• 산업기술연구
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• 제15권
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• pp.113-122
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• 1995

By integrating WDM to OPS unit which plays an important role for the reliability of CPN, we made it possible to provide CATV, VOD, and high-speed data services simultaneously and to meet the requirements for new services in the future. For the design of optimal system, the link analysis of power budget has been performed. Also, the prototyped system has been tested with STM-1 level signals to confirm functions such as transmission, distribution, and protection. The results proved that when occurred out-of-order or recovery of ONU, the system did the pertinent switching with minimum loss for high-speed data services. Also for video distribution services, the system has distributed STM-1 level signals successfully.

• 전자공학회논문지A
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• 제33A권3호
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• pp.18-27
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• 1996

By integrating WDM to OPS unit which plays an improtant role for the reliability of CPN, we made it possible to provide CATV, VOD, and high-speed data services simultaneously and to meet easily the requirements for new services in the future. For the design of optimal system, the link analysis of power budget has been perfomred. Also, the prototyped system has been tested with STM-1 level signals to confirm functions such as transmission, distribution, and protection. The results proved that when occurred out-of-order or recovery of ONU, the system did the pertinent switching with minimum loss for high-speed data services. Also for video distribution services, the system has distributed STM-1 level signals sucessfully.

• 전자공학회논문지D
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• 제34D권6호
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• pp.58-64
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• 1997

The wavelengt lockin gsystem of the optical fabry-perot filter theoretially derived and experimentally realized by using the ithering method in order to compensate the laser wavelength drift increasing the BER of the WDM system. The deviation between the laser wavelength and the optical filter center wavelength is compensated by applying a suitable voltage to the PZT. Accordingly, the laser wavelength selected by the fabry-perot filter always maintains the condition of maximum transmission powr. A wavelength locking system has been demonstrated using a fiber fabry-perot filter with a free spectral range of 80nm and an FWH of 1nm. The voltages of the sine wave generated for dithering was 20mV and 10mV, the frequency was 2kHz and center wavelength of the tunable laser was 1550nm. In this paper, the locking system have 20ms of locking time and 2nm of locking range.

• 한국통신학회논문지
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• 제26권9B호
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• pp.1203-1208
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• 2001

1545∼1560nm 파장의 C 대역에서 0.8nm 간격의 16 채널 WDM을 갖는 펌프 LD 타입의 2단 이득 제어 어븀 첨가 광섬유증폭기(GC-EDFA)를 버스트 패킷 모드 광스위칭 시스템에 사용하기 위하여 실험을 통해 입증하였다.

• 전자공학회논문지
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• 제52권11호
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• pp.156-163
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• 2015

국내에서 개발된 단일모드 균일한 단주기형 광섬유 격자소자(FBG: Fiber Bragg Grating)를 이용하여, 수중에서 음파를 검출할 수 있는 FBG 일체형 Transducer를 설계 및 제작하였다. 이를 통하여 신호검출 시스템구성 시, 최근 제작된 Hopper WDM(특허번호 제10-1502954)을 이용하여 수중에서 다중점신호검출과 지향성 연구를 한 결과, 기존의 광섬유 센서가 지니고 있는 우수한 장점들을 모두 지니고 있을 뿐만 아니라, Sensor Arm 구성이 간단하여 실용화에 큰 장점을 지니고 있다. 제작된 FBG 일체형 트랜스듀서는 30 Hz~2.5KHz 범위에서 주파수 검출이 가능하고, 최적의 공진조건 주파수는 1.2KHz로 나타났다. 또한, 이를 이용한 수중에서 넓은 영역에 대한 다중점 신호 검출을 구현하기 위하여, WDM(Wavelength Division Multiplexing) 방법과 Passive band-pass filter system을 이용하여 FBG Hydrophone Arrays System을 구축하고, 2개의 FBG 일체형 Transducers에서 주파수 200Hz~1.3 KHz대까지 다중점 수중 음파 신호 검출을 성공 하였다. 아울러, 음원의 방향과 각도에 따라 검출된 신호의 세기가 변화되므로 음원의 물체에 대한 방향성 검출이 가능함으로서, 향후 FBG Hydrophone의 실용화 연구에 새로운 기틀을 마련하였다.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2293-2302
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• 2012

