冷原子实验用的半导体激光器稳频系统

Frequency Stabilization System of Diode Laser for Cold Atom Experiment

基于冷原子实验对激光器的频率稳定性有很高的要求,设计了一套基于原子蒸气饱和吸收法的激光稳频系统。该激光稳频系统有较高的集成度,射频(RF)调制信号的产生、放大、滤波、混频以及误差信号的检出电路被集成到了一块3U的插件上,用于寻找光谱的扫描电路和锁频控制器(PI)集成到了另一块3U插件上。专门设计了一个14槽,19英寸(482.6 mm)宽的3U机箱来安放这些插件。这种高集成度的方式,不仅具有占用空间少、易于管理和维护等优点,其抗干扰能力也大大提高。采用高达21.4 MHz的调制信号,避开了低频的干扰,并使误差信号能反应出激光管更快速的相位抖动。

Lasers with high stability of frequency are required on ultra-cold atom experiment.A compact frequency stabilization system of diode laser is proposed,which is based on the principle of saturated absorption of atom vapor.The generation, amplification, filtering,mixing of radio frequency（RF） modulation signal,as well as the error signal detection,are integrated into a 3U plug-in module.The scan circuit for finding the spectroscopy and PI controller for frequency locking are also integrated into another 3U plug-in module.For holding those modules,a 3U rack of 14-slot and 19 inches（482.6 mm） width is designed.Experiments show that the high level of integration means not only take up less space,easy to manage and maintain,but its anti-interference ability also greatly enhanced.In order to detect the faster phase jitter of the laser diode,and to avoid the noisy low frequency,a modulation frequency as high as 21.4 MHz is adopted.