Abstract

An adaptive null-steering phased-array optical processor that utilizes a photorefractive crystal to time integrate the adaptive weights and null out correlated jammers is described. This is a beam-steering processor in which the temporal waveform of the desired signal is known but the look direction is not. The processor computes the angle(s) of arrival of the desired signal and steers the array to look in that direction while rotating the nulls of the antenna pattern toward any narrow-band jammers that may be present. We have experimentally demonstrated a simplified version of this adaptive phased-array-radar processor that nulls out the narrow-band jammers by using feedback-correlation detection. In this processor it is assumed that we know a priori only that the signal is broadband and the jammers are narrow band. These are examples of a class of optical processors that use the angular selectivity of volume holograms to form the nulls and look directions in an adaptive phased-array-radar pattern and thereby to harness the computational abilities of three-dimensional parallelism in the volume of photorefractive crystals. The development of this processing in volume holographic system has led to a new algorithm for phased-array-radar processing that uses fewer tapped-delay lines than does the classic time-domain beam former. The optical implementation of the new algorithm has the further advantage of utilization of a single photorefractive crystal to implement as many as a million adaptive weights, allowing the radar system to scale to large size with no increase in processing hardware.

© 1996 Optical Society of America

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  31. P. W. Howells, “Exploration in fixed and adaptive resolution at GE and SURC,” IEEE Trans. Antennas Propag. AP-24, 575–584 (1976).
  32. S. P. Applebaum, “Adaptive arrays,” IEEE Trans. Antennas Propag. AP-24, 585–598 (1976).
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  34. P. Yeh, “Two-wave mixing in nonlinear media,” IEEE J. Quantum Electron. 25, 484–518 (1989).
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  36. A. Gabel, L. S. Lee, I. C. Chang, “Front-end RF channelization using optical techniques,” in Optical Technology for Microwave Applications, S. K. Yao, ed., Proc. Soc. Photo-Opt. Instrum. Eng.477, 150–154 (1984).
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  40. L. H. Gesell, R. E. Feinleib, J. L. Lafuse, T. M. Turpin, “Acousto-optic control of time delays for array beam steering,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Eng.2155, 194–204 (1994).
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1993 (1)

R. D. Esman, M. Y. Fankel, J. L. Dexter, L. G. G., M. G. Parent, D. Stilwell, D. G. Cooper, “Fiber-optic prism true time-delay antenna feed,” IEEE Photon. Technol. Lett. 5, 1347–1349 (1993).

1992 (2)

W. S. Birkmayer, M. J. Wale, “Proof-of-concept model of a coherent optical beam-forming network,” Inst. Electr. Eng. Part Proc. J 139, 301–304 (1992).

M. Volker, “Coherent all-fibre optical beam-steering technique for phased-array antennas,” Inst. Electr. Eng. Part Proc. J 139, 305–308 (1992).

1991 (1)

1990 (1)

1989 (2)

P. Yeh, “Two-wave mixing in nonlinear media,” IEEE J. Quantum Electron. 25, 484–518 (1989).

M. Kam, J. Wilcox, P. R. Herczfeld, “Design for steering accuracy in antenna arrays using shared optical phase shifters,” IEEE Trans. Antennas Propag. 37,1102–1108 (1989).

1983 (2)

J. F. Rhodes, “Adaptive filter with a time-domain implementation using correlation cancellation loops,” Appl. Opt. 22, 282–287 (1983).

G. C. Valley, M. B. Klein, “Optimal properties of photore- fractive materials for optical data processing,” Opt. Eng. 22, 706–711 (1983).

1982 (1)

L. J. Griffiths, C. W. Jim, “An alternative approach to linearly constrained adaptive beamforming,” IEEE Trans. Antennas Propag. AP-30, 27–34 (1982).

1979 (1)

1976 (2)

P. W. Howells, “Exploration in fixed and adaptive resolution at GE and SURC,” IEEE Trans. Antennas Propag. AP-24, 575–584 (1976).

S. P. Applebaum, “Adaptive arrays,” IEEE Trans. Antennas Propag. AP-24, 585–598 (1976).

1968 (1)

D. Gabor, G. W. Stroke, “The theory of deep holograms,” Proc. R. Soc. London Ser. A 304, 275–289 (1968).

1967 (1)

B. Widrow, P. E. Mantey, L. J. Griffiths, B. B. Goode, “Adaptive antenna systems,” Proc. IEEE 55, 2143–2159 (1967).

Aimette, A.

L. B. Lambert, M. Arm, A. Aimette, “Electro-optical signal processing for phased-array antennas,” in Optical and Electro-Optic Information Processing, J. Tippett, ed. (MIT, Cambridge, Mass., 1965).

Alexander, E. M.

E. M. Alexander, R. W. Gammon, “The Fabry–Perot etalon as an RF frequency channelizer,” in Solid State Optical Control Devices, P. Yeh, ed., Proc. Soc. Photo-Opt. Instrum. Eng.464, 45–52 (1984).

Applebaum, S. P.

S. P. Applebaum, “Adaptive arrays,” IEEE Trans. Antennas Propag. AP-24, 585–598 (1976).

Arm, M.

