针对低频周期振动光纤传感的应用，通过光纤光栅的周期调谐，构建了环形腔结构的低频周期扫频光纤激光器。以光纤光栅珐布里珀罗腔为梳状滤波器，利用光学倍频法设计了光源扫频周期的测量系统。实验产生了7.2 Hz的周期扫频激光输出，通过测量系统得到了14.39 Hz的倍频电信号。实验结果表明该系统可有效地模拟低频光源周期扫频，并进行扫频频率的准确测量。

To simulate the periodic and weak vibration in the fiber sensor application, a loop-cavity fiber laser of the periodic frequency sweeping is constructed by tuning the fiber Bragg grating (FBG). To measure the sweeping frequency, the optical frequency multiplication is applied with the help of fiber Bragg grating Fabry-Perot cavity. This fiber laser has experimentally radiated a 7.2 Hz frequency-swept laser and 14.39 Hz electric signal is obtained by the frequency multiplication method. The experimental results show that this system can efficiently simulate the periodic frequency-swept light wave and exactly measure the sweeping frequency.