针对半导体激光光源连续调频时光学频率呈非线性变化的问题,提出一种电流节点校正方法。建立激光器驱动电流节点与实际拍频信号极小值点位置的关系,根据实际与理想信号极值点之间的位置偏差,对电流节点参数进行补偿,经过多次迭代实现激光器的调频非线性校正。通过搭建光纤调频连续波激光干涉测距系统,利用电流节点校正法实现DFB半导体激光器的调频线性化输出,并进行测距实验。结果表明,该校正方法简单有效,测距结果标准差小于11 μm,800 mm测量范围内线性度达0.03%,可广泛应用于调频连续波干涉。

A current node correction method is proposed herein to solve the nonlinear variation of optical frequency during continuous frequency modulation of semiconductor laser sources. First, the proposed method establishes the relationship between the laser drive current nodes and the position of the minimum points of the actual beat signal; then, the current node parameters are compensated according to the position deviation between these actual minimum points and the ideal points. After several iterations, the laser frequency modulation is nonlinearly corrected. A fiber-optic frequency-modulated continuous wave laser interferometric ranging system is realized, and the linearization output of the distributed feedback semiconductor laser is obtained via the proposed current node correction method to perform a ranging experiment. The results show that the proposed method is a simple and effective calibration method, and a standard deviation below 11 μm and a linearity of 0.03% within the measurement range of 800 mm are obtained. The proposed method can be widely used for frequency-modulated continuous wave interference.