High Sensitivity Fiber Bragg Grating Pressure Sensor

As a new sensor, pressure sensor based on fiber Bragg grating(FBG) is developed rapidly. Following the widely use of optical fiber sensors, it becomes more necessary to develop high sensitive pressure sensor based on fiber. Optical fiber sensors can work in high temperature, causticity, strong magnetic field, inflammable and explosive environmental extremes. As an obligate part of fiber sensor, pressure sensor based on FBG is being perfected. Pressure sensors based on FBG are adopted by wavelength, more insensitive to external parameter compared with other fiber sensors. Therefore they are high precision, more stable, and as well as distributed meter. Therefore, research on FBG sensors are hot these years. New high sensitive sensors based on FBG are always getting rid of the stale and bring forth the fresh.This thesis summarizes main pressure sensors based on FBG, analyses their merit and demerit. Then optical fiber Bragg grating pressure sensor based on thin-walled cylinder structure with temperature compensation, fiber Bragg grating pressure sensor based on eccentric diaphram and fiber Bragg grating pressure sensor based on non-eccentric diaphram are described in this thesis. The pressure metered by these three different sensors diminishes gradually but precision increases. Passive temperature-compensation package and active correction for the residual temperature drift are mutually adopted to eliminate the thermal induced errors. By a series of improvement, eccentric diaphram changed into non-eccentric diaphram, the errors are diminished effectively. Research shows that the response of optical fiber Bragg grating pressure sensor based on thin-walled cylinder structure with temperature compensation is 0.0319nm/MPa, the response of fiber Bragg grating pressure sensor based on eccentric diaphram is 0.2166nm/MPa, the response of fiber Bragg grating pressure sensor based on non-eccentric diaphram is 86.9nm/MPa which is the best response in the same style internal sensors.This thesis refers to several subjects such as mechanism, material,and information. Main jobs completed are as follows:1. Expound the working principle of FBG and theory of the fiber Bragg grating coupling model, analyze the sensing properties of FBG in strain, tempetature and pressure.2. Analyze the domestic technology on optical fiber Bragg grating sensors, compare their working principles, merits and experimental data.3. Devise an optical fiber Bragg grating pressure sensor based on thin-walled cylinder structure with temperature compensation. Passive temperature-compensation package and active correction for the residual temperature drift are mutually adopted to eliminate the thermal induced errors. The research shows that this sensor can work in high temperature condition.4. Devise an fiber Bragg grating pressure sensor based on eccentric diaphram which is more sensitive than the thin-walled cylinder structure.5. Devise an fiber Bragg grating pressure sensor based on non-eccentric diaphram. The research shows that the response is 86nm/Mpa and comes the top of the same style internal sensors.6. Synthesize the experimental data and give some advise to the following improvement on high sensitive sensors.