• The Journal of Korean Institute of Communications and Information Sciences
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• 제21권11호
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• pp.3012-3023
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• 1996

In this paper, we analyze the compression of optical soliton which is obtained by proceeding the optical pulse in FSDD(Fiber with Slowly Decreasing Dispersion) using both NSE(Nonlinear Schrodinger Equation) and GNSE(General Nonlinear Schrodinger Equation) and compare the results. We replace the FSDD with a sequence of fibers having different dispersion values and pompre the results with those obtained in FSDD. It is found that the same results in peak value and FWHM(Full width Half Maximum) can be obtained by replacing FSDD with a sequence of fibers having proper length. We vary the shape of initial pulse which is the input of FSDD and suggest the condition to obtain higher compression rate.

• Journal of IKEEE
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• 제11권3호
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• pp.117-121
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• 2007

20 GHz and 40 GHz micro/millimeter-wave photonic pulse trains have been generated from a fiber ring laser with a semiconductor optical amplifier (SOA) by injecting 2 GHz gain-switched Fabry-Perot laser diode (GS-FPLD) output. To achieve efficient cross-gain modulation in the SOA at 20 GHz and 40 GHz, individual lasing modes of the 2 GHz GS-FPLD output separated to 25 and 50 picoseconds respectively by passing dispersion compensating fibers.

• Korean Journal of Optics and Photonics
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• 제5권4호
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• pp.466-472
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• 1994

An Argon laser pumped Ti:Sapphire laser has been constructed and self-mode locked. Mode-locking was initiated by a moving mirror mounted on the ball slider and maintained by the self-focusing in the laser crystal and an aperture inside the resonator. A prism pair was used to reduce group velocity dispersion. The bandwidth and the pulse width of the mode-locked pulse were 11 nm, $1000\pm20fs$, respectively. ively.

• Transactions of the Korean Society of Automotive Engineers
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• 제6권4호
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• pp.211-218
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• 1998

The purpose of this study is to investigate the reduction rate of NOX according to several parameters(NOX concentration, the flow rate of gas, the additional amount of C2H4, input voltage, input frequency and so in) when NOX is reduced by using PPCP(Pulse-induced Plasma Chemical Process). PPCP is based on the plasma-chemical technology, which induces narrow voltage pulses to binary electrode structure.

• Journal of Sensor Science and Technology
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• 제24권3호
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• pp.145-150
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• 2015

We introduce a new method of time-division visible light communication (VLC) using LED lamp light for the generation of synchronizing pulses. The LED lamp, driven by an AC 220-V power line, radiates light that has a 120-Hz frequency component. The pulse generator in each VLC system receives the LED lamp light and generates the synchronizing pulses that are required for time-division transmission of multiple VLC channels. The pulse period is subdivided into several time slots for VLC channels. In experiments, 120-Hz synchronizing pulses were generated using LED lamp light, and three VLC channels were transmitted independently without interfering with each other in a condition where the VLC signals overlapped in space. This configuration is useful in constructing multiple wireless sensor networks that are safe and without interference in locations where LED lamps are used for illumination.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.203-204
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• 2006

We present and demonstrate a novel method of alternate-phase return-to-zero (RZ) signal generation and pulse-amplitude equalization simultaneously in a rational harmonic mode-locked fiber ring laser, using a dual-drive Mach-Zehnder (MZ) modulator. By adjusting the voltages applied to both arms of the modulator, the rational harmonic mode-locked pulse trains are equalized in their amplitudes. In addition to that, the amplitude-equalized pulse trains multiplying the repetition rate at ${\sim}10\;GHz$ have alternate $\pi$ phase difference between adjacent pulses. The alternate-phase RZ signal generated by the proposed method enhances transmission performance through the single-mode fiber (SMF) links without dispersion compensation.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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• pp.215-218
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• 2001

A pulsed Nd:YAG laser is used widely for materials processing and medical instrument. It's very important to control the laser energy density in those fields using a pulsed Nd:YAG laser. A pulse repetition rate and a pulse width are regarded as the most dominant factors to control the energy density of laser beam. In this paper, the alternating charge and discharge system was designed to adjust a pulse repetition rate. This system is controlled by microprocessor and allows to frequence an expensive condenser for high frequency to cheap one for low frequency. In addtion, The microcontroller monitors the flow of cooling water, short circuit, and miss firing and so on. We designed Nd:YAG laser firmware with smart microcontroller, and want to explain general matters about the firmware from now.

• Korean Journal of Optics and Photonics
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• 제10권3호
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• pp.243-247
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• 1999

We report the generation of inherently stable, high-speed, nearly transform-limited, optical pulses by chirped pulse compression, in which sinusoidally driven phase modulator generates frequency chirped pulses that are subsequently compressed by a dispersive optical fiber. Experimental results show that $sech^2$ shape pulses with a pulse width of ~14 ps and a time bandwidth product of ~0.34 are successfully generated at 10 GHz repetition rate. In contrast to other methods, such as higher order soliton compression, this approach does not depend on the optical power and thus shows promise for application to low-power lasers.

• Proceedings of the KIPE Conference
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.198-199
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• 2017

This paper proposed a new control method for supercapacitor (SC) to compensate the pulse load transient and enhance the power quality of dc microgrid. By coordinating the operation frequency, the supercapacitor is controlled to handle the surge current component while the low-frequency current component is dealt with by remaining sources in the system. Based on the state of charge and dc bus voltage level, the SC unit operation mode is automatically decided. Meanwhile, the dc bus voltage level indicates the power demand of the whole system; by regulating the dc bus voltage, the mismatch of power demand is covered by SC unit. The effectiveness of proposed method is verified by experiment prototype formed by two distributed generation and one supercapacitor unit.

• Proceedings of the KIEE Conference
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1521-1523
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• 2005

High voltage plasma power supply was adopted to control polluted gases and an ozone generation. Bidirectional pulse power supply consisted of power semiconductor switch devices, a high voltage transformer, and a control board adapted switching method. Plasma power supply with sinusoidal bidirectional pulse, which has output voltage range of 0-20kV and output frequency range of 1kHz-20kHz, is realized. Using proposed system, pulsed high voltage/high frequency discharges were tested in a DBD(dielectric barrier discharge) reactor, and the spatial distribution of a glow discharge was observed. The system showed stable operational characteristics, even though the voltage and the frequency increased. Above features were verified by experiments.