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Photonic Crystal Fiber Sensor Based On Sensitive Materials Filling And Research On Its Key Technologies

Posted on:2014-01-06Degree:MasterType:Thesis
Country:ChinaCandidate:N XuFull Text:PDF
GTID:2308330473951268Subject:Detection Technology and Automation
Abstract/Summary:PDF Full Text Request
The micro pore structure of photonic crystal fiber (PCF) determines its potential to be restructured to different models with different features, such as dispersion characteristics and birefringence characteristics. Experiments have shown that sensing characteristics of PCF changed by altering the arrangement of air holes, In addition, it has also been proved that the optical characteristics of optical fiber can be adjusted through filling particles, gas or liquid into the air holes. Due to the high sensitivity of PCF, it has been increasingly applied to the sensing area in recent years.In this paper, sensitive materials such as magnetic fluid and ethanol have been applied in the research given their unique characteristics, for example, magnetic fluid has characteristics of adjustable refractive index, while ethanol has the characteristics of controllable refractive temperature. By exploring and studying the techniques and methods of filling such sensitive materials into PCF, this research enhanced the understanding of underlying sensing principles of PCF filled with sensitive materials.Following parts of the work have been carried out:(1) In the first part, the structures and characteristics of PCF were introduced. The research progress of PCF filled with sensitive materials in recent years of sensing field has been critically reviewed and summarized, which provides reference for the PCF sensing experiments in next step.(2) The second part analyzed the sensing principle of two kinds of interferometric fiber sensors. Furthermore, numerical calculation method of PCF was introduced, and the model of PCF sensing system was built up, which simulated the relation between changes of sensitive materials’ refractive index and the system output spectrum.(3) In the third part, experiments on optical properties of magnetic fluid and ethanol have been initiated, analyzing and testing the relation between refractive index of magnetic fluid and the external magnetic field strength, and the changing rule of refractive index of ethanol subject to the changing temperature was obtained. It has been tested and proved that, when the light path parallels the magnetic field, magnetic fluid indicates its sensitivity coefficient of magnetic field refractive index as 2.77×10-5 Gs-1, while the light path and magnetic field becomes vertical, this sensitivity coefficient is 1.54×10-5 Gs-1, however, ethanol shows its sensitivity coefficient on temperature refractive index as 3.97×10-4℃-1, All of these data constructed solid foundation for the final experiments.(4) In the fourth part, key techniques of PCF filling and fusion splicing generally applied in experiments were introduced, which have been improved in this research. And then the basic theory of fusion splice between PCF and single mode fiber was analyzed. At the same time, the optimal splicing parameters have been reached through a large number of experiments, which minimized the splicing loss between the single mode fiber and PCF to 1dB.(5) In the fifth part, sensing system of PCF filled with sensitive materials was designed and set up, including two parts:magnetic field sensing subject to magnetic fluid-filled PCF, and temperature sensing corresponding to ethanol-filled PCF.The interactive relation between change of sensitive materials refractive index and change of output spectrum has been analyzed in theory; PCF sensing system based on sensitive material-filling techniques has been designed; The problems that occurred during the process of fusion splicing and filling PCF were analyzed and solved, and the optimal fusion splicing index through numerous experiments was obtained; The following experimental results were provided that the temperature resolution of temperature sensing system based on ethanol-filled PCF reached 0.017℃; while the temperature resolution of temperature sensing system corresponding to ethanol-filled long-tailed PCF reached 0.027℃.
Keywords/Search Tags:Photonic Crystal Fiber, Fiber Sensing, Fiber Splicing, Magnetic Fluid, Ethanol, Refractive Index
PDF Full Text Request
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