| Summary: | 碩士 === 中原大學 === 應用物理研究所 === 91 === In this dissertation we study the fabrication and applications of the Long period Fiber Gratings（LPG）. The characters of the bent Long period Fiber Gratings are analyzed with different curvature. A preliminary scheme of the accelerometer with LPG is proposed.
LPG fabricated by an amplitude mask and excimer laser with a wavelength of 248 nm. In order to optimize the fabrication, the parameters needed in the process are obtained by simulation. This simulation is carried out by IFO_Grating software. The transmission spectra of the bent LPG are very sensitive to the curvature of the bent LPG. With the increase of the curvature, each mode of the absorption spectra will split into two. The left absorption spectra of LP05 move towards short wavelength and the right absorption spectra towards long wavelength. However, when the curvature is 2.3 m-1, the left and the right absorption spectra move the other way round. In application, the acceleration is measured by pendulum mechanism. The pendulum dangles when it senses the external force produced by the mobile platform. The Long period Fiber Grating’s curvature radius is thus due to change. This effect is similar to the energy transformation in sine wave, of which the acceleration is in direct ratio to the amplitude.
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