窄线宽半导体激光器广泛应用于雷达和传感等领域，因此窄线宽激光器的研究具有十分重要的意义。设计采用了电反馈的结构，从激光器发射出来的光经过一个专门设计的频率鉴别器，来稳定激光器的中心波长。光电探测器将频率鉴别器发射出来的光转化成电流，与激光器内部探测器的电信号比较，比较之后的差值反馈到激光器将激光器的线宽锁定在环路带宽范围内；从而将激光器线宽由原始的0.5 nm降低到0.08 nm。

Narrow linewidth semiconductor lasers are widely used in the field of radar and sensor. So the research of narrow linewidth laser is necessary. Using electric feedback structure, and with a frequency discriminators, the center wavelength is stablized. The laser from frequency discriminators is converted to current by photoelectric detector. Different signals of inherent detector and the current are injected into laser to reduce the frequency noise. So the laser line width of 0.5 nm reduces to 0.08 nm.