Application Of Optical Fiber In Micro-displacement Measurement

Choosing Y type reflection fiber optic detector, this thesis create a tiny displacement-detecting sensor that is made up of LED (Light Emitting diode), fiber optic detector, electric eye, lock-in amplifier, display and other electro circuits. This thesis is not only discussing and analyzing mathematically the working principle of Y type reflection fiber optic detector, but also deducing the fundamental calculating formula of reflection light intensity, and drawing the Displacement-Responding sensitivity curve. This thesis also points out the three characteristics curves corresponding to the detections in tiny displacement, biggish displacement, and superficial roughness. These are very creative and completely valuable in practicality. At the same time, this thesis also did the reasonably research about the weak light telecommunication technique, and designed an optic-electricity signal handling system, in which the lock-in amplifier is the core. The gain of this system could be 10^6, and SNR (Signal-to-Noise) could be 1000:1.his thesis presents many test results of: the superficial roughness of standard slice, aluminum slice, and glass slice by using the outline detector; the frequency characteristic of experimenting device; the characteristic of pivotal instruments; the displacement characteristic of layer-piezoelectricity actuator; tiny displacement detection. The experimental data are believable and the theoretic analysis is correct. So it is very important in directing the research and exploiture in the future.