基于光纤阵列的激光光斑测量方法

Laser intensity distribution measuring method based on fiber array

提出一种基于光纤阵列的激光光斑时空分布测量方法,采用在多层石英平板上制作V型槽并层叠石英光纤阵列的方法,获得了具有较高抗激光损伤能力和空间分辨力的光纤阵列取样器,实现了激光光斑的空间分布取样。给出了光纤阵列的取样原理、取样器结构和大倍数光强衰减的设计。实验结果表明:光纤阵列抗激光损伤能力优于10kW/cm2(50s),系统空间分辨力优于3mm,测量误差小于3%。

A method for measuring laser intensity distribution based on fiber array is presented. The principle and structural design of the fiber array are introduced. The attenuation characteristic is analyzed theoretically. A demonstration module is built in our lab. And experiments are carried out with a high power fiber laser operating at 1064 nm. The experimental results show that this system can provide laser power density distribution information with a spatial resolution better than 3 mm and with a measurement error less than 3~. Experiments with fiber laser radiation and numerical simulation by the finite element method in- dicate that the damage threshold of the fiber array is higher than 10 kW/cm2 with a radiation time of 50 s. Therefore, it might be appropriate for the method to measure the high energy laser beam directly.