Theoretical And Experimental Research On Digital Resonator Fiber Optic Gyroscope

Fiber optic gyroscope (FOG) is an advanced instrument to measure the angle velocity of rotation body. It realizes the measurement of optical Sagnac effect using solid all-fiber structure. It overcomes mechanical-electrical gyro's reduction of dynamic performance and life-span caused by the structure or the requirement of high rotation rate mass, and the laser gyro's fabrication technology complication and high cost caused by the rigid requirement of optical circuit resonation. So it becomes the most competitive new type of gyroscope. The interference FOG is in the application process. The resonance FOG needs shorter fiber or waveguide to realize the same sensitivity, comparing with the interference FOG It can realize integration in silicon planar waveguide module and integration of ring cavity, input and output optical circuits and modulator in single chip of planar waveguide. It fits the RMOG very much, which stands for the trend of miniaturization of gyroscope.This thesis first introduces the basic theory used in FOG, and then analyses the resonator-one of the key parts. This analysis illustrates the output character under certain laser frequency width. The output character is converted into Lorentz function form considering the laser frequency width. At the same time, according to the output character, this thesis analyses the relationship between the laser frequency width and the resonator normalized output function, as well as the relationship between the laser width and the one of the key parameters in resonator-Free Spectral Range (FSR).Second, this thesis analyses the scenario of a closed resonator fiber gyro, as well as the theory. According to the actual need, here analyses the circuit design in detail. Because of the importance of the phase modulator in the detection procedure in resonator fiber gyro, this thesis analyses the band side frequency caused by the phase modulation, proposing the methods how to eliminate the band side frequency effect and how to make use of the band side frequency. This thesis also proves how to use D/A converter with low number of bits to realize high grade application and discusses the scenario in detail. Here theoretically proves the possibility of this scenario. Thisscenario makes full use of the characteristic of digital circuits, easily to be realized, no complicated calculation needed. What is more, the precision of it is quite high. It can almost be realized without any error.In the end, this thesis tests the resonator with three methods in case that it is both open looped and closed looped, and gets the results listed below:1 Taking 1 MHz frequency width LD as the light source, using current injecting frequency modulation method, the output characteristic of the resonator is got, which proves that the laser used in the lab can be used to modulate the frequency using current injecting frequency modulation. 2 Through altering the length of the resonator, more clear resonator characteristic is observed, which proves that using the method of altering the length of the resonator may be a better way that using current injecting frequency modulation.3 Using current injecting frequency modulation method and modulating sine wave around the resonator point, the lock-in phenomena is observed in a comparatively short period of time. This has achieved the basic goal for a closed loop R-FOG...