适度光反馈机制下线宽展宽因数的自动测量

介绍了光反馈自混合干涉(OFSMI)法测量半导体激光器线宽展宽因数(LEF)的基本原理。针对不同参数条件,分析了该测量方法的理论误差,找出了最佳测量条件和最佳测量条纹位置。并根据光反馈自混合干涉信号特点,设计了一个自动测量算法。该算法可以自动识别提取一个振动周期内的光反馈自混合干涉信号所有特征值,采用最佳测量条纹位置所对应的特征值,就可以精确得到线宽展宽因数。仿真数据验证了自动测量算法的正确性。实验结果表明,自动测量算法在实际数据处理时测量参数的精确度较好,当自混合信号的峰-峰值为1.75 V时,线宽展宽因数的相对标准差只有3.26%。

Automatic Measurement of the Linewidth Enhancement Factor Based on Moderate Optical Feedback

The basic principle of measuring the linewidth enhancement factor(LEF) using optical feedback self-mixing interference(OFSMI) method is introduced.The theoretical errors are analyzed at different parameters,and the optimal measurement conditions and stripe positions are given.Based on the charcteristics of optical feedback self-mixing interfence signal,an automatic measurement algorithm is developed.The algorithm can automatically identify and extract all eigenvalues of optical feedback self-mixing interference signal in one vibrant period,and the accurate estimation linewidth enhancement factor can be obtained by the eigenvalues at the optimal measurement stripe position.The simulative data have verified the effectiveness of automatic measurement algorithm.The experimental results show that the accuracy of measuring paramters is better in processing data,and the relative standard error of linewidth enhancement factor is 3.26% when peak-peak value of self-mixing signal is 1.75 V.