• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2456-2458
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• 1999

The polarization mode dispersion (PMD) that restricts the transmission bandwidth was investigated in standard long single mode fiber which optimized at 1.3${\mu}m$. Although fiber has perfect circular symmetry, each optical fiber has different refractive index profiles. The investigation of PMD with random mode couplings were conducted in three kinds of fiber by the time-domain interferometric method. By using two manufacturing methods, MCVD(Modified Chemical Vapor Deposition) method and VAD(Vapor Phase Axial Deposition) method, the property of mechanical asymmetric lateral pressure, bending and twisting induced polarization mode dispersion were measured. The concatenated optical fibers were compared with other types.

• Journal of the Optical Society of Korea
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• 제9권4호
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• pp.135-139
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• 2005

We demonstrate a simple and effective wavelength-tunable add/drop filter suitable for coarse wavelength division multiplexing (CWDM) systems. The filter consists of two fibers in contact side by side, with identical long-period fiber gratings (LPG) in each fiber. The LPG couples the power in the fundamental core mode to one of the cladding modes, which is then coupled to the same order cladding mode in the other fiber through evanescent-field coupling between two fibers. Finally, the cladding mode in the second fiber is coupled to its core mode with the help of the other LPG. With an optimal longitudinal offset distance of 10 em, coupling efficiency as high as -1.68 dB and side lobes smaller than -24 dB were experimentally obtained. The experimental results agreed well with the theoretical ones. The operating wavelength of the proposed add/drop filter was tunable by varying the temperature. The temperature sensitivity was measured to be -0.43 nm/$^{\circ}C$.

• 한국전기전자재료학회논문지
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• 제20권12호
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• pp.1077-1081
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• 2007

Thermal expanded core (TEC) fiber can reduce, being advantaged from thermal diffusion technology, connection loss by expanding the tolerance in relation to axial offset and gap when making optical connection having mode field diameter (MFD) of optical fiber expanded locally. In this paper, TEC fiber fabrication system based on the frame brushing techniques using twin-torch tip was designed and developed in order to maintain a stable thermal diffusion and single-mode when manufacturing TEC fiber. We were able to obtain that varied kinds of TEC fibers of which MFD could have been extended between $20\;{\mu}m$ and $40\;{\mu}m$ by TEC fiber fabrication system. In addition, the characteristic of connection loss was measured by alignment two TEC fibers of which MFD was $30\;{\mu}m$.

• 한국통신학회논문지
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• 제15권4호
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• pp.278-285
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• 1990

연마된 단일 모드 광섬유로 구성된 광 결합기는 임의의 두 파장을 분리 할 수 있다는 것을 잘 알려져 있다. 곡률 반경 R로 구부러진 광섬유로, 만들어진 WDM 광결합기의 파장 분리 구간 는 신호의 중심 파장과 두 코아 사이의 거리에 따라서 변한다. 본 논문에서는 광 섬유가 곡률 반경 R로 고정되어 있을 때 최소 파장분리 구간 를 얻을 수 있는 두 코아 사이의 거리를 제시한다. 또한 신호의 임의의 두 파장을 분리하기 위해서 필요한 최고 곡률 반경R를 제시한다.

• 대한전자공학회논문지
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• 제21권1호
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• pp.38-44
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• 1984

비선형 라만 산란현상을 이용하여 광섬유 라만 레이저를 실현함으로써 0.8-1.8μrm 파장 영역에서 200ps의 펄스 폭을 갖는 광 펄스를 생성시켰다. 이 광섬유 라만 레이저는 모드 고정과 Q-스위치가 동시에 된 Nd-YAG 레이저를 펌프로 사용한다. 본 실험과정에서 관찰된 2파동의 합 주파수 생성(two-wave sun frequency generation) 현상도 보고한다. 구현된 광섬유 라만 레이저를 이용하여 단일 모드 광섬유의 장파장 영역 색분산 특성을 측정하였으며, 측정된 광섬유의 재료분산 특성을 산정하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.275-278
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• 2002

The purpose of this study is to investigate the combustion characteristics of the flat burner using metal fiber. By changing the excess air ratio which affects strongly to the combustion characteristics, the flame stability range in the metal fiber were found and the range of the blue flame mode and radiant mode were distinguished and $NOx\;and\;O_{2}$ distributions in combustor were measured at two conditions which represents the blue flame mode and radiant mode.

• 정보저장시스템학회논문집
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• 제7권2호
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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.

• 대한전자공학회논문지SD
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• 제41권10호
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• pp.57-62
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• 2004

단일 모드 광섬유의 측면을 일부분 연마하여 연마된 상부에 열 광학 폴리머 층과 금속열선을 형성한 광섬유형 전류센서를 보고한다. 금속 열선에 인가된 전류에 의해서 발생하는 저항열은 폴리머 층의 굴절률을 변화시키고 광섬유의 소산장을 통한 광 감쇄를 유도하게 된다 두 가지 유형의 센서구조를 제안하였고 전류센서로서의 특징을 조사하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 제6회 파동 및 레이저 학술발표회 Prodeedings of 6th Conference on Waves and Lasers
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• pp.102-108
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• 1991

Utilizing self-phase modulation effects of a dispersion-shifted fiber and delay-line characteristics of two gratings, mode-locked 80 ps pulses at 1.319${\mu}{\textrm}{m}$ wavelength from a Nd: YAG laser are compressed down to 2.1 ps. These pulses are further compressed down to 340 fs using higher order soliton effects in a common single mode fiber.

• Composites Research
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• 제22권5호
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• pp.30-36
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• 2009

복합재 부품의 전형적인 조인트 형태를 평가하기 위해서, 2열 볼트 체결 탄소섬유강화 복합재의 파손강도와 파손 모드에 대하여 연구를 수행하였다. 연구는 상온과 고온다습 조건에서 적층과 형상을 변수로 실험적으로 수행되었다. 실험결과를 바탕으로 다음과 같은 결론을 얻었다. 하중-변위 선도는 두 가지 형태로 관찰되었으며, 각 파손 모드는 하중-변위 선도로 특징지어진다. 고온다습 조건의 파손형태는 베어링 파손 모드이며, 베어링 파손 모드에서 파손 강도는 유효강성의 영향이 크지 않다고 분석된다. 고온다습 조건의 파손강도 감소는 침투한 수분에 의해 섬유와 모재의 층간 결합부의 물성 저하에 기인한다.