A Research On Fiber Bragg Grating (FBG) Liquid Level Sensor

Fiber Bragg grating(FBG) sensor has many advantages such as Anti-Electromagnetic,anti-corrosion,high sensitivity,small size and so on, because of those advantages, it has been used in many fields, and becomes a focus in optical sensing fields.In this paper, we have described the development of liquid level measurement technology, and summarize the main method of liquid level measurement, liquid level sensor development situation at home and abroad. In the FBG sensor parts, we have emphasized FBG sensor mode, and analyzed its strain sensor sensitivity,temperature sensor sensitivity and strain & temperature cross-sensitivity in detailed.In the design part of FBG liquid level sensor, we have made an overall planning of the program. Through a large number of theoretical derivations, we get the principle of FBG liquid level sensor which is based on spring tube, we also obtain the linear relations between liquid level pressure and the offset of FBG wavelength. At the same time, temperature compensation of FBG is given a discussion.In this thesis, we have designed a liquid level sensor based on the C spring tube through theoretical derivation and finished the experiment with piston gauge,OSA,LED broadband light source, etc. In the temperature sensor experiment, get the FBG temperature sensing properties, which is in good agreement with the theoretical value of the fiber Bragg grating temperature sensitivity coefficient; through the strain sensing experiment, a task that production of Fiber Bragg Grating pressure sensor has good characteristics hysteresis, repeatability, linearity, sensitivity is about 0.671nm/MPa.Papers on Fiber Bragg Grating demodulation technology do a certain amount of study, completed the design of light and its drive circuit,photoelectric detection parts,power supply circuit,reset circuit, clock circuit, A&D converter circuit,PC control and the simulation design pages.