- 學位論文
運用光纖環與光纖光柵於同時測量溫度與位移
Using Fiber Loop and Fiber Bragg Grating for Simultaneous Measuring Temperature and Displacement
摘要
隨著光纖通訊的快速發展，利用光纖及光纖元件來進行分布式感測，一直是眾人注目的研究焦點。光纖擁有體積小質量輕，柔軟可彎曲、不受電磁干擾等優異特性，已被廣泛應用於各種領域中，像是自動化工廠、電力、航空、橋樑、軍事系統、醫療等眾多領域。光纖布拉格光柵(Fiber Bragg Grating , FBG)的發明，對於光纖應用上有很大的突破，因此光纖布拉格光柵已被廣泛使用於光纖通訊與光纖感測系統上。光纖布拉格光柵在通訊方面，主要用於分波多工系統，作為波長選擇的濾波器。在光纖感測方面，利用周圍環境因素(如溫度、應變、電壓等等) ，對於FBG的影響來量測物理參數。引起光纖布拉格光柵中心波長位移的因素有溫度及應變，如果僅僅量測中心波長的位移是無法同時量測溫度與應變兩個參數。因此必須使用額外的設備來幫助光纖布拉格光柵區別溫度與應變兩參數。在本文中，將光纖環(Fiber Loop)與光纖布拉格光柵作結合為一個能同時量測位移與溫度的光纖感測器。將光纖環安置在熱電致冷晶片(Thermoelectric Cooling Chip)上，而光纖布拉格光柵則是固定於熱電致冷晶片上，使光纖布拉格光柵的中心波長位移只受溫度變化的影響。利用平移台的轉動縮小光纖環半徑時，傳輸在光纖環上的光訊號會因光纖環縮小導致光功率明顯損耗。最後藉由測量傳輸光功率與布拉格波長位移的變化，量測出位移量與溫度。
並列摘要
Optical fiber and optical fiber components using for distributed sensing have been attention with the optical fiber communication developed. Optic fiber has many advantages, such as small size, compactness, pliable and electromagnetic noise immunity, it has been applied to many fields, like the factory automation, electricity, aviation, bridges, military systems, medical and other fields. The invention of Fiber Bragg Grating ( FBG ) is the optical fiber communication and fiber sensing systems. In optical fiber communications, it’s mainly applied for WDM, such as wavelength filter. In optical fiber sensing, using the impact of environment factor of FBG to measure physical parameters, such as temperature, strain, voltage and other parameters. Induced center wavelength shift of fiber Bragg grating has factors, i.e., temperature and strain. If only to measure the displacement of center wavelength, then it can’t distinguish the two parameters. Therefore, it must be used additional equipment or exceptional setting to distinguish the two parameters with FBG. In this research, we proposed fiber optic sensors which using fiber loop combined with fiber Bragg grating for simultaneous measuring displacement and temperature. The optical fiber ring placed on thermoelectric cooling chip, the fiber Bragg grating fixed on the thermo-electric cooling chip, so that the displacement of center wavelength only by the temperature changes. Using translation stage reduce the radius of fiber loop, when the fiber ring radius smaller than a certain extent, the light power of transmission in the fiber loop caused loss by reduced fiber loop optical. Finally, calculate the displacement and temperature by measuring transmission light power and the Bragg wavelength shift of changes.