L. B. Lambert, M. Arm, A. Aimette, “Electro-optical signal processing for phased-array antennas,” in Optical and Electro-Optic Information Processing, J. Tippett, ed. (MIT, Cambridge, Mass., 1965).

Bader, T. R.

Birkmayer, W. S.

W. S. Birkmayer, M. J. Wale, “Proof-of-concept model of a coherent optical beam-forming network,” Inst. Electr. Eng. Part Proc. J 139, 301–304 (1992).

Boughton, R.

S. Lin, J. Hong, R. Boughton, D. Psaltis, “Broad-band beamforming via acousto-optics,” in Advances in Optical Information Processing III, D. Pape, ed., Proc. Soc. Photo-Opt. Instrum. Eng.936, 152–162 (1988).

Carroll, C. W.

C. W. Carroll, B. V. K. V. Kumar, “Adaptive phased aray radar processing on a multichannel acousto-optic linear algebra system: experimental results,” in Optoelectronic Signal Processing for Phased-Array Antennas, K. Bhasin, B. Hendrickson, eds., Proc. Soc. Photo-Opt. Instrum. Eng.886, 203–213 (1988).

Chang, I. C.

A. Gabel, L. S. Lee, I. C. Chang, “Front-end RF channelization using optical techniques,” in Optical Technology for Microwave Applications, S. K. Yao, ed., Proc. Soc. Photo-Opt. Instrum. Eng.477, 150–154 (1984).

Compton, R. T.

R. T. Compton, Adaptive Antennas (Prentice-Hall, Engle-wood Cliffs, N.J., 1988), Chap. 2.

Cooper, D. G.

R. D. Esman, M. Y. Fankel, J. L. Dexter, L. G. G., M. G. Parent, D. Stilwell, D. G. Cooper, “Fiber-optic prism true time-delay antenna feed,” IEEE Photon. Technol. Lett. 5, 1347–1349 (1993).

Dexter, J. L.

R. D. Esman, M. Y. Fankel, J. L. Dexter, L. G. G., M. G. Parent, D. Stilwell, D. G. Cooper, “Fiber-optic prism true time-delay antenna feed,” IEEE Photon. Technol. Lett. 5, 1347–1349 (1993).

Esman, R. D.

R. D. Esman, M. Y. Fankel, J. L. Dexter, L. G. G., M. G. Parent, D. Stilwell, D. G. Cooper, “Fiber-optic prism true time-delay antenna feed,” IEEE Photon. Technol. Lett. 5, 1347–1349 (1993).

Fankel, M. Y.

R. D. Esman, M. Y. Fankel, J. L. Dexter, L. G. G., M. G. Parent, D. Stilwell, D. G. Cooper, “Fiber-optic prism true time-delay antenna feed,” IEEE Photon. Technol. Lett. 5, 1347–1349 (1993).

Farden, D. C.

L. L. Scharf, D. C. Farden, “Optimum and adaptive array processing in frequency-wavenumber space,” in USAG/NUSC Workshop on Multidimensional Analysis of Acoustic Fields (Department of Commerce, Washington, D.C., 1973), available from National Technical Information Service, Springfield, Va., order no. CSCL20/1.

Feinleib, R. E.

L. H. Gesell, R. E. Feinleib, J. L. Lafuse, T. M. Turpin, “Acousto-optic control of time delays for array beam steering,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Eng.2155, 194–204 (1994).

G., L. G.

R. D. Esman, M. Y. Fankel, J. L. Dexter, L. G. G., M. G. Parent, D. Stilwell, D. G. Cooper, “Fiber-optic prism true time-delay antenna feed,” IEEE Photon. Technol. Lett. 5, 1347–1349 (1993).

Gabel, A.

A. Gabel, L. S. Lee, I. C. Chang, “Front-end RF channelization using optical techniques,” in Optical Technology for Microwave Applications, S. K. Yao, ed., Proc. Soc. Photo-Opt. Instrum. Eng.477, 150–154 (1984).

Gabor, D.

D. Gabor, G. W. Stroke, “The theory of deep holograms,” Proc. R. Soc. London Ser. A 304, 275–289 (1968).

Gammon, R. W.

E. M. Alexander, R. W. Gammon, “The Fabry–Perot etalon as an RF frequency channelizer,” in Solid State Optical Control Devices, P. Yeh, ed., Proc. Soc. Photo-Opt. Instrum. Eng.464, 45–52 (1984).

Gesell, L. H.

L. H. Gesell, R. E. Feinleib, J. L. Lafuse, T. M. Turpin, “Acousto-optic control of time delays for array beam steering,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Eng.2155, 194–204 (1994).

Goode, B. B.

B. Widrow, P. E. Mantey, L. J. Griffiths, B. B. Goode, “Adaptive antenna systems,” Proc. IEEE 55, 2143–2159 (1967).

Griffiths, L. J.

L. J. Griffiths, C. W. Jim, “An alternative approach to linearly constrained adaptive beamforming,” IEEE Trans. Antennas Propag. AP-30, 27–34 (1982).

B. Widrow, P. E. Mantey, L. J. Griffiths, B. B. Goode, “Adaptive antenna systems,” Proc. IEEE 55, 2143–2159 (1967).

Grinev, A. I.

