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Research On The Fiber Bragg Grating Demodulation Technique Based On High Birefringence Fiber Loop Mirror

Posted on:2015-08-22Degree:MasterType:Thesis
Country:ChinaCandidate:D M BaiFull Text:PDF
GTID:2298330452453432Subject:Physics
Abstract/Summary:PDF Full Text Request
In this paper, a fiber Bragg grating wavelength demodulation technique based onhigh birefringence fiber loop mirror is studied.Firstly, the filtering characteristic of single section high birefringence fiber loopmirror is deduced. Its temperature character is experimentally researched and theresults show that the filtering curve shifts with the temperature and the sensitivity is-1.35nm/℃. Then a novelliquid density sensor based on high birefringence fiberloop mirror is proposed and demonstrated. The results show the sensitivity of theliquid density sensor is-7.6nm/(kg/m3).Two sections of high birefringence with different length are orthogonally weldedto form a two stage high birefringence fiber loop mirror and its transmittance functionis deduced and verified by experiment. The temperature character of the two stageHi-Bi FLM is experimentally studied and the temperature shift of its transmittancefunction is-1.34nm/℃,which is the same with the temperature shift of singlesection high birefringence fiber loop mirror. A novel temperature compensationmethod by adhering part of the longer Hi-Bi fiber to aluminum plate is proposed anddemonstrated. The length of the adhered fiber is deduced and experimental resultsshow that the temperature shift of the transmittance function is-0.039nm/℃, verysmall comparing with the shift of uncompensated Hi-Bi FLM.Fiber Bragg grating is used to measure strain and the sensitivity is0.0011nm/με.A fiber Bragg grating wavelength demodulation system using temperaturecompensated two stage Hi-Bi FLM is proposed and demonstrated. This demodulationmethod has advantages of wide demodulation range, low price, good temperaturestability and simple structure.
Keywords/Search Tags:wavelength demodulation, fiber Bragg grating, high birefringence fiberloop mirror, density sensor, temperature compensation
PDF Full Text Request
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