Experimental Study Of The Extinction Ratio And Stability Of Light Source On Interferometric Fiber Optic Gyroscope

Interferometric fiber optic gyroscope (I-FOG) is the earliest developed, and the most widely applied fiber gyroscope. At present, the research and development of its inertia-class products are growing maturer. However, some random and nonreciprocal factors greatly limit the improvement of its performance. How to effectively inhibit the various noise of I-FOG, thereby improving measurement accuracy, has become a major research focus.Changes of polarization and stability of light source are two important factors which greatly influence the measurement accuracy of I-FOG. In order to improve the performance of I-FOG, we focus on these two aspects to conduct a series of studies.Firstly, we established an optic model for fiber optic gyroscope and analyzed the impact of changes of polarization on the output of I-FOG. Then we developed a testing platform and successfully tested extinction ratio of the single-mode polarization-maintaining fiber. The extinction ratio of two I-FOG fiber optic ring under different temperatures was tested and the testing results were analyzed. There is a problem in testing the extinction ratio of polarization-maintaining fiber, which is how to find the axis orientation of polarization-maintaining fiber. After understanding general methods, we conducted a theory analysis on the diffraction of light perpendicularly impinging the polarization-maintaining fiber by using the optical diffraction theory, and we have proposed a number of feasible ideas.The performance of light source directly determines the measurement accuracy of a I-FOG. We analyzed the impact of stability of light source on the output of I-FOG, then we designed the drive of SLD light source. We combined Auto Power Control with Auto Temperature Control, using proportion-integral-derivative control circuit. In addition, we have also introduced a temperature compensation circuit, and the test proved to be a very good result. Through stability test under different temperatures, the performance of light source can be given a evaluation test.