D. I. Voskresenskii, A. I. Grinev, E. N. Voronin, Electrooptical Arrays (Springer-Verlag, New York, 1989).

Herczfeld, P. R.

M. Kam, J. Wilcox, P. R. Herczfeld, “Design for steering accuracy in antenna arrays using shared optical phase shifters,” IEEE Trans. Antennas Propag. 37,1102–1108 (1989).

Hong, J.

D. Psaltis, J. Hong, “Adaptive acoustooptic processor,” in Analog Optical Processing and Computing, H. J. Caulfield, ed., Proc. Soc. Photo-Opt. Instrum. Env.519, 62–68 (1984).

S. Lin, J. Hong, R. Boughton, D. Psaltis, “Broad-band beamforming via acousto-optics,” in Advances in Optical Information Processing III, D. Pape, ed., Proc. Soc. Photo-Opt. Instrum. Eng.936, 152–162 (1988).

Howells, P. W.

P. W. Howells, “Exploration in fixed and adaptive resolution at GE and SURC,” IEEE Trans. Antennas Propag. AP-24, 575–584 (1976).

Iodice, R. M.

W. A. Penn, R. Wasiewicz, R. M. Iodice, “Optical adaptive multipath canceller for surveillance radar,” in Optoelectronic Signal Processing for Phased-Array Antennas II, B. Hendrickson, G. Koepf, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1217, 151–160 (1990).

Jim, C. W.

L. J. Griffiths, C. W. Jim, “An alternative approach to linearly constrained adaptive beamforming,” IEEE Trans. Antennas Propag. AP-30, 27–34 (1982).

Kam, M.

M. Kam, J. Wilcox, P. R. Herczfeld, “Design for steering accuracy in antenna arrays using shared optical phase shifters,” IEEE Trans. Antennas Propag. 37,1102–1108 (1989).

Keefer, C. W.

C. W. Keefer, J. E. Malowicki, P. M. Payson, “Wideband operation of a photorefractive based adaptive processor,” in Analog Photonics, A. Pirich, P. Sierak, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1790, 145–156 (1992).

Klein, M. B.

G. C. Valley, M. B. Klein, “Optimal properties of photore- fractive materials for optical data processing,” Opt. Eng. 22, 706–711 (1983).

Krainak, M.

D. R. Pape, P. Wasilousky, M. Krainak, “A high performance apodized phased array Bragg cell,” in Optical Technology for Microwave Applications III, S. K. Yao, ed., Proc. Soc. Photo-Opt. Instrum. Eng.789, 117–126 (1987).

Kumar, B. V. K. V.

C. W. Carroll, B. V. K. V. Kumar, “Adaptive phased aray radar processing on a multichannel acousto-optic linear algebra system: experimental results,” in Optoelectronic Signal Processing for Phased-Array Antennas, K. Bhasin, B. Hendrickson, eds., Proc. Soc. Photo-Opt. Instrum. Eng.886, 203–213 (1988).

Lafuse, J. L.

L. H. Gesell, R. E. Feinleib, J. L. Lafuse, T. M. Turpin, “Acousto-optic control of time delays for array beam steering,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Eng.2155, 194–204 (1994).

Lambert, L. B.

L. B. Lambert, M. Arm, A. Aimette, “Electro-optical signal processing for phased-array antennas,” in Optical and Electro-Optic Information Processing, J. Tippett, ed. (MIT, Cambridge, Mass., 1965).

Lange, M. R.

Lee, L. S.

A. Gabel, L. S. Lee, I. C. Chang, “Front-end RF channelization using optical techniques,” in Optical Technology for Microwave Applications, S. K. Yao, ed., Proc. Soc. Photo-Opt. Instrum. Eng.477, 150–154 (1984).

Lin, S.

S. Lin, J. Hong, R. Boughton, D. Psaltis, “Broad-band beamforming via acousto-optics,” in Advances in Optical Information Processing III, D. Pape, ed., Proc. Soc. Photo-Opt. Instrum. Eng.936, 152–162 (1988).

Malowicki, J. E.

C. W. Keefer, J. E. Malowicki, P. M. Payson, “Wideband operation of a photorefractive based adaptive processor,” in Analog Photonics, A. Pirich, P. Sierak, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1790, 145–156 (1992).

Mantey, P. E.

B. Widrow, P. E. Mantey, L. J. Griffiths, B. B. Goode, “Adaptive antenna systems,” Proc. IEEE 55, 2143–2159 (1967).

Montgomery, R. M.

R. M. Montgomery, M. R. Lange, “Photorefractive adaptive filter structure with 40-dB interference rejection,” Appl. Opt. 30, 2844–2849 (1991).

R. M. Montgomery, “Acousto-optic/photorefractive processor for adaptive antenna arrays,” in Optoelectronic Signal Processing for Phased-Array Antennas II, B. Hendrickson, G. Koepf, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1217, 207–217 (1990.

Pape, D. R.

D. R. Pape, P. Wasilousky, M. Krainak, “A high performance apodized phased array Bragg cell,” in Optical Technology for Microwave Applications III, S. K. Yao, ed., Proc. Soc. Photo-Opt. Instrum. Eng.789, 117–126 (1987).

Parent, M. G.

