• Journal of the Optical Society of Korea
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• v.1 no.1
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• pp.52-59
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• 1997

In this paper, we propose a system design for a parallel3-dimensional optical interconnection network utilizing variable grating mode liquid crystal devices (VGM LCD's) which are optical transducers capable of performing intensity-to-spatial-frequency conversion. The proposed system performs real-time, reconfigurable, but blocking and nonbroadcasting 3-dimensional optical interconnections. The operating principles of the 3-D optical interconnection network are described, and some of the fundamental limitations are addressed. The system presented in this paper can be directly used as a configuration of switching elements for the 2-D optical perfect-shuffle dynamic interconnection network, as well as for a B-ISDN photonic switching system.

• ETRI Journal
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• v.24 no.4
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• pp.311-322
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• 2002

Presently, optical burst switching (OBS) technology is under study as a promising solution for the backbone of the optical Internet in the near future because OBS eliminates the optical buffer problem at the switching node with the help of no optical/electro/optical conversion and guarantees class of service without any buffering. To implement the OBS network, there are a lot of challenging issues to be solved. The edge router, burst offset time management, and burst assembly mechanism are critical issues. In addition, the core router needs data burst and control header packet scheduling, a protection and restoration mechanism, and a contention resolution scheme. In this paper, we focus on the burst assembly mechanism. We present a novel data burst generation algorithm that uses hysteresis characteristics in the queueing model for the ingress edge node in optical burst switching networks. Simulation with Poisson and self-similar traffic models shows that this algorithm adaptively changes the data burst size according to the offered load and offers high average data burst utilization with a lower timer operation. It also reduces the possibility of a continuous blocking problem in the bandwidth reservation request, limits the maximum queueing delay, and minimizes the required burst size by lifting up data burst utilization for bursty input IP traffic.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2464-2466
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• 1998

A switch is a component with two or more ports that selectively transmits, redirects, or blocks optical power in a fiber transmission line. Our switch uses rotation mechanism using stepping motor, hence the common optical fiber can scan and allign to one of the arrayed N optical fibers to provide optical path by electronic precise control. The developed switch is consisted of switching module and its control module. The performance parameters of a switching loss and a repeatability are considered very important. We performed the study to reduce the switching loss and improve the repeatability of switch. The switch can be widely used as a test instrument of optical device and of optical cable in factory, also of optical cable monitoring systems.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.5
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• pp.60-70
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• 1995

As a Basic study to implement a wide-band photonic switching sysetm, we proposed a scheme of free-space-division-multiplexed photonic switching based on a holographic interconnectio method and carried out simple experiments on it. First, we recorded holgraphic interconnection element array for nonblocking optical interconnections. Just a single stage of the array realizes full optical interconnections between NN${\times}$NN input prots and NN${\times}$NN output ports in 3-D space. Next, in reading of the array for optical internnections, we showed that the zeroth-order diffacted beam could be eliminated in the output port by introducing a right angle prism. The elimination of the zeroth-order diffracted beam reduces optical noise in the output ports and provides conveniences of interconnection control in our scheme. Finally, from the experiments on ON-OFF switching of the optical interconnection paths one by one using a spatial (display of the liquid crystal telecision), we showed the feasibility of photonic wsitching based on the holographic interconnection method. We also estimated approximately the maximum interconnectio scale that can be realized without difficulty with current optical devices.

• ETRI Journal
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• v.30 no.1
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• pp.164-166
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• 2008

This paper proposes a priority-based duplicate burst transmission mechanism in an optical burst switching network to enhance the probability of successful reception of bursts. The performance of the proposed mechanism is evaluated by NS2 simulations. Our results show that the burst loss rate is improved especially under light traffic loads.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.149.2-149
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• 1998

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.177-180
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• 2000

Optical burst switching(OBS) is a new switching paradigm to supporting bursty traffic on the Internet efficiently. OBS separates burst level and control level. To handle data burst efficiently, the scheduling schemes in optical burst switching systems must keep track of future resource availability when assigning arriving data bursts to wavelength channels. In this paper, we evaluate the performance of three scheduling schemes which are called Horizon, Single-gap and Multiple-gap, as a basic study for the future research of Optical Internet. Thus, firstly, we analyze the trade-off between the performance and the processing overhead of each scheme. In addition, the performance of OBS system which uses Multiple-gap scheduling is evaluated in detail under various network size. We use simulation for performance evaluation in terms of burst loss rate(BLR), wavelength channel utilization and the number of management data.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1547-1549
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• 1996

The electrical and optical switching characteristics of gold-doped silicon p-i-n diodes have been investigated. The device shows a dark switching voltage of about 500 V. The switching voltage decreases rapidly when the illumination level is increased. The differential sensitivity of optical gating over linear region is $d(V_{Th}/V_{Tho})/dP_{Ph}$=0.25/uW. The turn-on delay time and the turn-on rise time decrease with increasing optical pulse power. The turn-off delay and the fall time are negligible.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3955-3966
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• 2014

With the exponentially increasing Internet traffic and emergence of more versatile and heterogeneous applications, the design of datacenter networks (DCNs) is subject to unprecedented requirements for larger capacity and more flexible switching granularities. Envisioning Optical-Orthogonal Frequency Division Multiplexing (O-OFDM) as a promising candidate for such a scenario, we motivate the use of O-OFDM as the underlying switching technology in order to provide sufficient switching capacity and elastic bandwidth allocation. For this purpose, this article reviews the recent progresses of DCN deployment and assesses the scenario where the O-OFDM transmission and switching technology is employed in the underlying transport plane. We discuss the key issues of the datacenter-oriented O-OFDM optical networks, and in particular, elaborate on a number of open issues and solutions including system interconnection architecture, routing and resource assignment, survivability, and energy-efficiency.

• Electrical & Electronic Materials
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• v.4 no.2
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• pp.159-174
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• 1991

이중주입효과에 의한 고내압 반도체 스위칭소자의 설계 제작에 촛점을 맞추어 Injection Gate구조와 MOS Gate 구조로 시료소자를 제작해 그 특성을 검토하고 Electrical Switching 및 Oxide막에서의 Breakdown현상에 의한 문제점을 해결해 보고자 Optical Gate구조를 제안하여 이 optically Gated Semiconductor Switching 소자의 동작특성을 연구하고 Injection Gate 구조를 제안하여 이 optically Gated Semiconductor Switching 소자의 동작특성을 연구하고 Injection Gate 및 MOS Gate 구조(Planar type, V-Groove type, Injection Gate mode, Optical Gate mode)로 설계제작된 소자와 특성을 비교 분석하였다.