Study Of Fiber Bragg Grating Sensor System Based On Wdm/Tdm

The available resource of FBG sensor network is extremely rich in the frequency and time-domain. A network employing single multiplexing technology only uses the resources on the one hand. The utilization of network resources is low in thus network. Therefore, The mixed-multiplexed fiber Bragg grating sensor networks has become one of the research hotspots.In the first place, start with theoretic model of FBG sensing network, sensing principle of fiber Bragg grating is analyzed and FBG sensing network model is created. On the basis of analyzing advantages and disadvantages of several familiar multiplexing and demodulation techniques, the traditional WDM / TDM hybrid multiplexing technology is introduced, whose part of TDM is serial topology, On the basis of the above, detection error of wavelength is analyzed which is affected by the spectrum effects and multi- reflection, pointing out the limitations of its application.In the next place, the modules of the network are analyzed on principle, a multiplexing method based on wavelength division multiplexing (WDM) and time division multiplexing is proposed to address FBG sensing array. It firstly utilizes the fiber bandwidth employing Wavelength Division Multiplexing with AWG (arrayed waveguide grating), and then employs TDM on each WDM channel. So it solves the defects of a small of FBGs multiplexed by the network. Because its part of TDM uses a tree topology, thus avoiding the wavelength detection errors caused by the multi-reflection and spectral effects. It analyses the effects caused by shot noise and channel crosstalk based on above.Compared with the effect caused by channel crosstalk, the effect is very small caused by shot noise, it can be ignored. The sensor network can achieve a large of capacity, increase the utilization of bandwidth, and save costs. In the end, temperature and strain performance of FBG is tested and the experiment that temperature performance of FBG is measured and the simulation experiment during process of the grating array addressing are made, and the experimental diagram of WDM and TDM demodulation results is obtained, describing the feasibility of this system.