• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.12
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• pp.1106-1110
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• 2005

We fabricated (110) silicon hard master by using anisotropic wet etching for embossing. The etching chemical for the silicon wafer was a TMAH $25\%$ solution. The anisotropic wet etching produces a smooth sidewall surface and the surface roughness of the fabricated master is about 3 nm. After spin coating an organic-inorganic sol-gel hybrid material on a silicon substrate, we employed hot embossing technique operated at a low pressure and temperature to form patterns on the silicon substrate by using the fabricated master. We successfully fabricated the multi-mode planar optical waveguides showing low propagation loss of 0.4 dB/cm. The surface roughness of embossed patterns was uniform for more than 10 times of the embossing processes with a single hydrophobic surface treatment of the silicon hard master.

• Journal of the Optical Society of Korea
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• v.12 no.3
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• pp.157-161
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• 2008

A wavelength-selective reflector, composed of a double-ring-resonator add/drop filter and a loop-back mirror at the drop port to be used for a hybrid-integrated tunable laser is designed and fabricated. High-index-contrast polymer waveguide is used to realize a compact device as small as $2mm{\times}0.4mm$. The radii of the rings are slightly different from each other to obtain a wide wavelength tuning via a vernier effect. Peak reflectivity is measured to be 52% for TE mode and polarization-dependent wavelength shift is 0.95 nm. The tuning range is measured to be about 42 nm for applied current as small as 46 mA.

• Journal of the Optical Society of Korea
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• v.11 no.2
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• pp.59-62
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• 2007

In this paper, we introduce a reliable, scalable, and cost-effective switchless wavelength division multiplexing (WDM) network based on a quality-of-service supporting reservation-based medium access control (MAC) protocol. The protocol not only provides both packet and circuit switching but also supports multicasting. The network efficiency is significantly increased by spatially reusing wavelengths and exploiting multiple free spectral ranges (FSRs) of arrayed waveguide grating (AWG) employed in the architecture. We have demonstrated the feasibility of this architecture by simulating in $Optsim^{TM}$.

• Korean Journal of Optics and Photonics
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• v.11 no.6
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• pp.405-410
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• 2000

We propose a novel design concept to improve extinction ratio by minimizing $Cv_e-Cv_o$ . Improvements of loss and fabrication error limit are also obtained by this hybrid design of the lateral shift and curved waveguide to control transfer coefficients, $Cv_e and Cv_o$ . The concept of lateral shift merges two transfer coefficients, and additional curved waveguide controls mode profile asymmetrically to help this minimizing effect of $Cv_e-Cv_o$ with no serious decrease in transfer efficiency. For a given InP based waveguide structure, the mode propagation analysis with an effective index approximation provided a calculational improvement of extinction ratio to -39 dB and fabrication error limit to $57.19\mu\textrm{m}$, with a structure design of $300\mu\textrm{m}$ waveguide curvature and $0.1\mu\textrm{m}$lateral shift. shift.

• Korean Journal of Optics and Photonics
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• v.19 no.3
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• pp.187-192
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• 2008

The design and analysis of a novel photonic crystal electro-optic modulator are presented in this paper. The device incorporates an electro-optic (EO) polymer slot waveguide into the center of a silicon photonic crystal waveguide. In this device, strong optical confinement in the EO polymer core and small group velocity from the photonic crystal structure provide a surprise enhancement of the EO effect.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.666-671
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• 1990

The characteristics of the corrugated conical horn antenna for the satellite communication earth station operating at C band is analyzed and its radiation patterns is measured. We obtain the characterstic equations for corrugated horn in the condition that the balanced hybrid mode is formed on born aperture and calculate radiation patterns in the Fresnel region from the aperture integral expressions obtained by the equivalence principle. The radiation patterns which are calculated for the frequency of 3.85GHz and 6.18GHz are well agreed with the measured data.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.296-297
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• 2003

사회의 정보화가 급속하게 진전됨에 따라 취급해야 할 데이터 양이 증가되면서 정보 저장장치의 고속화, 소형화, 및 대용량화의 필요성이 대두되고 있다. 많은 양의 데이터를 저장하기 위해서는 저장장치의 물리적 디스크 공간이 높은 기록밀도를 가져야 한다. 이를 위한 방법으로 하드디스크 기술과 광자기 디스크 장치(magneto-optical disk drive) 기술을 결합하는 근접장 복합 기록 방법(Near field hybrid recording method)들이 보고 되었다. (중략)

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.231.1-231
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• 2003

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.4
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• pp.651-658
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• 2001

A novel multi-section power divider configuration is proposed to obtain wide-band frequency performance up to microwave frequency region. Design procedures for the proposed microwave broadband power divider are composed of a planar multi-section three-ports hybrid and a waveguide transformer design procedures. The multi-section power divider is based on design theory of the optimum quarter-wave transformer. Furthermore, in order to obtain the broadband isolation performance between the two adjacent output ports, the odd mode equivalent circuit should be matched by using the lossy element such as resistor. The derived design formula for calculating these odd mode matching elements is based on the singly terminated filter design theory. The waveguide transformer section is designed to suppress the propagation of the higher order modes such as waveguide modes due to employing the metallic electric wall. Thus, each section of the designed waveguide transformer should be operated with evanescent mode over the whole design frequency band of the proposed microwave broadband power divider. This paper presents several simulations and experimental results of multi-section power divider to show validity of the proposed microwave broadband power divider configuration. Simulation and experiment show excellent performance of multi section power divider.

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.255-260
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• 2000

We report that the crack-free organic-inorganic hybrid silica thin films were fabricated by sol-gel process using organometallic compounds as a precursor and that we have established very reproducible fabrication condition with systematic investigation of thickness and refractive index variations for various control parameters, such as, coating type, coating speed, chemical composition, prebake and postbake temperature. Additionally, we measured and compared the change of optical property with the UV exposure dose for three different kinds of photoinitiators. Furthermore, the fabrication of Ix4 MMI optical power splitter using the sol-gel thin film provides the possibility of various applications to the optical waveguide devices. vices.