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Investigation On SMS Optical Fiber Sensors

Posted on:2011-12-30Degree:MasterType:Thesis
Country:ChinaCandidate:F ZhaoFull Text:PDF
GTID:2178330338480938Subject:Optics
Abstract/Summary:PDF Full Text Request
Optical fiber sensors possess small size, light weight, anti-electromagnetic interference, corrosion resistance, and high sensitivity. In many special fields, optical fiber sensors can complete some tough tasks which are difficult to finish by human. They have important applications in the fields of aerospace, military, national defense. The optical fiber sensors based on multimode interference and self-imaging effect have brought new vigor and vitality into the field of optical sensing. Recently, the research of optical fiber sensors becomes a hot research topic and has great practical significance and potential applications.In this paper, the method to solve the electromagnetic characteristics equation of cylindrical coordinates is introduced theoretically and the relationship between the location and image for both the multimode interference effect and self-imaging effect is analyzed. The coupling efficiency of multimode fiber in different models is simulated by MATLAB and the self-imaging position equation is derived. The sensing principles structure and the relevant theories of Single-mode-Multimode-Single-mode (SMS) are emphasized.The experiment results show that the output power of SMS structure sensor does not change obviously with temperature changing from 25℃to 85℃. In order to improve the sensitivity, we fabricated a sensor based on bending effect which can be realized by gluing the bimetal to the sensitive parts of the SMS sensor. The improved SMS structure sensor has a good sensitivity. The output power and temperature have linear relationship in the range of 55℃to 70℃.The changes of the output optical power are monitored in order to obtain the best corrosion results. The relationship between output power and time is analyzed in the corrosion process. The relationship between the SMS structure refractive index and output power is obtained by analyzing the corrosion images, choosing different corrosion locations, using sodium chloride and glycerol solution at different concentration. In addition, this experiment is extremely repetitive and the sensitive range for the refractive index measurements can be chosen according to the actual needs.
Keywords/Search Tags:optical fiber sensors, refractive index sensing, multimode interference, self-imaging effect, SMS structure
PDF Full Text Request
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