R. D. Esman, M. Y. Fankel, J. L. Dexter, L. G. G., M. G. Parent, D. Stilwell, D. G. Cooper, “Fiber-optic prism true time-delay antenna feed,” IEEE Photon. Technol. Lett. 5, 1347–1349 (1993).

Payson, P. M.

C. W. Keefer, J. E. Malowicki, P. M. Payson, “Wideband operation of a photorefractive based adaptive processor,” in Analog Photonics, A. Pirich, P. Sierak, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1790, 145–156 (1992).

Penn, W. A.

W. A. Penn, R. Wasiewicz, R. M. Iodice, “Optical adaptive multipath canceller for surveillance radar,” in Optoelectronic Signal Processing for Phased-Array Antennas II, B. Hendrickson, G. Koepf, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1217, 151–160 (1990).

Psaltis, D.

S. Lin, J. Hong, R. Boughton, D. Psaltis, “Broad-band beamforming via acousto-optics,” in Advances in Optical Information Processing III, D. Pape, ed., Proc. Soc. Photo-Opt. Instrum. Eng.936, 152–162 (1988).

D. Psaltis, J. Hong, “Adaptive acoustooptic processor,” in Analog Optical Processing and Computing, H. J. Caulfield, ed., Proc. Soc. Photo-Opt. Instrum. Env.519, 62–68 (1984).

Rhodes, J. F.

Rob, M. A.

Sarto, A. W.

A. W. Sarto, R. T. Weverka, K. Wagner, S. Weaver, “Wide angular aperture holograms in photorefractive crystal using orthogonally polarized write and read beams,” in Photorefrac-tive Materials, Effects, and Devices, J. Feinberg, D. Anderson, eds. (National Institute of Standards and Technology, Gaithersburg, Md., 1995) pp. 214–217.

A. W. Sarto, R. T. Weverka, K. Wagner, “Beam-steering and jammer-nulling photorefractive phased-array radar processor,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Env.2155, 378–388 (1994).

R. T. Weverka, A. W. Sarto, K. Wagner, “Photorefractive phased-array-radar processor dynamics,” in Optical Computing, Vol. 7 of 1993 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1993), pp. 111–114.

A. W. Sarto, R. T. Weverka, K. Wagner, “Adaptive beam-steering and jammer-nulling photorefractive phasedarray radar processor,” in Optical Computing, Vol. 10 of 1995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), pp. 233–235.

Scharf, L. L.

L. L. Scharf, D. C. Farden, “Optimum and adaptive array processing in frequency-wavenumber space,” in USAG/NUSC Workshop on Multidimensional Analysis of Acoustic Fields (Department of Commerce, Washington, D.C., 1973), available from National Technical Information Service, Springfield, Va., order no. CSCL20/1.

Stearns, S. D.

B. Widrow, S. D. Stearns, Adaptive Signal Processing, Prentice-Hall Signal Processing Series (Prentice-Hall, Engle-wood Cliffs, N.J., 1985).

Stilwell, D.

R. D. Esman, M. Y. Fankel, J. L. Dexter, L. G. G., M. G. Parent, D. Stilwell, D. G. Cooper, “Fiber-optic prism true time-delay antenna feed,” IEEE Photon. Technol. Lett. 5, 1347–1349 (1993).

Stroke, G. W.

D. Gabor, G. W. Stroke, “The theory of deep holograms,” Proc. R. Soc. London Ser. A 304, 275–289 (1968).

Turpin, T. M.

L. H. Gesell, R. E. Feinleib, J. L. Lafuse, T. M. Turpin, “Acousto-optic control of time delays for array beam steering,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Eng.2155, 194–204 (1994).

Valley, G. C.

G. C. Valley, M. B. Klein, “Optimal properties of photore- fractive materials for optical data processing,” Opt. Eng. 22, 706–711 (1983).

Vannicola, V. C.

V. C. Vannicola, “Optical processing for adaptive radar systems,” in Optical Signal Processing for C3I, W. Miceli, ed., Proc. Soc. Photo-Opt. Instrum. Eng.209, 32–37 (1979).

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R. T. Weverka, A. W. Sarto, K. Wagner, “Photorefractive phased-array-radar processor dynamics,” in Optical Computing, Vol. 7 of 1993 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1993), pp. 111–114.

R. T. Weverka, K. Wagner, “Staring phased-array radar using photorefractive crystals,” in Optical Information Processing Systems and Architectures III, B. Javidi, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1564, 676–684 (1991).

A. W. Sarto, R. T. Weverka, K. Wagner, “Beam-steering and jammer-nulling photorefractive phased-array radar processor,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Env.2155, 378–388 (1994).

R. T. Weverka, K. Wagner, “Adaptive phased-array radar processing using photrefractive crystals,” in Optoelectronic Signal Processing for Phased-Array Antennas II, B. M. Hendrickson, G. A. Koepf, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1217, 173–182 (1990).

A. W. Sarto, R. T. Weverka, K. Wagner, “Adaptive beam-steering and jammer-nulling photorefractive phasedarray radar processor,” in Optical Computing, Vol. 10 of 1995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), pp. 233–235.

R. T. Weverka, K. Wagner, “Wide angular aperture acoustooptic Bragg cell,” in Devices for Optical Processing, D. Gookin, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1562, 66–72 (1992).

