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Studies On Microstructured-optical Fiber-based Interferometric Temperature And Strain Sensors

Posted on:2014-02-19Degree:MasterType:Thesis
Country:ChinaCandidate:F QiFull Text:PDF
GTID:2268330401956312Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
With the development of the photonics technology, fiber-optic sensorshave been gradually mature for30years with small size, light weight, low loss andanti-electromagnetic interference and etc. The appearance of the microstructure fiberpromotes the development of fiber-optic sensors. As a new special structure kind ofoptical fiber, it has broken the shackle of traditional fiber-optics and has brought thesensing theory and applications new potentials. Based on the technical equipmentand laboratory condition, in this work we have studied and designed somemicrostructure fiber interferometer based temperature and strain sensors, and thecorresponding contents is as follows:1. The developing history of the microstructure fiber has been introduced; thelight-guiding mechanism, classifications and applications of the microstructure fiberhave been analyzed; the working principles and modal interference theories have beenintensively analyzed, providing new ideas and theoretical basis for the design of thetemperature and pressure sensors.2. A temperature sensor by using an alcohol-filled side-hole fiber (SHF) basedSagnac interferometer is proposed and experimentally demonstrated. SHF is a highlybirefringent fiber, which has two air holes running aside the core in the cladding ofthe fiber. Temperature changes refractive index of the alcohol liquid filled in the airholes of the SHF, leading to the variation in birefringence of the SHF and henceinterference pattern shift of the Sagnac interferometer. Sensitivity of86.8pm/°C isachieved when temperature is changed between20°C and80°C. It is about eighttimes higher than that of a normal fiber Bragg grating sensor.3. A hollow core fiber based all-fiber intermodal interferometer is proposed formeasurement of strain and temperature. The sensing structure is simply a shortsegment of hollow core silica fiber being spliced between two normal single modefibers. The fabrication process only involves a conventional fusion splicer and a mechanical fiber cleaver. Experimental results show that sensitivities of-1.21pm/μεand21.30pm/°C are achieved for strain and temperature measurements, respectively.
Keywords/Search Tags:microstructure fiber, Fiber optic sensor, fiber Sagnac interferometer, Intermodalinterference
PDF Full Text Request
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