• Journal of Software Assessment and Valuation
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• v.16 no.2
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• pp.117-125
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• 2020

In this paper, when both the refractive index grating and the gain grating exist in a 1.55um DFB laser with two cleaved mirror facets, when the phase of ρ_l is fixed to 0 and the phase of ρ_r is changed to -π/2, π, π/2, 0, the change in frequency and oscillation gain was theoretically analyzed. In the case of δL<0, the oscillation gain required for lasing is the lowest and the most stable frequency operation is obtained in the case of (ρ_l phase=0, ρ_r phase=0) and κL=10, when κL is varied from 0.1 to 10. In the case of δL>0, when (ρ_l phase=0, ρ_r phase=π) and κL=10, the oscillation gain required for lasing is the lowest and the difference between the oscillation gains of the higher-order modes is large so that the most stable frequency operation is obtained.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.5-8
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• 2002

The erbium doped fibre ring laser (EDFL) is modelled using the standard propagation and rate equations of a homogeneous, two-level gain medium. The EDFL numerical simulations provide comparable results with the experimental data. The process of lasing mode competition and mode selection is clearly depicted and explained.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.35-36
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• 2006

Excited-state intramolecular proton transfer (ESIPT) is a phototautomerization occurring in the excited states of the molecules possessing a cyclic intramolecular or solvent-bridged hydrogen bond. Recently, we have developed novel ESIPT chromophores, molecules, dendrimers and polymers which show very high fluorescence quantum efficiency combined with the characteristic features of optical switching, fluorescence patterining, lasing, and electroluminescence. Broad overview of these topics will be given in this talk.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.186-186
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• 2010

The crack behavior in the ceramic Nd:YAG at a laser-diode end-pumped Nd:YAG ceramic laser was investigated. The fracture critical temperature difference of the ceramic Nd:YAG is about $355^{\circ}C$. The fracture of the 2 at% and the 4 at.% ceramic Nd:YAG occurred more than 14.9 W and 6.9 W pump powers, respectively, under lasing conditions.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.5
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• pp.18-26
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• 1994

We express fundamental second-order and third- order harmonic distortions and intermodulation distortions in terms of the laser parameters. Compared to the Darcie `s result only limited to the high frequency (f >1GHz), these expression are quite valid in the entire modulation frequency region. It is found that the fundamental nonlinear distortions are strongly effected by the spontaneous emission to lasing mode as well as the gain compresion damping in the low frequency region.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.909-912
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• 1999

This paper describes realized APC and pre-equalizer circuit, and their operation principle and test results. In analog optical transmitter, constant lasing power control, free of signal clipping and linearity are important considerations. We examined pre-equalizer and APC(Automatic Power Control) circuit to improve the analog optical transmitter performance.

• Journal of the Korean Vacuum Society
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• v.12 no.S1
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• pp.52-55
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• 2003

GaAs/AlGaAs quantum-wire (QWR) gain-coupled distributed-feedback (GC-DFB) lasers are fabricated and characterized Constant metalorganic chemical vapor deposition (MOCVD) growth is used to avoid grating overgrowth during the fabrication of DFB structures. Numerical calculation shows large gain anisotropy by optical feedback along the DFB directions near Bragg wavelength. DFB lasing via QWR active gratings is also experimentally achieved.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.180-181
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• 2003

주기적인 유전율의 변화를 가지는 광결정에 대한 연구가 최근 10여년간 활발하게 이루어지고 있다. 광결정에 존재하는 특성인 광 밴드갭(photonic bandgap) 효과를 이용한 단일 결함 구조의 레이저나 선결함의 도파로에 응용성이 활발하게 이루어지는 가운데 새로운 시도로 표면파(surface wave)를 이용한 광결정의 응용성을 고찰해 보았다. 주기적으로 층이 진 물질과 균일한 물질의 경계면에서 전자기파가 구속 될 수 있다는 것이 보고된 바 있다. (중략)

• Korean Journal of Optics and Photonics
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• v.25 no.3
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• pp.146-149
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• 2014

The homogeneous line broadening in EDF leads to unstable lasing and strong mode competition. In this paper a multiwavelength fiber ring laser that overcomes these effects by using variable attenuators between the DWDM and $1{\times}N$ coupler, has been proposed. Fiber ring lasers with four and eight wavelength outputs are implemented, and we show that the output powers can be adjusted with stable operation. The EDF ring laser has one four-wavelength output and four of single wavelengths, with OSNR of 50 and 60 dB respectively.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.211-212
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• 2008