단일 모드 광섬유의 그룹 속도 분산과 자기 위상 변조에 의해 왜곡된 파장 분할 다중 신호의 효율적인 보상을 위한 새로운 광전송 링크 기술을 제안하였다. 제안된 전송 링크는 WDM 송신이나 수신단 근처에 광 위상 공액기(OPC; optical phase conjugator)가 위치하고 각 중계 구간의 SMF 길이와 RDPS(residual dispersion per span)가 인위적으로 분포하는 구조이다. 시스템 성능을 개선하여 유효 입사 전력 범위와 유효 전체 잉여 분산 (NRD; net residual dispersion)을 늘릴 수 있는 최적의 링크 구조는 OPC가 WDM 수신단에 가깝게 위치하고 후치 보상(postcompensation)에 의해 NRD를 결정하고 중계 구간이 증가할수록 SMF 길이와 RDPS를 점진적으로 감소시키는 링크라는 것을 확인하였다.

• Journal of the Optical Society of Korea
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• 제11권3호
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• pp.101-107
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• 2007

In this paper, we have presented the results of Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) based fiber-to-the-home (FTTH) field trial test which was held in the city of Gwangju. We have implemented an injection locked Fabry-Perot Laser Diode (FP-LD) based WDM-PON system and reliably delivered Internet Protocol TV (IP-TV), networked Personal Video Recorder (N-PVR), High-Definition Video on Demand (HD-VoD), Education on Demand (EoD) and Internet service as FTTH service through the system during the field trial test. We have also verified that the WDM-PON system worked well to provide quality of service (QoS) guaranteed 100Mbps bandwidth per subscriber. Furthermore, we have presented network designing issues in Outside Plant (OSP) and Customer Premises Network (CPN) that should be overcome to efficiently deploy FTTH service. Finally, based on the field trial test results, we proposed FTTH service deployment strategies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권12호
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• pp.3310-3329
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• 2023

This work designs an eighteen-channel bidirectional Intensity Modulation with Direct Detection (IM/DD) Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) system. The proposed system meets the requirement of the ITU-T 5G fronthaul link suggested design in G-series Recommendations-Supplement 66. The newly designed system, with a 25Gb/s/λ data rate (450Gbps as a system capacity), has been tested and simulated using OptiSystem V.19 software. The system has been evaluated by the BER with respect to variable the optical span and CW laser power. Based on the ITU-T recommendations, the simulation results demonstrate that this system might be used as an F1 and as an Fx 5G fronthaul link for functional split choices starting from options 1 to 7a. These options are required under 25Gbps/λ for each upstream and downstream link direction. Furthermore, the proposed system utilized a bidirectional single-mode optical fiber within short optical spans of up to 10 km. The proposed system is characterized by a low-cost, simple, DSP-free and amplifier-free system with a reasonable system capacity.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2001년도 추계학술대회 논문집
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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.

• Journal of electromagnetic engineering and science
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• 제3권2호
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• pp.79-85
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• 2003

In this paper, we investigated the degree of compensation for distorted optical pulse of wavelength division multiplexed(WDM) channel with initial frequency chirp generated in optical transmitter. The WDM channel signal distortion is due to chromatic dispersion, self phase modulation(SPM) and cross phase modulation(XPM) in fiber. The considered system is 3 ${\times}$ 40 Gbps intensity modulation direct detection(IM/DD) WDM transmission systems, which adopted mid-span spectral inversion(MSSI) as compensation method. We confirmed that the effect of initial frequency chirp on compensation for signal distortion due to a SPM is gradually decreased as a dispersion coefficient of fiber becomes gradually small. But, in the aspect of a compensation for signal distortion due to both SPM and XPM, the effect of initial frequency chirp on compensation is gradually decreased as a dispersion coefficient of fiber becomes gradually large.