• Title/Summary/Keyword: 클래딩

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Fabrication of All-fiber 7x1 Pump Combiner Based on a Fiber Chip for High Power Fiber Lasers (고출력 광섬유 레이저를 위한 광섬유 칩 기반 All-fiber 7x1 펌프 광 결합기 제작)

  • Choi, In Seok;Jeon, Min Yong;Seo, Hong-Seok
    • Korean Journal of Optics and Photonics
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    • v.28 no.4
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    • pp.135-140
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    • 2017

  • In this paper, we report measured results for an all-fiber $7{\times}1$ pump combiner based on an optical fiber chip for high-power fiber lasers. An optical-fiber chip was fabricated by etching a fiber, having core and cladding diameters of 20 and $400{\mu}m$, in the longitudinal direction. To both ends of the etched chip, we spliced input and output fibers. First, we tied together seven optical fibers, having core and cladding diameters of 105 and $125{\mu}m$ respectively, in a cylindrical bundle and spliced them to the $375-{\mu}m$ end of the optical-fiber chip. Then, we attached an output DCF with core and cladding diameters of 25 and $250{\mu}m$ to the $250-{\mu}m$ end of the optical-fiber chip. Finally, the fabricated $7{\times}1$ pump combiner showed an average optical coupling efficiency of about 90.2% per port. This chip-based pump combiner may replace conventional pump combiners by massive production of fiber chips.

  • https://doi.org/10.3807/KJOP.2017.28.4.135 인용 PDF KSCI

Bending Characteristics Change of Long-Period fiber Grating due to Co-doping of Boron for Optical fiber Sensors (광섬유 센서 구성을 위한 보론 첨가에 따른 장주기 광섬유 격자의 구부림 특성 변화)

  • Moon, Dae-Seung;Chung, Young-Joo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.25 no.5
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    • pp.339-342
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    • 2005

  • In long-period fiber grating (LPFG) to be made up optical fiber sensors, resonance coupling occurs between the forward-propagating core mode and cladding modes at the wavelength that satisfy the Phase matching condition. The resonance wavelength and the coupling strength depends strongly on the external environment like temperature, strain, and ambient index. These characteristics can be utilized for various applications as optical fiber sensors. fabrication of optical fiber gratings is typically based on the photosensitivity effect, i.e. the permanent change of the refractive index upon irradiation of the UV beam, and therefore, fabrication of the optical fiber with high phososensitivity is an important part of the research on optical fiber gratings. In this work, we measured the effort of to-doping of boron on the index difference between the core and cladding of the optical fiber and the sensitivity of the LPFC to the temperature and bending changes. We observed that the index difference between the core and the cladding decreased by $(1.69{\times}10^{-4}/SCCM)$ and the temperature sensitivity of the resonance wavelength shirt decreased by $(0.01145nm/^{\circ}C/SCCM)$. The dependence or the bending-induced changes or the transmission characteristics of LPFG on the tore-cladding index difference was investigated experimentally. The measurement results indicate that the bending sensitivity increases as the index difference decreases.

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Comparison of clad layer characteristics with overlapping criterion in multi pass laser cladding (멀티패스 레이저 클래딩에 있어서 중첩률의 기준에 따른 클래드 층의 특성 비교)

  • Kim, Jong-Do;Lee, Eun-Jin;Whang, Jun-Gu
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.9
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    • pp.768-773
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    • 2016

  • Engine valve seat and face, which are the important factors affecting engine performance, are required to have wear, heat and corrosion resistance. In order to produce surface layer with these characteristics, PTA(plasma transferred arc) surfacing procedure is generally employed, but problems, such as large HAZ and high dilution etc., frequently occurr. Laser cladding, which overcomes the drawbacks of conventional technologies, can be employed to create a superior clad layer with low dilution, small heat affected zone, and minimal distortion. However, in case cladding is to be applied to a large area, it is necessary to overlap 1 pass clad layer because of limited clad layer width. Two criteria for the overlapping ratio-beam size and clad layer width-have been considered thus far. Upon inspection of multi pass clads, produced by different overlapping criteria, it was observed that the greater the increase in overlapping ratio, the greater was the decrease in clad layer width and increase in clad layer height regardless of the criterion used. However, a multi pass clad overlapped by the beam size criterion demonstrated a higher hardness value than a clad overlapped by the clad layer width owing to decreasing dilution of the substrate. In conclusion, the beam size was defined as the criterion for the overlapping, because the clad layer width increased or decreased depending upon process parameters.

  • https://doi.org/10.5916/jkosme.2016.40.9.768 인용 PDF KSCI