• 한국광학회지
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• 제14권1호
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• pp.80-84
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• 2003

두 가지의 다른 방법으로 광섬유를 직접 구동하여 공초점 현미경을 제작하였다. 압전소자와 튜닝 포크는 광섬유를 진동시키는데 사용하였다. 6 frame의 640$\times$480 픽셀 영상을 압전소자 진동으로 1초 동안 얻었고, 1 frame의 640$\times$480 픽셀 영상을 튜닝 포크 진동으로 1초 동안 얻었다 이러한 광섬유의 진동은 confocal 영상에 일그러짐을 주지 않았다.

• 한국광학회지
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• 제15권2호
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• pp.104-108
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• 2004

폐경로를 통한 Fabry-Perot 레이저의 자기궤환 레이저 발진(self-seeding laser oscillation)을 이용하여 구조가 간단하고 경제적인 색분산(chromatic dispersion) 측정법을 제안하였다. 저가의 Fabry-Perot 레이저를 이용하여 광펄스들을 생성하고, 광섬유를 통해 전송되는 광펄스들 사이의 군속도 차(group delay difference)를 Fabry-Perot 레이저의 자기궤환 발진 현상을 통해 감지함으로써 광섬유의 색분산계수를 측정할 수 있도록 하였다. 제안된 측정법에 따라 구현된 측정 장치는 고가의 상용 계측기와 비슷한 수준의 색분산계수 측정 정확도를 제공하고, 재현성은 0.5%보다 좋음을 실험적으로 검증하였다.

• ETRI Journal
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• 제25권6호
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• pp.531-534
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• 2003

This report describes the effect of optical delay on the suppression of the power transient excursion in a combined gain-controlled erbium-doped fiber amplifier with an internal optical feedback loop (OFL). A simple homogeneous model showed that the optical delay caused a phase change in the oscillation of the surviving and laser channels, which resulted in a reduction of the overall power transient excursion. In addition to the reduction, a real system with a 1528.7-nm OFL shifted the oscillation upward or downward according to channel removal or addition, whereas another one with a 1560.9-nm OFL did not. This different transient behavior reflected a control-wavelength dependence on optical automatic gain control, where spectral-hole burning dominated over relaxation oscillation for 1528.7 nm, and vice versa for 1560.9 nm.

• Journal of Mechanical Science and Technology
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• 제18권10호
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• pp.1859-1868
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• 2004

Monitoring of OH chemiluminescence through an optical fiber was demonstrated to be a useful method in detecting self-excited combustion oscillations. OH chemiluminescence intensity detected by the optical fiber showed mostly excellent agreement with those obtained by high speed CCD camera measurements when combustion oscillations were strong. Symptoms of self-excited combustion oscillation were also studied in order to predict the onset of combustion oscillation before it proceeded to a catastrophic failure. For the purpose, we have found and proposed unique measures to tell the onset of self-excited combustion oscillations based on the careful statistics of fluctuating properties in flames, such as pressure or emission of OH radicals.

• 한국정보전자통신기술학회논문지
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• 제6권4호
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• pp.272-277
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• 2013

In this paper the effect of instability and chaos in optical fiber networks based on the Internet is described. Nonlinear optical fiber effect especially Brillouin scattering in networks has emerged as the essential means for the construction of active optical devices used for all-optic in-line switching, channel selection, amplification, oscillation in optical communications and a host of other applications. The inherent optical feedback by the back-scattered Stokes wave in optical networks also leads to instabilities in the form of optical chaos. This paradigm of optical chaos in fiber Internet serves as a test for fundamental study of chaos and its suppression and exploitation in practical application in optical fiber communication. This paper attempts to present a survey and some of our research findings on the nature of Brillouin chaotic effect on Internet based optical communication.

• 한국정보전자통신기술학회논문지
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• 제1권1호
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• pp.61-66
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• 2008

In this paper the effect of instability and chaos in optical fiber networks based on the Internet is described. Nonlinear optical fiber effect especially Brillouin scattering in networks has emerged as the essential means for the construction of active optical devices used for all-optic in-line switching, channel selection, amplification, oscillation in optical communications and a host of other applications. The inherent optical feedback by the back-scattered Stokes wave in optical networks also leads to instabilities in the form of optical chaos. This paradigm of optical chaos in fiber Internet serves as a test for fundamental study of chaos and its suppression and exploitation in practical application in optical fiber communication. This paper attempts to present a survey and some of our research findings on the nature of Brillouin chaotic effect on Internet based optical communication.

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
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• pp.86-87
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• 2004

• 전기학회논문지
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• 제58권7호
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• pp.1393-1397
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• 2009

A high-speed wavelength swept laser, which is based on oscillation characteristics of a fiber Fabry-Perot tunable filter, is described. The laser is constructed by using a semiconductor optical amplifier, a fiber Fabry-Perot tunable filter, and 3.348 km fiber ring cavity. The wavelength sweeps are repeatatively generated with the repetition period of 61 kHz which is the first parallel oscillation frequency of the Fabry-Perot tunable filter for the low power consumption. Mode-locking is implemented by 3.348 km fiber ring cavity for matching the fundamental of cavity roundtrip time to the sweep period. The wavelength tuning range of the laser is 87 nm(FWHM) and the average output power is 1.284 mW.

• Journal of the Optical Society of Korea
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• 제4권1호
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• pp.11-13
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• 2000

We experimentally measured the cold cavity loss of a mode-locked erbium-doped fiber ring laser in situ by using the relaxation oscillation frequency method. The relaxation oscillation frequency is measured for various pumping powers and the data is fitted by the least squares method with a theoretical curve of parameters including the cavity loss. We obtained a cavity loss of 15.3$\pm$0.5 dB which was found to agree with the results of direct transmission loss measurements.

• ETRI Journal
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• 제24권3호
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• pp.255-258
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• 2002

We created a new design for an Nd-doped clad-pumped silica fiber laser to enhance the pump absorption and lasing efficiency for a butt-coupled, end-pumped scheme. Two concatenated adiabatic tapers formed within the laser cavity simultaneously removed higher order modes and were spliced to conventional single mode fibers. We theoretically analyzed mode propagation along the composite cavity and experimentally achieved continuous wave oscillation in the $LP_{01}$ mode at $1.06\;{\mu}m$ and a laser output power of over 820 mW with a slope efficiency of 27%.