• Korean Journal of Optics and Photonics
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• v.5 no.3
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• pp.394-403
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• 1994

Chaos characteristics of laser diodes with external optical feedback is investigated. For a FabryPerot resonator laser, optical feedback by external mirror is assumed. The simulation is performed in such a way that a current of $1.3J_{th}$ is injected into the $1.3{\mu}m$wavelength "InGaAsP" buried hetero structure laser. With the increment of K, the system shows the evolution of four steps as follows: i) When the optical feedback coefficient K is very small, the relaxation oscillation is damped and the system reaches the steady state showing the stable operation characteristics. ii) As K increases a little bit, the relaxation oscillation is not damped any more and the system begins to maintain the periodic oscillation. iii) When K is increased further, the oscillation shows the larger amplitude and the long periodic length. iv) When K is increased very large, the system gets unstable and enters into the coherejlce collapse state. state.

• Korean Journal of Optics and Photonics
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• v.10 no.6
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• pp.512-517
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• 1999

Quenched dye laser (QDL), which operates with relaxation oscillation mode, is one of the most powerful source for ultra-short pulse light. In this paper, the output characteristics of QDL is theoretically analyzed by a computer simulation. The QDL is assumed that the laser dye is Rhodamine 6G which has the oscillation wavelength of 590 nrn and that the active length is 5 mm and that the pumping source is XeCllaser which has oscillation wavelength of 308 nm. It is revealed ilim the pulse width of short cavity dye laser reduced less than 1/100 than pumping pulse duration and has the linear relationship with spatial width of pumping beam approximately. In addition, it is revealed that the short cavity dye laser is a powerful candidate of pulse width variable light source, which is adjusted by spatial size of pumping beam_ beam_

• Proceedings of the Korean Magnestics Society Conference
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• 2002.04a
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• pp.164-165
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• 2002

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.152-156
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• 1999

We have developed the pulse-width variable Quenched Dye Laser (QDL). QDL consisted of the dye cell of 5 mm length containing a $2.5{\times}10^{-3}$[mol/l] solution of Rhodamine 6G and the cylindrical lens focal length of 150 mm and quenching mirror. QDL system was pumped by s XeCl excimer laser with 150 mJ pulse energy in a 20 ns pulse at 1 Hz repetition rate. Pulse-width of QDL was measured by a noncollinear intensity autocorrelator. The focused thckness was measured by changing the position of the focusing cylindrical lens. Pulse-width of QDL as a function of the focused thickness (273.0${\mu}{\textrm}{m}$~845.0${\mu}{\textrm}{m}$) varied continuously from 86 ps to 201 ps.

• Journal of the Korean Professional Engineers Association
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• v.16 no.1
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• pp.39-47
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• 1983

전자산업의 발전은 전자분야 자체뿐 아니라, 관련 전산업분야의 발진을 기초로 카는 것이며, 납땜성이 뛰어난 전기 주석 도금 System의 개발도 그 일익을 담당하게 되는 것이다. 그러나 주석도금 System의 종류와 방법에 따라서 납땜성의 차이는 아주 크며, 그 이유는 주석도그에 사용된 첨가제의 동시전착에 큰 영향이 있음을 알게 되었다. 본 조사는 납땜이 뛰어난 반광택 산성주석도금 방법에 대한 것으로 그 첨가제의 개발 및 사용방법을 기술하고 있다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.12
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• pp.606-610
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• 2006

We investigated the output characteristics of Nd:YAG lasers at wavelength of 1444 nm, which were pumped by 450 Xe-flashlamp, 700 torr Xe-flashlamp and 700 torr Kr-flashlamp. With a Xe-flashlamp of 700 torr of gas pressure, the pulse energy of 0.738 J was obtained with repetition rate of 9.16 Hz and pumping pulse width of 400 ms. In case pumping pulse width of 5 ms and repetition rate of 1 Hz, 700 torr Kr-flashlamp showed the highest pulse energy of 1.44 J.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.4
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• pp.538-542
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• 2018

In order to generate a clock source with low cost and high performance in system on chip(SoC), a relaxation oscillator with stable output characteristics according to PVT(process, voltage and temperature) fluctuation require a low area and a low power. In this paper, we propose a solution to reduce the current loss caused by parasitic components in the conventional relaxation oscillator. Since the slew rate of the bias current and the capacitor are adjusted to be the same through the proposed solution, a relaxation oscillator with low area characteristics is designed for the same clock source frequency implementation. The proposed circuit is designed using the TSMC CMOS 0.18um process. The Simulation results show that the relaxation oscillator using the proposed solution can prevent the current loss of about $279{\mu}A$ and reduce the total chip area by 20.8% compared with the conventional oscillator in the clock source frequency of 96 MHz.

• Journal of the Korean Institute of Telematics and Electronics
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• v.9 no.3
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• pp.1-8
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• 1972

The characteristics of tunnel diode pair circuit biased within the negative resistance region has also the voltage-control type negative resistance region, and the voltage at the center point of negative resistance region is described as the square-wave relaxation oscillation. In this paper, the period T, positive duration T1, negative duration T2 of the pulse are obatined from the characteristic curve T, positive duration T1, negative duration T2 of the pulse are obtained from the characteristic curve and observed actually, considring the fact that the pulse width and the period of square-wave at the center point of the negative resistance region is able to be controlle dby the blas volgate. Mereover, the relationship between T, T1 or T2 and circuit parameters is searched for and the Circuit parameters that satisfy the conditions of T1-T2 being proportional to the variation of bias voltage with Teonstant are determined. Thereafter, the bias voltage and the signal voltage are inserted serially to the PWM circuit and the characteristics of that circuit is analyzed.