调相谱检测技术是谐振式光纤陀螺(R- FOG)角速率信号提取的关键技术,通过选取合适的调制参数,可大大提升陀螺的综合性能。利用相位调制频谱展开式,依据调相谱载波分量和调制信号的幅度关系,提出了双光路调相谱最优参数的确定方法,该方法在保证陀螺最佳灵敏度工作点的同时,有效地抑制了背向散射噪声的影响;在正弦波调相谱下,采用自外差法实测了相位调制器的半波电压,得到了调相谱载波分量与调制电压幅度的关系曲线,与理论分析相符;以长度为12 m的保偏光纤熔接环为敏感谐振腔,直径为0.15 m,耦合系数为50%,进行了不同角速率的转动测试,得到了动态范围为±480(°)/s、非线性度为3%的转动结果。
The phase modulation technique is the key technique to obtain the angular rate in resonator fiber optic gyro (R- FOG). Adopting the appropriate modulation parameters, the performance of the gyro can be greatly improved. Based on the phase modulation spectroscopy expression, and the relationship between the amplitude of modulated carrier signal and the amplitude of phase modulation voltage, the method for determining the optimized phase modulation parameters was proposed. Using the method, the backreflection noise can be effectively suppressed, while the optimized sensitivity of the gyro can also be ensured; The half-wave voltage of the modulator was measured using the self-heterodyne interferometer technique with sine wave phase modulation. And the relationship between the amplitude of modulated carrier signal and the amplitude of phase modulation voltage was obtained, which was consistent with the theoretical analysis; The fiber ring resonator (FRR) was composed of a 12 m length polarization maintaining fiber and a polarization maintaining fiber coupler with the coupling ratio 50%. The diameter of the resonator was 0.15 m. The rotation experiments under various angular rates were conducted, and the dynamic range and output nonlinearity of the R- FOG were ±480 (°)/s and 3%, respectively.