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Fiber Grating Sensing Network Based On FMCW/WDM Hybrid Multiplex Technique

Posted on:2013-12-09Degree:MasterType:Thesis
Country:ChinaCandidate:Y WangFull Text:PDF
GTID:2248330395986816Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
Fiber Bragg grating (FBG) has been widely used in fiber-optic sensing systemand optical fiber communication due to its unique advantages. Multipointmeasurement can be realized through the distributed sensor network based ondistributed sensor network. Because of this outstanding advantage of FBG, thedemodulation and multiplexing technologies become the hotspots of internationalresearches.The FBG sensing mechanism was analyzed, and several common FBG sensordemodulation and multiplexing technologies were briefly introduced in this thesis.The frequency modulation continuous wave (FMCW) multiplexing technologyprinciple and distributed FBG sensor network scheme based on frequency modulatedcontinuous wave/wavelength division (FMCW/WDM) mixed multiplexingtechnology were presented.The MATLAB software was used to simulate the basic principles of thedemodulation system. An addressing simulation model based on the FMCWmultiplexing was established, and the effects of grating position information,scanning time and frequency range on the spectrum signal of FMCW multiplexingsystem were analyzed.A FBG sensor demodulation system based on tunable Fabry-Perot (F-P) filterwas established, and the temperature demodulation experiments were studied. TheFMCW multiplexing system was set up by an arbitrary waveform generator, a lightmodulator, a multiplier circuit and a lock-in amplifier, and the distance resolution ofthe system is about10m. The addressing experiments for different distances werecarried out by FBG sensor, and the experimental results agree with the theoreticalcalculations ones. Thus, this system could be used in distributed FBG sensor networkaddressing. Finally, temperature compensation scheme of the system were presented,the effect of temperature variation on the measuring system was reduced; a new system scheme was proposed to improve the measuring accuracy of the system andthe intelligent degree.
Keywords/Search Tags:Frequency modulated continuous wave multiplexing, Wavelengthdivision multiplexing, Fiber Bragg grating, Sensing network
PDF Full Text Request
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