• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.372-376
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• 2009

In this paper, new and simple optical transmission link with fixed dispersion management (DM) scheme, i.e., pre(post) compensation and residual dispersion per span (RDPS) are fixed to net residual dispersion (NRD) = 0 ps/nm, and optical phase conjugator (OPC) having optimal position depending on launch power in WDM transmission system is proposed. Also, effective launch power range of WDM channels resulting 1 dB eye opening penalty (EOP) is induced as a function of OPC position. First, it is confirmed that, for applying DM into WDM transmission link fixed pre(post)compensation and RDPS, which are independence on exact system parameters except launch power, sufficiently are used in WDM links, but OPC with optimal position is needed for effective compensating impairments of WDM channels. And, it is confirmed that effective launch power is broader in case of RDPS = 100 ps/nm than in RDPS = 50 ps/nm. But, it is shown that the best OPC position offset is -0.6 km from a point of view of power window, which is defined as difference between maximum and minimum effective launch power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.813-817
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• 2000

A bidirectional 4-fiber path switched WDM ring is proposed, which provides 1:1 system protection for a digital client layer such as SONET system. It can provide better optical SNR than usual bidirectional line switched ring. Two implementation schemes are proposed and especially, a distributed control scheme is found to be feasible in simple structure with good performance even without supervisory channel.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.35-43
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• 2019

A metro ring network using WDM technology requires many issues to be considered even though its transmission distance is shorter and its transmission capacity is lower than a long-haul WDM system. Unlike a long-haul WDM system, which is basically point-to-point configuration, a metro ring network usually equips with capabilty of wavelength reconfiguration. Therefore network performance considering crosstalk within OADM and the network behavior when the ring network is closed should be analyzed before implemented. We discussed some of results analyzed for the issues. Furthermore we proposed a novel method to design a dispersion map for a ring network, and demonstrated the methodology with an exemplary 8-node ring network of 399km circumference.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.656-661
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• 2009

High-quality transmission of $24{\times}40$ Gbps WDM signals obtained through controling residual dispersion per span (RDPS) in optical transmission links with zero net residual dispersion (NRD) of inline dispersion management (DM) of optical transmission links is researched. It is confirmed that RDPS values, which is improving system performance, depends on launch power of WDM channels, but optimal RDPS, which can simultaneously improve WDM signals with relative wide launch power ranges, becomes to be 210~230 ps/nm. Also, it is shown that effective launch power range that making eye opening penalty (EOP) of worst channel to below 1 dB is more increased as RDPS is more increased.

• Journal of Advanced Navigation Technology
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• v.7 no.1
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• pp.14-21
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• 2003

We investigated the optimum pump light power compensating distorted WDM signal due to both chromatic dispersion and self phase modulation (SPM). The considered system is $3{\times}40$ Gbps intensity modulation direct detection (IM/DD) WDM transmission system with path-averaged intensity approximation (PAIA) mid-span spectral inversion (MSSI) as compensation method. This system have highly nonlinear dispersion shifted fiber (HNL-DSF) as nonlinear medium of optical phase conjugator (OPC) in the mid-way of total transmission line. We confirmed that HNL-DSF is an useful nonlinear medium in OPC for wideband WDM transmission, and the excellent compensation is obtained when the pump light power of HNL-DSF OPC was selected to equalize the conjugated light power into the second half fiber section with the input WDM signal light power depending on total transmission length. By this approach, it is verified the possibility to realize a long-haul high capacities WDM system by using PAIA MSSI compensation method, which have HNL-DSF OPC with optimal pump light power depending on transmission length.

• Journal of the Korean earth science society
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• v.41 no.1
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• pp.1-18
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• 2020

This study presented the effects of the assumed mass-size relationship for snow on the simulated surface precipitation by using cloud microphysics parameterizations in Weather Research and Forecasting (WRF) model. The selected cloud microphysics parameterizations are WRF Double-Moment 6-class (WDM6) and WRF Single-Moment 6-class (WSM6) in the WRF model. We replaced the mass-size relationship for snow in WDM6 and WSM6 with Thompson's mass-size relationship retrieved from measurement data. The sensitivity of the modified WDM6 and WSM6 was tested for the idealized 2-dimensional squall line and winter precipitation system over the Korean peninsula, respectively. The modified WDM6 and WSM6 resulted in the increase of graupel/rain mixing ratios and the decrease of snow mixing ratio in the low atmosphere. The changes of hydrometeor mixing ratio and surface precipitation could be due to the collision-coalescence process between raindrops and snow and the graupel melting process.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.429-434
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• 2007

광 위상 공액기(OPC ; Optical Phase Conjugator)를 이용하여 WDM 채널들의 광 신호의 왜곡을 보상하는 MSSI (Mid-Span Spectral Inversion) 기술에서 OPC를 중심으로 한 광 전력과 색분산 비대칭에 의한 한계를 OPC의 위치 변동과 그에 따른 광섬유 구간의 최적 분산 계수들의 적용만으로도 극복할 수 있다는 것을 살펴보았다.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.472-474
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• 2005

In WDM/SCM-PON system more than thousand signals must be gathered to monitor for operation. We have implemented IEEE STD 1149.1 JTAG serial interface bus to gather and monitor analog signals. Required area is just $5{\times}5mm^2$. Gathering time per one signal is $1.75{\mu}$ second. Performance to gather is better than that defined in SFF-8472.

• Journal of Advanced Navigation Technology
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• v.15 no.2
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• pp.248-255
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• 2011

An investigation has been carried out, by computer simulation, to evaluate the impact of dispersion compensation configurations on 960 Gbps wavelength division multiplexed (WDM) system with optical phase conjugator (OPC). The considered dispersion compensation configurations in this research are conventional one-end type and bi-end type. One-end and bi-end type are made by using one dispersion compensating fiber (DCF) and two DCFs to decrease dispersion accumulated in one single mode fiber (SMF) span, respectively. It is found that bi-end compensation configuration offers the equal performance with that of one-end configuration in WDM system with residual dispersion per span (RDPS) of 400 ps/nm if net residual dispersion (NRD) had to be optimized in each cases.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.62-63
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• 2002