• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
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• pp.364-365
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• 2004

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.232-236
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• 1990

Optical waveguide was fabricated in the soda lime glass substrate using rapid thermal method. A chirped grating having period variation of 0.41 - 0.51${\mu}{\textrm}{m}$ on this waveguide for WDM was made. And then, arranging input and output optical fiber, wavelength division multiplexer with 5 channels in short wavelength region was realized. Experiment result of this WDM showed that wavelength spacing, 3 dB bandwidth, insertion loss and crosstalk were 5nm, 4nm, 40dB and less than -10dB, respectively.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.981-982
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• 1998

We fabricated sampled fiber grating by double-exposure method. First, a short-period grating was written into the hydrogen-loaded single mode fiber and then the refractive index was modulated over it by an amplitude mask. It was observed that several transmission dips appear due to the index modulation. The thermal and strain responses were measured over $40-180^{\circ}C$ and $0-1800\mu\varepsilon,$ respectively. The dips have the same and linear sensitivity to both physical quantities over the range of measurement.

• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.180-187
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• 2016

The independent operation of a color filter for incident polarization is demonstrated using a guided-mode resonance (GMR) filter employing a metal-insulator-metal (MIM) waveguide. To achieve independent operation, a rectangular MIM grating is proposed as a wave-guide resonator. The design considerations are discussed and include how to determine the grating period and slit width. Power flow distribution is observed with slit width variation. Blue-green, green-red, and blue-red filters for corresponding x- and y-polarizations are demonstrated as application examples with numerical simulation with rectangle-shaped MIM grating. As a practical application, feasibility as a chromatic polarizer is discussed.

• 한국광학회:학술대회논문집
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• 한국광학회 2007년도 하계학술발표회 논문집
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• pp.255-256
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• 2007

We propose a novel method for the beam focusing by a single subwavelength metal slit surrounded by chirped dielectric surface gratings. In the proposed method, the period of each grating is chirped to make a focused beam at the desired position. Design of the grating structures for optimal beam focusing and the analysis of the field distribution are conducted based on the rigorous coupled wave analysis (RCWA). It is shown that the focused beam is formed at 1.5${\mu}m$ from the metal substrate and its full width at half maximum (FWHM) is 411nm.

• 전자공학회논문지D
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• 제34D권7호
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• pp.97-104
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• 1997

Using the ray optics technique, we derive the analytic expressions of TE mode coupling coefficient for five-layer distributed feedback (DFB) structure devices. We compare the coupling coefficient calculated by the ray optics technique with those calulated by the extended additional layer method (EALM) which may be a most accurate method of calculating the coupling coefficient. The difference between the results of the ray optics technique and those of the EALM is small for most cases of grating depth and forms being practically made. In the case of rectangular gratings, the difference increases as the duty cycle of graing deviates from 0.5. In the case of the trapezoidal grating, the difference increases as the ratio of the top to the period of grating deviates from 0.5 and as the length of the top becomes longer than that of the base. The difference of theree-layer DFB structures is smaller than that of five-layer DFB structures.

• 대한전자공학회논문지SD
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• 제39권10호
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• pp.48-56
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• 2002

일반 광섬유에 아크 방전을 인가하여 코어 및 클래딩의 직경 변화를 발생시켜 장주기 격자를 제작하는 방법이 소개되었다. 본 연구에서는 매우 약한 아크를 반복적으로 발생시켜 광섬유에 매우 약한 변형을 수 차례 주어 광섬유 격자 직경을 정밀하게 조절 할 수있는 방법을 사용한 중첩 장주기 광섬유 격자 제조 방법을 제안하였다. 또한 위상정합 조건을 이용하여 장주기 광섬유 격자의 직경 변화에 따른 공진 파장의 변화를 이론적으로 유도하였으며, 실험을 통해 확인하였다. 또한 실험 결과 아크 유도 광섬유 격자의 주기와 공진 파장과의 관계가 위상 정합 조건과 일치하는 것을 확인하였으며, 온도 변화에 따른 공진 파장의 변화를 측정하고 기계적 강도를 측정하였다.

• 한국광학회지
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• 제27권2호
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• pp.67-72
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• 2016

영사식 무아레 토포그래피에서 실제 물체에 대한 측정오차를 줄이기 위해서는 물체높이에 따른 무늬차수의 변화율인 무늬 민감도에 대한 조사가 필수적이며, 또한 무늬 민감도를 활용을 하면 절대 차수 결정이 매우 편리하고 정확해진다. 영사기를 사용한 영사식 무아레 토포그래피에서 무늬차수를 결정하기 위한 변수는 광원의 위치와 물체의 위치, 격자주기이다. 이 변수들 중에서 광원의 위치를 횡축으로 움직이는 광원 횡축 이동법과 물체를 종축으로 움직인 물체 종축 이동법에 따른 무늬 민감도를 격자주기에 따라 서로 비교하고 이를 분석하였다. 그 결과 광원 횡축 이동법에서 광원과 상검출기 사이의 간격이 클수록 민감도가 높았으나, 물체 종축 이동법에서 물체와 결상렌즈 사이의 거리가 작을수록 민감도가 높았다. 그리고 두 방법에서 격자주기가 작을수록 민감도가 더 높았으며 변수 변화에 따른 무늬 민감도 변화량은 더 컸다.

• 대한전자공학회논문지
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• 제25권4호
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• pp.460-466
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• 1988

In this paper, the theory and experiments on the one-way optical image transmission through optical fiber by using degenerate four wave mixing in BSO single crystal are demonstrated. From the theoretical analysis, the diffraction efficiency of phase conjugate wave in BSO single crystal is greatly dependent on applied electric field intensity, diffraction grating period formed in the crystal and incident beam ratio, those are also in good agreement with the experimental results. Based on the experimental results, we have arranged the typical degenerate four wave mixing system in the optimal conditions (applied electric field, E. = 5kV/cm` diffraction grating period, 3\ulcorner` beam ratio of backward pump wave versus signal wave, 2.7) and realized one-way optical image transmission system through optical fiber using BSO single crystal.

• Journal of the Optical Society of Korea
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• 제6권1호
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• pp.5-12
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• 2002

A novel interrogation scheme to detect fine Bragg wavelength shift using a long period fiber grating pair with erbium-doped fiber inserted between the two gratings is reported. The technique is shown to feature high resolution and much more immunity to temperature perturbation compared to the conventioned Mach-Zehnder interferometer demodulation system. For quasi-static strain measurement, this approach provides high wavelength resolution of 0.05 pm that corresponds to 41.7 ne in strain and $3.8 $\times$ 10^{-3}$$^{\circ}C$ in temperature. This interrogation system is also employed in dynamic measurement to obtain the minimum detectable strain perturbation of ~ 8.76 ne/H $z^{{\frac}{1}{2}}$ at 100 Hz. Moreover, this interrogation system has prominent thermal stability. This thermal stability comes from the fact that two arms of the interferometer, the core and cladding in erbium-doped fiber, are exposed to nearly the same environment .