• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.986-993
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• 2000

In this paper, we analyze transmission characteristics of ultrashort laser pulses using the properties of high-order pulses which are systematically obtained following their orders. The high-order pulses are easily derived from a modified PRS system model. But we make clear they are very useful to cover wider area and to show more accurate transmission characteristics of ultrashort pulses than Gaussian or Sech pulse approximations used conventionally. These are based on the fact that the spectra and bandwidths of the high-order pulses are geautifully related to their orders. First modifying the generalized PRS system model, we propose a new model for deriving any type of high-order pulse. And we offer a novel analysis method of ultrashort pulse transmission varying the order of the pulse from n=1 to n=100, we obtain spectra of ultrashort pulses with 1(ps)∼150(fs) FWHM's, which are widely used in optical pulse communications. One-step further, we derive PSD's of their pulse-tr ins when they are applied to Unipolar signaling scheme. These PSD's are decided in the range of possible pulse intervals. All of these results are not only coincided with some conventional experimental works but will be applied to any pioneering ultrashort pulse in the future.

• Journal of IKEEE
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• v.10 no.2 s.19
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• pp.109-115
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• 2006

In this paper, High order derivative Gaussian pulse generator for DS-UWB communication satisfying the regulation of FCC was proposed and fabricated. In order to transform rectangular signal of 100Mbps to a Gaussian pulse, the fabricated Gaussian pulse generator consists of only two SRD. The output pulse had the widths of 330 psec and amplitudes of 920 mV. In addition, the designed and fabricated dual bandpass filter shows high order derivate characteristics by using micro-strip line and parallel stub to remove WLAN band. We generated the 13th Gaussian pulse restricted frequency spectrum of WLAN band more than -25dB. The pulse had pulse width of 1 nsec and amplitude of 25 mV.

• Current Optics and Photonics
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• v.6 no.6
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• pp.576-582
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• 2022

Plasmonic high-order harmonic generation (HHG) is used in nanoscale optical applications because it can help in realizing a compact coherent ultrashort pulse generator on the nanoscale, using plasmonic field enhancement. The plasmonic amplification of nanostructures induces nonlinear optical phenomena such as second-order harmonic generation, third-order harmonic generation, frequency mixing, and HHG. This amplification also causes damage to the structure itself. In this study, the plasmonic amplification according to the design of a metal-coated sapphire conical structure is theoretically calculated, and we analyze the effects of this optical amplification on HHG and damage to the sample.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.237-242
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• 1999

In this paper, we analyze transmission characteristics of ultrashort laser pulses using the property of high-order pulses which are systematically obtained following their orders. The high-order pulses are easily derived from a modified PRS system model. But we make clear they are very useful to cover wider area and more accurate transmission characteristics of ultrashort pulses than Gaussian or Sech pulse approximations used conventionally. This may be based on the fact that the spectra and bandwidths of the high-order pulses are beautifully related to their orders. first modifying the generalized PRS system model, we propose a new model for deriving any type of high-order pulse. And we offer a novel analysis method of ultrashort pulse transmission which has any shape and FWHM, using the proposed model. In addition, by fixing the pulse range $\tau$=1(ps) and varying the order of the pulse from n:1 to n=100, we obtain spectra of ultrashort pulses with 1(ps)-150(fs) FWHM's, which are widely used in fiber communications. As a one-step further, we derive PSD's of their pulse trains when they are applied to Unipolar signaling scheme. These PSD's are decided in the range of possible pulse intervals. All of these results are not only coincided with some conventional experimental works but also will be applied to any pioneering ultrashort pulse in the future.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.475-487
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• 2011

