• Journal of the Korean Geophysical Society
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• v.4 no.4
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• pp.297-311
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• 2001

The gain-clamped EDFA has been developed to eliminate the output power change of WDM surving channels to occur with added or dropped channels, which degrades the performance of WDM optical network. It maintains the constant gain of surviving channels when WDM channels are added or dropped in a network amplifying node. In this paper, the bi-directionally pumped gain-clamped EDFA is implemented to compensate the change of the input power by a lasing. The results show that the lasing of a short wavelength and backward propagation is the optimal condition to minimize the transient response of surviving channels in terms of the overshoot and gain saturation due to the inhomogeneous broadening effect.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.82-90
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• 2013

An Optical Network-on-Chip(ONoC) based on silicon photonics is one of promising technology for next generation exascale computing architectures. Recent active researches on ONoC focus on improving bandwidth further and avoiding path collisions by using wavelength division multiplexing (WDM). However, the number of wavelengths used for the WDM increases linearly as the number of Processing Element (PE) increases in existing ONoCs which adopt centralized routing architecture. The problem will also arises growing cost of optical devices such as light switches and light sources and limits the scalability of ONoC due to the sinal loss caused by interference of distinct light sources. In this paper, we proposes a distributed routing architecture for ONoC which is based on 2D-mesh structure using WDM technique and present a method that minimize the required number of wavelengths exploiting the connectivity of communication. In comparison with existing centralized routing architectures, results show reduction by 56% of the number of wavelengths and 21% of the number of optical switches in $8{\times}8$ networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.11
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• pp.1689-1700
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• 1993

WDM(Wavelength Division Multiplexing) based-on fixed wavelengths is a new means of utilizing the bandwidth of optical fibers. In this Paper, an improved virtual topology called "(a, $\beta$,${\gamma}$) ShuffleNet " is introdced for designing large-scale WDM switches. The proposed one is an architecture created by vertically stacking x planes of a ($\beta$,${\gamma}$) ShuffleNet in parallel via $\beta$r nodes called "bridge nodes" so that N-by-N(N=(x*$\beta$${\gamma}$*${\gamma}$) switching is achieved based on the self-routing algorithm for each ($\beta$,${\gamma}$) ShuffleNet. With the topological parallelism, in contrast to the conventional virtual topologies, the diameter of 2${\gamma}$ hops can be fixed and high utilization and performance are provided while N increases. Such a scalability characteristic allows to design a growable broadband switch. As for the delay, we show that the traffic locality, due to the topological feature. result in low delay characteristics.lay characteristics.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.351-354
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• 2008

We demonstrate an ultra-dense wavelength-division- multiplexed (UD-WDM) passive optical network (PON) where 12.5-GHz spaced 1 GbE ${\times}$ 256 optical channels are distributed using 12.5- and 200-GHz arrayed waveguide gratings in series. For the generation of upstream signals, we use reflective semiconductor optical amplifiers. We use two optical fiber amplifiers at the optical line terminal to amplify downstream and upstream channels.

• Electronics and Telecommunications Trends
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• v.19 no.6 s.90
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• pp.43-54
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• 2004

WDM-PON은 가입자망의 트래픽 병목 현상을 해결하고, 다양한 서비스 품질을 제공하면서 고속화된 데이터 전송을 위해 가입자 당 독립 파장을 할당함으로써 가입자의 요구 대역에 제한을 받지 않으며, 보안성이 보장되는 차세대 WDM 기반 수동형 광가입자망이다. 특히 고성능, 저가인 광소자를 포함한 광모듈의 조기개발이 FTTH 네트워크 초기 시장 및 서비스를 선점하는 척도가 될 것으로 예상된다. 본 논문은 WDM 기반 수동형 광가입자망 동작 방식, 광다중화기 및 역다중화기, 그리고 WDM -PON과 WDM 다중화 기술인WDM/TDM, WDM/SCM, WDM/CDM을 포함한 다양한 광 수동 가입자망 구성 기술을 소개한다.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.229-235
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• 2019

As the demand for broadband multimedia including the Internet explosively increases, the advancement of the subscriber network is becoming the biggest issue in the telecommunication industry due to the surge of data traffic caused by the emergence of new services such as smart phone, IPTV, VoIP, VOD and cloud services. In this paper, we have developed WDM(Wavelength Division Multiplexing)-PON(passive optical network) based on the 1-Gigabit Reach Externder (RE) technique to reduce optical core. Particularly, in order to strengthen the market competitiveness, we considered low cost, miniaturization, integration technique, and low power of optical parts. In addition, we have developed a batch system by integrating all techniques for reliability, remote management through the development of transmission distance extension and development of capacity increase of optical line by using RE technology in existing PON network. Based on system interworking with existing commercial 1G PON devices, it can be worthy of achievement of wide nationalization and optical core reduction by using this developed system. Based on these results, we are studying development of 10G PON technology.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.440-448
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• 2012

Optimal net residual dispersion (NRD) and effective launching power range of optical transmission links with optical phase conjugator (OPC) and dispersion management (DM) for compensating the distorted wavelength division multiplexing (WDM) signals due to interaction of group velocity dispersion (GVD) and optical nonlinear effects. WDM systems considered in this research have optical links with the random distribution of residual dispersion per span (RDPS) in each single mode fiber (SMF) spans of only one half transmission section for designing the adaptive optical transmission system configurations. It is confirmed that optimal NRD is 10 ps/nm and effective launching power range is obtained to be -8~1 dBm under NRD = 10 ps/nm in optical links with total dispersion controlled by precompensation. And, it is also confirmed that optimal NRD is -10 ps/nm and effective launching power range is obtained to be -7.5~1 dBm under NRD = -10 ps/nm in optical links with total dispersion controlled by postcompensation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.2
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• pp.1-5
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• 2007

Wavelength-division multiplexed (WDM) networks are emerging to be the right choice for the future transport networks. In WDM networks, the optical layer provides circuit-switched lightpath services to the client layer such as IP, SONET and ATM. The set of lightpaths in the optical layer defines the virtual topology. Since the optical switches are reconfigurable, the virtual topology can be reconfigured in accordance with the changing traffic demand pattern at theclient layer in order to optimize the network performance. We present a new approach to the virtual topology reconfiguration and loadbalancing problem for wavelength-routed, optical wide-area networks under dynamic traffic demand. By utilizing the measured Internet backbone traffic characteristics, our approach follows the changes in traffic without assuming that the future traffic pattern is known. For the simulation traffic modeling, we collected the data from real backbone traffic. Experiments show that the standard deviation compared to previous technique is reduced.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.354-357
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• 2001

Optical transport has been sucessfully developed as a fast information transfer since 1970s, and a WDM system, based on the wavelength division multiplexing technique, was implemented to the backbone network. The WDM technique is able to improve its data traffic by utilizing its optical fiber efficiently, and is suitable for an easy network operation and management. Therefore, trend for DWDM, which is known to be one of DWM system being currently used, and the direction for optical network development will be investigated in this study.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.283-286
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• 2008

This article describes developments in fiber to the home (FTTH), and introduces the technical reviews for the various types to realize FTTH. Also, we have presented the results of each EPON, GPON and WDM-PON standardization by each IEEE, ITU-T and TTA. Finally, based on the above results, we proposed the trend of FTTH service deployment strategies.