在讨论半导体激光线宽压窄理论的基础上，利用闪耀光栅作为外部反馈元件，介绍了由中心波长为949．6nm、原始线宽为1．2THz的单管半导体激光器构成的反馈外腔，它能够很好的改善半导体激光器的性能。实验得到了中心波长稳定的、单纵模的高质量激光输出，边模抑制比大于30dB，线宽优于1．2MHz(△λ＜3．6×10^－6nm)。实验证实了强反馈能够很好地改善外腔半导体激光器的动态特性。

Based on the discussion of linewidth-narrowing of the semiconductor laser,experimental results of external cavity semiconductor laser with narrow-linewidth are reported. With a blaze grating offering external feedback,strong coupled external cavity for a commercial semiconductor laser can improve the output characteristics of 949.6nm semiconductor laser. Its side mode suppression ratio is more than 30dB,and spectrum linewidth is narrower than 3.6 × 10^－6nm. The experiment shows that the strong feedback can improve the dynamical characteristics of an external cavity semiconductor laser.