针对可调谐光纤法布里珀罗滤波器(FFP-TF)在环境温度变化过程中扫频非线性曲线的随机波动增大, 引起光纤布拉格光栅(FBG)传感系统解调不稳定的现象, 提出了基于光纤迈克耳孙辅助干涉仪的一种稳定解调性能的方法, 通过辅助干涉仪实现了对法布里珀罗标准具光波长间隔的细分, 编制了局部光频细分解调算法。利用搭建的光谱周期为9.53 GHz的辅助干涉仪进行了变温解调实验研究, 结果表明, 以往未引入光纤辅助干涉仪的波长解调值波动的最大幅度为±28.5 pm, 标准差为8.6 pm; 引入辅助干涉仪的波长解调值波动的最大幅度为±3.5 pm, 标准差为1.4 pm, 有效提高了变温过程中的光纤光栅传感解调波长稳定性。

For the random fluctuation of nonlinearity curve of fiber Fabry-Perot tunable filter (FFP-TF) increasing in temperature changing environment, which results in the instability of fiber Bragg grating (FBG) demodulation system, a novel method based on auxiliary optical fiber Michelson interferometer (AFMI) to stabilize demodulation performance is proposed. The optical frequency subdivision in wavelength interval of Fabry-Perot etalon is achieved, and the demodulation algorithm by local optical frequency subdivision is compiled. Under temperature changing environment, we investigate amplitude of fluctuation by an AFMI, whose spectral interval is 9.53 GHz. The experiment shows that the amplitude of fluctuation is ±28.5 pm without AFMI, and standard deviation is 8.6 pm. However, the amplitude of fluctuation is ±3.5 pm with AFMI, and standard deviation is 1.4 pm. The wavelength demodulation stability of fiber Bragg grating in temperature-variable situation is effectively improved.