• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.5
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• pp.328-341
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• 2014

The object of this paper is to develop optimal optical filter, which can be used to identify the financial account and read the information. The five factors which affect the performance of the optical filter are identified as optical glass type, existence of Fe, Photo pic coating type, and coating form. In this study we seek to determine the optimal combination for the best design of the optical filter. For each combination, the performances of optical filter are investigated using the proper experimental equipments and methods. White-state voltage, black-state voltage, and black-state error rate are used for the performance measures. Through the statistical analysis of the performance data collected, we have determined the optimal design of the optical filter.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.3
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• pp.109-119
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• 1996

We propsoed a multiplexed optical correlation filter method for an optical parallel addition based on symbolic substitution. In the proposed mthod, we used redundant binary number which was easy to minimize the number of the symbolic substitution rules. We chose MACE filter which had very low sidelobes and good correlation peak compared with SDF filter as the optical correlation recognition filter and encoded input numbers properly to increase the discrimination capability. In order to minimize the number of symbolic substitution rules, sixteen input patterns were divided into six groups of the same addition results and six filters for recognizing the input patterns were used. these filters were multiplexed in two MMACE filter planes and the corresponding substitution method was proposed. Through the computer simulation, we confirmed the proposed method was suitable to implement the optical parallel adder.

• Journal of IKEEE
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• v.19 no.1
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• pp.27-32
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• 2015

A flexible and tunable microwave photonic filter based on adjustable optical frequency comb source is demonstrated. We use a combination of a dual parallel Mach Zehnder modulator and an intensity modulator to generate fifteen comb lines with proper weights to implement a desired filter. The optical comb weights, corresponding to the tap coefficients of the filter, are flexibly changed by adjusting the operation parameters of the modulators. The achieved bandwidth and stopband attenuation of the tunable filter are 0.7 GHz and 20 dB, respectively. In addition, we overcome the undesired low frequency suppression appeared in a conventional scheme by applying a dual parallel Mach Zehnder modulator for single sideband suppressed carrier modulation.

• Korean Journal of Optics and Photonics
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• v.4 no.1
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• pp.9-14
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• 1993

We chose Bessel beamu[$J_o(ar)}$)l in order to investigate image forming property of the optical system with combined filter of amplitude and phase(CFAP). This paper investigated numerically the influence of number of nodes of these beams on the PSF, encircled energy(E), transmission ratio(TR), gain((;) for an aberrated(1aberration-free) optical system. These results showed that the property of PSF differ considerably from the one of the existing amplitude filter and that Bessel beam has super compensating effect for an optical system with spherical aberration. Particularly, the Bessel beam has less the size of central spot than the radius of Airy disk, this result can therefore be applied to the fabrication of semiconductor device.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.11
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• pp.1481-1488
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• 1995

Due to the low loss, broadband and accurate short time delay properties of optical fiber, it has attracted as a delay medium for high speed and broad-band signal processing. In this paper, we consider the coherent optical fiber filter of IIR lattice structure, which uses coherent light sources and consists of directional couplers whose coupling coefficients are restricted between 0 and 1. Considering restrictions of directional coupler, the design formulae and condition for realibility of optical fiber filter of IIR lattice structure which makes the optimal use of optical signal energy are derived.

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.121-126
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• 2012

We propose a novel technique that records the horizontal-parallax-only (HPO) hologram of a real object using optical scanning holography (OSH). The proposing HPO-OSH is composed of a conventional OSH and an electronics low pass filter. When we scan an object along vertical direction before horizontal direction, the electronic low pass filter filters the vertical fringes with preserving horizontal fringes and gives an HPO hologram. To the best of our knowledge, this is the first time to record the HPO hologram using OSH without either truncation of the scanning beam or digital post processing.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.211-215
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• 2004

Recently, one of remarkable tends in the development of optical communication industry is the miniaturization and integration of products. The alignment system of micro optical module is a key apparatus for the miniaturization of optical module and the development of optical communication parts with high functionality. In this research, we have developed a system capable of automatic alignment of a $30\mu\textrm{m}$-thick film filter and a lensed fiber in order to improve the speed and losses in the optical fiber-to-filter alignment of optical modules. Using the developed automatic alignment system and silicon optical bench, we have measured optical loss and characteristics of the assembled optical add/drop module before packaging $1{\times}1$ OADM optical module. Whole size of add/drop module was less than $5mm{\times}5mm{\times}1mm$. The measured maximum insertion loss was 0.294㏈ that is below 0.3㏈ which is a standard loss of optical module.

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.261-264
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• 2000

Continuous ND filters are fabricated on the silver halide photoplates. These filters enable us to get intensity modulated laser beam. Two kinds of continuous ND filters are fabricated. Optical density of one filter is increased radically and that of the other is decreased. In order to get a filter having desirable optical density, a mask which has reversed optical density has to be made. made.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.6
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• pp.87-93
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• 2014

Optical brightening agents (OBA) is generally used to improve the optical property of printing paper in the paper industry. However, effects of OBA addition on paper preservability has been not fully understood yet. Therefore, this study was aimed to investigate effects of a OBA on the aging characteristics of paper. The OBA treatment of three different types was performed by dipping a filter paper into each a OBA solutions of different concentrations. The filter papers applied with a OBA were artificially aged at 80oC and 65% RH, and their optical and mechanical properties were evaluated. It was found that application of OBAs influenced the aging characteristics of paper. Especially, after aging, the optical and mechanical properties of the filter paper treated with the tetra-type OBA were more significantly decreased than those of the non-treated filter paper. The more the concentration of the tetra-type OBA increased, the more decreasing rate of optical and mechanical properties of the filter paper. While, in case of di-type OBA and hexa-type OBA, paper optical and mechanical properties were slightly decreased or not changed with a OBA treatment.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.833-839
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• 1986

This paper describes the development of a new type of an integrated optical filter using the frequency characteristics of a directly-connected directional coupler with a Rib waveguide. It has been designed for multiplexing and demultiplexing light froups in different wavelength regions. Also, the effects of higher modes, couplings between input waveguides or output waveguides, and dispersion of material are considered.