• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.450-451
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• 2008

In this paper, we have designed the Anti-Reflection (AR) coating for 850, 1310 nm(multi type) and 1310, 1550 nm(multi type) wavelength ranges on the ferrule facet of special optical connector. The reflectance of the AR coated ferrule facet is designed under 5% for 850, 1310 nm(multi type) and 1310, 1550 nm (multi type). AR thin film was deposited by ion- assisted deposition in low temperature. The average return loss of the AR coated ferrule facet is 47.1 dB.

• Journal of the Optical Society of Korea
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• 제15권3호
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• pp.227-231
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• 2011

An external optical modulation using absorption s in a Fabry-Perot laser diode (FP-LD), has been proposed and experimentally demonstrated for multicasting in a WDM-PON. The center wavelengths of absorption s in an FP-LD move to short-wavelength rapidly by only a small current (~1 mA) injection. If the current injection is stopped, the s move back to the original position. Such a movement of the s can make the FP-LD act as an external optical modulator, which is found to modulate at a maximum modulation speed of 800 Mbps or more. For a multicasting transmitter in a WDM-PON, the proposed modulator can be cost-effectively applied to a multi-wavelength laser source with the same periodicity of the longitudinal mode. Instead of the multi-wavelength laser source, tunable-LDs are used for experiments. The 32 channel multicasting system with the proposed modulator has been demonstrated, showing power penalties of 1.53~4.15 dB at a bit error rate of $10^{-9}$ with extinction ratios better than 14.5 dB at 622 Mbps.

• ETRI Journal
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• 제28권5호
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• pp.631-637
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• 2006

In this paper we study the optimization issues of ring networks employing novel parallel multi-granularity hierarchical optical add-drop multiplexers (OADMs). In particular, we attempt to minimize the number of control elements for the off-line case. We present an integer linear programming formulation to obtain the lower bound in optimization, and propose an efficient heuristic algorithm called global bandwidth resource assignment that is suitable for the design of large-scale OADM networks.

• 대한전자공학회논문지TC
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• 제43권8호
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• pp.1-14
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• 2006

실시간 멀티미디어 서비스들을 전송하는 DWDM(Dense-Wavelength Division Multiplexing) 기반의 차세대 인터넷에서는 DWDM 망의 다양한 QoS(Quality of Service) 파라미터들을 복합적으로 고려하는 QoS RWA(Routing and Wavelength Assignment) 방식으로의 접근이 요구되어진다. 본 논문은 flooding 방법을 기반으로 하고, 다중제약조건을 만족하는 새로운 QoS 라우팅 알고리즘인 Bounded Flooding Routing (BFR)을 제안한다. BFR 알고리즘의 주요 목적은 network overhead, blocking probability 그리고 wavelength utilization의 성능 분석 파라메터의 향상에 있다. 더욱이, 이러한 목적을 달성하기 위해 본 논문에서는 새로운 개념인 ripple count 개념을 제안하여, 링크 상태정보 및 계산량을 줄임으로써 라우팅의 성능을 높인다. 또한, 제안된 알고리즘의 광범위한 분석을 위해서, DWDM을 기반으로 하는 망에서 중요한 요소인 제한된 파장 변환기를 적용한다. 제안된 BFR 알고리즘의 성능분석 결과는 본 논문에서 제시하는 방법이 network overhead, blocking Probability 그리고 wavelength utilization 측면의 성능 평가를 통해 제안된 알고리즘들의 효율성을 검증하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.821-822
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• 2010

• 한국광학회:학술대회논문집
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• 한국광학회 2001년도 제12회 정기총회 및 01년도 동계학술발표회
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• pp.166-167
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• 2001

과장 변환기는 WDM (wavelength division multiplexing) 시스템에서 wavelength relocation을 가능하게 하여 시스템의 유연성과 효율성을 향상시킨다는 측면에서 매우 중요한 기능을 갖는다. WDM 시스템의 채널의 수가 점차 증가함에 따라 채널의 간격이 100 GHz에 이르고 있으며 향후 더욱 조밀해 질것이다. 이러한 DWDM (Dense WDM)시스템에서 사용될 수 있는 파장변환기는 100 GHz단위의 파장변환 기능과 광대역 가변 변위가 필수적이다. (중략)

