Theoretic Research On Fiber Accelerometer Of Mems

Acceleration sensor with high reliability and high fidelity is concerned more and more in the field of automotive industry, spaceflight, biology, medicine and etc. Currently, the measurement principle of micro-accelerometer uses mostly capacitive, thermocouple type, and so a more mature structure, the optical-type micro acceleration sensor less, but with a mature combination of optical fiber sensing technology little research on fiber-optic accelerometer. Application of MEMS technology and paper all-fiber interferometer theory proposes a combination of fiber-optic accelerometer sensor mechanism of the system, optical system, and signal processing system research. Fiber is a new type of waveguide wires with the diameters on the micro,even nanometer scale.and the characteristics of this fiber are different from both conventional optical fibers and integrated optical waveguide structures.First of all, this paper introduces researches and development trends about the Micro accelerometer sensor at home and abroad. Then the basic principles of the optical fiber sensing technology are discussed, and sensing mechanism of several typical phase modulation-based interferometers is analyzed, which provides a theoretical foundation for the derived acceleration measurement principle in the later part.Secondly, the principle and structure of the fiber-optic accelerometer based on Michelson's interferometer are deeply analyzed in this dissertation. Starting with the transducing mechanism, discussion and derivation of the phase change of the optical wave. The main working procedure of the fiber-optic sensor is: the sensing element detects the acceleration signal, this signal modulates the fringe, and the fringe change is corresponding to the acceleration signal.Thirdly, it builds the space motion equation of the diaphragm displacement by using the relevant principles of mechanics of materials, and their interference fringes and measurement of contact information, and thereby realizes the conversion from movement parameter to optical parameter. It analyses how each design parameter of sensor system influences the capability of sensor range, resolution and measurement accuracy and etc., and also gives principles of selecting design parameters and the theoretical value of technical indicators.Finally, since the output signals are usually corrupted by stochastic noises, so we discussion the noise sources of the acceleration sensor. Based above, we put forward some possible solutions for these reasons.