應用模式耦合理論計算了外腔式Fabry-Perot（F-P）干涉型光纖傳感器的輸出光強與F-P
腔長的關系。對組成F-P 腔的光纖端面進行了磨平拋光及鍍多層電介質膜處理，使光纖端面反射率為70%，從而提高了傳感器的抗干擾能力,簡化了探測系統。將該傳感器與電阻應變片作對比測量實驗，其結果完全一致。
關鍵詞：光纖傳感器; 法布里-珀羅干涉；模式耦合理論; 電介質薄膜
Abstract: The relation between the output light intensity of extra-cavity type Fabry-Perot (F-P) interferometric optic fiber sensor and F-P cavity length is calculated with mode coupling theory. The end face of optic fiber that formed F-P cavity is ground, polished and coated with multi-layer dielectric film. In this way the reflectivity of the end face of optic fiber is as high as 70%, thus anti-interference capability of the sensor is improved and the detecting system is simplified. A comparison for the measuring experiments carried out by the sensor and resistance strain gauge, their results are entirely consistent.
Key words: Optical fiber sensor; Fabry-Perot interferometry; Mode coupling theory; Dielectric film