Doppler Optical Speed Sensor

The Laser Doppler system for measuring the velocity, which applies isolate optical components to construct the optical path, has the following disadvantages: complex system structure, large size and narrow measure range. This dissertation puts forward a kind of sensor with wide measure velocity range based on the Doppler Frequency Shift and all-fiber path, namely Doppler Fiber Velocity sensor.This dissertation brings forward the method to divide unequal arms of M-Z optical fiber interference rings into sections, which greatly enlarge the range for measuring velocity.This dissertation also puts forward the method of optical intensity normalization to solve the errors as a result of various reflection coefficients to various parts of the same object.Through optimize design of optical transmitter, the stability of Laser output can be improved. After analysis and calculation, the author suggests decreasing noise as follows: avoid the temperature raising by ATC and narrow the system bandwidth as possible as it can. In order to lower the receiver noise and improve sensitivity and signal-to-noise ratios, the author optimizes light receiver. By analyzing the relativity and independence of signal and noise, the signal-to-noise ratios and system disturbance ability can further be improved by certain times' signal-digital-averaging.Finally, the dissertation proves the correctness of theories above and optimize design and also gives out experiment result and system specification.