The Research Of Thermometric Model And Anti-Acrosstalk Method Based On Bragg Fiber Grating

Optical fiber grating is a kind of optical fiber passive device, it is developed quickly and widely used in recent years. It has great application prospective in optical sensor field and so on for its many unique merits. Optical fiber grating sensors have become the focus in sensor and measurement field. The purpose of the thesis is to develop an anti-crosstalk method based on model to enhance the range and reduce the cost of Bragg fiber sensor.Based on the Maxwell-field equations, we derive the coupled-mode equations that describe the interaction between the modes. Based on these, we get the simulation results of reflect spectrum, and analyze the characteristics of fiber Bragg grating of a constant refractive index modulation and period. Then, using transfer matrix theory get the spectrum's simulation results of apodization grating.A thermometric model is established and proved by experiment.After researching many Multiplexing technologies, an anti-crosstalk method is given. This method can enhance the range of fiber grating sensors by data process technique, without changing any thing of original systems. During this research, A concept of individual spectrum is given, and we deduce two fiber grating overlaying equation, then deduce the overlaying equation after many fiber grating condition.The crosstalk process of two fiber grating is simulated by the software Matlab. We use the anti-crosstalk method to process the simulated data, and find that the difference between the actual Bragg wavelength and the wavelength getting by the anti-crosstalk method is less than spectrum's resolution. After all, we design an experiment to examine this method, and find the experiment's result have a good agreement with simulated result.