| Summary: | 碩士 === 逢甲大學 === 材料科學學系 === 88 === Abstract
Hermetical coatings of optical fibers have a higher resistance to external environment such as water or hydrogen infiltration, so they have been extensively studied. In this paper, the thermally and hydrostatic pressure induced stresses in hermetically metal-coated optical fibers have been analyzed by the thermoelastic approach. These stresses can be reduced by appropriately selecting the material''s properties of metallic coatings and their thicknesses. The calculated stresses in hermetically metal-coated optical fibers with some selected metallic coatings are discussed. No pure metal is found to be suitable for the simultaneous minimization of thermally and hydrostatic pressure induced stresses. As a result, the metal alloy will be expected to be the next candidate for the metallic coating of optical fibers. Alternatively, the carbon-coated optical fibers are fabricated by plasma enhanced chemical vapor deposition method. By manipulating the deposition time, we obtain fourteen carbon-coated optical fibers with different thickness. Using Raman spectra analyzer, the structure of carbon coatings is analyzed as hydrogen diamond-like carbon. Examining the surface of the carbon coating at a low temperature by the optical microscope, the cracks on the coating surface decrease with increasing the coating thickness in the beginning and then increase. Consequently, the optimal thickness of carbon coating is 255nm.
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