Some Problems Of Sagnac Interferometer And Light Source Control Research

Fiber optic gyroscope (FOG) is a sensor based on the the Sagnac effect. In ac-cordance with the theory, FOG can be divided into the resonator fiber optic gyro, interferometer fiber optic gyro and stimulated Brillouin scattering FOG. As of now, the interferometric fiber optic gyroscope theoretical research is the most mature and has been widely used in engineering. Resonator fiber optic gyro and stimulated Bril-louin scattering FOG is still in the stage of laboratory research, there is a wide gap from the actual engineering applications.In this paper, first of all, I discuss the significance of the supply current and the stability of the working environment for the light source stability, according to the relevant literature, the relationship between the current change with the wavelength of light change:40ppm/mA. The current change with the wavelength of light change:400ppm/℃.Then I discuss the various programs of the constant current source, com-pare the advantages and disadvantages of various options and the practical application of the program in this work. In the following pages, first I give a brief introduction to the method of controlling the light source stability, and then explain the relevant characteristics of the thermistor and TEC, because these two devices are important parts of the light source temperature control system: the thermistor resistance change can reflect the difference between the actual temperature and set temperature, and the effect of the temperature control circuit by detecting the stability of the thermistor re-sistance; There are two TEC current flow directions, both the flow, respectively, cor-respond to the TEC of heating and cooling, and therefore, when the circuit tempera-ture changes, and by controlling the current direction and the amount of the current can make the circuit heating or cooling, so that the working temperature is maintained in the vicinity of the set temperature.In the next chapter, I discusses the separation of the Shupe effect and with all polarization maintaining birefringent Sagnac ring. First, I briefly introduce Shupe effect, then I give the mathematical expression of error caused by the Shupe effect. Next, from the theoretical aspects I discussed the separa- tion between the Shupe effect and the Sagnac effect. In the last section of this chapter, I focus on the all polarization with birefringence Sagnac ring. This section shows that it is possible to build stable filters which is input state of polarization insensitive by using a polarization-maintaining fiber(PMF) coupler instead of a single-mode coupler. This structure has two applications:First, it can detect the quality of the optical fiber ring. Second, it can be used as the filter. At the end of this section, I discuss the solu-tion of a simplest filter.