Browsing by Author "Wu, Chia-Cheng"

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1D photonic crystal strain sensors
(2018-07-01)
Lu, Tsan-Wen
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Wu, Chia-Cheng
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Lee, Po-Tsung
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光電工程學系
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Department of Photonics
We introduce a photonic crystal nanocavity consisting of one-dimensional periodic nanorods embedded in a deformable polydimethylsiloxane substrate, which exhibits a high-quality factor and a large wavelength response to the applied strain. By further investigating its wavelength response to nonaxial planar strains, we propose and experimentally demonstrate a sensor unit that can precisely identify different planar strains, including their application direction, type, and value. This sensor prototype with small footprint and feasible coupling with optical waveguides could provide additional flexibility for strain analysis in a wide range of fields.
Architecture Exploration and Delay Minimization Synthesis for SET-Based Programmable Gate Arrays
(2018-01-01)
Wu, Chia-Cheng
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Ho, Kung-Han
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Huang, Juinn-Dar
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Wang, Chun-Yao
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電子工程學系及電子研究所
Power consumption has become a primary obstacle for circuit designs at present. Single-Electron Transistor (SET) at room temperature has been demonstrated as a promising device for extending Moore's law due to its low power consumption. Since, only a few electrons are involved in the switching process, the drivability of SETs is ultra-low such that the height of an SET array is limited to a small number. This paper presents a delay minimization synthesis flow that decomposes a circuit into a network of SET Array Blocks (SABs) with a fixed height and width. The experiments were conducted for different sizes of SABs over a set of benchmarks. The experimental results showed that we can have the smallest average Area Delay Product (ADP) when the height is 5 and the width is 10 of an SAB, which indicates that such size of SABs is proper to synthesize SET networks.
Compressible 1D photonic crystal nanolasers with wide wavelength tuning
(2017-06-15)
Lu, Tsan-Wen
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Wu, Chia-Cheng
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Wang, Chun
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Lee, Po-Tsung
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資訊工程學系
We propose and demonstrate a tunable photonic crystal nanolaser consisting of 1D periodic nanorods wrapped in deformable polydimethylsiloxane. In addition to low-threshold and long-term lasing stability, the nanolaser also displays reproducible and reliable wavelength tuning with a large tunability of 7.7 nm under 1% compression. By further associating with stretching, a very wide wavelength-tunable range of 155 nm that almost spans the entire S + C + L telecommunication bands is successfully demonstrated with a single nanolaser device. (C) 2017 Optical Society of America
Constructing an Optimal Spanning Tree Over a Hybrid Network with SDN and Legacy Switches
(2015)
Wang, Shie-Yuan
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Wu, Chia-Cheng
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Chou, Chih-Liang
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資訊工程學系
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Department of Computer Science
In this paper, we design and implement a scheme to build an optimal spanning tree over a hybrid network composed of SDN and legacy switches. SDN is an emerging network technology and gradually gaining adoption worldwide. However, during the technology transition period, which may last several years from now on, inevitably SDN switches and legacy switches will need to coexist in a network. In a legacy network with loops, the IEEE 802.11D distributed spanning tree protocol is used to construct a spanning tree to avoid the packet broadcast storm problem. In an SDN network, the SDN controller can use the collected global knowledge of the network topology to centrally construct a spanning tree to solve this problem. However, so far there is no scheme to integrate together the spanning trees separately built in multiple isolated legacy networks and isolated SDN networks to build an optimal spanning tree across the hybrid network. Our scheme presented in this paper is the first scheme designed and implemented for this purpose. In this paper, we used the EstiNet OpenFlow network simulator and emulator to simulate hybrid networks. Our scheme is implemented as a module of the Floodlight SDN controller to construct an optimal spanning tree over the simulated hybrid networks. Our simulation results show that our scheme can correctly generate an optimal spanning tree based on two performance metrics: the average path latency and the average path throughput of a spanning tree.
Hybridtrace: A Traceroute Tool for Hybrid Networks Composed of SDN and Legacy Switches
(2016)
Wang, Shie-Yuan
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Wu, Chia-Cheng
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Chou, Chih-Liang
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資訊工程學系
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Department of Computer Science
Traceroute is a very useful troubleshooting tool. It reveals the routing path taken by a packet destined to a remote host. Traceroute is originally designed for the legacy IP network. However, the mechanism used by it does not work in an SDN network. In an SDN network, there has been a similar tool called SDN traceroute that provides similar functions as traceroute. However, SDN traceroute does not work in the legacy IP network. Nowadays, hybrid networks composed of both legacy and SDN switches are expected to exist for several years during the transition period. For such a hybrid network, we design and implement a tool called hybridtrace that can reveal the routing path taken by a packet that needs to traverse multiple legacy network islands and SDN network islands to reach its destination. In this paper, we present the design and implementation of hybridtrace, show the path-tracing information provided by it, and demonstrate its functions and operations.