A Study Of All-fiber Velocity Sensors

FVISAR (Fiber velocity interferometer system for any reflector) which is made up of fiber can measure the velocity for any reflector without touching. It is widely used in the velocity measurement, especially in the field of material impact characteristics researching. Since it is posed in 1996 by scientist L.Levin, it attracts widely attention all over the world.In this paper, firstly, all kinds of laser velocity interferometers are summarized and their principles and characters are contrasted. As a new velocity sensor, FVISAR has the merit of compact structure, short coherence length, easy to adjustment light path, any fringe constant and so on.The principle of FVISAR analyzed from two different theories (traditional coherent theory and Doppler frequency shift theory) lead to the same velocity equation which is the solid theory foundation of the FVISAR design.The system designing of FVISAR are discussed in detail in charpter three. Especially, the quantitative analysis and simulation research of the velocity range, fringe constant selection and attenuation of fiber delay line are intruduced.The system simulation and analysis on the platform of Labview are developed in charpter four.Based on the theory analysis, the whole scheme of FVISAR is designed, the system is developed and a lot of work such as loudspeaker vibrating measurement has been done with good experiment result.Due to the single detector system cannot distinguish acceleration and deceleration, the improved method is put forward basing on former FVISAR. The program used for experiment data processing is developed in the platform of VC++. The simulation of different moving target validates the reliability and practicability of the program. Finally, based on optical reflection principle, a new velocimeter is introduced.This thesis offers significant referenced value to further develop FVISAR.