针对干涉型光纤传感器中存在的偏振诱导信号衰落现象,对偏振分集器(PDR)抗衰落原理进行了理论推导与软件仿真。设计并搭建了基于相位产生载波(PGC)调制解调、全光纤偏振分集器接收的光纤迈克耳孙型干涉传感实验系统,系统得出的信号与压电陶瓷光纤相位调制器产生的模拟信号基本相符。通过静态扭动干涉臂光纤改变干涉仪偏振状态,测量了PDR三通道可视度,得出信号稳定性、系统本底噪声与可视度的关系。结果表明,选择可视度大于0.5的偏振分集器通道输出可抑制信号衰落并实现信号稳定输出。

Aiming at polarization-induced signal fading phenomenon generally existing in interferometric fiber-optic sensor,the principle of polarization diversity receiver (PDR) is theoretically introduced and demonstrated by simulation. Experimental sensing system of fiber-optic Michelson interferometer based on phase generated carrier (PGC) is designed and set up. An all-fiber tri-cell polarization diversity receiver is designed to receive the signal from the sensing system. The demodulated signal is in good accordance with the simulation signal produced by a piezoelectric phase modulator in one arm of the interferometer. The fringe visibilities obtained from the three output-channels of PDR are observed with the polarization state of the interferometer changed by twisting the fiber of the interferometer. The relationship of the signal stability,self-noise of the system,and fringe visibility are obtained. The results show that polarization-induced signal fading can be inhibited by selecting an output-channel of PDR with the fringe visibility higher than 0.5.