Research On Polarization Error And Lock Control Of Long Fiber Cavity Low Frequency Modulation Scheme Of Resonator Fiber Optic Gyro

The study of RFOG(resonant fiber optic gyro)has been in the laboratory stage for decades,for its implementation schemes are too complex or its performance indicators are often not meet the practical requirements.Compared with the IFOG(interferometric fiber optic gyroscope),the advantage of the RFOG is that it can achieve the same shot noise limit sensitivity by only a few tens of fiber lengths.The resonant micro optical gyro(RMOG),which can be integrated with optics,has great potential in the miniaturization of the system.Therefore,the research of related topics is of great significance and value.In this paper,we select the appropriate parameters of the optical devices,construct resonant cavity modulation frequency in the vicinity of 20kHz~30kHz.Compared with the traditional structure of hundreds of kHz or even MHz level modulation frequency,due to the narrow resonance linewidth,this strcucture has a higher detection sensitivity of the shot noise.So there are some potential values.Because of the limit of laser linewidth or phase noise,more narrow linewidth of resonance is diff'icult to achieve in the current loop lock mechanism.So it is not feasible.The contents include:(1)The determination and calculation of basic parameters for given device parameters,including the actual linewidth of system with the effect of white noise,the loop characteristic frequency and fiber fineness,modulation and demodulation related parameters;(2)The theoretical analysis for Sagnac phase shift caused by various optical noise,which is introduced by device characteristics,device processing and polarization characteristics;(3)The theoretical analysis and experimental verification of the principle and parameters of the feedback control of the loop lock are presented.It is shown that the optimal PI parameter combination is obtained under certain criteria,and it has strong robustness.(4)The free spectral width of the resonator is measured accurately through the high frequency modulation scheme.