干涉型保偏光纤微振动矢量传感器研究

报道了干涉型保偏光纤微振动矢量传感器的理论与实验结果。传感器采用全保偏光纤结构 ,消除了偏振不稳定性 ,系统采用光频调制相位载波 (PGC)解调信号处理技术 ,消除了干涉仪初始相差的影响 ,从而实现了对传感信号的稳定检测。对三轴正交芯轴式干涉型全保偏推挽结构的光纤微振动矢量传感器进行了理论和实验研究。由理论得到了简化公式 ,并通过公式分析了各种参数对传感器谐振频率与灵敏度等特性的影响。由实验得到系统谐振频率约为 370Hz,与 375Hz的理论结果基本一致。在 5～ 2 0 0Hz频段系统灵敏度响应平坦 ,约为 340rad/g ,略低于 35 6rad/g的理论值。该传感器具有良好的矢量性 ,在 4 5°方向的灵敏度约为轴向灵敏度的 0 7倍 ,与理论结果一致 ,正交方向串扰小于 - 2 6dB。系统最小可测相位为 10 -5rad ,最小可测加速度为 3× 10 -8g。

Research on Interferometric Polarization Maintaining Fiber Optic Micro-Vibration Vector Sensor

The theoretic and experimental result of interferometric polarization-maintaining fiber micro-vibration vector sensor are represented. Because of polarization-maintaining fiber structure, the sensor avoided instability of polarization. With phase generated carrier (PGC) technology, the influence of initial phase of interferometer was sliminated. Based on these methods, the stable signal detect was realized by the fiber optic micro-vibration vector sensor. The measured natural frequency of the system was 370 Hz, which agrees with the theoretic result 375 Hz. The acceleration sensitivity in experimental results reached 340 rad/g in frequency band of 5～200 Hz, and it matched 356 rad/g predicted by theory. Vector character of the sensor was obtained too. The acceleration sensitivity in 45° was 0.7 times of that in 0° and the orthogonal crosstalk coupling was -26 dB below. In the system, minimum measurable phase was 10-5 rad and minimum measurable acceleration reached 3×10-8 g.