对一种复合外腔半导体激光器的阈值增益进行分析,引入等效反射率建立该复合外腔半导体激光器阈值增益系数和阈值电流密度公式。通过数值模拟分析研究了闪耀光栅一级衍射效率、分光板反射率及谐振腔输出端面反射率对阈值增益系数的影响。最后对该复合外腔结构进行了简要分析,探索了进一步优化的可能性。 The threshold gain of a compound external cavity semiconductor laser is analyzed, and the equivalent reflectivity is introduced to establish the threshold gain coefficient and threshold current density formula of the compound external cavity semiconductor laser. The effects of the first-order diffraction efficiency, the reflectance of the splitter and the reflectivity of the resonator output facet on the threshold gain coefficient were studied by numerical simulation. Finally, the structure of the composite outer chamber was briefly analyzed to explore the possibility of further optimization.