In this paper, we present a systematic method to derive spectrum of high-order pulse and a novel design of e-Learning system that deals with deriving the spectrum using concept-based branching method. Spectrum of high-order pulse can be derived using conventional methods including 'Consecutive Differentiations' or 'Convolutions', however, their complexity of calculation should be too high to be used as the order of the pulse increase. We develop a recursive algorithm according to the order of pulse, and then derive the formula of spectrum connected to the order with a newly designed look-up table. Moving along, we design an e-Learning content for studying the procedure of deriving high-order pulse spectrum described above. In this authoring, we use the concept-based object branching method including conventional page or title-type branching in sequential playing. We design all four Content-pages divided into 'Modeling', 'Impulse Response and Transfer Function', 'Parameters' and 'Look-up Table' by these conceptual objects. And modules and sub-modules are constructed hierarchically as conceptual elements from the Content-pages. Students can easily approach to the core concepts of the analysis because of the effects of our new teaching method. We offer step-by-step processes of the e-Learning content through unit-based branching scheme for difficult modules and sub-modules in our system. In addition we can offer repetitive learning processes for necessary block of given learning objects. Moreover, this method of constructing content will be considered as an advanced effectiveness of content itself.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.333-336
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• 2009

the equipment increase switching frequency in order to achieve small size, a low noise, and light weight. however, the power switches have high power losses and switching stresses as the switching frequency is increased. In order to solve like this problem point from the present paper it proposed Intese Pulse Light of the half bridge methods which apply the start current circuit which applies the auxiliary equipment. Simulation and experimental result it leads and it brings is more qualitative there is 20% improvement and it confirmed that a possibility of measuring to the patient.

• Journal of the Korean institute of surface engineering
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• v.36 no.2
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• pp.161-167
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• 2003

In order to investigate the effects of pulse plating conditions on the electrodeposition of trivalent chromium, electroplating experiments from bath with low concentration of trivalent chromium were performed. The variation of current efficiency of chromium electroplating with the electroplating conditions was explained. The maximum current efficiency of pulse plating is 6.4 times as high as that of direct plating at the same mean current density The nodular size increased with pulse plating time and the pulse frequency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.939-944
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• 2010

A high voltage air-cored helical strip/wire type pulse transformer has been fabricated for charging of a high voltage pulse forming line. As a primary coil, copper strip of 25mm width was wound helically around a MC nylon cylinder. For a secondary coil, copper enameled wire of 1mm diameter was wound around conical cylinder in order to provide insulation between two windings. The coupling coefficient of 0.53 was obtained when two coils were combined coaxially in the insulation oil filled chamber. Voltage gain and energy transfer efficiency were investigated by varying the parameters of primary and secondary circuit. Test results shows that the voltage gain increases up to 17 with increasing the primary capacitance up to 200nF. And highest energy transfer efficiency of 44% was obtained when the dual resonant operation condition was nearly satisfied. The pulse transformer developed in this study can be used for charging the middle conductor of a Blumlein pulse forming line.

• 전기의세계
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• v.31 no.5
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• pp.383-390
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• 1982

The high power glass laser system was designed and constracted which consisted of a TEM$\_$00/ mode Q-switching oscillator, a pulse shaping, system, two-stage pre-amplifiers, five-stage main amplifiers, a Faraday rotator, and a uni-guide slit. The laser output of 3OGW with the pulsewidth of 2 nsec was obtained by performing the amplifiing experiment in this system. When the laser light with the pulsewidth of 10 nsec was amplified, the large factor of amplification was obtained in the beginning of pulse, but the factor of amplification decreased gradually in the later part of pulse. Therefore, the laser light which has short pulsewidth of-2nsec must be amplified in order to obtain the larger factor of amplification. When the laser beam from the high power glass laser system was irradiated to plasma, the reflected laser light from plasma which occured inevitably could be attenuated to the order of 10$\^$-4/ by using the Faraday rotator and the uni-guide slit.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.15-21
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• 2009

High-order harmonic generation from a solid surface affected by the contrast of a laser pulse was studied using an oscillating mirror model. High-order harmonics generated from solid surfaces have unusual properties such as spectral redshift, and an intensity difference between even- and odd-order harmonics which is not reported for high-order harmonics generated by a gas medium. We confirmed that high-order harmonics from solid surfaces have selectivity of polarization as well as cut-off extension and the enhancement of conversion efficiency proportional to laser intensity. And the principle of operation and the characteristics of a plasma mirror system developed for achieving high contrast laser pulses to pursue the experimental realization of high-harmonic generation from solid surfaces are reported. Energy fluence on the plasma mirrors is tunable between $10\;J/cm^2$ and $1000\;J/cm^2$ and around 1000 shots are available before the plasma mirrors require replacement.