• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1599-1601
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• 1999

The characteristics of ultrasonic signal in insulation oil were investigated by optical fiber sensor(OFS) utilizing Mach-Zehnder interferometer. For checking the response properties of OFS ultrasonic signal was generated by function generator in various kinds of insulation oil. The attenuation of ultrasonic signal linearly increased with the increase of viscosity of insulation oil in log scale. Discharging signal was produced by neele-sphere electrode system. Intensity of discharging signal was plotted in terms of cumulative $y^2$ and the intensity of discharging signal in new oil was little bigger than that in serviced one.

• 한국인터넷방송통신학회논문지
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• 제10권6호
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• pp.119-123
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• 2010

마크-젠더 변조기와 광 간섭계를 이용한 10Gb/s 광 듀오바이너리 송신기의 전송 성능을 고찰하였다. 전송 거리를 증가시키기 위해서 전송 시스템이 받는 영향을 변조기의 구동 전압비와 광 간섭계의 시간 지연 관점에서 컴퓨터 모의실험을 통하여 이론적 분석을 하였다. 구동 전압비를 줄이고 부분 비트 시간 지연을 최적화하여 보다 향상된 전송 성능을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1240-1243
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• 2003

In this paper, an encryption method to share a secret binary image is proposed. It divides the image to be encrypted into an arbitrary number of images and encrypts them using XOR process with different binary random images which was prepared by the means of the XOR process, too. Each encrypted slice image can be distributed to the authenticated ones. However, we transfer the encrypted images to the binary phase masks to strengthen the security power, that means phase masks can not be copied with general light-intensity sensitive tools such as CCDs or cameras. For decryption, we used the Mach-Zehnder interferometer in which linearly polarized two light beams in orthogonal direction, respectively. The experimental result proved the efficiency of the proposed method.

• 전자공학회논문지A
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• 제32A권2호
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• pp.96-110
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• 1995

Traveling-wave electrodes for the high-speed Ti:LiNbO$_{3}$ modulators are designed. For a solution to the problems of 1) phase-velocity mismatching between the optical wave and the Modulating M/W, 2) M/W electrode characteristic impedance mismateching, we assume devices with 1$\mu$m thick SiO$_{2}$ buffer layer between the electrode and the Ti:LiNbO$_{3}$ substrate. The electrode analyses are performed by the FEM using the second-order triangular elements. The optimum design parameters to satisfy the phase-velocity matching and the characteristic impedance matching are sought for. By use of the analyses' results, a Mach-Zehnder optical modulator with a CPW electrode is designed as an example. the band-width estimation is also illustrated.

• 전자공학회논문지A
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• 제32A권11호
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• pp.86-93
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• 1995

An optical transmitter was designed and implemented using a commercially available LiNbO$_{3}$ Mach-Zehnder modulator and the power amplifiers. We have adopted a new method to stabilize the bias voltage of the modulator using the second order harmonic component of the dithering signal. This technique has been applied successfully to the 2.5 Gbit/s external modulator for more than 6 hours without bit error rate degradaton. We demonstrated a repeaterless transmission of a 2.5 Gbit/s signal over 150 km nondispersion-shifted fiber using the transmitter. The receiver sensitivity was -34.5 dBm at 10$_{-10}$ bit error rate. No appreciable BER degradation due to fiber dispersion were observed after transmission.

• 전자공학회논문지B
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• 제33B권6호
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• pp.149-155
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• 1996

In this paper, we designed binary phase grating with SA (simulated annealing) algorithm for image generation, and used LCTV(liquid crystal television) as phase modulator. We generated optical image using LCTV which controlled by personal computer in real time. Many parameters in SA algorithm are determined by average deviation of the cost function, not experimental method. It was confirmed that the LCTV could be used as a phase modulator through mach-zehnder interferometering experiment. The various optical images are generated in real itme by fourier transforming of the phase gratings on LCTV which is controlled by personal computer and they can be used for optical interconnection in a neural network and addressing information in a volume hologram etc.

• The Journal of the Acoustical Society of Korea
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• 제21권1E호
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• pp.25-30
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• 2002

We report on the development of a fiber optic hydrophone consists of a sensing Michelson interferometer and a compensating Mach-Zehnder interferometer for optical path length compensation. The double interferometer configuration has the following advantages: the hydrophone can be made more small; a laser source with a relatively short coherence length can be used; and the compensating interferometer can be located near the signal processing electronics, far away from the sensing interferometer and noise introduced by reference arm can be greatly reduced. The performance of the hydrophone is evaluated experimentally by immersing the sensing interferometer in a water tank to detect underwater acoustic signals generated by an acoustic wave projector. Experimental results show that over the frequency range of 1 to 4 kHz, the hydrophone has an almost flat response with an average normalized sensitivity of -302 dB re 1/ μ Pa.

• 설비공학논문집
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• 제3권2호
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• pp.123-130
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• 1991

The mixed convection heat transfer from vertical inline plates has been studied numerically by the finite difference method and experimentally with Mach-Zehnder interferometer. The dimensionless spacing, $s/L_1$, the relative length, $L_2/L_1$ and the dimensionless temperature ratio, ${\Phi}_2/{\Phi}_1$ are varied parametically. The lower plate mean Nusselt numbers show same values as $s/L_1$, ${\Phi}_2/{\Phi}_1$ and $L_2/L_1$ increase. The upper plate mean Nusselt numbers increase as $s/L_1$ and ${\Phi}_2/{\Phi}_1$ increase, but $L_2/L_1$ decreases. The upper plate mean Nusselt number is higher than the lower plate mean Nusselt for $s/L_1$ 1.8 at Re=100, $Gr=10^4$, Pr=0.71, $L_2/L_1=0.5$ and ${\Phi}_2/{\Phi}_1=1.0$. A comparison between the experimental and numerical results show good agreement.

• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 하계학술발표회
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• pp.150-151
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• 2002

파장 분할 다중화(Wavelength division multiplexing ： WDM) 광전송 장치의 용량확대를 위한 방안으로 여러 가지 방법들이 연구 개발되고 있으며, 최근 들어 테라 급(Tb/s) 광전송 연구 결과들이 발표되고 있다. 이러한 장거리 광전송 장치의 광송신기는 LiNbO$_3$ 마하-젠더(Mach-Zehnder) 간섭계형 외부 변조기를 주로 사용하고 있다. 한편 반도체 레이저 집적된 전계 흡수형 변조기(Electro-absorption modulator integrated laser ： EML)를 이용한 외부 변조 방식 적용을 위해서 여러 연구소 및 기업체에서는 40Gb/s의 성능을 지닌 EML의 개발 결과들을 발표하고 있다. (중략)

• 전자공학회논문지S
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• 제34S권5호
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• pp.15-24
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• 1997

We propose a tunable add/drop filter in a form of an all-fiber mach-zehnder interferometer iwth one bragg grating at each arm. This device can be tuned by inducing a strain in the bragg grating. We also theoretically analyze the outut characteristics of the tunable add/drop filter. As a result of simulation, we know that the proposed tunable add/drop filter works well. When 2*10$^{-3}$ of strain is induced, the reflected spectrum shifts about 3nm. And its reflected spectral width is about 0.3nm. In this case roughly 5 channels can be tuned, assuming the channel spacing is 0.3nm. When the pathlengths of the both arms are not the same, the transmissivities at the add and output ports and the reflectivity at the tap port varies sinusoidally with the pthlength difference. To maintain the transmissivities above 90% in the wavelength tuning range of 20nm the pathlength difference less than 16.mu.m is required.