• 한국정밀공학회지
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• 제24권4호
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• pp.153-158
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• 2007

Recently nano imprint lithography to fabricate photonic crystal on polymer is preferred because of its simplicity and short process time and ease of precise manufacturing. But, the technique requires the precise mold as an imprinting tool for good replication. These molds are made of the silicon, nickel and quartz. But this is not desirable due to complex fabrication process, high cost. So, we describe a simple, precise and low cost method of fabricating PDMS stamp to make the photonic crystals. In order to fabricate the PDMS mold, we make the original pattern with designed hole array by finding the optimal electron beam writing condition. And then, we have tried to fabricate PDMS mold by the replica molding with ultrasonic vibration and pressure system. We have used the cleaning process to solve the detaching problem on the interface. Using these methods, we acquired the PDMS mold for photonic crystals with characteristics of a good replication. And the accuracy of replication shows below 1% in 440nm at diameter and in 610nm at lattice constant by dimensional analysis by SEM and AFM.

• 한국재료학회지
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• 제12권4호
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• pp.254-258
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• 2002

To realize channel cross-connecting in optical communications systems, a high speed optical matrix switch was fabricated using z-cut $LiNbO_3$. For switch fabrication was design bending structure and coupling length and four $2{\times}2$ directional couplers were integrated on one substrate far construction of a $4{\times}4$ switch. Single-mode optical waveguides were formed by Ti-diffusion at a wet $O_2$ atmosphere. Ti-diffusion profile, refractive index variation and waveguide morphology were analyzed by Prism coupler and optical microscopy, respectively.

• 한국전자파학회논문지
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• 제10권2호
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• pp.237-246
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• 1999

본 논문에서는 corrugated 구조 도파관의 저역통과 특성과 이중 계단형 불연속 구조 도파관의 고역통과 특성 을 결합하여 기존의 반파장 공진기를 이용한 여파기보다 크기가 상당히 작고 SpUriOUS 특성이 우수한 소형 도파관 대역통과 여파기를 설계하였다. 불연속면에서 발생하는 고차 모드에 의한 영향을 고려하기 위하여 최저차 모드만으로 설계한 여파기의 특성을 길이 보상을 통해 수정하였고, 모드 정합법을 이용한 특성 해석 프로그램과 상용 소프트웨어 $OSA90^{TM}$을 통해 최적화 하였다. 중심주파수 10 GHz, 대역폭 800 MHz의 7단 대역통과 여파기 를 대칭 구조로 설계, 제작하였다. 측정 결과에서 중심주파수 9.97 GHz, 대역폭 840 MHz, 삽입손실 0.97 dB의 특성을 얻었고, 그 길이는 64.38 mm이다. 첫 번째 spunous 응답은 26.1 GHz에서 나타났다.

• 한국전기전자재료학회논문지
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• 제15권12호
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• pp.1085-1089
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• 2002

The circular cavity resonator which can measure the dielectric properties of dielectrics in the Ka-band(26.5GHz∼400Hz) frequency range was designed and fabricated. A structure of the resonator is divided into two equal parts of the length and the dielectric plate sample is placed between two halves. Exciting and detecting of the resonator is Performed by WR28 rectangular waveguides using Bethe's small hole coupling. The GaAs plate sample, whose performance is known to be 13 in millimeter wave range, was used for the verification of the performance of the fabricated circular cavity resonator In the measurement of GaAs single crystal using that resonator, the resonant frequency of the dominant TE$\sub$011/ mode, the permittivity and Q${\times}$f$\sub$0/ were measured as 26.69GHz, 12.9 and 124,000GHz, respectively.

• 한국광학회지
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• 제22권1호
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• pp.40-45
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• 2011

동일한 주회 길이의 통상적인 DCRR (Double-coupler Ring Resonator) 에 비하여 두 배의 FSR (Free Spectral Range) 성능을 나타낼 수 있는 TCRR (Triple-coupler Ring Resonator: 삼중 결합 링 공진기) 필터의 설계 및 제작에 대하여 논의하였다. 열-광학 특성이 우수하고, 코어-클래딩 굴절률 차가 큰 폴리머 물질을 이용하여 작은 반경의 곡선도파로가 가능한 매립형 도파구조의 컴팩트한 TCRR 필터를 설계 및 제작하였다. 파장가변 레이저와 광섬유 배열 블록을 이용하여 TCRR 필터의 Through 및 Drop 포트 출력 특성을 측정한 결과, DCRR 필터의 두 배인 4.4 nm의 FSR을 확인하였고, 이는 전달행렬 방법을 이용하여 해석한 결과와 거의 동일하였다.

