• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.157-158
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• 2006

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.381-383
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• 2005

바이오센서 응용을 위한 대칭 및 비대칭 마하젠더 간섭계 광도파로 소자의 설계, 제작 및 광학적 응답특성을 평가하였다. 설계 제작된 광도파로 소자의 압력광원은 각각 1550nm와 632.8nm이고, 코어와 클래딩의 굴절률차는 0.45 $\Delta$%로 설계 제작하였다. 센서부(상위 클래드)의 금 박막의 미소 굴절률 변화에 따른 TE, TM모드의 특성을 분석하였다. 센서의 보다 높은 감도 개선을 위한 나노-광자결정 구조가 주목받고 있는데, 광자결정 구조의 구현를 위한 리소그래피 공정은 높은 분해능과 신뢰성 있는 나노스케일의 공정이 요구된다. 광-바이오센서의 감도 개선을 위해 센서부 표면에 2차원 나노-광자결정 배열을 제안하고 이를 구현하기 위한 Dip-Pen Nanolithography 공정에 대해 고찰하였다.

• Korean Journal of Optics and Photonics
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• v.12 no.5
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• pp.371-375
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• 2001

We have implemented a sensor head which consists of erbium doped fiber pumped by 1480 nm LD and single fiber Bragg grating for simultaneous measurement of strain and temperature. The measurement precision and speed are improved by using Mach-Zehnder interferometer instead of optical spectrum analyzer (OSA) as a demodulator. The measurement precision of temperature measured by the amplitude variation of output signal is 0.05$^{\circ}C$ and that of strain measured by the phase variation of output signal is 0.1$\mu$strain. The measurement precision of temperature and strain are improved nearly 140 times and 700 times, respectively, compared to those using an OSA with wavelength resolution of 0.97 nm as d demodulator.

• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.469-474
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• 2006

A $1{\times}16$ thermo-optic switch with small excess loss using multimode interference(MMI) couplers is designed, fabricated, and measured. This paper introduces the proposed $1{\times}16$ thermo-optic switch, and discusses the measurement results. The $1{\times}16$ thermo-optic switch is farmed as 4-stage which consists of 15 unit devices. The unit devices are the $2{\times}2$ thermo-optic switches with Mach-Zehnder interferometer(MZI) structure. The characteristics of the $1{\times}16$ thermo-optic switch depends strongly on each unit device. The unit deviceconsists of two 3-dB general interference MMI couplers and two single mode waveguide arms as a phase shifter. First of all, the 3-dB optical splitter and $2{\times}2$ MZI thermo-optic switch have been tested to confirm the characteristics of the unit devices of the $1{\times}16$ MZI thermo-optic switch. Using the measurement results of the unit devices, the $1{\times}16$ MZI thermo-optic switch can be produced with better characteristics. The resultant structure of the MMI coupler with the optical light source of wavelength of 1550nm for the $1{\times}16$ thermo-optic switch is that the width and the optimized length are $25{\mu}m\;and\;1580{\mu}m$, respectively. The smallest excess loss fur the unit device is -0.5dB and the average excess loss is -0.7dB.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.43-48
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• 2009

We constructed a simple wavelength readout system for a tunable fiber laser which was used for a fiber Bragg grating sensor array system. A quadrature sampling method was used to demodulate wavelength variations of the tunable laser which consisted of a SOA(semi-conductor optical amplifier) and a fiber-optic Fabry-Perot filter. Internal triggers, which have a 90 degree phase period, have been generated by using a double-pass Mach-Zehnder interferometer. From Lissajous plots with quadrature sampled data, a mean phase error of ${\sim}2.51$ mrad was obtained. From the wavelength readout experiments, an accurate and fast linear wavelength demodulation has been confirmed.

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.363-364
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• 2009

본 논문에서는 Z-cut Congruent $LiNbO_3$ 패브리-페롯 에탈론에서 다중빔간섭에 의한 간섭무늬의 위상변화 분석을 이용한 넓은 파장영역에서의 전기광학계수 ${r^T}_{13}$ 측정방법을 소개한다. 광통신파장 영역의 넓은 파장대역을 갖는 SLD를 광원으로 사용하여 전기광학계수의 분산을 측정하였으며 마하젠더 간섭계 구조에서 벌크형태의 샘플로 측정한 결과 값과 비교하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.2
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• pp.160-168
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• 1982

수평으로 놓여진 2개의 동심타원 사이의 환상공간에서의 자연대류현상이 수치계산 및 실험적으로 연구되었다. 수치적 연구는 정상 2차원 층류유동영역에서 수행되었으며 유선 및 등온선이 구하여 졌다. 또한 특수한 경우로서 수평동심원 사이의 환상공간에 관한 기존연구와 비교하여 좋은 일치 를 보았다. 실험적 연구에서는 3개의 실험모델을 제작하였으며 마하젠더 간섭계에 의한 간섭사진 으로부터 등온선 분포를 얻었으며 아울러 유동에 관한 정보도 얻을 수 있었다. 실험과 수치계산 결과는 상당히 좋은 일치를 보였으며 기존 동심원환상공간에 편심율이 추가된 이론전개 및 수치 계산방법의 적합성을 알 수 있었고 이로서 환상공간에서의 자연대류에 관한 연구를 확장시켰다.

• Journal of KSNVE
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• v.7 no.6
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• pp.931-936
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• 1997

Optical fiber sensor is a subject which has been attracted considerable attention in recent years. Detection of sound pressure with optical fibers positioned in the arms of a Mach-Zehnder interferometer is presented in this paper. A fiber length of the order of 150m is wounded is made by hollow cylinder type. To increase the sound signal 3${\times}3$ directional coupler is used. Fiber optic hydrophone is the underwater tank with 2kHz sound source. Finally, it is shown that the fiber optic hydeophone can stably detec 2kHz sound.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7C
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• pp.652-657
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• 2007

Optical subcarrier-multiplexed (OSCM) labels in optical label switching networks have been detected using interleavers composed of fiber-optic Mach-Zehnder interferometer. 10-GHz optical single-/double-sideband signals generated from dual-electrode Mach-Zehnder intensity modulator have been used as the OSCM labels. In the case of single-sideband signals, the upper-sideband was observed to be suppressed about 16.8 dB compared with the lower-sideband from the optical spectrum measured at the label extraction output. For the case of double-sideband signals, both sidebands appeared with small insertion loss at the interleaver output. Since we used the phase-shift method to generate single-sideband signals, the power level of the single-sideband was higher by 3 dB than that of the double-sidebands.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.290-295
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• 2000

An experimental study was carried out in a cavity with upper channel and square heat surface by visualization equipment with Mach-Zehnder interferometer and laser apparatus. The visualization system consists of 2-dimensional sheet light by Argon-Ion Laser with cylindrical lens and flow picture recording system. Instant simultaneous velocity vectors at whole field were measured by 2-D PIV system(CACTUS'2000). Obtained result showed various flow patterns. Severe unsteady flow fluctuation within the cavity are remarkable and sheared mixing layer phenomena are also found at the region where inlet flow is collided with the counter-clockwise rotating main primary vortex. Photographs of Mach-Zehnder are also compared in terms of constant heat flux.