Doppler Study Of The Optical Fiber Speed Sensor

Doppler fiber velocity sensor is widely used in the velocity measurement. Because of its merit such as compact structure, short coherence length, easy to adjustment light path and so on, it's possible to replace the traditional velocity sensor. A lot of work has been done about the system principle, structure, key technologies and experiments. In this paper, firstly, all kinds of laser velocity interferometers are summarized and their principles and characters are contrasted. Then we get the conclusion that Doppler fiber velocity sensor is the best velocity interferometer.The principle of Doppler fiber velocity sensor is analyzed from two different theories (traditional coherent theory and Doppler frequency shift theory), which lead to the same conclusion. Based on the theory analysis, the whole scheme of Doppler velocity sensor is designed, the system is developed and a lot of work such as light path debugging and experiments has been done. Then, the source of noise is analyzed, especially the noise created by the reflection of non-measured surface is discussed in detail and the way that can decrease these noises is presented. Getting rid of noise by wavelet analysis based on MATLAB is simulated also.Due to the single detector system cannot distinguish acceleration and deceleration, the improved method is put forward. How to increase signal sensitivity by the improved system is discussed and the data signal process is introduced .This thesis offers significant referenced value to further develop Doppler fiber velocity senor.