激光自外差相干测量中分布反馈半导体激光器电流调谐非线性的补偿方法

A method to compensate the tuned nonlinearity of DFB diode laser in the laser self-heterodyne coherent measuring system

半导体激光器的电流调谐非线性对自外差相干测量的精度影响很大.研究了分布反馈半导体(DFB)激光器的电流调谐特性,据此提出一种数学模型补偿方法.利用己知光程差下的差拍频率,建立了动态调频系数的数学模型.以此模型对DFB激光器的电流调谐非线性进行补偿,可以将差拍信号频率预测值的相对误差减小约3%,提高了系统的测量精度.数学模型补偿方法简化了测量系统的结构,适用于高精度的电流调谐激光在线测量系统.

The measuring accuracy of self-heterodyne coherent measuring system can be deteriorated by the tuning nonlinearity of the diode laser with injection current.The tuning characteristics of a DFB laser were analyzed,and a mathematical model for compensating Mach-Zehnder interferometer based self-heterodyne system was presented.The dynamic frequency modulation coefficient of the model was built by prior beat frequency of foregone optical path difference.The relative error of predicted beat frequency is reduced about 3%.This method could simplify the setup of the system,and is especially suited for online tunable laser measurement system.