• Title, Summary, Keyword: optical link terminal

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Physical Media Dependent Prototype for 10-Gigabit-Capable PON OLT

  • Kim, Jongdeog;Lee, Jong Jin;Lee, Seihyoung;Kim, Young-Sun
    • ETRI Journal
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    • v.35 no.2
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    • pp.245-252
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    • 2013
  • In this work, we study the physical layer solutions for 10-gigabit-capable passive optical networks (PONs), particularly for an optical link terminal (OLT) including a 10-Gbit/s electroabsorption modulated laser (EML) and a 2.5-Gbit/s burst mode receiver (BM-Rx) in a novel bidirectional optical subassembly (BOSA). As unique features, a bidirectional mini-flat package and a 9-pin TO package are developed for a 10-gigabit-capable PON OLT BOSA composed of a 1,577-nm EML and a 1,270-nm avalanche photodiode BM-Rx, including a single-chip burst mode integrated circuit that is integrated with a transimpedance and limiting amplifier. In the developed prototype, the 10-Gbit/s transmitter and 2.5-Gbit/s receiver characteristics are evaluated and compared with the physical media dependent (PMD) specifications in ITU-T G.987.2 for XG-PON1. By conducting the 10-Gbit/s downstream and 2.5-Gbit/s upstream transmission experiments, we verify that the developed 10-gigabitcapable PON PMD prototype can operate for extended network coverage of up to a 40-km fiber reach.

Noisy OTDR Data Event Detection Analysis for the Real Time Optical Fiber Link Monitoring (실시간 광선로망 감시를 위한 Noisy OTDR 신호 분석 방법)

  • Ko, Dae-Young;Baek, Sung-June;Park, Aaron;Kim, Jin-Bong;Nah, Yong-Su
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.4
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    • pp.122-128
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    • 2016
  • This paper, proposes a new analysis method for the event detection of an OTDR signal. An OTDR signal was passed through the Hamming filter to remove the high frequency noise included in the signal. The signal was then passed consecutively through a differential filter to detect the events of interest. The terminal position was determined using the fact that there is a large gap between the signal and the trailing noise power beyond the terminal. This study examined the local maxima of the signal up to the terminal position and determined the peak regions. The real events were determined from the peak regions using noise information and peak threshold. Finally, the user events were found by inspecting the user peaks beyond the terminal position. The events of the OTDR signal without users are located at less than 17m compared to the optical fiber link setup. The events of the JDSU device are located less than 25m and their users are less than 5m. For the RadianTech device, the events are detected at less than 19m and the users are found in 5m. The results suggest that the proposed method is sufficiently applicable to an optical fiber link monitoring system.

Transmission Performance Evaluation of Hybrid Lines Composed of SMF and MMP for FTTx Systems (단일 모드 광섬유와 다중 모드 광섬유 혼합 라인으로 구성된 FTTx 시스템의 전송 성능 평가)

  • Park, Seung-Hyeon;Kim, Kyong-Hon;Lee, El-Hang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.7A
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    • pp.535-541
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    • 2005
  • This paper proposes a hybrid optical lines composed of single-mode fiber(SMF) and multi-mode fiber(MMF) for gigabit-capable Passive Optical Network(GPON) using a WDM method with a single light source per each channel, and reports the results of transmission performance the proposed lines. The transmission link uses a direct modulated DFB-LD for high speed downstreams at the optical line terminal(OLT) of central office(CO) and a low cost SFP type transceiver for low-speed upstream in optical network unit(ONU). To split or combine the transmission channels, wavelength MUX/DEMUX are used in the optical line section, and MMFs not longer than 1 km are attached to the SMF lines at the ONU side of the WDM-PON links. We have performed the transmission experiment on the downstream of 2.5 Gbit/s, and 1.25 Gbit/s, and the upstream of 1.25 Gbit/s, and 622 Mbit/s which are recommended by ITU-T G.984.2. The transmission margin and feasibility of the proposed links have been tested to be suitable up to 2.5 Gbit/s transmission.

Synthesis and Properties of Liquid Crystal Compounds and Epoxy Resin Based Side Chain Liquid Crystal Polymers I. Low Molecular Weight Liquid Crystal Compounds (방향족 액정동족체 및 Epoxy형 측쇄 액정고분자의 합성 및 성질 I. 저분자 액정 동족체)

  • Park, Se Kwang;Ahn, Wonsool;Keum, Chang Dae;Park, Lee Soon
    • Applied Chemistry for Engineering
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    • v.9 no.1
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    • pp.66-70
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    • 1998
  • Several liquid crystalline monomers were synthesized and characterized to utilize as new matrix materials of liquid crystal/polymer composite films for display application. Liquid crystalline compounds which have azo group as center link, cyano group at one of the terminal position in common and bromoalkyl(azo(n)), azidoalkyl(AZI(n)), aminoalkyl(ALC(n)) as the terminal group were synthesized and identified respectively by FT-lR, $^1H-NMR$ spectrometer and elemental analysis. All these compounds exhibited nematic liquid crystalline region in the certain temperature range as determined by DSC and polarized optical microscope. These liquid crystalline compounds also showed a typical even-odd effect in both $T_{KN}$ and $T_{NI}$ due to conformational change as the length of terminal alkyl chain, $-(CH_2)n-$. was varied.

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