针对窄线宽激光器输出谱线窄，难以被锁定的情况，利用F-P腔特有极窄线宽、高精细度特性对激光器谱线线宽实施压窄及频率锁定。通过设计实验方案并搭建锁频测试平台，利用F-P腔外部光反馈将窄线宽半导体激光器线宽压窄来提高锁频精度。通过监测正弦波调制下F-P腔对于4种不同直流电压下激光PZT扫频段的透射谱线，并对其分别进行解调和锁频精度测试，得到直流高压放大器电压为73 V时对窄线宽激光器进行扫频，激光器反馈锁频精度最高可达1.5 MHz。

Aiming at the problem that the output spectrum of narrow linewidth laser is narrow and difficult to be locked, the Fabry-Perot(F-P) cavity which has the unique narrow linewidth and high-definition features was used to do linewidth narrowing and the frequency locking. Based on the advantages of F-P cavity, the experiment plan was designed and a test platform was built, the external cavity optical feedback technology was employed to improve the accuracy of locked frequency. The transmission line was monitored under the sine wave modulation of F-P cavity with different laser piezoelectricity (PZT) sweep frequencies at four direct current(DC) voltages, then the demodulation was conducted and the locked frequency accuracy was tested. As a result, when using 73 V DC high voltage amplifier to sweep the narrow linewidth laser, the laser feedback locked frequency precision can be up to 1.5 MHz.