A. W. Sarto, R. T. Weverka, K. Wagner, S. Weaver, “Wide angular aperture holograms in photorefractive crystal using orthogonally polarized write and read beams,” in Photorefrac-tive Materials, Effects, and Devices, J. Feinberg, D. Anderson, eds. (National Institute of Standards and Technology, Gaithersburg, Md., 1995) pp. 214–217.

J. Xu, R. T. Weverka, K. Wagner, “Wide angular aperture lithium niobate acoustooptic Bragg cells,” in Advances in Optical Information Processing VI, D. R. Pape, ed., Proc. Soc. Photo-Opt. Instrum. Eng.2240, 96–107 (1994).

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Weaver, S.

A. W. Sarto, R. T. Weverka, K. Wagner, S. Weaver, “Wide angular aperture holograms in photorefractive crystal using orthogonally polarized write and read beams,” in Photorefrac-tive Materials, Effects, and Devices, J. Feinberg, D. Anderson, eds. (National Institute of Standards and Technology, Gaithersburg, Md., 1995) pp. 214–217.

Weverka, R. T.

A. W. Sarto, R. T. Weverka, K. Wagner, S. Weaver, “Wide angular aperture holograms in photorefractive crystal using orthogonally polarized write and read beams,” in Photorefrac-tive Materials, Effects, and Devices, J. Feinberg, D. Anderson, eds. (National Institute of Standards and Technology, Gaithersburg, Md., 1995) pp. 214–217.

J. Xu, R. T. Weverka, K. Wagner, “Wide angular aperture lithium niobate acoustooptic Bragg cells,” in Advances in Optical Information Processing VI, D. R. Pape, ed., Proc. Soc. Photo-Opt. Instrum. Eng.2240, 96–107 (1994).

R. T. Weverka, K. Wagner, “Wide angular aperture acoustooptic Bragg cell,” in Devices for Optical Processing, D. Gookin, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1562, 66–72 (1992).

R. T. Weverka, K. Wagner, “Staring phased-array radar using photorefractive crystals,” in Optical Information Processing Systems and Architectures III, B. Javidi, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1564, 676–684 (1991).

R. T. Weverka, K. Wagner, “Adaptive phased-array radar processing using photrefractive crystals,” in Optoelectronic Signal Processing for Phased-Array Antennas II, B. M. Hendrickson, G. A. Koepf, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1217, 173–182 (1990).

A. W. Sarto, R. T. Weverka, K. Wagner, “Beam-steering and jammer-nulling photorefractive phased-array radar processor,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Env.2155, 378–388 (1994).

R. T. Weverka, A. W. Sarto, K. Wagner, “Photorefractive phased-array-radar processor dynamics,” in Optical Computing, Vol. 7 of 1993 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1993), pp. 111–114.

A. W. Sarto, R. T. Weverka, K. Wagner, “Adaptive beam-steering and jammer-nulling photorefractive phasedarray radar processor,” in Optical Computing, Vol. 10 of 1995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), pp. 233–235.

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A. W. Sarto, R. T. Weverka, K. Wagner, S. Weaver, “Wide angular aperture holograms in photorefractive crystal using orthogonally polarized write and read beams,” in Photorefrac-tive Materials, Effects, and Devices, J. Feinberg, D. Anderson, eds. (National Institute of Standards and Technology, Gaithersburg, Md., 1995) pp. 214–217.

L. H. Gesell, R. E. Feinleib, J. L. Lafuse, T. M. Turpin, “Acousto-optic control of time delays for array beam steering,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. M. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Eng.2155, 194–204 (1994).

R. T. Weverka, K. Wagner, “Wide angular aperture acoustooptic Bragg cell,” in Devices for Optical Processing, D. Gookin, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1562, 66–72 (1992).

J. Xu, R. T. Weverka, K. Wagner, “Wide angular aperture lithium niobate acoustooptic Bragg cells,” in Advances in Optical Information Processing VI, D. R. Pape, ed., Proc. Soc. Photo-Opt. Instrum. Eng.2240, 96–107 (1994).

R. T. Compton, Adaptive Antennas (Prentice-Hall, Engle-wood Cliffs, N.J., 1988), Chap. 2.

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B. M. Hendrickson, ed., Optoelectronic Signal Processing for Phased-Array Antenns IV, Proc. Soc. Photo-Opt. Instrum. Eng.2155 (1994).

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C. W. Keefer, J. E. Malowicki, P. M. Payson, “Wideband operation of a photorefractive based adaptive processor,” in Analog Photonics, A. Pirich, P. Sierak, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1790, 145–156 (1992).

D. R. Pape, P. Wasilousky, M. Krainak, “A high performance apodized phased array Bragg cell,” in Optical Technology for Microwave Applications III, S. K. Yao, ed., Proc. Soc. Photo-Opt. Instrum. Eng.789, 117–126 (1987).

R. T. Weverka, K. Wagner, “Adaptive phased-array radar processing using photrefractive crystals,” in Optoelectronic Signal Processing for Phased-Array Antennas II, B. M. Hendrickson, G. A. Koepf, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1217, 173–182 (1990).