• 한국재료학회지
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• 제17권4호
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• pp.222-226
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• 2007

[ $SiO_2$ ]thin films containing Si-nanocrystals and $Er^{3+}$ were fabricated by the RF-sputtering method. Intense emission of $Er^{3+}$ was observed at 1530 nm region after the annealing of the film at $1050^{circ}C$ for 5 min. Channel waveguides were fabricated using such films for the core. The films containing Si higher than 2.4 at% exhibited the change in stress from compression to tension after annealing, which induced the fatal loss-increase in waveguide. The optical gain might be attained by the Er-doped waveguide with Si lower than 2.4 at% by a visible-light-excitation.

• 한국전자파학회논문지
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• 제14권11호
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• pp.1143-1148
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• 2003

CPW와 마이크로스트립선로에서 수십 피코초의 펄스 폭을 갖는 가우시안(Gaussian) 펄스 신호가 진행해 갈 때 기판 및 선로 구조에 따른 분산 및 펄스의 전파 특성을 시간 영역에서 해석하고 측정하였다. 특히, 선로에 사용된 기판의 기본 TE 모드에 대한 차단 주파수( $f_{TE}$ )의 변화에 따른 CPW와 마이크로스트립 선로간의 전송특성을 구하고 비교하였다. 이를 실험적으로 확인하기 위해 $f_{TE}$ 가 다른 기판에 두 가지 50 $\Omega$ 선로를 제작하여 수십 피코초 펄스가 진행되었을 때의 전송 특성을 시간 영역 분석기능이 내장된 VNA(Vector Network Analyzer)를 이용해서 측정하였다.

• 한국전기전자재료학회논문지
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• 제11권7호
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• pp.557-564
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• 1998

A low loss x-cut $LiNbO_3$optical waveguide was fabricated by Yi in-diffusion, and the properties of guided-mode and the total insertion loss of the pigtailed waveguide with polarization maintaining fiber(PMF) were measured at optical wavelength 1550nm. for forming the waveguides, the parameters of diffusion, Ti thickness, waveguide line-width, length, diffusion temperature, time and atmosphere were set $1400{\AA}$, $8{\mu}m$, 3.3cm, $1050^{\circ}C$, 8 hours and wet bubbled oxygen, respectively. And then after the polishing and piatailing, it showed that the total insertion loss was -4.1dB for TM mode, -5.5dB for TE mode, and mode size, that is, the horizontal/ vertical size were $13.8{\mu}m/18{\mu}m$ for TM mode, $9.6{\mu}m/6.5{\mu}m$ for TE mode.

• 한국전기전자재료학회논문지
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• 제11권10호
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• pp.924-930
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• 1998

In this study, we describe the properties of an electro-optical modulator with CPW(coplanar waveguide) electrode fabricated on $LiNvO_3$ optical waveguide, that is applicable to optical communications. These optical modulators have features that use a buffer layer to reduce velocity mismatch between microwaves and optical wave as well as employ CPW to improve impedance and propagation mode mismatch between the electrode and the external circuits. And an annealed proton exchange technique for obtaining low-loss optical waveguides and good reproducibility was employed. Taking into consideration the mentioned background, to achieve the lower driving voltage of optical modulator, we have re-disigned the longer interaction length. And their device properties are discussed also. As a result, fabricated optical modulators of good 10Gps operation and low voltage(5.6V of the halfwave lengfth voltage) at an $1.5{\mu}m$ wavelength are achived with good reproducibility.

• ETRI Journal
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• 제33권2호
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• pp.275-278
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• 2011

This letter presents a polymer $1{\times}2$ thermo-optic totalinternal-reflection digital optical switch (TIR-DOS) with an index contrast of 1.5%-${\delta}$ operating at low power consumption. The structure of our $1{\times}2$ TIR-DOS was created by adding a reflection port to that of a conventional multimode filtering variable optical attenuator. To improve the total-internalr-eflection efficiency, a heater offset was applied to the crossing region of multimode waveguides of the TIR-DOS. The fabricated $1{\times}2$ TIR-DOS shows a low electrical power consumption of 18 mW for an on-off ratio of 35 dB.