Study On Fiber Bragg Grating Sensing System Of Rough Time Division Multiplexing Technology

Fiber Bragg grating sensor with unique low energy, reliability, corrosion resistance, wide application and strong ability to resist electromagnetic interference many virtues, is popularity in many domain, and soon become a research hotspot in the sensor industry. With the progress of science and technology, bridges, tunnels, oil exploration and other large engineering are increasing the requirements for sensor, and multi-point detection become the basic requirements to the sensor. Fiber Bragg grating sensor is easy to networking, and it has rich resources both in the time domain and frequency domain when optical signal transfers in the fiber. This thesis put forward a Fiber Bragg grating sensing system of rough time division multiplexing technology. It has many advantages, such as more check points, more stable system, strong reflection signals, easy to implement and so on.Firstly, this thesis introduces the basic principle and advantages of optical fiber grating sensor, analyses the sensing principle of temperature sensor and temperature sensor. It Introduces the existing fiber Bragg grating sensing system. From the multiplexing and demodulation, this thesis elaborates the single multiplexing and mixed multiplexing, and analyses the advantages and disadvantages of the sensing system.Secondly, the thesis analyzes the TDM and WDM performance respectively and then puts forward a Fiber Bragg grating sensing system of rough time division multiplexing technology. It has defined the concepts of “rough” and “tolerance”. The system uses TDM and WDM mixture multiplexing, the optical switch to realize time division multiplexing, and the Arrayed Waveguide Grating(AWG) to realize wavelength division multiplexing. The system uses the tree structure to reduce crosstalk of the TDM, the strong reflection grating to increase the SNR(Signal to Noise Ratio). The more important is that the rough time division multiplexing structure reduces System requirement for signal source and optical switch. In the end of this part, it introduces the system’s structure and analysis the performance of the system.In the end, the thesis makes simulation for the system on the Optisystem 7.0 simulation software. The simulation uses the methods of control variables. The experiment is divided into three groups, to prove the feasibility of the theory, summarizes the deficiency of the system and improves of the method.