• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.174-175
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• 2003

광섬유-평면도파로 결합기는 평면도파로의 재료와 구조에 따라 다양한 응응이 가능하다. 특히 평면도파로의 전기광학 효과를 이용하면 고속 광변조 현상을 얻을 수 있다. 평면도파롱에 전기장을 인가하기 위해서는 두개의 도체 전극이 필요하다. 전극으로 주로 금속을 많이 이용하기 때문에 금속층이 포함된 광섬유-평면도파로 결합기의 특성을 연구하는 것이 요구된다. 본 논문에서 그림 1과 같이 금속 중간층이 포함된 광섬유-평면도파로 결합기의 구조의 동작특성을 측정하고 결과를 보고한다. (중략)

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.4
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• pp.326-334
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• 1991

We propose an optical Asynchronous Transfer Mode(ATM) switching system using free-space optics and an output buffer memory. The distributor system in the switching fabric was analyzed using the Huygens-Fresnel principle and lens transformation. For monochromatic illumination, a pattern similar to the Fourier transform of the input distribution was observed across the output plane. A spatially broadened intensity distribution across the the output plane can be expected when the system is illminated with a partially coherent, quasimonochromatic beam. Spatially coherent pulses as short as 100fs can propagate through the distributor without severe spatial broadening.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.37-41
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• 2018

This paper presents the integrated fluorescent oxygen sensor probe module based on planner lightwave circuits using UV imprint lithography. The oxygen sensor system is consisted of the optical source part, optical detector part and optical sensing probe part to be composed of the planner lightwave circuit and oxygen sensitive thin film layer. Firstly, we optimally designed the planner lightwave circuit with asymmetric $1{\times}2$ beam splitter using beam propagation method. Then, we fabricated the planner lightwave circuits using UV imprint lithography process. This planner lightwave circuits transmitted the optical power with 76% efficiency and the fluorescence signal with 70% efficiency. The oxygen sensitive thin film layer is coated on the end face of planner lightwave circuit. The oxygen sensor system using this sensor probe module with planner lightwave circuit could measure the concentration with 0.3% resolution from 0% to 20% gas range. This optical oxygen sensor probe module make it possible to compact, simple and cheap measurement system.

• Journal of the Korean Society of Visualization
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• v.14 no.1
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• pp.51-56
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• 2016

Oxygen is a key factor in aerobic reactions and most biological activities. Visualization of oxygen distribution of a chemical process or biological system has been a very challenging object despite of its significance and potential impact. To monitor and visualize the spatial distribution of oxygen concentration, various techniques such as electro-chemical probe, polarographic electrode, LIF(laser-induced fluorescence) and so on have been introduced. Oxygen planar optode which utilizes the oxygen quenching of fluorescence light is one of the currently available methods for time-resolved visualization of oxygen distribution on a planar surface. In this study, we utilized VisiSens oxygen planar optode system to visualize the spatial distribution of oxygen concentration on leaves of Korean azalea. As a result, temporal variation of oxygen concentration distribution caused by respiratory activity of the leaf could be quantitatively monitored.

• Journal of the Korean Society of Safety
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• v.16 no.2
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• pp.121-129
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• 2001

This paper demonstrates the development of optical temperature sensor based on the etched planar waveguide Bragg grating. Topics include design and fabrication of the etched planar waveguide Bragg grating, investigation of the grating reflection characteristics, and temperature measurement capabilities. The typical bandwidth and reflectivity of the surface etched grating has been ~0.2nm and ~7%, respectively, at a wavelength of ～1552nm. The temperature-induced wavelength change of the optical sensor is found to be slightly non-linear over ～20$0^{\circ}C$ temperature range. Theoretical models for the grating response of the sensor based on waveguide and plate deformation theories agree with experiments to within acceptable tolerance.

