• Current Optics and Photonics
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• 제7권6호
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• pp.761-765
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• 2023

We analyzed the absorption spectra of acetone in the 3.37 ㎛ mid-infrared range using the off-axis integrated cavity output spectroscopy technique to develop a real-time, in-line breath analysis device. The linear relationship between acetone concentration and absorption increase was confirmed as 0.32%/ppm, indicating that the developed device allows for a quantitative analysis of acetone concentration in exhaled breath. To further confirm the feasibility of using our device for breath analysis, we measured the acetone concentration of human breath samples at the sub-ppm level.

• Journal of the Optical Society of Korea
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• 제19권5호
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• pp.521-530
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• 2015

Active optics is a key technology for future large-aperture space telescopes. In the design of deformable mirrors for space applications, the design parameter trade-off between the number of regularly configured actuators and the correction capability is essential but rarely analyzed, due to the lack of design legacy. This paper presents a parametric module method for integrated modeling of deformable mirrors with regularly configured actuators. A full design parameter space is explored to evaluate the correction capability and the mass of deformable mirrors, using an autoconstructed finite-element parametric modeling method that utilizes manual finite-element meshing for complex structures. These results are used to provide design guidelines for deformable mirrors. The integrated modeling method presented here can be used for future applied optics projects.

• Journal of the Optical Society of Korea
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• 제11권1호
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• pp.40-43
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• 2007

We propose a taper-underlaid spot-size converter (TU-SSC) with an offset which consists of two vertically stacked taper layers. The designed TU-SSC reduces coupling loss of a high index-contrast waveguide with $1.5%{\Delta}$ to a single mode fiber from 1.5 dB to 0.27 dB. We also considered the effects of mask misalignment in the fabrication process of TU-SSC, and optimized the design of TU-SSC so that the additional loss of TU-SSC for the mask misalignment of $3{\mu}m$ in the photo-lithography process was as low as 0.13 dB.

• Journal of the Optical Society of Korea
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• 제12권3호
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• pp.162-165
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• 2008

A novel planar lightwave circuit(PLC) triplexer using a three-waveguide interferometer(TWI) is proposed and examined using the transfer matrix and the beam propagation methods. The proposed triplexer consists of two three-waveguide couplers and three waveguides connecting the couplers. Simulation for the TWI triplexer shows the excess losses of 0.03 dB and 0.94 dB with the crosstalks of -22.3 dB and -14.5 dB in reception, respectively, for the wavelength of 1490- and 1550-nm, while showing the excess loss of 1.75 dB in transmission for the wavelength of 1310 nm. The proposed design shows compact feature as short as 11.5 mm for the refractive-index contrast of 0.45%.

• 한국광학회지
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• 제7권4호
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• pp.333-340
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• 1996

기존 퓨리에 변환의 일반화된 형식인 분수차 퓨리에 변환을 평판집적 광학계로 구현하였다. 구현된 평판집적 광학계는 동일한 2차원 입력패턴에 대해 서로 다른 분수차를 갖는 4개의 FRT의 결과를 얻을 수 있는 구조를 가지며 모든 부품들은 레이저 빔 묘화장치를 이용하여 하나의 유리판에 동시에 제작되었다. FRT 실험결과를 계산치와 비교 분석함으로써 평판집적 광학계가 기존의 자유공간 광학계가 갖는 3차원적 광신호 전달 특성과 이에 따른 높은 신호의 공간대역폭을 가지고 매우 정확한 FTR를 수행할 수 있음을 검증하였다.

• Current Optics and Photonics
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• 제3권4호
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• pp.298-303
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• 2019

We propose a photonic quasi-crystal fiber (PQF) for supporting up to 14 orbital angular momentum (OAM) modes with low and ultra-flat dispersion characteristics over the C+L bands. The designed PQF which consists of a large hollow center and quasi structural small air holes in the clad region exhibits low confinement losses and a large effective index separation (>$10^{-4}$) between the vector modes. This proposed fiber could potentially be exploited for mode division multiplexing and other OAM mode applications in fibers.

• 한국안광학회지
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• 제5권2호
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• pp.163-165
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• 2000

펄스형 방전플라즈마 발생장치인 플라스마 포커스장치에서 발생하는 가시광선영역의 빛을 시간적분 분석법으로 분광 분석하였다. 플라스마 포커스장치는 펄스방전에 의해 전기에너지를 빛에너지로 발생시킬 수 있는 장치이다. 분광분석기는 초점거리가 0.5 m인 모노크로메터를 사용하였다. 시간적분 분석법은 분광된 일정한 범위의 가시광선영역의 파장대를 필름에 현상하여 densitometer로 분석하는 방법이다. 가시광선 발생은 방전전압과 기체압력의 최적조건에서 발생되었는데 방전전압은 13kV이고 아르곤과 헬륨기체가 가시광선영역의 빛을 발생시키는데 사용되었다.

• 천문학회보
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• 제34권1호
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• pp.75.1-75.1
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• 2009

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권1호
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• pp.39.3-39.3
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• 2009

• Journal of the Optical Society of Korea
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• 제20권3호
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• pp.389-395
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• 2016

A Carbon Fiber Composite (CFC) framework was designed for a small lightweight space camera. According to the distribution characteristics of each optical element in the optical system, CFC (M40J) was chosen to accomplish the design of the framework. TC4 embedded parts were used to solve the low accuracy of the CFC framework interface problem. An integrated optimization method and the optimization strategy which combined a genetic global optimization algorithm with a downhill simplex local optimization algorithm were adopted to optimize the structure parameters of the framework. After optimization, the total weight of the CFC framework and the TC4 embedded parts is 15.6 kg, accounting for only 18.4% that of the camera. The first order frequency of the camera reaches 104.8 Hz. Finally, a mechanical environment test was performed, and the result demonstrates that the first order frequency of the camera is 102 Hz, which is consistent with the simulation result. It further verifies the rationality and correctness of the optimization result. The integrated optimization method mentioned in this paper can be applied to the structure design of other space cameras, which can greatly improve the structure design efficiency.