• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.469-474
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• 2006

A $1{\times}16$ thermo-optic switch with small excess loss using multimode interference(MMI) couplers is designed, fabricated, and measured. This paper introduces the proposed $1{\times}16$ thermo-optic switch, and discusses the measurement results. The $1{\times}16$ thermo-optic switch is farmed as 4-stage which consists of 15 unit devices. The unit devices are the $2{\times}2$ thermo-optic switches with Mach-Zehnder interferometer(MZI) structure. The characteristics of the $1{\times}16$ thermo-optic switch depends strongly on each unit device. The unit deviceconsists of two 3-dB general interference MMI couplers and two single mode waveguide arms as a phase shifter. First of all, the 3-dB optical splitter and $2{\times}2$ MZI thermo-optic switch have been tested to confirm the characteristics of the unit devices of the $1{\times}16$ MZI thermo-optic switch. Using the measurement results of the unit devices, the $1{\times}16$ MZI thermo-optic switch can be produced with better characteristics. The resultant structure of the MMI coupler with the optical light source of wavelength of 1550nm for the $1{\times}16$ thermo-optic switch is that the width and the optimized length are $25{\mu}m\;and\;1580{\mu}m$, respectively. The smallest excess loss fur the unit device is -0.5dB and the average excess loss is -0.7dB.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.9
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• pp.23-30
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• 2000

The performance of two types of surface reflecting all-optical switches with InGaAs/InAlAs multiple quantum wells are investigated. The absorption spectra and the refractive index changes of the quantum well are calculated for various pump and probe beam intensities and device conditions. From theses results, on ON/OFF ratio and switching speed of the two switches are compared. It is shown that the switch using DBR has higher ON/OFF ratio and higher switching speed than the switch without DBR.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.971-978
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• 2018

This paper deals with the design and implementation of a limiter, which is a key component of the Ku-band radar system. The limiter design with the multi-pin diode switch was complemented by wideband signal attenuation, and realized the physical implementation. In the test result of implemented limiter, when the pin diode switch is all off, it is possible to transmit the incoming signal without distortion. Also when the pin diode switch is turned on sequentially, the input signal is attenuated about 20dB or more step by step. Finally when all of them were turned on, attenuation about 50dB or more were measured for a wide bandwidth(1000MHz) in Ku-band.

• Journal of the Korea Society of Computer and Information
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• v.11 no.1 s.39
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• pp.157-165
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• 2006

This paper proposes a new output-buffered multicast ATM switch with tandem crosspoints switching fabric, named the MTCOS(Multicast Tandem Crosspoint Output-buffered Switch). The MTCOS consists of multiple simple crosspoint switch fabrics, named TCSF(Tandem Crosspoint Switch Fabric) , and concentrated output buffers for efficient multicasting. The TCSF resolves the cell delay deviation problem which the self-routing crossbar switches inherently have. Further, it offers multiple concurrent pathes from one input to multiple output ports. It also provides multi-channel switching by easy software configuration and has several desirable characteristics such as scalability, high Performance, and modularity. A shared traffic concentration and output queuing strategies of the MTCOS results in lower cell loss as well as lower cell delay time over a wide range of multicast traffic. Furthermore, it has lower hardware complexity than that of the SCOQ and Knockout multicast switch to achieve the same Knockout concentration rate as the conventional switches. It is shown that the proposed switch can be easily applied to design high performance for any multicast traffic by analytic analysis and computer simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.2
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• pp.181-186
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• 1998

This paper presents multiplexing structures to provide various subscriber interfaces in an ATM switching system with a high speed internal link, and analyzes the schemes in terms of a mean cell delay and a buffer sin. And we proposed a buffer management strategy to minimize a cell loss and accommodate new ATM transfer capabilities.

• Journal of the Korea Society of Computer and Information
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• v.4 no.1
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• pp.68-75
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• 1999

In this paper, we propose a Baysian method estimating system reliability which is more effective and precise than conventional methods using prior information. This technique estimates system reliabilities that an entire system and multiprocessing system is normally working in multiprocessor system and multiple port connected memory architecture. The reason is why internetwork with multiprocessor system is mainly connected as multiple bus structure, crossbar switching structure and multiport connected memory structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10C
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• pp.937-944
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• 2002

The current fast-growing Internet traffic is demanding more and more network capacity. Photonic packet switching offers high-speed, data rate/format transparency, and configurability, which are some of the important characteristics needed in future networks supporting different forms of data. In this paper, we define that optical backbone networks for IP transport consist of optical packet core switches and optical fibers. We propose a multi-link photonic packet switch managing as single media which unifies the whole bandwidth of multiple wavelengths on the optical fiber in the WDM optical networks. The proposed switch uses optical packet memories of output link equally as well as using the WDM buffer. So it cuts down the required number of buffers and realizes of the optical packet memory economically.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9B
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• pp.1631-1642
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• 1999

In this paper, we propose a new fault tolerant ATM Switch and a new adaptive self-routing scheme used to make the switch to be fault tolerant. It can provide more multiple paths than the related previous switches between an input/output pair of a switch by adding extra links between switching elements in the same stage and extending the self-routing scheme of the Banyan network. Our routing scheme is as simple as that of the banyan network, which is based on the topological relationships among the switching elements (SE’s) that render a packet to the same destination with the regular self-routing. These topological properties of the Banyan network are discovered in this paper. We present an algebraic proof to show the correctness of this scheme, and an analytic reliability analysis to provide quantitative comparisons with other switches, which shows that the new switch is more cost effective than the Banyan network and other augmented MIN’s in terms of the reliability.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.223-229
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• 2023

This papart proposes single pole double throw (SPDT) switch with six-stage radial stub resonators in the 3.6~4.0 GHz band. The switch was simulated using ADS (Advanced Design Software), a design tool for the wireless communication circuits, and evaluated on a pcb substrate. The measurement results of the radial SPDT switch showed an average 90 dB isolation, and 1.5 dB insertion loss. This isolation characteristic was 20 dB superior to higher than those laboratory or commercial products reported thus far. The proposed SPDT switch is applicable to multi-band RF front-end systems, such as WiMAX, LTE/5G, Wi-Fi, and HyperLAN.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.46-53
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• 2009

A new zero-current switching LLC resonant post-regulator for multi-output power system is proposed in this paper. A conventional LLC resonant converter employs extra non-isolated DC/DC converters to obtain tight-regulated multi-slave output voltages. Therefore, it has several serious problems such as a poor efficiency and high cost of production. The proposed post-regulator features low voltage and current stress across the output rectifier diodes and power switches. Moreover, the proposed post-regulator requires only one power switch instead of the bulky and expensive non-isolated DC/DC converter. Therefore, it features a simple structure and lower cost. Especially, since the proposed post-regulator can ensure the ZCS of all power switches, it has very desirable advantages such as more improved EMI characteristics and reduced switching losses. Finally, to confirm the operation, validity, and features of the proposed circuit, experimental results from a proposed zero-current LLC resonant post-regulator are presented.