• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.3
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• pp.459-463
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• 2002

We studied the effect of gain recovery at the optical fiber amplifier by the input pulse trains We also theoretically analyzed the limitation of the saturation and recovery time for the PDFA(Praseodymium-Doped Fiber Amplifier) which has the spectral gain at 1.3${\mu}{\textrm}{m}$ band. We can predict the interval between the pulse train, pump power, and the effect of the saturation and recovery time which is affected to the amplification of the optical pulse.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.505-508
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• 2002

We studied the effect of gain recovery at the optical fiber amplifier by the input pulse trains. We also theoretically analyzed the limitation of the saturation and recovery time for the PDFA(Praseodymium-Doped Fiber Amplifier) which has the spectral gain at 1.3${\mu}{\textrm}{m}$ band. We can predict the interval between the pulse train, pump power, and the effect of the saturation and recovery time which is affected to the amplification of the optical pulse.

• Korean Journal of Optics and Photonics
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• v.29 no.1
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• pp.32-39
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• 2018

The impact of the amplified spontaneous emission (ASE) on the gain recovery time of a bulk semiconductor optical amplifier (SOA) is investigated. The gain-recovery time is obtained by determining the time evolution of the gain, carrier density, and ASE in an SOA, after the propagation of a short pump pulse and continuous-wave (CW) probe of gain dynamics. In the simulation, a wide-band-semiconductor model, which can be characterized by the material gain coefficient over a wide wavelength range, is used, because the gain bandwidth of a practical SOA is very wide. The pump pulse and counterpropagating CW probe field are considered in the simulation, with the ASE noise spectrum equally divided.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.533-534
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• 2002

In this paper, we studied the transient gain response in TDFA(Thulium-Doped Fiber Amplifier) theoretically. We also investigated the limitation of the gain saturation and recovery time when the short pulse trains are incident into the TDFA with the spectral gain band in 1.47${\mu}{\textrm}{m}$ for using at WDM. We can predict the interval between the pulse train, pump power and the effect of the saturation and recovery time which is affected to the amplification of the optical pulse.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.12
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• pp.1644-1651
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• 1995

A data and clock recovery integrated circuit for MAC (Multiplexed Analog Component) TV standard is described. The chip performs the recovery of a system clock from a digitally encoded voice signal, clamping of a video signal for DC-level restoration, and precise gain control of a video signal in the presence of a large amplitude variation. A PLL (Phase Locked Loop) is used for timing recovery and a new gain control circuit is proposed which enhances its accuracy and dynamic range by employing two identical four-quadrant analog multipliers. The chip is designed in full custom with 1.5um BiCMOS technology, and layout verification is completed by post-simulation with the extracted circuit.

• Child Health Nursing Research
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• v.5 no.3
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• pp.250-261
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• 1999

This study has been conducted on the nonequivalent control group Pretest-posttest design in quasi experimental basis and newly born premature infants from intensive care unit of G Medical University Hospital in Inchon Metropolitan were selected in two groups of 21 infants each. The first group for experimental and the other for control. Data has been collected form October 30, 1997 to August 29, 1998. For the experimental group tactile and kinesthetic stimulation was applied 2 times a day for 10 days(10:00～ll:00 hours in the morning and 17:00～18:00 in the afternoon). As, a weight weighing instrument, electronic indicator scale(Cas Co. korea) was used. Collected data were analyzed with the SAS program using x²-test, student t-test, repeated measures ANOVA, Pearson correlated coefficient and Stepwise multiple regression. The result were as follow. 1. As for the daily weight gain, the experimental group showed first change in weight and this group also showed higher weight in the average weight than the control group. Statistically, however. there was no significant factor between the two groups. 2. In the correlation between general characteristics and weight gain, gestation Period. apgar score, admission Period before study, N.P.O. period after birth, recovery Period to birth weight showed statistical significance negative correlation with weight gam in the experimental group than control group. 3. In the factor with affected the weight gain by general characteristics showed recovery period to birth weight and head circumference in the experimental group, control group showed recovery period to birth weight, N. P. O. period after birth. admission period before study, feeding amount, weight of study. In conclusion. the sensory stimulation in this study showed a Positive aspect through there was no statistical significance in the weight gam. Tn the correlation of general characteristics and weight gam showed statistical significance negative correlation The main factor which affected the weight gain by general characteristics showed recover period to birth weight.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.44-45
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• 2002

1.3$mu extrm{m}$ 대역에서 증폭특성을 갖는 광섬유 증폭기인 Praseodymium-doped fiber amplifier(PDFA)는 Ohishi 등에 의해서 처음으로 제안되었다. 수십 nm의 이득 대역폭을 갖고, 30dB 이상의 높은 신호 이득을 갖는 PDFA는 1.3～l.6$\mu\textrm{m}$에 이르는 광대역 WDM을 위한 중요한 증폭기로 사용되고 있다. 최근에는 1.3~1.6$\mu\textrm{m}$에 이르는 광대역 WDM을 위해 광섬유 증폭기의 이득을 shift시키고, 이득 평탄화를 위한 많은 연구가 진해되어 지고 있으나, 광섬유 내에서 초고속의 광 신호를 증폭 시 발생할 수 있는 상호채널 간섭, 상호변조 왜곡, bit rate 높은 펄스열의 증폭 시 발생할 수 있는 이득소멸(gain depletion)과 이득회복(gain recovery) 등과 같은 과도응답 현상에 관한 연구는 충분히 보고되어있지 않다. (중략)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.349-352
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• 2001

The transient response in TDFA(Thulium-Doped Fiber Amplifier) is theoretically investigated. The TDFA has the spectral gain band in 1.47 ${\mu}{\textrm}{m}$. The transient model includes the transient buildup of the population inversion, the pump power, the signal power and their transient variation along the fiber amplifier. The results of numerical analysis can predict the gain saturation and recovery time at the fiber amplifier. It also shows the gain saturation and recovery effect depending on the pumping and saturation rate.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.6 s.336
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• pp.61-66
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• 2005

In this paper, we implemented a impulse generator, the one of the part in UWB(Ultra Wide Band) system using step recovery diode(SRD) and gain-switced semiconductor laser. The impulse generator was consisted of four stages; The first stage used SRD to generate the first impulse for gain switching. The second stage controled current for the suitable gain switching condition. The third was the second impulse generator to generate gaussian pulse. For gain switching, the first impulse was applied to semiconductor laser. In the last stage the gain switched impulse was converted into mono-gaussian pulse. The measured mono-gaussian pulse was 360 psec pulse-width and $-70mV \~ +50mV$ amplitude in time domain. In frequency domain its magnitude and bandwidth was, respectively, -41dBm and 3.6GHz. Accordingly, the impulse generator that we suggested was suitable for UWB systems.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.2
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• pp.64-70
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• 2009

A 6-Gbps feed-forward equalizer having a 6.2-dB gain at 3GHz is designed in 0.13-um CMOS technology and the equalizer helps error-free data recovery over a 7-m SATA cable with 14.7dB loss. Based on a differentially-connected varactor, the proposed equalizer uses only a one-fourth varactor size of a conventional equalizer, which enables the equalizer's integration in a pad-frame, high operating frequency, and low power dissipation of 3.6mW.