimating said plurality of input optical signals and directing said plurality of input optical signals to said first side of said bulk media optical deflector;

d) second positioning means for precision positioning of a plurality of columns of a plurality of secondary optical fibers positioned near said second side of said bulk media optical deflector;

e) imaging means positioned between said second side of said bulk media optical deflector and said second positioning means for receiving said at least one output optical signal from said bulk media optical deflector, imaging said output signal and directing said output optical signal to said secondary optical fibers; and

,

f) means for providing said selectable electronic steering signals, wherein selecting a desired electronic steering signal provides selection of a desired set of said secondary optical fibers; and

a plurality of columns, each having a plurality of beamsteering optical fiber delay lines, each said delay line being connected on a first end to an associated secondary optical fibers of a first of said pair of electronic multi-throw switches and being connected on a second end to associated secondary optical fibers of a second of said pair of electronic multi-throw switches.

5. The multiple element TTD shifter of claim 4, wherein a row of said plurality of columns of a plurality of beamsteering optical fiber delay lines, comprise the TTD control for a specific far field antenna beam pointing squint-free in 3-dimensional space.

6. The multiple element TTD shifter of claim 4, wherein a plurality of rows of said plurality of said columns, each having of a plurality of beamsteering optical fiber delay lines, comprise the TTD control for a plurality of far field antenna beams pointing squint-free in 3-dimensional space with a common antenna scanning coherence center.

7. A re-entrant true time-delay (TTD) shifter, comprising:

a multi-throw electronic switch comprising;

a) a bulk media optical deflector angularly controllable by selectable electronic steering signals, said bulk media optical deflector having a first side for receiving an input optical signal and transmitting an output signal, said input optical signal being collimated to a degree necessary for Bragg deflection and for being re-imagable and said output optical signal being collimated to a degree necessary for being re-imagable, and a second side for transmitting at least one collimated electronically selectable output optical signal and for receiving at least one input optical signal;

b) first positioning means for precision positioning of at least one primary optical fiber positioned near said first side of said bulk media optical deflector, said primary optical fiber guides at least one input optical signal and at least one output optical signal;

c) collimating and imaging means positioned between said first positioning means and said first side of said bulk media optical deflector for receiving said input optical signal from said first positioning means, collimating said input optical signals and directing said input optical signal to said first side of said bulk media optical deflector, and for receiving said at least one output optical signal from said bulk media optical deflector, imaging said output signal and directing said output optical signal to said primary optical fibers;

d) second positioning means for precision positioning of a column of a plurality of secondary optical fibers positioned near said second side of said bulk media optical deflector, said column of a plurality of secondary optical fibers guides at least one output optical signal and at least one input optical signal;

e) imaging and collimating means positioned between said second side of said bulk media optical deflector and said second positioning means for receiving said at least one output optical signal from said bulk media optical deflector, imaging said output signal and directing said output optical signal to said secondary optical fibers and for receiving said input optical signal from said second positioning means, collimating said input optical signals and directing said input optical signal to said second side of said bulk media optical deflector; and

,

f) means for providing said selectable electronic steering signals, wherein selecting a desired electronic steering signal provides selection of a desired set of said secondary optical fibers;

beamsteering optical fiber delay lines, said delay lines being connected on first ends thereof to said column of said plurality of secondary optical fibers, second ends of said delay lines having highly reflecting coatings formed thereon for reflecting and redirecting said input optical signal in the reverse direction back through the multi-throw electronic switch to the fibers in said first positioning means; and

a circulator with at least three ports to separate said input optical signal from said output optical signal.

8. A loop-back true time-delay (TTD) shifter, comprising:

a multi-throw electronic switch comprising;

a) a bulk media optical deflector angularly controllable by selectable electronic steering signals, said bulk media optical deflector having a first side for receiving an input optical signal and transmitting an output signal, said input optical signal being collimated to a degree necessary for Bragg deflection and for being re-imagable and said output optical being collimated to a degree necessary for being re-imagable, and a second side for transmitting at least one collimated electronically selectable output optical signal and for receiving at least one input optical signal;

b) first positioning means for precision positioning a row of a plurality of primary optical fibers positioned near said first side of said bulk media optical deflector, said primary optical fibers guide at least one input optical signal and at least one output optical signal;