R. T. Weverka, K. Wagner, “Staring phased-array radar using photorefractive crystals,” in Optical Information Processing Systems and Architectures III, B. Javidi, ed., Proc. Soc. Photo-Opt. Instrum. Eng.1564, 676–684 (1991).

R. T. Weverka, A. W. Sarto, K. Wagner, “Photorefractive phased-array-radar processor dynamics,” in Optical Computing, Vol. 7 of 1993 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1993), pp. 111–114.

A. W. Sarto, R. T. Weverka, K. Wagner, “Beam-steering and jammer-nulling photorefractive phased-array radar processor,” in Optoelectronic Signal Processing for Phased-Array Antennas IV, B. Hendrickson, ed., Proc. Soc. Photo-Opt. Instrum. Env.2155, 378–388 (1994).

A. W. Sarto, R. T. Weverka, K. Wagner, “Adaptive beam-steering and jammer-nulling photorefractive phasedarray radar processor,” in Optical Computing, Vol. 10 of 1995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), pp. 233–235.

L. B. Lambert, M. Arm, A. Aimette, “Electro-optical signal processing for phased-array antennas,” in Optical and Electro-Optic Information Processing, J. Tippett, ed. (MIT, Cambridge, Mass., 1965).

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C. W. Carroll, B. V. K. V. Kumar, “Adaptive phased aray radar processing on a multichannel acousto-optic linear algebra system: experimental results,” in Optoelectronic Signal Processing for Phased-Array Antennas, K. Bhasin, B. Hendrickson, eds., Proc. Soc. Photo-Opt. Instrum. Eng.886, 203–213 (1988).

S. Lin, J. Hong, R. Boughton, D. Psaltis, “Broad-band beamforming via acousto-optics,” in Advances in Optical Information Processing III, D. Pape, ed., Proc. Soc. Photo-Opt. Instrum. Eng.936, 152–162 (1988).

D. I. Voskresenskii, A. I. Grinev, E. N. Voronin, Electrooptical Arrays (Springer-Verlag, New York, 1989).

W. A. Penn, R. Wasiewicz, R. M. Iodice, “Optical adaptive multipath canceller for surveillance radar,” in Optoelectronic Signal Processing for Phased-Array Antennas II, B. Hendrickson, G. Koepf, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1217, 151–160 (1990).

R. M. Montgomery, “Acousto-optic/photorefractive processor for adaptive antenna arrays,” in Optoelectronic Signal Processing for Phased-Array Antennas II, B. Hendrickson, G. Koepf, eds., Proc. Soc. Photo-Opt. Instrum. Eng.1217, 207–217 (1990.

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Figures (16)

Fig. 1
Fig. 1

Block diagram for the Widrow time-domain adaptive beam-forming algorithm. Signals from the antenna elements at left are delayed by multiple unit delays τ, multiplied by the output signal, and time integrated to form the adaptive weights. These weights are multiplied by the delayed versions of the incoming signals and the products are summed to form the jammer estimate at top. This jammer estimate is subtracted from the main beam signal to give the output with the jammer nulled.

Fig. 2
Fig. 2

Block diagram of modified algorithm. A single tapped-delay line delays the output signal by multiple unit delays τ. The delayed signal multiplies the current-time antenna signals to form the adaptive weights. The weights multiply the incoming signals, the products are summed vertically, and these partial sums are spatially Fourier transformed, passed through an array of linearly increasing center frequency filters, and summed to give the jammer estimate. This jammer estimate is subtracted from the main beam signal to give the output. BPF's, bandpass filters.

Fig. 3
Fig. 3

Schematic hardware implementation of algorithm of Fig. 2 for 2-D phased arrays. The optical implementation of the modified algorithm shows a 2-D antenna array and a continuous version of the 1-D delay line. The 3-D photorefractive crystal (PRC) implements both the products of input signal with the feedback signal in grating formation and the multiplication of the input signals with the weights in diffraction. The spatial Fourier transform is accomplished with a lens, and the array of bandpass filters is accomplished with a wedged Fabry–Perot filter.

Fig. 4
Fig. 4

rf to optical conversion by electro-optic phase modulators at the antennas and fiber-optic transmission to the processor. A single coherent laser is split N ways to feed each modulator, and the fiber feed network must be cut to within a length that corresponds to the inverse radar bandwidth and the laser coherence length. An rf plane wave over the ±90° degree range is transduced into an optical wave over less than ± 1°.

Fig. 5
Fig. 5

Photorefractive adaptive phased-array-radar beam-forming and jammer-nulling processor. The diagonal train, falling from left to right, is the main-beam-forming portion of the processor. The correlation of inputs with the steering signal forms a phase grating that diffracts the signal of interest toward the main-beam detector. The optical train rising from left to right is the jammer estimator. Correlations of the incoming signal with the delayed input build up gratings in proportion to the narrow-band signals that, after filtering, are incident upon the jammer-estimate detector. The self-consistent subtraction and feedback of the detector signals nulls out correlated jammers.

Fig. 6
Fig. 6

Jammer-nulling portion of the photorefractive adaptive phased-array-radar processor implemented in the laboratory. The main beam is taken from the undiffracted light from the PRC.

