• Title/Summary/Keyword: 귀환펌프

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Performances of gain-clamped EDFAs with different optical feedback wavelengths for use in WDM networks (WDM네트웍을 위한 광 귀환에 의해 이득이 고정된 EDFA의 귀환 파장에 따른 특성)

  • Kim, Sang-Yong;Chung, Joon;Chae, Cahgn-Joon;Lee, Byoung-Ho
    • Korean Journal of Optics and Photonics
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    • v.8 no.3
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    • pp.236-240
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    • 1997
  • We compare feedback wavelength-dependent performances of all-optical gain-clamped 980-nm pumped erbium-doped fiber amplifiers. In a 2.5-Gbps 8-channel WDM system, we have measured and compared gain compressions, signal power variations due to cross-saturation, power penalties caused by relaxation oscillations and noise figures for three different feedback wavelengths - 1532, 1543, and 1565 nm.

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Mean wavelength stability of broadband erbium-doped fiber sources (광대역폭 Erbium 첨가 광섬유 광원의 중심파장 안정성)

  • 진영준;박희갑
    • Korean Journal of Optics and Photonics
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    • v.8 no.6
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    • pp.476-481
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    • 1997
  • Optimum operating conditions of the 0.98 $\mu\textrm{m}$-pumped broadband erbium-doped fiber sources, where the mean wavelength variation is minimized, have been experimentally investigated. The optimum conditions for the mean wavelength stabilization were found to be different between the case of the isolated source and the case of the presence of feedback. In case of feedback, the proper pump power that yields zero slope of mean wavelength variation was found to be lower than that of the isolated case, and the mean wavelength was found nearly unchanged over the wide range of pump power. Howerer, the feedback resulted in lower output power and the mean wavelength was found to be sensitive to the variation of feedback level. In the respect of mean wavelength stability, the better performance could be obtained with some feedback, provided that the feedback level is kept constant. Thus we could also enhance the mean wavelength stability by allowing appropriate constant feedback into the source.

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Gain and spectra stabilization in erbium-doped fiber amplifier with optical feedback (광 귀환에 의한 erbium 첨가 광섬유 증폭기의 이득과 ASE 스펙트럼 안정화)

  • 김호삼;박희갑
    • Korean Journal of Optics and Photonics
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    • v.5 no.2
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    • pp.291-297
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    • 1994
  • A feedback loop with bandpass filter is introduced in erbium-doped fiber amplifier to clamp the amplifier gain by lasing the amplifier at a selected wavelength. The gain and the ASE (amplified spontaneous emission) output spectra are found to be independent of input signal power and pump power variation so long as the amplifier is lasing. Also they are found to be dependent only on the overall loss of the feedback loop. Even in the case of slowly modulated large signal input, signal distortion due to gain saturation is not observed.served.

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Construction and characterization of broadband erbium-doped fiber sources for gyroscope (Gyroscope용 광대역폭 Erbium 첨가 광섬유 광원의 구성과 특성 측정)

  • 임경아;진영준;박희갑
    • Korean Journal of Optics and Photonics
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    • v.8 no.4
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    • pp.320-326
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    • 1997
  • Broadband sources for fiber-optic gyroscope were constructed using erbium-doped fibers. Output power, linewidth, and mean wavelength were compared between four different source configurations. Among them, double pass configuration exhibited the highest output power, as high as 5.5 mW with 25 mW pumping at 1.48 ${\mu}{\textrm}{m}$ wavelength. It also showed nearly zero sensitivity of mean wavelength for the variation of pump power when a sufficient pumping was provided. Amplifier/Source configuration resulted in the highest detected power(power received by the gyro detector) that is more than 100 times larger than those of the other configurations, though it was the lowest of source output power. As the feedback level increased, the source power decreased while the linewidth increased, and mean wavelength varied significantly which would affect the scale factor of the gyroscope.

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Braking Pressure Characteristics of Solenoid-Flow Control Type ABS by PWM Control (PWM 제어에 의한 솔레노이드-유량제어방식 ABS의 제동압력 특성)

  • Song, Chang-Seop;Yang, Hae-Jeong
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.8
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    • pp.146-154
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    • 1997
  • Solenoid-folw control type ABS is used with a 'dump and reapply' pressure control arrangement instead of using 2/2 (normal open/close) solenoid valves in convensional systems(sol. -sol. control type), a flow control valve is used which replaces the (no) inlet valve. The flow control valve controls fluid flow providing a nearly constant reapply rate( .theta. ) after the dump plase of ABS operation. In this study, to investigate a characteristics of brake pressure by PWM control, test rig was consisted of ABS hydraulic modulator, digital controller, pneumatic power supply and brake master cylinder. For comparison with experi- mental results, system modelling and computer simulation were performed. As a result, experiment results showed fairly agreement with the simulation. Also, it is shown that the pressure gradient (tan .theta. ) is affected by pressure, frequency, duty ratio and expressed with an exponential funtion.

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The Field Test of bankfiltration(including alluvial and riverbed deposits) Source Heat Pump Cooling & Heating System (강변여과수(충적층 및 하상)를 이용한 열펌프 냉난방시스템의 실증연구)

  • Hwang, Ki-Sup;Jung, Woo-Sung;Ahn, Young-Sub
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.1186-1190
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    • 2006
  • Rising in important of alternative energy due to the recenfly high oil price and environment problem. Application of alternative energy has become higher than before. In this study, facility test of Geothermal energy to bankfiltration was examined appliying changwon pumping well. Initial installation cost was efficiently saved by connecting a heat pump system to pumping well in changwon bankfiltration site. A falling-off in efficiency of heat pump was free due to the bankfiltration that is rare for the temperature fluctuation. Therefore, Heat soure as bankfiltration system solve the existing facilities problems of geothermal heat pump system.

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Installation and Monitoring of Bankfiltration (including alluvial and riverbed deposits) Source Heat Pump Cooling System (강변여과수(충적층 및 하상)를 이용한 냉방시스템 설치 및 모니터링)

  • Jung, Woo-Sung;Hwang, Ki-Sup;Ahn, Young-Sub
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.11a
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    • pp.5-8
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    • 2006
  • The Alternative energy has lately attracted considerable attention due to the high oil price and environment problem. In this study, pilot test facility for using the geothermal energy source from riverbank filtration was constructed and monitoring devices are installed to estimate the efficiency of this system. Initial installation cost can be saved efficiently by connect ing a heat pump system into the exist ing pumping well in Changwon riverbank filtration site. One set of monitoring results during summer was presented and analyzed.

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