• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2496-2498
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• 2005

The transmission characteristics of multiply cascaded phase-shifted long-period fiber gratings (LPFGs) will be investigated theoretically and experimentally. Their passband can be changed by increasing the number of ${\pi}$ -shifted LPFGs. When two ${\pi}$ -shifted LPFGs with different grating lengths are cascaded in series, the bandwidth of the rejection band and passband can be controlled by the pristine characteristics of two gratings.

• 한국광학회지
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• 제15권6호
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• pp.485-489
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• 2004

색 분산과 색 분산 경사를 보상하기 위하여 결합 계수가 파장 축을 따라 첩 된 순 위상 샘플링 광섬유 Bragg 격자를 제안하였다. 기존의 샘플링 주기의 첩과 결합 계수의 첩을 동시에 이용하여 동일한 파장 다중 채널들의 대역폭들을 얻을 수 있었다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.335-341
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• 2005

The development of Shadow Moire in many kinds of methods for acquiring 3-dimensional information from an object is written in this paper. The fringe is appeared, when a grating mask makes its shadow on the object. The object is moved along x-axis more then 3 times to get phases from its fringe that contains data of the object's height. PMP{Phase Measuring Profilometry) is used for analyzing these images from a CCD camera. The calculated phase is remedied for expending the restricted results due to range of the $tan^{-1}$.

• 한국세라믹학회지
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• 제47권5호
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• pp.430-432
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• 2010

We verified through a noncritical phase-matched second-harmonic generation experiment that the periodically-poled $LiNbO_3$ (PPLN) had a large effective nonlinear optical coefficient, demonstrating that the QPM grating was uniform throughout the entire length of PPLN. The quasi-phase matching temperature was $193.4^{\circ}C$. The maximum SHG output power at the fundamental power of 2.0 W was found to be 18.0 mW; generated second-harmonic beam was found to have no photorefractive effect.

• 대한한의학회지
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• 제21권4호
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• pp.148-158
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• 2000

Objective : The purpose of this study was to investigate the back shape of school children using the phase-shifting scanning grating projection moire interferometer, which was developed by the Korea Advanced Institute of Science and Technology and is useful in evaluating three dimensional back shape. Methods : In this study the subjects consisted of 1,358 pupils [711 boys(52.36%), 647 girls(47.64%)] attending elementary and middle schools in Seoul. Their ages ranged from nine to fifteen and the average age was 12.2. With the phase-shifting scanning grating projection moire interferometer, the posterior view of the body were taken to see if there are correlations of moire fringe number, width difference between left and right, and correlation between differences in moire fringe number and width on both sides in the scapular, lumbar and gluteal regions. Results : The results were as follows : I. More frequent findings of fringe were observed on the right in all regions : in the scapular region, 309 boys(43.4%) and 156 girls(24.2%) had more fringe numbers on the right side; in the lumbar region, 68 boys(9.5%) and 11 girls(1.7%); and in the gluteal region, 160 boys(22.4%) and 63 girls(9.8%). Such tendency was striking especially in the scapular and lumbar regions, and in boys rather than in girls. In the scapula, 661 subjects(48.7%) with one moire fringe on either side need further attention and 110 subjects(8.I %) with two or more are required to do follow-up radiography for scoliosis. 2. In an analysis of width difference in the trunk, the left side is wider in all regions except for the gluteal region in boys : in the scapular region 21 boys(3.0%) and 103 girls(15.9%); in the lumbar region, 87 boys(12.2%) and 250 girls(38.6%); and in the gluteal region 197 girls(30.4%) had a wider left side and 45 boys(6.3%) showed a wider right side. 3. In correlation analysis of the number of moire fringe and width difference in each region, the side where more moire fringes were observed was significantly wider in the lumbar and gluteal regions, but not in the scapular region.(p<0.01) Conclusions : From these results, it is concluded that the back shape of elementary and middle school students in Seoul shows that the right side had more moire fringes; the left side was wider; and especially in the lumbar and gluteal regions the side where more moire fringes were observed was wider.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.27-30
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• 2002

PMFBG sensor was fabricated using phase mask and Excimer laser. The reflected wavelength of PMFBG sensor had dual peaks due to intrinsic birefringence. To discover the polarization axes, peak sensitivity was measured under compression test. The signal characteristics of PMFBG sensor were also examined in embedding condition. The embedded PMFBG sensor in epoxy block was loaded for the transverse strain measurements. Experiments showed that the PMFBG sensor could successfully measure the transverse strain. This PMFBG sensor is useful for the structures that require measuring transverse stram.

• 전기학회논문지
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• 제56권10호
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• pp.1820-1822
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• 2007

In this paper we fabricated a fiber device composed of cascaded long-period fiber gratings between which a birefringent erbium-doped fiber was inserted and proposed its application as a polarization-controlled interleaved signal gating fiber device. Because the core and cladding modes of the fabricated fiber device have polarization-dependent phase difference due to the birefringence of the erbium-doped fiber, its interference spectrum can be modulated by varying the input polarization.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.516-519
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• 2003

We modified the molecular structure of urethane acrylate oligomer by varying raw materials. Also fluorination of the host polymer matrices has been found to influence the morphological and the electrooptical properties of the resulting HPDLC grating. The incorporation of fluorinated monomers in HPDLC formulation enhance the LC phase separation and improved elctro-optical properties.

• 전기전자학회논문지
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• 제10권2호통권19호
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• pp.116-122
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• 2006

We have built a grating-based, high-resolution, spectral line-by-line pulse shaper. By controlling individual spectral lines of a mode-locked laser output, we demonstrate the interesting functionalities of the pulse shaper for arbitrary waveform generation, such as width tunable pulse generation, phase controlled waveform generation, microwave waveform generation, etc.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 광학 및 양자전자학 워크샵
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• pp.123-132
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• 1990

The method of characteristic matrix used in the calculation of multi-layered optical coating is applied to the analysis of DFB waveguide with arbitrary structure of grating by plecewise approximation where the DFB structure is devided into many sections in which the gain and period, amplitude and phase of DFB structure are assuced to be constant in each section. The DFB structure with two section is analyzed using this method of C-matrix. The possible applications for photonic devices using DFB waveguides are proposed.