• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.493-498
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• 1998

ZnS doped borosilicate glass for nonlinear optical application was prepared by melting and precipitation process. The optical band gap of the precipitated ZnS particles ranged from 3.83 to 3.96 eV compared with the bulk ZnS energy gap of 3.53 eV. This result was interpreted in terms of a quantum confinement effect due to small crystal size. ZnS partilcle size estimated by effective mass approximation ranged from about 39 to 83 $\AA$ It increased wtih the increase of heat tratment time and temperature.

• Applied Science and Convergence Technology
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• v.25 no.6
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• pp.133-137
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• 2016

The surface treatment of cover glass for conversion efficiency of photovoltaic cell is important to reduce reflectivity and to increase the incident light. In this work, random textured anti glare (RTAG) glass was prepared by wet surface coating method. Optical properties due to the changes of surface morphology of RTAG glass were compared and conversion efficiency of photovoltaic cell was researched. Grain size and changes of surface morphologies formed with surface etching time greatly affected optical transmittance and transmission haze. Current density (Jsc) were high at the condition when surface morphologies reflection haze were low and transmission haze were high. Jsc was $40.0mA/cm^2$ at glancing angle of $90^{\circ}$. Incidence light source was strongly influenced by surface treatment of cover glass at high incidence angle but was hardly affected light source at the low angle of incidence.

• Journal of the Korean Ceramic Society
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• v.52 no.2
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• pp.119-122
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• 2015

Laser sealing with glass frits appears a promising technology for sealing various electronic devices (e.g., solar cells, displays) due to its several advantages. The purpose of this study is to understand the relationship between the composition of glasses and their laser-heating conditions. To allow glass to be sealed using laser heating, CuO was added to two different glass systems, in different amounts. The optical absorptivity of the glass samples was related directly to their CuO content. The laser-heating temperature and the CuO content exhibited a proportional relationship. Furthermore, the heating temperature increased linearly with the laser power used. From these results, we could determine the appropriate laser-heating conditions and CuO content for sealing electronic devices using laser-sealing technology.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.2
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• pp.124-130
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• 2014

In a mass manufacturing system of optical fibers, the sufficient cooling of glass fibers freshly drawn from a draw furnace is essential, asinadequately cooled glass fibers can lead to poor resin coating on the fiber surface and possibly fiber breakage during the process. In order to improve fiber cooling at a high drawing speed, it is common to use a helium injection into a glass fiber cooling unit in spite of the high cost of the helium supply. The present numerical analysis carried out three-dimensional thermo-fluid computations of the cooling gas flow and heat transfer on moving glass fiber to determine the cooling performance of glass fiber cooling depending on the method of helium injection. The results showed that afront injection of helium is most effective compared to a uniform or rear injection for reducing air entrainment into the unit and thus cooling the glass fibers at a high fiber drawing speed. However, above a certain amount of injected helium, there was no more increase of the cooling effect regardless of the helium injection method.

• Journal of the Optical Society of Korea
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• v.7 no.3
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• pp.156-159
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• 2003

Permanent structure of photoinduced singlemode waveguide in optical fluoride glasses was demonstrated using the self-channeled plasma filament excited by a femtosecond (110 fs) Ti:sapphire laser ($λ_p$ = 800 nm). The photoinduced refractive index modification in ZBLAN glasses reached a length of approximately 10 - 15 mm from the input surface of the optical glass with the diameters ranging from 5 to 8 ${\mu}{\textrm}{m}$ at input intensities more than l.0 ${\times}$ $10^{12}$ W/$\textrm{cm}^2$. The graded refractive index profiles were fabricated to be a symmetric form from the center of an optical fluoride glass and a maximum value of refractive index change (ㅿn) was measured to be l.3${\times}$$10^{-2}$. The beam profile of the output beam transmitted through the modified region showed that the photoinduced refractive index modification produced a permanent structure of singlemode waveguide.

• Journal of Power System Engineering
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• v.19 no.3
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• pp.5-10
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• 2015

Femtosecond laser machining has been applied for creating a sensor function in silica glass optical fibers. Femtosecond laser pulses make it possible to fabricate micro structures in processed regions of a very thin glass fiber line because femtosecond laser pulses can extremely minimize thermal effects. With the laser machining to optical fiber using a single shot of 210-fs laser at a wavelength of 800 nm, it was observed that a processed region surrounded a thin layer which seemed to be a hollow cavity monitored by scanning electron microscopy (SEM). This study aims at a theoretical investigation for the processed region by using a numerical analysis in order to embed sensing function to optical fibers. Numerical methods based finite element method (FEM) has been used for an optical waveguide modeling. This report suggests two types modeling and describes a comparative study on optical losses obtained by the experiment and the numerical analysis.

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.399-405
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• 2003

We manufactured a clamp-type optical current transformer (COCT) head using FD10 glass. It was manufactured of two parts of FD10 glass with symmetrical structure and was designed so that light propagates along the critical angle in order to avoid a phase difference with the light within the sensor head at reflection. Also, we measured and analyzed the current of conductor from 0 to 1,000 AT, change of optical power with incidence angle of light, temperature and polarization of light, long-term current measurement using COCT head, and demonstrated the feasibility of manufactured COCT through those experiments.

• Journal of the Optical Society of Korea
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• v.14 no.2
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• pp.163-169
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• 2010

Novel wafer-level fabrication of a glass ball-lens is realized for optoelectronic applications. A Pyrex wafer is bonded to a silicon wafer and cross-cut into a square-tile pattern, followed by wet-etching of the underlying silicon. Cubes of Pyrex on the undercut silicon are then turned into ball shapes by thermal reflow, and separated from the wafer by further etching of the silicon support. Radial variation and surface roughness are measured to be less than ${\pm}3\;{\mu}m$ and ${\pm}1\;nm$, respectively, for ball diameter of about $500\;{\mu}m$. A surface defect on the ball that is due to the silicon support is shown to be healed by using a silicon-optical-bench. Optical power-relay of the ball lens showed the maximum efficiency of 65% between two single-mode fibers on the silicon-optical-bench.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.1
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• pp.84-93
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• 1998

Planar graded index optical waveguides have been formed by Ag$^{+}$ ion exchange in the BK7 optical glass. The experimental results of diffusion and modal characteristics of Ag$^{+}$-Na$^{+}$ exchanged BK7 glass waveguides are presented. Measurements of the mode indices have been measured. We found the relations between the process and device parameters such as the diffusion depth and the square root of the diffusion time, diffusion coefficient and diffusion temperature, and diffusion ion concentration and surface index change. A theoretical gaussian function refractive index profile matched best with the measured data for all the guided modes. The empirical relations between the process and the device parameters are derived and subsequently used to formulate a systematic procedure for fabricating singlemode and multimode waveguides.uides.

• Proceedings of the Optical Society of Korea Conference
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• 2005.07a
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• pp.34-35
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• 2005

Eye Glass Display(EGD)에 사용되는 광학계를 비구면과 Diffractive Optical Element(DOC)를 이용한 플라스틱 렌즈로 구성하여 소형, 경량으로 제작이 가능하게 설계하였다. 비구면과 DOE를 최적화한 1매의 렌즈로 광학계를 구성하여 display의 길이를 줄이고, 왜곡과 색수차를 보정하며 해상력을 향상 시켰다. 더불어, 광학계는 안경 착용자가 불편하지 않을 정도의 eye relief와 눈의 움직임에 여유를 가질 수 있는 크기의 eye motion box(exit pupil)를 가진다.