半导体激光器LIV测试中阈值电流的小波提取方法

针对传统半导体激光器阈值提取方法容易受噪声影响、存在重复性不好的问题，根据小波变换奇异性检测原理，提出一种采用小波变换的阈值电流提取法，其采用三阶样条函数的二倍膨胀作为光滑函数，取它的二阶导数为小波函数,并结合多尺度来对半导体激光器光功率-电流（L-I）信号中的奇异点和不规则突变点进行检测分析。实验结果表明，与传统的二段直线拟合法、一次微分法和二次微分法相比，小波提取法不受噪声影响，能够真实、准确地得到半导体激光器的阈值电流。

Threshold current extraction method based on wavelet transform for laser diode LIV testing

Conventional semiconductor laser threshold extraction method can be affected by noise, poor reproducibility. Under the principle of singularity detection of wavelet transform, It is proposed that wavelet transform is adopted for threshold current extraction, which uses third-order spline function as a double expansion smooth, taking its second derivative for the wavelet function, and multi-scale integration. Experimental results show that compared with several traditional methods, such as the two-segment line fits method, first derivative method and second derivative method, the method based on wavelet extraction is not susceptible to noise and can truly and accurately obtain the threshold current of semiconductor lasers.