• 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.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.221-222
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• 2006

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.1117-1120
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• 2003

DWDM(DensedWavelengthDivisionMultiplexing)은 광 파이버를 이용하여 기존의 통신보다 높은 대역폭(B/W)을 얻기 위한 기술로 여러 신호를 각각 다른 파장으로 변조해 하나의 Fiber 를 통해 전송하는 방식이며, 기본적으로 EDFA(Erbium Doped Fiber Amplifier), AWG(Arrayed Wave guide Grating), OADM(Optical Add/Drop Multiplexer) 등의 주요 부품과 여러 광 관련 부품들로 구성돼 있으며, 다수의 파장을 MUX(AWG)에서 다중화하고, 장거리 전송을 위해 OA(EDFA)에서 광신호를 증폭하게 된다 그리고 일부 특정 파장만 Add/Drop하기 위해 OADM이 놓이게 되며, 또한 선로(광섬유)의 손실을 보상하기 위해 필요한 구간에 리피터(EDFA)를 두어 광신호를 증폭 송신하며 수신단에서는 들어오는 여러 파장을 OA(EDFA)를 통해 증폭한 후 DEMUX(AWG)에서 역 다중화해 수신하게 된다. 이와 같은 DWDM방식을 이용한 Network는 Star, Mesh, Ring 등의 다양한 형태로 구성될 수 있으며, 초기에는 Point-to-Point 방식의 장거리 전송에 주로 사용돼 왔으나 Metro 구간의 Traffic 이 급격히 증가하면서 Metro- DWDM Network 이 부각되고 있어 본 논문에서는 현재 SK Telecom에서 상용화되고 있는 1,600G DWDM과 Metro-DWDM간의 망 구축의 최적화 방안을 연구해 본다.

• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.133-140
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• 1999

When the current optical communication system is used for the DWDM, it raise the serious interference because an interval between the adjacent channels is narrow. The FBG filter for the DWDM is able to reduce the interferences between the adjacent channels. In this paper, therefore, we find the reflection spectrums for the three types of induced index changes, that is, uniform, Gaussian apodized, and raised-cosine apodized. From the obtained results in this paper, we can see that uniform FBG does not fit, and that the smaller the maximum induced index change ${\sigma}$ is and the larger the value of parameter C in the raised-cosine apodized FBG and G in the Gaussian apodized FBG are, the fitter they are on the narrow filter for DWDM. But, we can also see that the raised-cosine apodized FBG has more excellent property than the Gaussian apodized FBG because it has the narrower maximum reflection spectrum band and the lower sidelobes than the other.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.237-240
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• 2001

Dense Wavelength division multiplexing(DWDM) lightwave system requires multiplexer, demultiplexer and optical filter. In this paper, thus, we propose the Add-Drop Mux/Demux based on a Mach-Zehnder interferometer(MZI) with fiber Bragg grating(FBG). The Add-Drop Mux/Demux using FBG and MZI is able to minimize system and reduce weight. We also analyze output characteristics of Add-Drop Mux/Demux and present the optimum design data through the computer simulation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.9-14
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• 2004

Lightwave communication system for Wavelength division multiplexing(WDM) consists of multiplexer, demultiplexer and optical Inter. But, the existing multiplexer, demultiplexer and optical filter is difficult to minimize system and reduce weight because they are not integrated device type. In this paper, thus, we propose the OADM baed on a Mach-Zehnder interferometer(MZI) with FBG(fiber Bragg Slating) in the interferometer Ems. The OADM using FBG. and MZI is able to minimize system and reduce weight. We analyze output characteristics of OADM and present the optimum design data through the computer simulation and experimentation. Also unposed OADM fits for DWDM(Dense WDM) system because of wide bandwidth by tuning narrow linewidth.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.90-99
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• 2007

We demonstrate an 80km-reach 64-channel DWDM-PON based on wavelength-locked F-P LDs by changing the position of the C-band BLS for upstream channels from the CO to the RN. It mitigates the necessity of the high power C-band BLS and its handling problems. It also reduces back scattering induced penalty. We obtained less than $10^{-6}$ PLRs in all 128channels through 80km SMF. We also demonstrate a 240km-reach DWDM-PON based on wavelength-locked F-P LDs by adding a bidirectional erbium-doped fiber amplifier(EDFA). We show packet-loss-free transmission in all 128channels at 125 Mb/s per channel over 240km SMF We report the detuning effect of arrayed waveguide gratings(AWGs) and crosstalk effect in the implemented system. We Propose an architecture of a next generation defense wire communication system with the demonstrated long-reach DWDM-PON.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.10
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• pp.522-531
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• 2001

A large dispersion value in optical fiber cable should be maintained to suppress the nonlinear effect induced distortion for the narrow channel spaced DWDM system while small value of dispersion is needed for high bit rate transmission. To meet these two requirement simultaneously, dispersion distribution control method during the cabling process was exploited. And dispersion distribution cable was fabricated by the way of designing alternation sections in single cable piece with standard single mode fiber(SSMF) and newly developed negative dispersion fiber(NDF). It is shown that the discretely dispersion varying cable along the axis keep the same average dispersion value of an entire cable length as that of nonzero dispersion shifted fiber(NZDSF) with 3.6 ps/km/nm while the local dispersion is around 17 ps/km/nm of absolute value. Moreover, the developed cable had good optical and mechanical properties and the feasibility of this cable for practical use was confirmed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.534-543
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• 2000

In this paper, when the current optical communication system is used for the DWDM. The FBG filter for the DWDN is able to reduce the interferences between the adjacent channels. In this paper, therefore, we find the relection spectrums for the three types of induced index changes, that is, uniform, Gaussian apodized, and raised-cosine apodized. From the obtained result in this paper, we can see that uniform FBG does not fit, and that the smaller the maximum induced index change $\sigma$ is and the larger the value of parameter C in the raised-cosine apodized FBG and G in the Gaussian apodized FBG are the fitter they are on the narrow filter for DWDM.

• Journal of the Optical Society of Korea
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• v.18 no.2
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• pp.118-123
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• 2014

For multi parameter optimization of Raman Fiber Amplifier (RFA), a simple genetic algorithm is presented in the scenario of a 320 channel Dense Wavelength Division Multiplexed (DWDM) system at channel spacing of 25 GHz. The large average gain (> 22 dB) is observed from optimized RFA with the optimized parameters, such as 39.6 km of Raman length with counter-propagating pumps tuned to 205.5 THz and 211.9 THz at pump powers of 234.3 mW, 677.1 mW respectively. The gain flattening filter (GFF) has also been optimized to further reduce the gain ripple across the frequency range from 190 to 197.975 THz for broadband amplification.