Active, large-scale tuning of optical dispersion by free-space angular-chirp-enhanced delay (FACED)

2016 ◽  
Author(s):  
Jianglai Wu ◽  
Yiqing Xu ◽  
Xiaoming Wei ◽  
Jingjiang Xu ◽  
Antony C. S. Chan ◽  
...  
Keyword(s):  
Free Space ◽  
Large Scale ◽  
Optical Dispersion

Study on space absorbing of multilayer MWCNTs/Fe3O4/NBR composites

2021 ◽  
pp. 2150112
Author(s):  
Song Xinhua ◽  
Zhou Haiyang ◽  
Zhao Tiejun ◽  
Li Xiaojie ◽  
Yan Honghao
Keyword(s):  
Reflection Loss ◽  
Free Space ◽  
Large Scale ◽  
Comsol Multiphysics ◽  
Maximum Value ◽  
The Matrix ◽  
Attenuation Loss ◽  
Stealth Materials ◽  
Free Space Method ◽  
Space Method

In order to meet the requirements of “wide, thin, strong and light” for military stealth materials, it is of great practical value to study the absorbing characteristics of multi-layer MWCNTs/Fe3O4/NBR absorbing materials in space. First, we use the large-scale software COMSOL Multiphysics to simulate the absorbing characteristics of the composite thin plate in space. Then the four-port network matrix is used to calculate the absorbing characteristics of the composite plate in space. Finally, the Free-Space method is used to measure the reflection attenuation loss, and the results of the three methods are compared and analyzed. The results show that when the frequency is 10 GHz, the reflection loss of multi-layer MWCNTs/Fe3O4/NBR reaches the maximum value of −27.91, −27.01 and −22.56 dB by COMOSL numerical simulation, four-port network the matrix and Free-Space experimental measurement. The results of the three methods show that the reflection loss is less than −10 dB in the frequency band of 6–14 GHz.

scholarly journals Free Space Intra-Datacenter Interconnects Based on 2D Optical Beam Steering Enabled by Photonic Integrated Circuits

Photonics ◽  
2018 ◽  
Vol 5 (3) ◽  
pp. 21 ◽  
Author(s):  
Charidimos Chaintoutis ◽  
Behnam Shariati ◽  
Adonis Bogris ◽  
Paul Dijk ◽  
Chris Roeloffzen ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
Data Center ◽  
Free Space ◽  
Large Scale ◽  
Beam Steering ◽  
Optical Beam ◽  
Switching Network ◽  
Free Space Optical ◽  
Data Center Networks

Data centers are continuously growing in scale and can contain more than one million servers spreading across thousands of racks; requiring a large-scale switching network to provide broadband and reconfigurable interconnections of low latency. Traditional data center network architectures, through the use of electrical packet switches in a multi-tier topology, has fundamental weaknesses such as oversubscription and cabling complexity. Wireless intra-data center interconnection solutions have been proposed to deal with the cabling problem and can simultaneously address the over-provisioning problem by offering efficient topology re-configurability. In this work we introduce a novel free space optical interconnect solution for intra-data center networks that utilizes 2D optical beam steering for the transmitter, and high bandwidth wide-area photodiode arrays for the receiver. This new breed of free space optical interconnects can be developed on a photonic integrated circuit; offering ns switching at sub-μW consumption. The proposed interconnects together with a networking architecture that is suitable for utilizing those devices could support next generation intra-data center networks, fulfilling the requirements of seamless operation, high connectivity, and agility in terms of the reconfiguration time.

scholarly journals The Origins of Enhanced and Retarded Crystallization in Nanocomposite Polymers

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1472 ◽  
Author(s):  
Ahmad Jabbarzadeh
Keyword(s):  
Free Space ◽  
Large Scale ◽  
Volume Fraction ◽  
Functional Materials ◽  
Characteristic Size ◽  
Polymeric Systems ◽  
Planar Surfaces ◽  
Extended Length ◽  
Critical Particle Size ◽  
Dynamics Simulations

Controlling the crystallinity of hybrid polymeric systems has an important impact on their properties and is essential for developing novel functional materials. The crystallization of nanocomposite polymers with gold nanoparticles is shown to be determined by free space between nanoparticles. Results of large-scale molecular dynamics simulations reveal while crystallinity is affected by the nanoparticle size and its volume fraction, their combined effects can only be measured by interparticle free space and characteristic size of the crystals. When interparticle free space becomes smaller than the characteristic extended length of the polymer molecule, nanoparticles impede the crystallization because of the confinement effects. Based on the findings from this work, equations for critical particle size or volume fraction that lead to this confinement-induced retardation of crystallization are proposed. The findings based on these equations are demonstrated to agree with the results reported in experiments for nanocomposite systems. The results of simulations also explain the origin of a two-tier crystallization regime observed in some of the hybrid polymeric systems with planar surfaces where the crystallization is initially enhanced and then retarded by the presence of nanoparticles.

Addendum to "Self-aligned micromachining process for large-scale, free-space optical cross-connects"

2001 ◽  
Vol 19 (11) ◽  
pp. 1793-1793
Author(s):  
P. Helin ◽  
M. Mita ◽  
T. Bourouina ◽  
G. Reyne ◽  
H. Fujita
Keyword(s):  
Free Space ◽  
Large Scale ◽  
Free Space Optical ◽  
Scale Free

scholarly journals Urban Free-Space Optical Network Optimization

2020 ◽  
Vol 10 (21) ◽  
pp. 7872
Author(s):  
Revital Marbel ◽  
Boaz Ben-Moshe ◽  
Tal Grinshpoun
Keyword(s):  
Genetic Algorithm ◽  
Optical Networks ◽  
Free Space ◽  
Large Scale ◽  
Optimization Problems ◽  
Heuristic Method ◽  
Real Life ◽  
Free Space Optical ◽  
Time Performance ◽  
Run Time

This paper presents a set of graph optimization problems related to free-space optical communication networks. Such laser-based wireless networks require a line of sight to enable communication, thus a visibility graph model is used herein. The main objective is to provide connectivity from a communication source point to terminal points through the use of some subset of available intermediate points. To this end, we define a handful of problems that differ mainly in the costs applied to the nodes and/or edges of the graph. These problems should be optimized with respect to cost and performance. The problems at hand are shown to be NP-hard. A generic heuristic based on a genetic algorithm is proposed, followed by a set of simulation experiments that demonstrate the performance of the suggested heuristic method on real-life scenarios. The suggested genetic algorithm is compared with the Euclidean Steiner tree method. Our simulations show that in many settings, especially in dense graphs, the genetic algorithm finds lower-cost solutions than its competitor, while it falls behind in some settings. However, the run-time performance of the genetic algorithm is considerably better in graphs with 1000 nodes or more, being more than twice faster in some settings. We conclude that the suggested heuristic improves run-time performance on large-scale graphs and can handle a wider range of related optimization problems. The simulation results suggest that the 5G urban backbone may benefit significantly from using free-space optical networks.

Large scale cylindrical cloak in free space without superluminal propagation

2012 ◽  
Author(s):  
Hongsheng Chen ◽  
Su Xu ◽  
Baile Zhang ◽  
Runren Zhang ◽  
Herbert O. Moser ◽  
...  
Keyword(s):  
Free Space ◽  
Large Scale ◽  
Superluminal Propagation
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