• JSTS:Journal of Semiconductor Technology and Science
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• 제7권3호
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• pp.183-195
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• 2007

MEMS technology is proven to be an enabling technology to realize many components for optical networking applications. Due to its widespread applications, VOA has been one of the most attractive MEMS based key devices in optical communication market. Micromachined shutters and refractive mirrors on top of silicon substrate or on the device layer of SOI (Silicon-on-insulator) substrate are the approaches trapped tremendous research activities, because such approaches enable easier alignment and assembly works. These groups of devices are known as the planar VOAs, or two-dimensional (2-D) VOAs. In this review article, we conduct the comprehensively literature survey with respect to MEMS based planar VOA devices. Apparently MEMS VOA technology is still evolving into a mature technology. MEMS VOA technology is not only the cornerstone to support the future optical communication technology, but the best example for understanding the evolution of optical MEMS technology.

• 조명전기설비학회논문지
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• 제25권11호
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• pp.83-90
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• 2011

There are two main types of concentrating optical systems in use today: refractive types that use Fresnel lenses, and reflective systems that use one or more mirrors. Regardless of the chosen optical system, the result is concentrated sunlight being aimed at the sensitive face of the cell, to produce more energy from less photovoltaic material. In this paper, for the achieve trackerless CPV system, CPV module included that the spherical lens with reflect mirror makes it possible to achieve high and stable power generation performance for the high concentration photovoltaic power generation system and cope with the needs for a variety of shapes and sizes in flexible manners and that the multiple cavity assemble method greatly reduces costs. Development of these high performance multi-junction CPV module promises to accelerate growth in photovoltaic power generation.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2930-2934
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• 2009

Surface-enhanced Raman Scattering (SERS) spectroscopy is applied to the study of the adsorption of benzoimidazolic fungicides benzimidazole (BIZ) and thiabendazole (TBZ) on silver mirrors. The influence of pH on the adsorption mechanism was investigated. In case of BIZ, two different adsorption mechanisms are deduced depending on the experimental conditions: via the $\pi$ electrons of the ring in neutral conditions and through an ionic pairing of protonated nitrogen atom with the chloride adsorbed on the metal surface. The SERS spectra of TBZ revealed that most molecules were adsorbed on silver surface by the ${\pi}$ electrons in neutral and acidic conditions but in acid conditions, some molecules were adsorbed via the sulfur and nitrogen atoms tilted slightly to the surface.

• ETRI Journal
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• 제37권5호
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• pp.972-978
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• 2015

This paper proposes an accurate tunable-gain 1/x circuit. The output voltage of the 1/x circuit is generated by using a capacitor charging time that is inversely proportional to the input voltage. The output voltage is independent of the process parameters, because the output voltage depends on the ratios of the capacitors, resistors, and current mirrors. The voltage gain of the 1/x circuit is tuned by a 10-bit digital code. The 1/x circuit was fabricated using a $0.18{\mu}m$ CMOS process. Its core area is $0.011mm^2$ ($144{\mu}m{\times}78{\mu}m$), and it consumes $278{\mu}W$ at $V_{DD}=1.8V$ and $f_{CLK}=1MHz$. Its error is within 1.7% at $V_{IN}=0.05V$ to 1 V.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.474-480
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• 2002

Aspheric optical lenses and mirrors are widely used in recent. It is more difficult to manufacture and measure the aspherical optics compared to conventional spherical ones. The interferometric optical test is common for the measurement of spherical optical surface. But the application of the interferometry to the measurement of aspheric surface is difficult because it needs a precise null corrector and very careful environmental conditions such as keeping constant temperature, humidity, atmospheric pressure and vibrations. To enhance productivity of optics manufacturing on-machine measurement and correction has been developed in this study. For practical applications, robustness of the measurement method to environments is more important. For the purpose an optical OMM(On-Machine Measurement) system has been developed using Shack-Hartmann test which has robustness to the environment. The wavefront has been reconstructed from the measured data using the primary aberration polynomial function by least square fitting. The measured result of the developed only system gives the maximum deviation only in 200 nm from the result measured by a commercial Fizeau interferometer Wyko 6000.

• Journal of the Optical Society of Korea
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• 제19권2호
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• pp.154-158
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• 2015

We experimentally demonstrated a novel wavelength-swept laser using a cascaded Raman gain around 1310 nm. A 1064/1310 wavelength division multiplexing (WDM) coupler and coupled fiber Bragg gratings mirrors at 1064, 1117, 1175, 1240 nm are effectively used to increase the power efficiency in a laser ring cavity with highly non-linear fiber (HNLF) of 2 km. Linear wavelength sweeping is demonstrated with the 100 Hz triangular driving signal to fiber Fabry-Perot tunable filter (FFP-TF) around the 1310 nm region. The measured sweeping range and output power were 27 nm and 2.1 mW, respectively, which are suitable for optical coherence tomography (OCT) imaging.

• Journal of the Optical Society of Korea
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• 제18권1호
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• pp.32-36
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• 2014

A tangible floating display that can provide different perspective views without special glasses being introduced. The proposed system can display perspective floating images in the space in front of the system with the help of concave mirrors. In order to avoid wearing special equipment to interact and deliver the sense of touch, the proposed system adopted an ultrasound focusing technology. For providing an immersive experience to the viewers, the proposed system consists of a tangible floating display system and a multiple-view imaging system for generating three lenticular displays in front of the users.

• 한국광학회지
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• 제10권3호
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• pp.214-220
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• 1999

광자감쇠 분광신호에 실린 오차와 감쇠시간 편차와의 관계를 이론적으로 계산하였고 shot noise와 디지털오차에 의한 감쇠시간 편차로부터 측정 가능한 흡수율의 한계를 계산하였다. 광자감쇠 공동의 정렬과 관련된 오차와 공동 내부의 기체 압력에 따른 감쇠시간 변화 그리고 거울에서의 간섭에 의한 감쇠시간의 변화를 규명하였다.

• Journal of the Optical Society of Korea
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• 제16권3호
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• pp.299-304
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• 2012

A high angular tolerance spectral filter was realized incorporating an etalon, which consists of a $TiO_2$ cavity sandwiched between a pair of Ag/Ge mirrors. The effective angle was substantially extended thanks to the cavity's high refractive index. The device was created by embedding a 313-nm thick $TiO_2$ film in 16-nm thick Ag/Ge films through sputtering, with the Ge layer alleviating the roughness and adhesion of the Ag layer. For normal incidence, the observed center wavelength and transmission were ~900 nm and ~60%, respectively; throughout the range of $50^{\circ}$, the relative wavelength shift and transmission variation amounted to only ~0.06 and ~4%, respectively.

• 센서학회지
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• 제14권2호
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• pp.91-95
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• 2005

A fiber Fabry-Perot interferometric sensor for the measurement of current flowing into a small fuse have been studied. The proposed current sensor was fabricated with a fiber Fabry-Perot interferometer attached close to a fuse line inside a small fuse. The fiber Fabry-Perot interferometer used in the experiment had the 10 mm cavity length and the 3.5 % reflectance mirrors. The phase shift of the output signal of the current sensor was proportional to the square of current applied to the fuse and the sensitivity of the current sensor was 0.87 degree/$mA^{2}$. The experiment results show that this sensor can be used for measuring current flowing into the fuse.