| Summary: | 碩士 === 逢甲大學 === 電機工程所 === 99 === The fiber sensors based on the cascaded different types of fiber gratings is proposed in this thesis for applying in the simultaneous measurement of stress, temperature, and index. The fiber sensors are composed of the fiber Bragg grating (FBG) in polarization maintaining fiber (PMF) in series with the long period fiber grating (LPG) in photosensitive fibers and the etched tilted-fiber Bragg grating (TFBG) in series with the long period fiber grating in single mode fibers, respectively. The sensing mechanism is based on variation both of Bragg wavelength power and the Bragg wavelength corresponding to the Bragg peaks to be located on the positive or negative slope of the loss-dip of the long period fiber grating.
According to the experimental results of these two different types of the cascaded fiber sensors, the matrix determinant of the etched TFBG in series with the LPG in the single mode fiber is approximately linear independent. Therefore, this kind of structure is not suitable to be used for simultaneously measuring the three parameters of stress, temperature, and index. In the future, we expected that the fabrication process can be optimized for improving the sensitivity and repeatability.
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