Photorefractive processing for large adaptive phased arrays.

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.

[1]  Kelvin H. Wagner,et al.  Beam-steering and jammer-nulling photorefractive phased-array radar processor , 1994 .

[2]  Demetri Psaltis,et al.  Broadband Beamforming Via Acousto-Optics , 1988, Defense, Security, and Sensing.

[3]  Aaas News,et al.  Book Reviews , 1893, Buffalo Medical and Surgical Journal.

[4]  Leslie H. Gesell,et al.  Acousto-optic control of time delays for array beam steering , 1994 .

[5]  J F Rhodes.  Adaptive filter with a time-domain implementation using correlation cancellation loops. , 1983, Applied optics.

[6]  Kelvin H. Wagner,et al.  Wide angular aperture lithium niobate acousto-optic Bragg cells , 1994, Defense, Security, and Sensing.

[7]  Shi-Kay Yao,et al.  Optical technology for microwave applications VI and optoelectronic signal processing for phased-array antennas III : 20-23 April 1992, Orlando, Florida , 1992 .

[8]  Vincent C. Vannicola.  Optical Processing For Adaptive Radar Systems , 1980, Other Conferences.

[9]  M. Volker.  Coherent all-fibre optical beam-steering technique for phased-array antennas , 1992 .

[10]  T R Bader.  Acoustooptic spectrum analysis: a high performance hybrid technique. , 1979, Applied optics.

[11]  M. J. Wale,et al.  Proof-of-concept model of a coherent optical beam-forming network , 1992 .

[12]  P. Yeh.  Two-wave mixing in nonlinear media , 1989 .

[13]  Bahram Javidi.  Optical Information Processing Systems and Architectures III , 1990 .

[14]  Dennis R. Pape,et al.  A High Performance Apodized Phased Array Bragg Cell , 1987, Other Conferences.

[15]  E M. Alexander,et al.  The Fabry-Perot Etalon As An Rf Frequency Channelizer , 1984, Photonics West - Lasers and Applications in Science and Engineering.

[16]  S. Applebaum,et al.  Adaptive arrays , 1976 .

[17]  B. Widrow,et al.  Adaptive antenna systems , 1967 .

[18]  Robert M. Iodice,et al.  Optical adaptive multipath canceler for surveillance radar , 1990, Photonics West - Lasers and Applications in Science and Engineering.

[19]  P. Howells,et al.  Explorations in fixed and adaptive resolution at GE and SURC , 1976 .

[20]  Robert Morris Montgomery.  Acousto-optic/photorefractive processor for adaptive antenna arrays , 1990, Photonics West - Lasers and Applications in Science and Engineering.

[21]  Neck Surgery,et al.  Optoelectronic Signal Processing for Phased-Array Antennas , 1988 .

[22]  C. W. Carroll,et al.  Adaptive Phased Array Radar Processing On A Multi-Channel, Acousto-Optic, Linear Algebra System: Experimental Results , 1988, Photonics West - Lasers and Applications in Science and Engineering.

[23]  Moshe Kam,et al.  Design for steering accuracy in antenna arrays using shared optical phase shifters , 1989 .

[24]  B. Widrow,et al.  Adaptive antenna systems , 1967 .

[25]  Kelvin H. Wagner,et al.  Adaptive phased-array radar processing using photorefractive crystals , 1990, Photonics West - Lasers and Applications in Science and Engineering.

[26]  Dennis Gabor,et al.  The theory of deep holograms , 1968, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[27]  Kelvin H. Wagner,et al.  Wide-angular aperture acousto-optic Bragg cell , 1991, Optics & Photonics.

[28]  Bernard Widrow,et al.  Adaptive Signal Processing , 1985 .

[29]  Marvin B. Klein,et al.  Optimal Properties Of Photorefractive Materials For Optical Data Processing , 1983, Photonics West - Lasers and Applications in Science and Engineering.

[30]  Demetri Psaltis,et al.  Adaptive Acoustooptic Processor , 1985, Other Conferences.

[31]  John Malowicki,et al.  Wideband operation of a photorefractive-based adaptive processor , 1993, Other Conferences.

[32]  Kelvin H. Wagner,et al.  Staring phased-array radar using photorefractive crystals , 1991, Optics & Photonics.

[33]  Kelvin H. Wagner,et al.  Photorefractive phased-array-radar processor dynamics , 1993, Optics & Photonics.

[34]  L. Scharf,et al.  Optimum and adaptive array processing in frequency-wavenumber space , 1974, CDC 1974.

[35]  L. J. Griffiths,et al.  An alternative approach to linearly constrained adaptive beamforming , 1982 .

[36]  M. Rob,et al.  Limitation of a wedged etalon for high-resolution linewidth measurements. , 1990, Optics letters.

[37]  A. Gabel,et al.  Front-End RF Channelization Using Optical Techniques , 1984, Other Conferences.

[38]  Michael Y. Frankel,et al.  Fiber-optic Prism True Time-delay Antenna Feed , 1993, LEOS 1993 Summer Topical Meeting Digest on Optical Microwave Interactions/Visible Semiconductor Lasers/Impact of Fiber Nonlinearities on Lightwave Systems/Hybrid Optoelectronic Integration and Packagi.

[39]  R M Montgomery,et al.  Photorefractive adaptive filter structure with 40-dB interference rejection. , 1991, Applied optics.