• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.390-390
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.158-159
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• 2001

파장분할다중 방식에서 필요로 하는 격자들 간의 격자주기 차이는 1nm이하를 요구한다. 따라서, 하나의 위상형 마스크로 서로 다른 주기의 격자를 동시에 제작하려면 하나의 위상형 마스크 패턴들 간에도 nm 정도의 차이를 갖는 미세한 패턴이 있어야 한다. 그러나, 일반적으로 마스크를 제작하는데 이용되는 장비인 전자빔 묘화장치(electron-beam lithographic system)의 분해능은 수십 nm이므로, 그러한 nm 정도의 정확도로서 조합된 마스크 패턴들을 만드는 것은 매우 어렵다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.3-4
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 1991.07a
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• pp.77-82
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• 1991

여러개의 레이저 빔을 결합하여 대표적인 방법의 장단점을 비교 분석하였다. incoherent 방법으로는 wavelength multiplexing, spatial multiplexing, polarization multiplexing을 분석하였고 coherent 방법으로는 binary phase grating과 travelng-were amplification을 고려하였다. 특히 고출력 laser diode array를 이용한 대출력 증폭기 시스템을 분석하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.34-35
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• 2007

• Bulletin of the Korean Chemical Society
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• v.14 no.1
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• pp.4-5
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• 1993

• Korean Journal of Optics and Photonics
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• v.15 no.6
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• pp.591-596
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• 2004

In this paper, a photonic RF true-time delay based on a partially side-polished fiber Bragg grating with heating electrode has been proposed and fabricated. It features continuous voltage-controlled operation, requiring no mechanical perturbation and no moving parts. For an RF signal carried over an optical signal, the time delay has been obtained by controlling the voltage applied to the electrode and thus adjusting its reflection positions from the fiber grating via the thermooptic effect. The achieved time delay is about 100 ps with the electrical power consumption of 280 mW.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.3
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• pp.145-152
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• 1989

Volume phase diffraction grating is formed in 5${mu}m$ Agfa 8E75 photographic emulsion film using He-Ne laser. It is dependent on the chemical processing rather than materials themselves that high diffraction efficiency can obtained in silver halide emulsions. With potassium dichromate bleach and alcohol drying, overall efficiency of 71% (81% after allowing for reflection at the two surfaces) has been achieved at an exposure of 180${mu}J/cm^2.$ Dichromate cross-linkage and air void by rapid dehydration increase refractive index modulation depth. The grating is swollen, which is newly identified by Scanning Electronic Microscope(SEM) photography, and it causes on-Bragg at larger angle than the recording angle. It is pointed out that controlling the emulsion thickness has an important role as a potential source for high diffraction efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1425-1431
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• 2013

We have measured the radiation-induced Bragg wavelength shift (BWS) of fiber Bragg grating (FBG) which was inscribed in Ge-doped core silica using a phase mask during irradiation up to a dose of 23 kGy and annealing effects after the gamma-exposure. For packaged FBG sensors, we observed the maximum radiation-induced BWS of about 91 pm during irradiation. Packaged FBG sensors also show higher radiation sensitivity above nearly a factor of two than non-packaged type sensor in the same condition.

• Korean Journal of Optics and Photonics
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• v.15 no.1
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• pp.34-38
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• 2004

A fiber laser of which wavelength was scanned by an intra-cavity FP (Fabry-Perot) filter was used to interrogate a fiber Bragg grating strain sensor array. We calculated the wavelength variation of the fiber laser using quadrature signal processing with an unbalanced M/Z (Mach-Zehnder) interferometer and time-delayed sampling technique. The calculated wavelengths are mapped to corresponding temporal reflection peaks from the sensor array, which enables more accurate and stable interrogation without the problems caused by the FP filter's nonlinear characteristics. Wavelength resolution of ∼20 pm was obtained in our experimental setup, which could have been greatly enhanced with faster phase modulation.