用于冷原子干涉仪的声光调制器数字驱动系统

Digital driving system for acousto-optic modulators in cold atom interferometer

为了满足冷原子干涉实验对激光移频的需求、实现移频速率的精确可控,设计并实现了一个带有操作界面的声光调制器数字驱动与控制系统。该系统由三个部分组成,分别是上位机,微处理器控制芯片,射频信号产生芯片。其中上位机用于收集控制信息;微处理器控制芯片用于根据上位机发送来的控制信息实现对射频信号产生芯片的控制、产生驱动声光调制器晶体的射频信号,从而实现对实验中所需的激光进行移频。该系统可输出频率为0~150 MHz且相位噪声低至-116 dBc/Hz的射频信号,同时可有效控制输出信号的幅度、相位和扫频速率等,该系统提供了满足冷原子干涉实验需求的多种工作模式。

In order to meet the need of laser frequency shift and precision sweep in cold atom interferometry experiments, a control system for acousto-optic modulator with digital interface was designed and implemented. The control system consists of three components, namely upper computer （PC）, microcontroller （ARM） and radio-frequency generator （DDS）. Among them, PC is used to collect control information. ARM chip controls the DDS chip according to control information, so that the DDS chip can generate a RF driv- ing signal for acousto-optic modulator, and obtain the desired laser frequency for experiments. The control system can output RF signals with frequency of 0 - 150 MHz and phase noise as low as -116 dBc/Hz. Meanwhile, the amplitude, phase and frequency sweep rate and other parameters of the output signals can be controlled efficiently. Additionlly it offers a variety of operating modes to meet different requirements in cold atom interferometry experiments.