• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.893-899
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• 2000

WDM technology has been an emerging issue for the efficient use of optical links. WDM uses a number of different wavelengths that are assigned to each channel. The minimal number of optical transcievers and receivers should be used in a node to build an economic WDM transmission system without degrading system performance. Hence, the analysis of performance parameters such as throughput and delay is important to guarantee the WDM system performance. In this paper, the performance of a MAC protocol on a slotted WDM system that has a tunable transmitter(TTX), a tunable receiver(TRX), and a fixed receiver(FRX), respectively, on each node, was statistically analyzed. The computer simulation validates the performance analysis.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.131-135
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• 2003

WDM(Wavelength division multiplexing) light wave communication system requires MUX/DeMUX and optical filter OADM can be used to extract and add the specific wavelength channel from the transmission line. In this paper, we propose the OADM based on MZI and cascade FBG. It is able to minimize system and reduce sidelobe. So, we have considered MZI structure and 3dB coupler. Using the coupled mode theory. We also analyze out characteristics of OADM and experiment. From results obtained by experiment and computer. Simulation, the proposed OADM with cascade FBG works well. we hope that the obtained result in this paper con be used as the data to design the OADM with cascade FBG.

• ETRI Journal
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• v.24 no.2
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• pp.131-141
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• 2002

This paper considers a routing and wavelength assignment problem (RWAP) for the implementation of efficient Wavelength Division Multiplexing all-optical mesh networks without wavelength conversion. For a given physical network and required connections, the solution to the RWAP consists in how to select a suitable path and wavelength among the many possible choices for each connection so that no two paths using the same wavelength pass through the same link, while minimizing the number of required wavelengths. We introduce an integer programming formulation of the RWAP, which has an exponential number of variables, and propose an algorithm to solve it based on the column generation technique. The proposed algorithm can yield high quality solutions and tight lower bounds at the same time. Though the proposed algorithm cannot guarantee optimal solutions, computational results show that the algorithm yields provably good solutions within a reasonable time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.1
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• pp.159-169
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• 1994

A multichannel optical slotted ring network is designed using a wavelength division multiplexing(WDM) technique and photonic packet switching devices. The electronics speed bottleneck is removed out of the ring, which allows utilization of the full bandwidth for the optical fiber transmission medium. The ring channel adopts a slotted ring concept with a destination cell remove strategy for the eing access mechanism. The slot size in the ring is selected as the same as that of ATM based cell in order to be used as B-ISDN Access Networks. In this paper, we devised a mathematical method to measure the average transfer delay characteristics of the network. The analytical method turned out to yield accurate results over a broad range of parameters in comparison to simulation results. From the study, we observed the average transfer delay of the network as the network parameters vary.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4B
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• pp.351-360
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• 2003

All-optical network provede unlimited for bandwidth, the very low bit error rate, and the transparency to IP. Optical networks promise to be the next generation networks that can meet the higher bandwidth demands. However, the number of wavelengths is often not large enough to help a large amount of nodes. The blocking by wavelength contention can be reduced by wavelength conversion, which can't perfectly resolve all situations. Because of that, a lot of groups have proposed unique wavelength assingment algorithms and protocols. Most schemes don't support the priority concepts. This paper describes the unique priority scheme based on the throughput. In this paper, we apply our priority scheme to SWAP(Simple Wavelength Assignment Protocol) and show the performance of the proposed priority scheme. Our proposed priority scheme can be a better solution to solve an important problem about the blocking by wavelength contention into WDM optical networks.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.7
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• pp.507-517
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• 2003

A single fiber failure in mesh-based WDM networks may result in the loss of a large number of data. To remedy this problem, an efficient restoration algorithm for a single fiber failure in the mesh- based WDM network is necessary. We propose a new algorithm for restoration scheme in WDM networks and compare it with previous schemes. Path restoration and link restoration are two representative restoration schemes which deal with only a single link failure. In this paper, we propose two kinds of efficient restoration scheme. In the proposed schemes the restoration path for each link failure is not secured. The mesh network is decomposed into a number of small loops. In one algorithm, any link failure in a certain loop is regarded as the failure of the loop and the restoration lightpath is selected by detouring the failed loop. In another scheme any link failure in a certain loop is restored within the loop. We compare performance of the proposed schemes with conventional path restoration scheme and link restoration scheme. Simulation results show that CPU time in the proposed schemes decreases compared with that in path restoration scheme and link restoration scheme, although total wavelength mileage usage increases by 10% to 50%.

• Korean Journal of Optics and Photonics
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• v.13 no.1
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• pp.44-50
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• 2002

A new wavelength demultiplexing scheme using holographic volume phase grating formed in photopolymer is proposed and demonstrated. Through the analysis and experiments of the design parameters such as wavelength selectivity, operating spectral range, spatial channel distance and spatial intensity distribution of each channel, we proved that the proposed demultiplexing scheme is promising for wavelength division multiplexing (WDM). From the experimental results, the 3 dB bandwidth of 0.21nm and the crosstalk level of 26 dB for a 0.8 nm channel spacing are observed.

• Information and Communications Magazine
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• v.15 no.7
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• pp.144-157
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• 1998

100Gb/s급 WDM (Wavelength Division Multiplexing) 광전송시스템은 10Gb/s 신호 (STM-64) 를 최대 16채널까지 파장분할다중화하는 광전송시스템으로서 단국형 모드 (TM: Terminal Mode)와 분기결합형 모드(ADM: Add-Drop Mode)를 고려한 통합형 구조로 설계, 구현되었다. 본 시스템은 10Gb/s 광신호를 싣는 각각의 채널파장(채널파장간격: 1.6nm)에 최대 16개(파장영역: $1536.61\sim1560.61nm$)까지 광채널 신호를 결합하여 하나의 광섬유로 전송하는 기능을 갖는다. 또한 광전달망 계층구간의 감시제어 기능과 시스템 운용관리 기능 및 사용자 터미널 접속 기능을 수행하는 감시제어 기능을 갖는다. 본 고에서는 개발중인 100Gb/s급 WDM 광전송시스템의 시스템개요, 하드웨어 구현, 감시제어 구현, 다채널 광전송 실험 등에 관해서 기술한다.

• ETRI Journal
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• v.28 no.1
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• pp.99-102
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• 2006

In this letter, we study the protection problem in wavelength division multiplexing (WDM) optical networks, and propose a novel dynamic heuristic algorithm called differentiated reliable segment protection (DRSP). Differing from previous work, DRSP can effectively avoid the trap problem and is able to find a feasible solution for each connection request. Therefore, DRSP outperforms the previous work. Simulation results have shown to be promising.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.17-20
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• 1999

In these days, wavelength division multiplexing(WDM) all-optical network are being deployed to support various multimedia communication services. In this paper, various WDM all-optical network are discussed, and a design of an all-optical backbone network has been proposed by using multiple self-healing ring technology. The proposed multiple self-healing ring network improves network expandability and efficiency of bandwidth, while it retains simplicity and ease of network control, which are from the nature self-healing ring. Using PDI traffic modeling technique, a well-balanced all-optical backbone network using multiple self-healing ring is designed for the 2010s in Korea.