Ferroelectric liquid-crystal digital scanner

McRuer, Robert N.; McAdams, Larry R.; Goodman, Joseph W.

doi:10.1364/ol.15.001415

Cited by 15 publications

(14 citation statements)

References 10 publications

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“…Milner et al [3] implemented the beam steering using mechanical devices, while Khan et al [16] designed a 3-dimensional wide-angle no-moving-parts laser beam steering method. Many other design choices are also available and can be found from [17][18][19][20]. The omni-directionality assumption for the FSO receiver is also reasonable, as omni-directional FSO receivers are also implemented in [5].…”

Section: Fso Communication Modelmentioning

confidence: 99%

Throughput and delay analysis for hybrid radio-frequency and free-space-optical (RF/FSO) networks

Wang

Abouzeid

2011

Wireless Netw

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In this paper the per-node throughput and endto-end delay of randomly deployed (i.e. ad-hoc) hybrid radio frequency -free space optics (RF/FSO) networks are studied. The hybrid RF/FSO network consists of an RF ad hoc network of n nodes, f(n) of them, termed 'super nodes', are equipped with an additional FSO transceiver with transmission range s(n). Every RF and FSO transceiver is able to transmit at a maximum data rate of W 1 and W 2 bits/sec, respectively. An upper bound on the per node throughput capacity is derived. In order to prove that this upper bound is achievable, a hybrid routing scheme is designed whereby the data traffic is divided into two classes and assigned different forwarding strategies. The capacity improvement with the support of FSO nodes is evaluated and compared against the corresponding results for pure RF wireless networks. Under optimal throughput scaling, the scaling of average end-to-end delay is derived. A significant gain in throughput capacity and a notable reduction in delay will be achieved if. Furthermore, it is found that for fixed W 1 , f(n) and n where f(n) \ n, there is no capacity incentive to increase the FSO data rate beyond a critical value. In addition, both throughput and delay can achieve linear scaling by properly adjusting the FSO transmission range and the number of FSO nodes.

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Section: Fso Communication Modelmentioning

confidence: 99%

Throughput and delay analysis for hybrid radio-frequency and free-space-optical (RF/FSO) networks

Wang

Abouzeid

2011

Wireless Netw

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“…[11] designed a 3-dimensional wide-angle no-moving-parts laser beam steering method. Many other design choices are also available and can be found from [12], [13], [14] and [15]. The omni-directionality assumption for the FSO receiver is also reasonable, as omni-directional FSO receivers are also implemented in [4].…”

Section: Fso Communication Modelmentioning

confidence: 99%

“…(L -o(l))mA' <mW2 s (13) In order to minimize the total transmit power consumption, the FSO communication range s is chosen to be s = 6 (1 1) D- (14) To show that this upper bound is achievable, we design a routing scheme using similar techniques as in [1]. Let p'(m) := radius of a disk of area lOOlog m/m (15) We can construct a Voronoi tessellation Vm in relation to the number of nodes m and the locations of nodes, in which every Voronoi cell contains a disk of radius p'(m) and is contained in a disk of radius 2p'(m).…”

Section: Fso Communication Modelmentioning

confidence: 99%

Throughput Capacity of Hybrid Radio-Frequency and Free-Space-Optical (RF/FSO) Multi-Hop Networks

Wang

Abouzeid

2007

2007 Information Theory and Applications Workshop

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The per-node throughput capacity of hybrid radio frequency and free space optics (RF/FSO) networks is studied and the benefit of using this hybrid network architecture over the pure RF wireless networks is evaluated. The hybrid RF/FSO network consists of an RF ad hoc network of n nodes, m of them (so called super nodes) are equipped with an additional FSO transceiver. Every RF and FSO transceiver is able to transmit at a maximum data rate of W1 and W2 bits/sec, respectively. All the super node are connected by the FSO links and thus can form a stand-alone FSO network. With a minimum transmit power objective, an upper bound on the per node capacity of Ci W1 n + C2 W2 +log m is derived. In order to prove that this upper bound is achievable, we design a hybrid routing scheme in which the data traffic is divided into two classes and use different routing strategies: a portion of data will be forwarded with the (partial) support of super nodes in a hierarchical routing fashion, and the rest will be purely routed through RF links in a multi-hop fashion. By properly balancing the load between these two classes of traffic, it is shown that this upper bound is tight when the maximum data rate ratio of FSO and RF transceivers, w2 , grows slower than rn. Under such circumstances, the capacity improvement with the support of FSO nodes, as compared with the results for RF wireless networks in [1], is evaluated. A significant capacity gain will be achieved if Wmlogm = Q(n). The results characterize the number of super nodes and/or the FSO data rate necessary in order to cause a non-trivial increase in the per-node throughput.

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“…Recent advances in synthesis of new LC materials [10] and in the design of the nematic LC cells [11] significantly improved parameters important for effective beam steering, such as optical birefringence and response times. Among the prism-based DBDs, one of the most effective designs uses a cascade of elementary stages each of which represents a pair of an active polarization rotator and a prismatic deflector [12][13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Liquid Crystal Digital Beam Steering Device Based on Decoupled Birefringent Deflector and Polarization Rotator

Pishnyak

Kreminska

Lavrentovich

et al. 2005

Molecular Crystals and Liquid Crystals

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We describe digital beam deflectors (DBDs) based on liquid crystals. Each stage of the device comprises polarization rotator and birefringent prism deflector. We used prisms made of the uniaxial smectic A (SmA) liquid crystal and a solid yttrium orthovanadate crystal. SmA prisms have high birefringence and can be constructed in a variety of shapes. We address the challenges of uniform alignment of SmA, such as elimination of focal conic domains. Rotation of linear polarization is achieved by electrically switched twisted nematic or electrically controlled birefringent cell. We describe a four-stage DBD steering a normally incident laser beam within AE56 mrad range with 8 mrad steps.

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Ferroelectric liquid-crystal digital scanner

Cited by 15 publications

References 10 publications

Throughput and delay analysis for hybrid radio-frequency and free-space-optical (RF/FSO) networks

Throughput and delay analysis for hybrid radio-frequency and free-space-optical (RF/FSO) networks

Throughput Capacity of Hybrid Radio-Frequency and Free-Space-Optical (RF/FSO) Multi-Hop Networks

Liquid Crystal Digital Beam Steering Device Based on Decoupled Birefringent Deflector and Polarization Rotator

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