• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.186-187
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• 2001

광섬유 브래그 격자를 이용한 고정밀도 센서 시스템은 불균형(unbalanced) 마하 젠더 간섭계를 이용한 interrogation 기법을 많이 사용하고 있다. 그러나 간섭성을 이용한 interrogation 기법은 작은 온도 변화, 진동과 같은 외부 환경 변화에 매우 민감하다 이 논문은 불균형 마하 젠더 간섭계 대신 편광 유지 광섬유 (polarization maintaining fiber , PMF) 루프 미러(loop mirror)를 이용한 interrogation 시스템을 구현하였다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.188-189
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• 2001

광통신 분야에서 파장분할 방식(WDM)이 널리 이용됨에 따라, 파장 가감기는 광통신의 핵심 소자로 주목받고 있다. 특히, 광섬유 브래그 격자를 이용한 전광섬유(All-fiber) 소자는 좁은 선택파장 특성을 만족시키며 삽입손실이 작다는 장점을 가지고 있다. 본 논문에서는 기울어진 광섬유 브래그 격자(Tilted FBG)와 모드분할 방향성 결합기(Mode Selective Coupler, MSC)의 광섬유 공간모드(spatial mode)결합을 이용한 전광섬유 파장 가감기에 대하여 설명하고 있으며, 보다 좋은 성능의 소자제작을 위해 몇 가지 새로운 제작방법을 제안하고 구현하였다. (중략)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.812-813
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.517-518
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.515-516
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• 2009

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.289-289
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• 2011

• 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

• Korean Journal of Optics and Photonics
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• v.15 no.4
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• pp.369-374
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• 2004

In this paper, we propose a new tunable laser diode structure. The laser diode consists of a sampled-grating distributed feedback laser diode monolithically integrated with a sampled-grating distributed-Brags-Reflector. For a specific design, the possibility of continuous/discrete wavelength tuning over 27nm is confirmed by a numerical analysis using a split-step time domain model. Because the laser diode can be directly coupled with optical fiber without the intervention of the passive section, the laser diode exhibits higher output power than the conventional laser diode.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.135-139
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• 2001

This paper describes a string resonator that is used for the interrogation system of a Fiber Bragg Grating(FBG) strain sensor. The strain on the fiber piece is calculated from the measured frequency based on that the natural frequency of a string is a function of the applied absolute strain. Existing research considered a fiber as a string, but a fiber is not a string in the strict sense due to its bending stiffness, thus the fiber should be modeled as a beam accompanied with an axial force. In the vibration modeling, the relationship between the strain and the natural frequency is derived, and then the resonance condition is described in terms of both the phase and the mode shape for sustaining resonant motion. Several experiments verify the effectiveness of the proposed model of the fiber. The performance of the string resonator is analyzed by measuring the frequency change according to the applied strains in the dynamic range of 1100$\mu\varepsilon$ referred to the displacement from capacitance sensor. From the experimental results, the implemented string resonator provides the accuracy of $\pm$3$\mu\varepsilon$, the quasi-static resolution of ~0.1$\mu\varepsilon$(rms) which amount to be $\pm$0.17$\mu\textrm{m}$ and ~6nm respectively, in case of fiber length of 56mm. For a dynamic strain, it can provide the accuracy of ~3$\mu\varepsilon$ until the frequency comes to 8Hz. As a consequence, the string resonator proposed for FBG sensor provides the high accuracy and the high resolution in strain measurement, and also it is expecting to be used, for the application, to not only strain but also displacement measuring device.

• Korean Journal of Optics and Photonics
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• v.12 no.5
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• pp.401-405
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• 2001

We propose a novel channel-switching transmission filter using segmented chirped fiber Bragg gratings (CFBG's) each of which has separate transmission bands in the reflection spectrum of the CFBG. The segmented CFBG's are made by using specially designed slits. The separated reflection spectral bands of the segmented CFBG's are controlled by the attached fiber stretchers, and the controlled reflection bands are used to choose the channels independently. Tunability of the transmission spectra is experimentally demonstrated in WDM transmission experiments.