Researches On The Microstructured Plastic Optical Fiber Fluorescence Sensor

With the rapid development of optical fiber technology in recent decades,Fluorescence sensors have been widely used in sensing field due to its low loss and morecollection of fluorescence signals. Comparing with the traditional silica fiber sensors,microstructured plastic optical fiber has all the advantages of plastic optical fiber andmicrostructured fiber. They have many applications in the fields of environmental testingand biochemical sensing. Research of microstructured fiber in the field of optical sensingwas becoming a hot area. Usually, the collection ability of fluorescence in a generaloptical fiber fluorescence sensor was weak. Two types of microstructured plastic opticalfiber ring structure and holes structure have been designed in this paper. Then the abilityof collecting fluorescence of these fibers have been analyzed and discussed.Firstly, we introduced the principle and methods for the theoretical analysis of thefluorescent sensor, and described some microstructured fiber optical sensors which used inthe field of environmental and biological testing. This thesis also introduces thecalculation method of the performance of the fluorescent sensors, and which canaccurately calculate the effective capacity of optical fiber for fluorescence collection.Secondly, we have studied the ability to capture fluorescent in the microstructuredplastic optical fiber which designed in the thesis. The air holes of microstructure fiberwere filled with dyes mixed with a high refractive index liquid. In order to select the beststructure for fiber sensor, the fluorescent capture fraction was analyzed by changing theoptical fiber structure parameter and liquid refractive index.Finally, using the adjustable boundary condition fourier decomposition method, themode field profiling of these microstructured fibers were given. The result shows thatmicrostructured plastic optical fiber with small core radius and liquid index higher thancore refractive index, or microstructured plastic optical fiber with three holes in which theliquid index is low, can enhance the absorption efficiency of excitation, increase thefluorescence capture fraction, achieved the higher ability to collect fluorescence efficiently within a short distance, and improve the sensitivity of microstructured plastic optical fiberfluorescent sensors.