• 천문학회보
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• 제40권1호
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• pp.79.3-80
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• 2015

Galaxy overdensities such as galaxy clusters and superclusters are the largest gravitationally bound systems in the Universe. Since they contain many different levels of local densities, they are excellent places to test galaxy evolution models in connection to the environments. The environment studies of galaxies at z ~ 1 are important because the environmental quenching seems to be an important mechanism to reduce star formation activities in galaxies at z < 1. However, there have been not many studies about high redshift galaxy clusters at z ~ 1 because of the lack of wide and deep multi-wavelength data. We have used the multi-wavelength data from the UKIDSS DXS (J and K band), the SWIRE (4 IRAC bands), and the PAN-STARRS (g, r, i, z, y bands) in the ELAIS-N1 field. We identified galaxy cluster candidates at 0.2 < z < 1.6 using the multi-wavelength data. We found several superclusters where cluster candidates are concentrated on few tens of Mpc scale. Interestingly, some of the supercluster candidates consist of galaxy clusters which have high blue galaxy. We will present high redshift galaxy cluster and supercluster candidates in ELAIS-N1 field and galaxy properties in different environments including dense clusters and fields.

• 한국멀티미디어학회논문지
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• 제2권4호
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• pp.451-458
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• 1999

본 논문은 다중 광 네트워크상에서 WDM(Wavelength Division Multiplexing)을 이용한 경로 설정 및 파장 할당문제 즉, RWA문제를 해결하는 새로운 알고리즘을 개발하는데 있다. 현재까지 다중 광 네트워크상의 임의 경로에 파장을 할당하는 문제는 NP-hard 문제[1]로 알려져 있으며 , 또한 다중 광 네트워크상에서 주어진 노드쌍들을 연결하는 각각의 링크에는 서로 다른 파장을 할당해야 한다는 기술상에 제약조건을 안고 있다. 따라서, 본 논문에서 는 주어진 네트워크의 유형을 트리 형태로 한정지어 생각하고, 트리 구조상에서 위의 제약조건을 만족하면서 논문 [7]에서 제안한 이론을 토대로 Divided & Conquer방법을 이용하여 실제 모든 경로에 파장을 할당하는 다항시간 알고리즘을 제안하였다 새롭게 제안한 알고리즘의 분석 결과는 $O(n^4log\; n)$이다.

• 천문학회보
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• 제43권2호
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• pp.31.4-32
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• 2018

The ADF-S (AKARI Deep Field - South) toward South Ecliptic Pole is one of the deep survey fields designed for the study of Cosmic Infrared Background (CIB). Owing to the easy accessibility with space missions and its low background brightness, the deep extragalactic survey was initiated by AKARI deep far-infrared observations and it will be performed by other future missions (e.g., Euclid, NISS, SPHEREx). The recent optical survey with KMTNet enabled us to identify the optical counterparts for dusty star-forming galaxies such as ULIRG, DOG, SMG. In addition, the NISS will perform the valuable spectro-photometric survey in the ADF-S. Those multi-wavelength data sets helps to trace the major galaxy population contributing to the CIB. Here, we introduce the extragalactic survey with the NISS and report the current status of the multi-wavelength extragalactic studies in the ADF-S.

• 천문학회보
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• 제46권1호
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• pp.34.2-34.2
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• 2021

SPT-CL J2106-5844 is the most massive galaxy cluster at z>1 discovered to date. It has been known to be an isolated system with a singular, well-defined halo. However, recent studies provide lines of evidence for its merging state. We strengthen the case with the multi-wavelength observations from ALMA, ACA, ASKAP, ATCA, and Chandra. With the sensitive, high resolution ALMA+ACA observations, we reconstruct the ICM pressure map from the thermal SZ effect. It reveals two main gas components that are associated with the mass clumps inferred from the weak-lensing analysis. Furthermore, the X-ray hardness map supports the bimodal gas distribution. With these multi-wavelength data, we probe the merger phase in SPT-CL J2106-5844.