Fig. 7
Fig. 7

(a) Effect of feedback gain on the photorefractive diffraction efficiency and the response time of the system. The top curve is the photorefractive crystal response with the jammer-estimate detector off (g = 0). With higher gain, the photorefractive diffraction efficiency starts to build with the same slope and reaches the lower steady-state value quicker. (b) The role that photorefractive sensitivity plays in the high-gain feedback loop is shown by an illustration of the behavior of a slow but sensitive photorefractive crystal, PRC1, such as BaTiO3 and a fast but less sensitive photorefractive crystal, PRC2, such as BSO. The initial slope of the grating buildup is the photorefractive sensitivity, and the different sensitivities are manifested as shifted positions on this log–log plot. The sensitivity is part of the feedback gain that determines system response time, while for a given sensitivity photorefractive crystal response time does not have a direct impact on system response time.

Fig. 8
Fig. 8

Schematic of the jammer-estimate detector bandpass-filter arrays. The three suggested implementations are (a) a wedged Fabry–Perot in the Fourier plane of the Bragg cell, (b) a tilted Fabry–Perot in the image plane of the Bragg cell, and (c) an array of discrete photodetectors with electronic bandpass filters in the Fourier plane of the Bragg cell.

Fig. 9
Fig. 9

Experimental layout consisting of three primary subsystems, the phased-array simulator, the jammer-nulling processor, and the stabilization subsystem. BS's, beam splitters; AOM's acousto-optic modulators; ND, neutral-density filter; Cyl's, cylindrical lenses; PRC, BaTiO3 photorefractive crystal.

Fig. 10
Fig. 10

Grating degeneracy used to multiplex the write and the read beams: (a) setup used to generate two identical copies of the phased-array beam tilted by a small angle in the vertical dimension and the spatial filter used to select only one of the diffracted outputs, (b) the momentum space depiction of the gratings offset in angle in the Bragg-degenerate dimension. The three optical beams shown at left write the two indicated gratings. On readout, the two vertically displaced beams read out both gratings through Bragg degeneracy, giving the three output beams shown at right, which can be vertically spatially filtered to isolate the readout beams from the write beams.

Fig. 11
Fig. 11

rf circuitry experimental layout showing the subsystems for simulating the phased-array input, the jammer-nulling feedback electronics, the stabilization system, and the system for measuring the complex dynamics. Attn's, programmable attenuators; ZFL's, low noise amplifiers; ZHL's, power amplifiers; DHP, high-power amplifier, ×, mixers; −10 dB's, 10% output couplers.

Fig. 12
Fig. 12

Experimental measurement of the jammer excision versus time, with a fit to a complex exponential that shows more than 20-dB steady-state null depth and ∼0.2 s to reach this value for the high-gain case (lower curve) and more than 10-dB steady-state null depth and ∼4 s to reach this value for the low-gain case (upper curve).

Fig. 13
Fig. 13

Jammer suppression versus feedback gain. At low gain, −25–−10-dB attenuator settings, the jammer suppression obtained is proportional to feedback gain (feedback attenuator setting). At high gain the system is driven into oscillation. At these high gains the jammer suppression is unstable and jumps from high to low values, as shown for the attenuator settings of 0 and 5 dB at right.

Fig. 14
Fig. 14

Typical null depth of phased-array radar processor, showing >35 dB of suppression. The plots are from a spectrum analyzer in averaging mode that averages out the transient dips seen in Fig. 11. (a) With the feedback disabled, (b) with the correlation cancellation loop enabled. The dc and the second-harmonic signals are out of the processor bandwidth and are not nulled.

Fig. 15
Fig. 15

(a Two jammers differing by 10 dB before suppression, (b) asymmetric suppression that equalizes the residual jammer powers (0.5 MHz/div., 10 dB/div.). Figures (c) and (d) exhibit power-dependent decay rates for the two jammers, strong in (c) and weak in (d) (0.2 sec/div., 10 dB/div.).

Fig. 16
Fig. 16

Blinking jammer. The arrows point to one trace with the feedback on. The other trace is with the feedback off. With the feedback on, the jammer is nulled by 23 dB and the weights that store the null are not erased during the off time of the jammer, ∼0.1.

Tables (1)

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Table 1 Comparison of Hardware Requirements for Spatiotemporal Adaptive Beam Formers

Equations (26)

