使用数字锁相环ADF4107芯片,设计了锁频带宽为1～7GHz的光学锁相环(OPLL)。通过光学探测器得到两台外腔半导体激光器的拍频信号,经过OPLL,产生两种误差信号,它们分别被加载到半导体激光器的光栅压电陶瓷和反馈电流上,从而将拍频信号的噪声由兆赫兹降低到赫兹量级。将该系统应用到电磁诱导透明光谱实验中,成功地观察到电磁诱导透明现象。该方法还可应用到超冷原子拉曼光谱实验中。 Using the digital phase locked loop ADF4107 chip, an optical phase locked loop (OPLL) with a bandwidth of 1 ~ 7GHz is designed. Obtained by the optical detector beat frequency of two external semiconductor laser signal through the OPLL, resulting in two kinds of error signals, which are loaded into the semiconductor laser grating and piezoelectric ceramic feedback current, the beat signal noise from Megahertz down to the order of Hertz. The system was applied to the experiment of electromagnetic induced transparency spectroscopy, and the phenomenon of electromagnetic induced transparency was successfully observed. The method can also be applied to ultra-cold atomic Raman spectroscopy experiments.