• Journal of the Korean Society of Radiology
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• v.16 no.2
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• pp.157-162
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• 2022

Since preclinical positron emission tomography imaging is performed on small animals that are very small compared to the human body, a detector with excellent spatial resolution is required. For this purpose, a system was constructed using a detector using small scintillation pixels. Since the size of the currently developed and used photosensors is limited, excellent spatial resolution can be obtained when the minimum scintillation pixel and maximum array are used. In this study, the size of the photosensor is fixed and various scintillation pixel arrays are configured to match the size of the scintillation pixels, so that no overlap occurs in the flood image and the maximum scintillation pixel array in which all scintillation pixels are distinguished. For this purpose, DETECT2000, which can simulate a detector module composed of a scintillator and an photosensor, was used. A photosensor consisting of a 4 × 4 array of 3 mm × 3 mm pixels was used, and the scintillation pixel array was configured from 8 × 8 to 13 × 13, and simulations were performed. A flood image was constructed using the data obtained from the photosensor pixel, and the maximum scintillation pixel array that does not overlap the image was found through the flood image and the profile. As a result, the size of the scintillation pixel array in which all scintillation pixels are imaged without overlapping each other in the flood image was 11 × 11.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.260-261
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• 2000

광결정(photonic crystal)은 빛의 파장 크기 정도의 격자 상수를 지닌 1차원, 2차원, 또는 3차원의 주기적인 구조이다. 광결정에는 광밴드갭(photonic bandgap)이라는 빛의 자발 방출이 억제된 진동수의 영역이 존재하는데, 이 영역을 이용하여 빛의 자발 방출을 조절하고 빛의 흐름을 제어할 수 있다. $^{[1]}$ 지난 10여년간 2차원, 3차원의 광결정 구조에 대한 연구가 많이 이루어져 왔는데, 최근에는 슬랩 도파관(slab waveguide)에 2차원 광결정을 만든 구조에 대한 연구가 활발하게 진행중이다. 이 구조는 평면 방향으로는 광밴드갭 효과로 광모드를 가둘 수 있고 수직 방향으로는 전반사를 이용하여 모드를 가둘 수 있어서 3차원적인 모드 confinement 효과를 얻을 수 있다. [그림 1]의 (a)에 air-bridge 형태의 2차원 광결정 슬랩(photonic crystal slab) 구조를 도식적으로 나타내었고, (b)에는 본 연구실에서 제작한 구조 표면의 scanning electron micrograph을 나타내었다. 현재 몇몇 연구 그룹에서 이와 같은 광결정 슬랩 구조를 이용한 반도체 레이저를 실현하는데 성공하였다.$^{[2,3]}$ (중략)

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.6
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• pp.400-407
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• 2003

In this paper an optical encryption system, which can decrypt the original image by using the autocorrelation terms of a JTC, is proposed. Unlike the classical JTC, the joint input plane of the proposed system is composed in a frequency domain not a spatial domain, thus it needs only one Fourier transformation. To use like this, the phase component appeared in the output plane of JTC should be considered. We presents the effect of phase and provides the solution. An original image is encrypted to a complex-valued random image. The original image is reconstructed using the autocorrelation terms which is the main drawback of JTC, therefore the proposed system is more suitable for JTC and real time processing. By computer simulation and optical experiment, the analysis for the phase effect and the performance of the proposed system are confirmed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.639-646
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• 2016

In this study, the contactless measurement method with a optical displacement sensor(ODS, ADNS 9500) was proposed to overcome flaws in a rotary encoder based measurement under particular circumstances, such as a slippage and a case of little rotational inertia. The performance tests of the optical displacement sensor using data acquisition board and National Instruments's LabVIEW program were performed to accomplish accurate displacement measurements and the performance characteristics according to measurement direction, speed, acceleration, height and surface types were discovered through the repetitive tests. The experimental results indicate that, in order to get an accurate in-plane motion, the height(distance between the ODS and the target surface) has to be maintained at the range of 2.4 mm to 3.2 mm and the sensitivity(resolution) should be modified and applied to the formulae for displacement calculation, considering its measurement direction, speed and surface type.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.4
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• pp.371-378
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• 1992

In this paper we report the fabrication of a planar optical wavehuide lens on a Y-cut LiNbO3 substrate by Ti_indiffusion and Ti-indiffused proton-exchange(TIPE). LiNbo3 planar waveguides are fabricated and refractive indices of the waveguides are fabricated and refractive indices of the waveguides are measured. Based on the measured indices, palanr waveguide lenses are designed and fabricated. The measured focal point and spot size of the fabricated lens are in good agreement with those of the designed lens.