光纤可调F-P滤波器频率响应特性的实验研究

Frequency response characters of all-fiber Fabry-Perot tunable filter

为了提高基于可调Fabry-Perot(F-P)滤波器光纤光栅(FBG)解调系统的性能,根据可调F-P滤波器的特性,研究了不同驱动频率下光纤可调F-P滤波器的响应情况。实验中通过数据采集卡和LabVIEW软件平台得到滤波器不同输出波长所对应的电压,绘制出不同频率下电压—波长曲线。分析了在驱动电压频率改变时滤波器透射波长随电压的变化情况,发现直线拟合所得斜率有随频率增加单调递减的趋势,10Hz、100Hz和200Hz与1Hz的斜率误差分别为0.69%,5.10%,6.49%。实验数据分析表明,采用区分频率选择不同多项式拟合可以减小该误差对解调系统的影响。

To improve the performance of fiber Bragg grating （FBG） interrogation system based on Fabry-Perot （F-P） tunable filter, frequency response characters of the filter driven with different frequencies were presented. In experiment, the voltage corresponding to different output wavelength has been collected by the data acquisition card and Virtual Instrument （LabVIEW）. The relationship between wavelength and applied voltage for different frequencies was given. Fitting the data to linearity, it is found that the fitting slope has a monotonically decreasing trend with frequency increasing. Compared with 1Hz the slope errors of 10 Hz, 100 Hz and 200 Hz were respectively 0. 69%, 5. 10% and 6. 49%. Selecting different polynomial fitting with the change of frequency can reduce the errors of the interrogation systerrL