c) collimating and imaging means positioned between said first positioning means and said first side of said bulk media optical deflector for receiving said input optical signal from said first positioning means, collimating said input optical signals and directing said input optical signal to said first side of said bulk media optical deflector, and for receiving said at least one output optical signal from said bulk media optical deflector, imaging said output signal and directing said output optical signal to said primary optical fibers;

d) second positioning means for precision positioning a plurality of columns of a plurality of secondary optical fibers positioned near said second side of said bulk media optical deflector;

e) imaging and collimating means positioned between said second side of said bulk media optical deflector and said second positioning means for receiving said at least one output optical signal from said bulk media optical deflector, imaging said output signal and directing said output optical signal to said secondary optical fibers and for receiving said input optical signal from said second positioning means, collimating said input optical signals and directing said input optical signal to said second side of said bulk media optical deflector; and

,

f) means for providing said selectable electronic steering signals, wherein selecting a desired electronic steering signal provides selection of a desired set of said secondary optical fibers; and

beamsteering optical fiber delay lines, said delay lines each being connected on first end to each said column of said plurality of secondary optical fibers guiding output optical signals; and

each beamsteering optical fiber delay line being looped-back for the second end of said beamsteering optical fiber delay lines to be connected to said column of said plurality of secondary optical fibers in the second positioning means guiding input optical signals, redirecting said input optical signal in the reverse direction back through the multi-throw electronic switch to the fibers in said first positioning means;

wherein, said output optical signal is propagated on a separate and distinct fiber in the first positioning means.

9. A re-entrant multiple element true time-delay (TTD) shifter, comprising:

a multiple element multi-throw electronic switch comprising;

a) a bulk media optical deflector angularly controllable by selectable electronic steering signals, said bulk media optical deflector having a first side for receiving a row of a plurality of input optical signals and transmitting an output signal, said row of a plurality of input optical signals being collimated to a degree necessary for Bragg deflection and for being re-imagable and said output optical signal being collimated to a degree necessary for being re-imagable, and a second side for transmitting at least one collimated electronically selectable output optical signal and for receiving a row of a plurality of input optical signals;

b) first positioning means for precision positioning of at row of a plurality of primary optical fibers positioned near said first side of said bulk media optical deflector, said a row of a plurality of primary optical fibers guide said row of said plurality of input optical signals and said row of said plurality of output optical signals;

c) collimating and imaging means positioned between said first positioning means and said first side of said bulk media optical deflector for receiving said input optical signal from said first positioning means, collimating said row of said plurality of input optical signals and directing said row of said plurality of input optical signals to said first side of said bulk media optical deflector, and for receiving said row of said plurality of output optical signals from said bulk media optical deflector, imaging said row of said plurality of output signals and directing said row of said plurality of output optical signal to said primary optical fibers;

d) second positioning means for precision positioning of a row of said plurality of columns of a plurality of secondary optical fibers positioned near said second side of said bulk media optical deflector, said row of said plurality of columns of a plurality of secondary optical fibers guides said row of said plurality of output optical signals and said row of said plurality of input optical signals;

e) imaging and collimating means positioned between said second side of said bulk media optical deflector and said second positioning means for receiving said row of said plurality of output optical signals from said bulk media optical deflector, imaging said row of said plurality of output signals and directing said row of said plurality of output optical signal to said secondary optical fibers and for receiving said row of said plurality of input optical signals from said second positioning means, collimating said row of said plurality of input optical signals and directing said row of said plurality of input optical signals to said second side of said bulk media optical deflector; and

,

f) means for providing said selectable electronic steering signals, wherein selecting a desired electronic steering signal provides selection of a desired set of said secondary optical fibers;

beamsteering optical fiber delay lines, said delay lines being connected on a first ends thereof to said row of said plurality of columns of said plurality of secondary optical fibers, second ends of said beamsteering optical delay lines having highly reflecting coatings formed thereon for reflecting and redirecting said row of said plurality of columns of said plurality of optical signals in the reverse direction back through the multiple element, multi-throw electronic switch to the fibers in said first positioning means; and

a plurality of circulators with at least three ports to separate said row of said plurality of input optical signals from said row of said plurality of output optical signals.