基于振镜的准直光源功率稳定控制器

Power stability controller for collimating-light source based on scanlab

针对特殊准直光源的稳定性控制需求,提出一种基于振镜的激光功率稳定控制方法。将石英片与振镜连接固定,采用入射光角度与透过率的关系作为信号调节原理,当振镜带动石英片旋转时,对石英片透射的光信号大小进行调节。基于菲涅尔定律,开展平板玻璃旋转角度与透过率参数分析,论证旋转角度范围等参数,为实现光源的功率稳定提供输出参数支持。利用监视反馈探测器进行实时数据监测和反馈。通过PID算法,对监视探测器信号与参考调节功率对应电压的误差进行调制,实现对振镜输出角度的准确调节。采用该功率稳定器对He-Ne 632.8 nm激光器进行了稳功率实验,并采用Trap探测器进行功率输出的实验验证。试验结果表明:经过功率稳定控制后的激光器稳定性:其标准离差率CV为0.016%(1 800 s),其峰峰起伏SV为±0.042%(1 800 s)。峰峰起伏S_(V)降至激光器自由运行时约为1/8.79,标准离差率C_(V)改善1/13.76,稳定性得到了较好的改进。

Herein,a method based on Scanlab is proposed to satisfy the technical stability requirements of special collimating light sources. The relation between the angle of incidence and transmittance is used as the principle of signal regulation. A quartz plate is fixed with Scanlab,and the transmittance of quartz is adjusted when Scanlab rotates. Real-time data feedback is recorded using a monitoring detector. To achieve power stability of the light source,the rotation angle,transmittance parameters of quartz,and angular range are analyzed based on Fresnel’s law. A proportional-integral-derivative algorithm is used to modulate the error in the signal of the monitoring detector and the voltage corresponding to the reference power to accurately adjust the output of Scanlab. A stabilizer is used to control the power of a He-Ne632. 8 nm laser,and a trap detector is used to verify the level of power stability. The experimental results pertaining to the stability of the laser after modulation are as follows:The standard deviation C_(V) is0. 016%(1 800 s),and the peak-to-peak fluctuation SV is ±0. 042%(1 800 s). Compared with the freerunning result,S_(V )and C_(V) are improved by factors of 8. 79 and 13. 76,respectively,and the power stability of the laser is enhanced.