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Study Of Fiber Bragg Grating Sensor System Based On IWDM/TDM

Posted on:2012-06-14Degree:MasterType:Thesis
Country:ChinaCandidate:Q Y ZhangFull Text:PDF
GTID:2178330338491086Subject:Circuits and Systems
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With the increasing number of the sensor users,the network resources are increasingly limited.Although a variety of multiplexing solutions have been proposed,the utilization of network resources is low in thus network.Therefore mixed-multiplexed sensor network is still hot.First,in order to understand and study sensor networks better,sensing principle of fiber Bragg grating is analyzed.Then introduce the fiber Bragg grating(FBG) performance and composition.On the basis of the sensing principle of FBG,strain and temperature models are establised.The cross-sensitivity problem is proposed.And then,several solutions which is uded to solve this problem are analyzed.Second,start with principles of optical time-division multiplexing(TDM), wavelength-division multiplexing (WDM) and intensity and wavelength-division multiplexing(IWDM),the advantages and disadvantages are analyzed.This is prepared for the following new sensing network.Third,on the basis of TDM,WDM and IWDM,a mixed-multipexing method is proposed to address FBG sensing array.The principle of the network models are designed and analyzed.The broad band light source is divided into two different output ports by using a 2×2 coupler(60%:40%).In addition,the system divides the fiber bandwidth using WDM with arrayed waveguide grating (AWG),and then employs TDM techniques on each WDM channel in order to improve sensing capacity further. A tree topology is used ih the TDM network to decrease the wavelength detection errors caused by the spectral effects and multi-reflection.In the end,this paper analyzes that the intensity,wavelength and time can be all used to interrogate and demodulate the sensing signals.It uses the different power ratio of the coupler as a special character to address the information reflected from the sensing FBGs,when the Bragg wavelength of the FBG connected at different coupler output port overlaps together.
Keywords/Search Tags:Fiber Bragg Grating (FBG), Sensor system, Arrayed Waveguide Grating(AWG), Wavelength-Division Multiplexing (WDM), Time- Division Multiplexing (TDM), Intensity and Wavelength-Division Multiplexing(IWDM)
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