• 제어로봇시스템학회논문지
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• 제15권8호
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• pp.798-803
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• 2009

This paper proposes a grating scanner which is driven by a stack-type piezoelectric element. The mechanism of the grating scanner is based on flexure hinges. Using some constraints, the compliant mechanism is designed and then verified by Finite Element Analysis. The designed compliant mechanism is manufactured by wire electro-discharge machining, and then integrated with a stack-type piezoelectric element for actuation and a capacitance displacement sensor for measuring ultra-precision displacement. Experiments demonstrates the characteristics and the performances of the grating scanner using the terms of working range, resonance frequency, bandwidth and resolution. The grating scanner is applicable to a Moire interferometry for measuring 3-dimensional microscopic surface.

• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.294-298
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• 2009

In this paper we proposed a new Bragg grating waveguide in order to improve reflectivity and to achieve compactness. Bragg gratings with various thicknesses were engraved in the middle of the core layer with a length of 3 mm. For the sake of cost-effectiveness, the $3^{rd}$ order Bragg grating waveguides were fabricated via conventional photolithography. The maximum reflectivities for the fixed width waveguide of $6{\mu}m$ with the 0.1 and $0.3{\mu}m$-thick Bragg gratings were, -13.14 and -6.25 dB, respectively, and the Bragg wavelengths were 1562.28, 1564.10 nm, respectively. A slight increase in the Bragg grating thickness can result in a remarkable reduction in the length of the Bragg grating waveguide with a fixed reflectivity.

• International Journal of Aeronautical and Space Sciences
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• 제2권2호
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• pp.56-64
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• 2001

An optical temperature sensor based on the etched planar waveguide Bragg grating is developed and its performance is explored using theoretical and experimental methods. The planar waveguide is designed and fabricated using optical lithography and wet chemical etching. An efficient butt coupled optical fiber is used to examine the spectral characteristics of the grating sensor, and to investigate the grating parameters. The typical bandwidth and reflectivity of the surface etched grating has been ~0.2 nm and ~7%, respectively, at a wavelength of ~1,552 nm. The temperature-induced wavelength change of the optical sensor is found to be slightly non-linear over ${\sim}200^{\circ}C$ temperature range. Theoretical models for the grating response of the sensor based on waveguide and classical laminated plate deformation theories agree with experiments to within acceptable tolerance.

• 한국레이저가공학회지
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• 제15권2호
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• pp.6-10
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• 2012

We fabricated the diffraction grating on the surface of fused silica glass using a femtosecond laser. The grooves of diffraction grating has a lot of micro crack and debris result in reduced diffraction efficiency. So, we polished the diffraction grating with $CO_2$ laser beam. With different scan number of $CO_2$ laser beam, we observed the image of diffraction grating and measured the diffraction efficiency.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.175-180
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• 1999

Generally, When we measure of object 3D surfaces with phase shifting shadow moire method, it is use of optical system consist of light source, grating, and ccd camera. At this time, it is important parameter that vertical distance of grating and camera, grating and light source, and horizontal distance of camera and light source. When use camera consist of complex lens vertical distance of grating and camera is unknown parameter. From this cause equivalent wave length of moire fringe is uncertain. In this study, We exactly obtain a vertical distance of grating and camera so improve on measurement accuracy.

• 한국전기전자재료학회논문지
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• 제17권7호
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• pp.697-700
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• 2004

We propose a method that realizes the modified illumination by implementing a binary phase grating at the backside of a photomask. By modeling the relationship between the shape of a grating on the photomask and the light intensity at the pupil plane, we developed a program named MIDAS that finds the optimum grating pattern with a stochastic approach. After applying the program to several examples, we found that the program finds the grating pattern for the modified illumination that we want. By applying the grating at the backside of a photomask, the light efficiency of modified illumination may be improved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1430-1431
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• 2006

We investigated the formation of 2-dimension hologram grating by means of selective etching characteristic and photo-expansion effect according to photo irradiation on amorphous As-Ge-Se-S thin film. By method of phase holography, we made the 2-dimensional hologram grating by each (S:P) and ($+45^{\circ}:-45^{\circ}$) polarized beam with DPSS laser(532nm) and He-Ne laser(632nm). A recording property was observed at each polarized beam through 2-dimensional hologram surface relief grating. Chalcogenide thin film was etched selectively by NaOH solution after the formation of 1-dimensional diffraction grating. And then etched sample was rotated 90 degree to fabricate 2 dimensional hologram grating. We found that it was observed the formation of 2-dimensional hologram grating by AFM(Atomic Force Microscopy).

• 한국정보통신학회논문지
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• 제10권11호
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• pp.2049-2054
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• 2006

본 연구는 에칭된 실리카 기반의 평면 도파로 Bragg grating에 기반한 광 온도센서의 열전 광 효과에 대한 선형 및 비선형 해석에 대하여 제시하였다. 또한, 에칭된 평면 도파로 Bragg grating 광 온도센서의 이론적인 해석과 실험을 행하고 그 결과를 나타내었다. 도파로에 기반한 grating응답에 대하여 선형 온도 효과보다 비선형의 이론적 모델과 plate deformation이론이 허용오차 범위 내에서의 실험치와 일치함을 알 수 있었다.

• 전자공학회논문지D
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• 제36D권7호
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• pp.80-91
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• 1999

흡수 회절결자를 가지는 복소결합 다중양자우물 구조의 DFB 레이저가 작은 문턱이득, 좋은 변조 특성 그리고 작은 선폭계수를 보이며 또한 큰 제작 공차를 가지는 최적의 복소 회절격자 구조를 보였다. 이러한 구조를 찾기 위해 확장된 새로운 층 방법을 사용하여 복소 결합계수와 복소결합계수비를 계산하였으며 흡수 회절격자 층에서의 모달 손실을 포함하는 문턱이득을 직각사각형과 사다리꼴 회절격자에 대하여 계산하였다. 제안된 여러 구조에 대한 계산 결과의 비교를 통하여 작은 문턱이득과 큰 제작 공차를 얻기 위한 설계 지침을 얻었다. 제안된 여러 구조 중에서 이중 회절격자 층 방법을 이용한 구조중 흡수 회절격자가 윗층에 있는 구조가 복소 결합계수의 크기와 문턱이득에 대한 제작 공차가 가장 컸다. 복소결합계수비에 대한 제작 공차는 모든 구조에서 매우 큰 값을 가지고 있어 회절격자 설계시 중요한 고려 대상이 아님을 볼 수 있었다.

• 한국광학회지
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• 제28권2호
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• pp.53-58
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• 2017

본 논문은 집적화된 소형의 분광모듈 구현을 위한 나노회절격자의 설계 및 제작에 관한 연구이다. 제안된 평면 구조의 나노회절격자는 회절격자로부터 반사된 빛을 집광하기 위하여 비등간격의 구조로 설계되었으며, 400 nm에서 650 nm까지의 파장 대역폭에서 균등한 분해능을 가지도록 비대칭 V 홈 구조를 가지도록 설계되었다. 최적 설계된 나노회절격자를 저가, 대량 생산에 적합한 UV-NIL 공정을 통해 제작하기 위하여 FT-IR 흡수스펙트럼을 분석하였으며, 이를 통해 5 nm 이내의 치수 정밀도를 가진 고분자 나노회절격자를 제작 할 수 있었다. 제작된 고분자 기반 나노회절격자를 이용한 집적형 분광모듈은 250 nm의 파장 대역폭에서 각 첨두파장의 기준으로 5 nm의 균등한 파장 분해능을 확인하였으며, 이는 다양한 분광모듈의 적용분야에 적용될 것으로 기대된다.