LD的自动光功率控制(APC)——光控电路与自动温度控制(ATC)——温控电路,是光纤通信终端机的比较复杂难调的电路之一。HQD-Ⅲ模块将上述两部分集成起来,使LD发送盘的体积大为缩小,制作与维护变得容易。本文介绍了HQD-Ⅲ模块的主要性能、工作原理及测试方法,并给出了应用实例。 LD automatic optical power control (APC) - light control circuit and automatic temperature control (ATC) - temperature control circuit, optical communication terminal is one of the more complex and difficult circuit. HQD-III module integrates the above two parts, so that the size of the LD sending tray is greatly reduced, making it easy to manufacture and maintain. This paper introduces the main performance of the HQD-Ⅲ module, working principle and test methods, and gives examples of applications.