Article

# Experimental demonstration of a phased-array antenna optically controlled with phase and time delays

(Impact Factor: 1.78). 09/1996; 35(26):5293-300. DOI: 10.1364/AO.35.005293
Source: PubMed

ABSTRACT The experimental demonstration and the far-field pattern characterization of an optically controlled phased-array antenna are described. It operates between 2.5 and 3.5 GHz and is made of 16 radiating elements. The optical control uses a two-dimensional architecture based on free-space propagation and on polarization switching by N spatial light modulators of p × p pixels. It provides 2(N-1) time-delay values and an analog control of the 0 to 2π phase for each of the p × p signals feeding the antenna (N = 5, p = 4).

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• "Because the RF signals are transmitted via the optical fiber or the waveguide, the noise due to the external electromagnetic interference can be greatly reduced. Several OTTD technologies have been proposed and demonstrated, including acousto-optic (AO) integrated circuit technique [1] [2] [3], Fourier optical technique [4] [5] [6], bulky optics techniques [7] [8] [9] [10] [11] [12], slow light approach [13] [14], and substrate guided wave techniques [15] [16] [17]. A great deal of materials have been used to fabricate OTTD devices [18] [19] [20] [21]. "
##### Article: Polymer waveguide delay device using right-angle X junctions
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ABSTRACT: A four-channels polymer waveguide delay device is demonstrated and fabricated using direct ultra-violet photolithography process. The device is composed of right-angle junctions and bending waveguide. The optimized structural properties of the device and fabrication procedures are demonstrated. The loss of bending waveguides and right-angle X junction is calculated. The near-infrared field guided-mode patterns of the devices are obtained. Each incoming radio-frequency signal can be independently received. Measured delays are 0, 60.9, 121.9, and 182.9 ps. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26050
Microwave and Optical Technology Letters 07/2011; 53(7). DOI:10.1002/mop.26050 · 0.62 Impact Factor
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• "Free-space approaches typically use a series of spatial light modulators to select the paths for arrays of beams [18]–[20] or acousto-optic modulation [21], [22]. The advantage of free space is low weight and equal ease of implementing long and short delays. "
##### Article: Hardware Demonstration of Extremely Compact Optical True Time Delay Device for Wideband Electronically Steered Antennas
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ABSTRACT: An optical true time delay device is demonstrated that is capable of supporting 112 antennas with 81 different delays (>; 6 bits) in a volume 16" × 5" × 4" including the box with electronics. It uses a free-space design based on the White cell, and alignment is made simple, fast, and robust by the use of slow-tool diamond turning of many optics on a single substrate. Pointing accuracy of the 12 objective mirrors is better than 10 μrad, and surface roughness is ≈ 45 nm RMS. Delays vary from 0 to 25 ns in 312.5 ps increments. Short delays are implemented using delay rods of high refractive index, and long delays using folded mirror trains. Total insertion loss from fiber to detector was 7.82 dB for the no-delay path, and 10.22 dB for the longest lens train. A three-state tip-style MEMS micromirror array is used to select among the delays, with tilt angles ±1.4° plus flat, and switching time <; 100 μs for the entire array. An InP wideband optical combiner photodetector array converts the optical signal to RF with 20 GHz bandwidth. The unit survived temperature cycling 0 to 50 C and random vibration on three axes (9.84 g RMS) with no degradation of signal.
Journal of Lightwave Technology 05/2011; 29(9):1343-1353. DOI:10.1109/JLT.2011.2124444 · 2.86 Impact Factor
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• "Free-space approaches typically use a series of spatial light modulators to select the paths for arrays of beams [18]–[20] or acousto-optic modulation [21], [22]. The advantage of free space is low weight and equal ease of implementing long and short delays. "
##### Article: Hardware Demonstration of Extremely Compact Optical True Time Delay Device for Wideband Electronically Steered Antennas
[Hide abstract]
ABSTRACT: An optical true time delay device is demonstrated that is capable of supporting 112 antennas with 81 different delays (${>}6$ bits) in a volume $16' \times 5' \times 4'$ including the box with electronics. It uses a free-space design based on the White cell, and alignment is made simple, fast, and robust by the use of slow-tool diamond turning of many optics on a single substrate. Pointing accuracy of the 12 objective mirrors is better than 10 $\mu$rad, and surface roughness is ${\approx}45$ nm RMS. Delays vary from 0 to 25 ns in 312.5 ps increments. Short delays are implemented using delay rods of high refractive index, and long delays using folded mirror trains. Total insertion loss from fiber to detector was 7.82 dB for the no-delay path, and 10.22 dB for the longest lens train. A three-state tip-style MEMS micromirror array is used to select among the delays, with tilt angles ${\pm}1.4^{\circ}$ plus flat, and switching time ${<}100\ \mu$s for the entire array. An InP wideband optical combiner photodetector array converts the optical signal to RF with 20 GHz bandwidth. The unit survived temperature cycling 0 to 50 C and random vibration on three axes (9.84 g RMS) with no degradation of signal.
Journal of Lightwave Technology 04/2011; 29(9):1343-1353. · 2.86 Impact Factor