| Summary: | 碩士 === 大同大學 === 光電工程研究所 === 88 === Presented in this thesis includes the optical fiber Fabry-Perot interference (FFPI) temperature sensors, uncoated intrinsic FP fiber sensors, a direct thermo-optic coefficient measurement system, and the effects of FFPI temperature sensors with different kinds of fibers after exposing high dose gamma radiation. By vacuum deposition, TiO2 films are formed directly onto the end face of single mode fibers to serve as mirrors. FP mirrors are used in the experiment investigations. Applying the interference phenomenon of the FP cavity, we successfully fabricate the reflection-type FFPI sensor and use it to measure the temperature from 30℃ to 250℃. Conventionally, two dielectric mirrors construct the sensing cavities of the intrinsic FP fiber sensors. Nevertheless, difficult manufacture processes and expensive deposition equipments raise the cost of the fiber sensor. A novel designed FFPI sensor proposed in this thesis utilizes a special splicing method to fuse two different core diameter fibers as a reflective mirror. It not only has the clear advantages of the easier and cheaper manufacture procedures but also makes the same measurement function as a traditional FFPI fiber sensor does. The theoretical results are studied and confirmed with the experimental investigations.
The thermo-optic coefficient is an important factor for the temperature fiber sensor and high-speed fiber communication system. We study the thermo-optic coefficients of four kinds of commercial fibers and also analyze the thermal reliabilities for these fiber sensors. The results are in agreement with the value calculated from Sellmeier equation for the fused silica fiber, and the different error is only about 0.096% for the Corning single mode fiber SMF-28.
For the sensing systems in the harsh radiation environment, like in the outer space or nuclear power plant, the accurate measurement is a significant factor. In order to apply fiber sensors to such high radiation environments, we have investigated the thermo-optic coefficient for four different fibers after being exposed by high gamma radiation doses and also have demonstrated the radiation resistants for such fibers.
|
|---|