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w n * ( x , t ) = t s n * ( t 1 x / V ) f ( t 1 ) h w ( t t 1 ) d t 1 ,
o ( t ) = n 0 L s n ( t x / V ) w n * ( x , t ) d x = n 0 L s n ( t x / V ) t s n * ( t 1 x / V ) × f ( t 1 ) h w ( t t 1 ) d t 1 d x ,
W n * ( x , t ) = t s n * ( t 2 ) f ( t 2 x / V ) h w ( t t 2 ) d t 2 .
y ( t , x ) = n = 1 N s n ( t ) W n * ( x , t ) .
Y ( t , u ) = 0 L y ( t , x ) exp ( i u x ) d x .
o ( t ) = M / L 2 M / L 0 T Y ( t t 3 , u ) exp ( i u V t 3 ) d t 3 d u .
o ( t ) = M / L 2 M / L 0 T 0 L n = 1 N s n ( t t 3 ) t t 3 s n * ( t 2 ) × f ( t 2 x / V ) h w ( t t 2 τ ) d t 2 exp ( i u x ) d x × exp ( i u V t 3 ) d t 3 d u = n = 1 N 0 T d t 3 s n ( t t 3 ) t d t 1 0 L d x M / L 2 M / L d u × exp  ( i u x ) exp ( i u V t 3 ) s n * ( t 1 t 3 ) × f ( t 1 t 3 x / V ) h w ( t t 1 ) = n = 1 N 0 T d t 3 s n ( t t 3 ) t d t 1 s n * ( t 1 t 3 ) h w ( t t 1 ) × 0 L d x M L exp [ i ( x + V t 3 ) 3 M 2 L ] sinc [ M 2 L ( x + V t 3 ) ] × f ( t 1 t 3 x / V ) ,
o ( t ) = n = 1 N 0 T s n ( t t 3 ) t s n * ( t 1 t 3 ) f ( t 1 ) h w ( t t 1 ) d t 1 d t 3 .
s n ( t ) = g ( t n a   sin θ / c )     n = 0 , , N 1 g ˜ ( t n a   sin θ / c ) exp [ i ω 0 ( t n a   sin  θ / c ) ] g ˜ ( t ) exp [ i ω 0 ( t n a   sin θ / c ) ] .
s n ( t ) = p = 1 P g ˜ p ( t n a   sin  θ p / c ) exp [ i ω p ( t n a   sin  θ p / c )    n = 0 , , N 1 ,
E ( x , t ) = exp ( i 2 π v l t ) n = 0 N 1 H ( x n D d ) × p = 1 P g ˜ p ( t n a   sin  θ p / c ) × exp  [ i ω 0 ( t n a   sin  θ p / c ) ] .
E ( x , t ) = n = 0 N 1 exp ( i Φ n ) H ( x n D d ) { g ˜ ( t n a  sin  θ 0 / c ) × exp [ i ω 0 ( t n a  sin  θ 0 / c ) ] + p = 1 P 1 A p exp [ i ω p ( t n a  sin  θ p / c ) ] } × exp ( i 2 π v l t ) exp  ( i 2 π v l t ) exp [ i Φ ( x ) ] rect ( x N D ) × { g ˜ ( t ) exp [ i ω 0 ( t a x D sin  θ 0 / c ) ] + p = 1 P 1 A p exp [ i ω p ( t x D a  sin θ p / c ) ] × comb [ x D ] * H ( x d )
σ ( t ) = n = 1 N s n [ t n a   sin  ( θ g ) / c ]
σ ( t ) = n = 1 N 0 T s n ( t t 3 ) t s n * ( t 1 t 3 ) g σ ( t 1 ) × h w ( t t 1 ) d t 1 .
σ ( t ) = n = 1 N 0 T s n ( t t 3 ) t g n * ( t 1 t 3 ) g σ ( t 1 ) h w ( t t 1 ) d t 1 .
σ ( t ) = n = 1 N 0 T s n ( t t 3 t n g ) exp ( i Φ n ) × t exp ( i Φ n ) g n * ( t 1 t 3 t n g ) g σ ( t 1 ) d t 1 d t 3 = n = 1 N 0 T s n ( t t 3 ) δ ( t 3 t n g ) d t 3 = n = 1 N s n ( t t n g ) .
s n ( t ) d n ( t ) + A j ( t ) = d ( t + t n d ) + A  exp [ i ω A ( t + t n A ) ] ,
o ( t ) = n = 1 N t f ( t 1 ) h w ( t t 1 ) { 0 T d ( t t 3 + t n d ) × d * ( t 1 t 3 + t n d ) d t 3 + T A 2 exp [ i ω A ( t t 1 ) ] } d t 1 ,
0 T d ( t t 3 + t n d ) d * ( t 1 t 3 + t n d ) d t 3 = E d T δ ( t t 1 ) ,
o ( t ) = N E d T f ( t ) h w ( 0 ) + N T A 2 exp ( i ω A t ) f ˜ ( ω A , t ) ,
r ˜ ( ω , t ) t r ( t 1 ) h w ( t t 1 ) exp ( i ω t 1 ) d t 1 .
output = ( 1 / g 2 ) f ( t ) = σ ( t τ e ) g o ( t ) ,
1 g 2 f ( t ) = N d ( t τ e ) + A  exp [ i ω A ( t τ e ) ] × n = 1 N exp [ i ω A ( t n A t n d ) ] g N E d T f ( t ) h w ( 0 ) g N T A 2 exp ( i ω A t ) f ˜ ( ω A , t ) .
output  = 1 g 2 f ˜ ( ω , t ) = N   exp ( i ω τ e ) d ˜ ( ω , t τ e ) + A   exp  ( i ω A τ e ) n = 1 N exp [ i ω A ( t n A t n d ) ] δ ( ω ω A ) 1 + g 2 g N E d T h w ( 0 ) + g 2 g N T A 2 δ ( ω ω A ) ,
1 g 2 f ˜ ( ω A , t ) = 1 N n = 1 N exp  [ i ω A ( t n A t n d ) ] 1 g 2 g T A .
1 g 2 f ˜ ( ω ω A , t ) = N   exp  ( i ω τ e ) d ˜ ( ω , t τ e ) 1 + g 2 g N E d T h w ( 0 ) ,

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