| Summary: | 碩士 === 國立高雄應用科技大學 === 機械與精密工程研究所 === 104 === In this paper, two kinds of the optical fiber probe based on a U-bent single mode fiber (SMF) for liquid concentration measurement is proposed. The sensing mechanism of optical fiber probes is based on whispering gallery mode (WGM) resonance in bent optical fibers. The first part of this paper is use 3D printing technology to manufacture a model of the sensor, and then it allows the U-bent optical fiber sensor fix to the model. The process can effectively fixed the fiber radius and when the light traveled from the straight to the bent section, it will excited to the cladding froming WGM. Ultimately, when WGM re-couple back to the core mode, the interference occurs, a spectral shape of the WGM resonance generated in a bending single-mode optical fiber. We use this 3D printer WGM sensor to measure the glucose concentration. The range of the glucose solution in experiment is from 2.5% to 10%. Results show that the highest sensitivities of the wavelength from this sensor for glucose solution measurement can achieve in 1.475 nm/%.
Next, the second part of this paper is ultra-small U-shape WGM optical fiber probe. It’s manufactured by using a fixture with fire source. The process can also be effectively fixed the fiber radius. Compared with traditional WGM fiber optic sensor, stability is further enhanced. When the optical fiber sensor diameter is 127µm, bending radius is 0.5 mm, it's glucose solution measurement sensitivities can reach to -0.360 nm/%, and the reproducibility of the sensor is very well, the standard deviation of this sensor will be less than 0.1% while the optical fiber sensor diameter and bending radius is 67µm and 0.56 mm.
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