• Transactions of the Society of Information Storage Systems
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• v.7 no.2
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• pp.53-59
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• 2011

We have developed a compact and high-power mode-locked fiber laser for multilayered optical memory. Fiber lasers have the potential to be compact and stable light sources that can replace bulk solid-state lasers. To generate high-power pulses, we used stretched-pulse mode locking. The average power and pulse width of the output pulse from the fiber laser that we developed were 109 mW and 2.1 ps, respectively. The dispersion of the output pulse was compensated with an external single-mode fiber of 2.5 m length. The pulse was compressed from 2.1 ps to 93 fs by dispersion compensation. The fiber laser we have developed is possible to use as a light source of multilayered optical memory. We also present a fiber confocal microscope as an alignment-free readout system of multilayered optical memories. The fiber confocal microscope does not require fine pinhole position alignment because the fiber core is used as the point light source and the pinhole, and both of which are always located at the conjugated point. The configuration reduces the required accuracy of pinhole position alignment. With these techniques we can present an all-fiber recording and readout system for multilayered memories.

• Journal of IKEEE
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• v.12 no.4
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• pp.234-238
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• 2008

We demonstrate a simple method to generate a stable 40 GHz pulse train at 1550 nm by spectral filtering of a 10 GHz mode.locked pulse source using a fiber Fabry-Perot interferometer (FFPI). A high finesse FFPI with a 40 GHz free spectral range blocks successfully unwanted spectral components of a 10 GHz pulse source and passes only 40 GHz spaced spectral lines ensuring pulse repetition-frequency quadruplication of the input pulses.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.64-64
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• 1991

The interaction of high-intensity, focused, nanosecond laser light with matter results in the production of high-temperature plasma, which in turn emits an intense pulse of x rays. The x-ray spectrum consists of strong line components of several keV photon energy and broad continuum. Such an x-ray source provides many advantages over conventional ones for many applications. Pulse nature of the x-ray emission is well-suited for studying transient phenomena and for imaging living biological specimen. Recent experiments have also shown that the laser plasma x ray may be used for x ray lithography. These studies and other applications will be discussed in detail.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.5
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• pp.717-720
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• 2012

Various types of dielectric-barrier-discharge (DBD) devices have been developed for diverse applications for the last decade. In this study, a flat non-thermal DBD micro plasma source under atmospheric pressure has been developed. The flat-panel type plasma is generated by bipolar pulse voltages, and driving gas is air. In this study, the plasma source was investigated with intensified charge coupled device (ICCD) images and Optical Emission Spectroscopy (OES). The micro discharges are generated on the crossed electrodes. For theoretical analysis, 2-dimensional fluid simulation was performed. The plasma source can be driven in air, and thus the operation cost is low and the range of application is wide.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.46-47
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• 2007

• Journal of IKEEE
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• v.5 no.2 s.9
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• pp.201-210
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• 2001

Wavelength and repetition-rate tunable optical pulse-trains for ultrafast optical time- and wavelength division multiplexing are generated from a semiconductor fiber ring laser by optical injection mode-locking. The pulse trains show the pulse with of ${\sim}10$ ps and the wavelength tuning of wider than 30 nm at various repetition-rates of 10 GHz, 20 GHz, 30 GHz and 40 GHz, respectively.

• Journal of IKEEE
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• v.11 no.3
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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.

• Journal of the Optical Society of Korea
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• v.19 no.1
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• pp.1-6
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• 2015

We investigate the propagation characteristics of a pulse laser in a time-of-flight laser range finder (TOF-LRF) system with variations in atmospheric conditions, such as temperature, pressure, relative humidity, and the concentration of $CO_2$. The measurement error of distance related with the group velocity change in the TOF-LRF system is analyzed by considering the refractive index of the standard atmosphere with variations in atmospheric conditions. The dependence of the pulse width broadening induced by chromatic dispersion of the standard atmosphere on the operating wavelength and the initial pulse width of the light sources is discussed. The transmission of air with variations in the relative humidity or the concentration of $CO_2$ is analyzed by using different values of absorption coefficients depending on the operation wavelength of the light source in the TOF-LRF system.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.226-227
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• 2003

다양한 응용분야에서 극초단 펄스의 쓰임은 점점 증가하고 있는 추세이고, 따라서 고에너지의 극초단 펄스를 방출할 수 있는 소형화된 source 개발연구는 현재 활발히 진행되고 있다 극초단 펄스를 증폭, 보다 높은 에너지를 손쉽게 방출하기 위한 방법의 하나인 광 파라메트릭 chirped pulse amplification(OPCPA)은 처음으로 Dubietis et al.에 의해 시도되었으며, 기본원리는 피코 혹은 나노초 펄스의 고에너지를 효율적으로 시간상 stretching된 극초단 펄스로 전이하는 것이다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2001.08a
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• pp.154-155
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• 2001

A laser system for therapy of cancer is proposed in this paper. In order to accuracy and statistical output control we used the constant current control method and designed the power source to protect the resonator from the over -current, rush-current and electrical fault. The most important things are the radiation type for cancer therapy in laser system, we developed the radiation type of cw, pulse, and burst pulse. The experimental result show that laser beam power increase linearly from 100mW to 300mW for input current increasing and the exposure time.