相位调制非线性对开环光纤陀螺工作点测量与信号解调的影响

Influence of Phase Modulator Non-Linearities on Measurement of Work Point and Signal Demodulation in Open-Loop Fiber Optic Gyroscope

在全光纤开环光纤陀螺中 ,利用压电陶瓷调制器可以为光纤陀螺提供互易性正弦相位偏置 ,但相位调制中的寄生非线性会对陀螺测量产生影响。从理论上给出了二倍频非线性相位调制情况下开环光纤陀螺输出信号的一、二、四次谐波表达式 ,分析了相位调制非线性对陀螺工作点测量与信号解调的影响 ,实验验证了相关结果。实验结果与理论分析表明在陀螺应用中必须采取措施抑制非线性相位调制的幅度。

Piezoelectric transducer (PZT) are often used for providing reciprocal sine phase modulation in all-fiber optic gyroscope (FOG) and its non-linearities can affect the accuracy of FOG. In this article, expressions of the first, second and fourth harmonic components of the FOG signal are derived theoretically providing that the second harmonic phase modulation exists in open loop FOG. Influences of phase modulator non-linearities on measurement of work point and signal demodulation are analyzed theoretically and tested by experiments. Both experimental results and theoretic analyses indicate that steps must be taken to decrease the amplitude of non-linearities in phase modulation.