谐振腔光纤陀螺(R-FOG)是利用光学Sagnac效应实现对转动检测的一种高精度的惯性传感器件。在谐振腔光纤陀螺系统中,信号检测系统占有非常重要的地位,其检测精度的大小直接影响陀螺的分辨率。光纤环形谐振腔是谐振腔光纤陀螺的核心敏感部件。采用两种频率的锯齿波组合调制,考虑激光器有限光谱线宽条件下,采用洛仑兹线型描写光纤环形谐振腔的输出光强表达式。针对输出光强与谐振频率偏差在靠近谐振点附近的近似线性关系,利用多次反馈频率操作来依次跟踪谐振腔光纤陀螺顺时针和逆时针光束的谐振点,从而避免了谐振频率偏差复杂的求根算法。仿真结果表明,多次反馈频率操作,可以较快地锁定到谐振点。

Resonator fiber optic gyro (R-FOG) is an inertial rotation sensor with high accuracy which is based on the Sagnac effect. The signal detection system has important role in the R-FOG. The detecting precision influences the maximum resolution of the gyro directly. The fiber ring resonator is the core-sensing element in the R-FOG. This paper presents the scheme to detect the resonance point using two-frequency serrodyne modulation, and uses the Lorentzian function to describe the expression of the output power at the exit port of the fiber ring resonator taking the temporal coherence of the laser into account. According to near linear relationship between amplitude of the square waveform and the resonant frequency deviation near the resonant point, frequency feedback time after time is used for frequency tracking for both clockwise (CW) and counterclockwise (CCW) waves. Therefore, complex root finding process can be avoided. Simulation shows that both CW and CCW waves can be locked at the resonance frequency of the resonator quickly by frequency feedback operation.