• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.9A
• /
• pp.1395-1404
• /
• 2000

In this paper, we propose a heuristic wavelength routing algorithm for IP datagrams in WDM (Wavelength-Division Multiplexing) networks which operates in a distributed manner, while most previous works have focused centralized algorithms. We first present an efficient construction method for a loose virtual topology with a connectivity property, which reserves a few wavelength to cope with dynamic traffic demands properly. This connectivity property assures that data from any source node could reach any destination node by hopping one or multiple lightpaths. We then develop a high-speed distributed wavelength routing algorithm adaptive to dynamic traffic demands by using such a loose virtual topology and derive the general bounds on average utilization in the distributed wavelength routing algorithms. Finally, we show that the performance of the proposed algorithms is better than that of the FSP(Fixed Shortest-Path) wavelength routing algorithms through simulation using the NSFNET[1] and a dynamic hot-spot traffic model, and that the algorithms is a good candidate in distributed WDM networks in terms of the blocking performance, the control traffic overhead, and the computation complexity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.10a
• /
• pp.439-441
• /
• 2012

A new wavelength tunable laser source based on a self-seeded F-P LD for a WDM-PON system has been proposed in this paper. The proposed laser source has a merit of the wavelength tunable range of approximately 20 nm with very simple setup. The measured minimum relative intensity noise(RIN) was approximately -124 dB/Hz and the possibility of 10 Gb/s external modulation was showed.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.38 no.6
• /
• pp.1-10
• /
• 2001

In this paper, we propose a synchronous reservation protocol that is efficient for supporting variable sized messages in a wavelength division multiplexing (WDM) based local network using a passive star topology. A. control channel is used to coordinate transmission on data channels. Time is slotted with fixed-sized slots. The network can accommodate a variable number of nodes, and can operate independently of the change of the number of nodes. So, any 'new' node can join the network anytime without network re-initialization. Moreover, with the protocol, we can avoid data channel and destination conflicts. We analyze the performance by using EPA method according to the variation of the end to end propagation delay with respect to one slot time, and validate the results by simulation.

• Journal of Advanced Navigation Technology
• /
• v.17 no.4
• /
• pp.413-420
• /
• 2013

The design rule depending on total transmission length is induced in the optical links with residual dispersion per span (RDPS) of the random distribution, which is adopted for implementing the flexible systems of wavelength division multiplexing (WDM) transmission with dispersion management (DM) and optical phase conjugation. DM parameters used for the analysis of the design rule are the effective net residual dispersion (NRD) and the effective launch power. It is confirmed that the flexible optical network configuration with the total transmission length lower than 1,000 km is possible, because the system performance difference between the randomly distribution and the uniform distribution of RDPS is small. And, in the optical links with the randomly distributed RDPS, the wide NRD can be applied for transmitting WDM channels of the relatively wide launch power.

• ETRI Journal
• /
• v.28 no.3
• /
• pp.329-336
• /
• 2006

This paper investigates the problem of protecting multicast sessions in mesh wavelength-division multiplexing (WDM) networks against single link failures, for example, a fiber cut in optical networks. First, we study the two characteristics of multicast sessions in mesh WDM networks with sparse light splitter configuration. Traditionally, a multicast tree does not contain any circles, and the first characteristic is that a multicast tree has better performance if it contains some circles. Note that a multicast tree has several branches. If a path is added between the leave nodes on different branches, the segment between them on the multicast tree is protected. Based the two characteristics, the survivable multicast sessions routing problem is formulated into an Integer Linear Programming (ILP). Then, a heuristic algorithm, named the adaptive shared segment protection (ASSP) algorithm, is proposed for multicast sessions. The ASSP algorithm need not previously identify the segments for a multicast tree. The segments are determined during the algorithm process. Comparisons are made between the ASSP and two other reported schemes, link disjoint trees (LDT) and shared disjoint paths (SDP), in terms of blocking probability and resource cost on CERNET and USNET topologies. Simulations show that the ASSP algorithm has better performance than other existing schemes.

• Journal of the Optical Society of Korea
• /
• v.11 no.1
• /
• pp.44-48
• /
• 2007

A two-stage gain-clamped erbium doped fiber amplifier (GC-EDFA) using a pump laser diode and a 16 channel wavelength division multiplexing (WDM) with 0.8 nm spacing in C band of $1,545{\sim}1,560nm$ wavelength is experimentally demonstrated for a burst packet mode optical switching system.

• The Optical Journal
• /
• s.96
• /
• pp.55-59
• /
• 2005

광섬유격자 제조기술과 응용기술의 개발은 다양한 응용분야와 관련하여 광산업분야에 필수적인 요소이다. 또한 평판형 광도파로격자소자는 DWDM등 광전송 기술산업에 핵심적이고 원천적인 연구로서, WDM(Wavelength Division Multiplexing: 파중분할다중방식), Add/Drop Multiplexer 등 분야에 대한 응용기술연구가 필요하다. 광섬유 브래그격자(FBG: Fiber Bragg Grating)는 광통신 시스템의 핵심부품 중 하나이다. 제작공정의 특성상 다른 부품에 비하여 삽입손실(Insertion Loss)이 매우 작고, Fiber Laser, Laser wavelength stabilization, 광섬유 증폭기의 pump reflector, add/drop filter, optical circulator, 광증폭기의 이득평탄화 등 매우 다양한 응용분야를 가지고 있으며, 향후 수요시장이 대폭 증가할 것으로 기대된다.

• Korean Journal of Optics and Photonics
• /
• v.13 no.2
• /
• pp.113-116
• /
• 2002

We demonstrate 16 ch.$\times$2.5 Gb/s WDM transmission over 10,880 km using a re-circulating loop and forward error correction (FEC) code. The performances of all 16 channels were measured to be lower than 10$^{-10}$ .

• Proceedings of the IEEK Conference
• /
• 2003.11c
• /
• pp.121-124
• /
• 2003

Passive optical networks (PONs) will be the pervasive choice in the design of next-generation access networks. One possible solution to implementing Passive optical access network is to rely on wavelength-division multiplexing (WDM). In this paper, we solve the problem of providing real-time service to both hard and soft real-time messages in conjunction with a conventional vest-effort service in WDM. we propose an adaptive scheduling algorithm to schedule and manage the message transmissions in the optical access network. Proposed algorithm is MLF-MQF. Also, we suggest dynamic bandwidth algorithm(DBA) in Loop-back WDM-PON (LPB-PON).our mechanism based on bandwidth reservation protocol.

• Korean Journal of Optics and Photonics
• /
• v.16 no.2
• /
• pp.143-145
• /
• 2005

We demonstrated 5.12-Tb/s($l28 ch \times 43 Gb/s$) WDM transmission over 200 km of medium dispersion fiber. The spectral efficiency was 0.8-(bits/s)/Hz. After transmission, the average Q-factor was measured to be 15.2 dB.