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提出并实现了一种基于光纤光栅(FBG)激光器的高分辨率光纤传感系统。通过在一段高增益有源光纤写入光纤光栅形成光纤激光传感器,待测信号作用在激光器上引起激光频率变化,采用偏振无关的非平衡迈克耳孙光纤干涉仪将激光频率变化转化为干涉仪相位变化。干涉仪输出的信号经过光电转换后,用采集卡转换为数字信号输入计算机,最后利用改进的归一化相位载波(PGC)解调技术,实现信号的高分辨率解调。实验表明该传感系统的动态应变分辨率达到了5.6×10-4nε/Hz,并且解调结果与待测信号具有良好的线性关系。
A high resolution optical fiber sensing system based on fiber grating (FBG) laser is proposed and implemented. A fiber laser sensor is formed by writing a fiber grating on a high-gain active fiber. The signal to be measured is induced on the laser to cause a change of the laser frequency. The non-equilibrium non-equilibrium Michelson fiber interferometer is used to convert the laser frequency change into an interferometer phase Variety. The signal output from the interferometer is converted into a digital signal by a capture card and then input into the computer after the photoelectric conversion. Finally, an improved normalized phase carrier (PGC) demodulation technique is used to achieve high-resolution demodulation of the signal. Experimental results show that the dynamic strain resolution of the sensing system reaches 5.6 × 10-4nε / Hz, and the demodulation result has a good linear relationship with the signal under test.