一种可降低Littman-Metcalf光栅外腔半导体激光器衍射损耗的结构设计  

Optimal design for reducing diffraction loss of Littman-Metcalf grating external cavity semiconductor laser

作　　者：周平 吴永前[2] 张蓉竹[1] Zhou Ping;Wu Yongqian;Zhang Rongzhu(College of Electronic Information,Sichuan University,Chengdu 610065,China;Institute of Optics and Electronics,Chinese Academy of Sciences,Chengdu 610209,China)

机构地区：[1]四川大学电子信息学院,四川成都610065 [2]中国科学院光电技术研究所,四川成都610209

出　　处：《红外与激光工程》2023年第1期92-98,共7页Infrared and Laser Engineering

摘　　要：基于原有Littman-Metcalf型光栅外腔半导体激光器的工作原理,设计了一种可以降低衍射损耗的外腔结构。在Littman-Metcalf结构的基础上增加一个反射镜,将闪耀光栅二次衍射产生的零级衍射光反馈回半导体激光器本征腔。推导了新结构模型外腔损耗的表达式,通过等效腔的概念对两种结构激光器的外腔损耗、阈值电流、输出线宽以及输出功率进行了仿真分析。结果表明:将二次衍射产生的零级光反馈回有源区可有效降低Littman-Metcalf结构激光器的外腔损耗,提高了系统的耦合效率,从而降低阈值电流,提高了激光器的输出功率。同时,由于提高了外腔反射效率,该外腔结构进一步压窄激光器的输出线宽。对影响低损耗Littman-Metcalf外腔激光器输出线宽以及输出功率的因素(端面反射率、内外腔长、闪耀光栅衍射效率以及反射镜反射率等)也进行了仿真分析,为后期激光器制作提高了理论指导。Based on the working principle of Littman-Metcalf type grating external cavity semiconductor laser,an external cavity structure which can reduce diffraction loss is designed. Based on the Littman-Metcalf structure,a reflector is added to feed back the zero-order diffraction light generated by the secondary diffraction of the shining grating to the intrinsic cavity of the semiconductor laser. The expression of the external cavity loss of the new structure model is derived, and the external cavity loss, threshold current, output line width and output power of the two laser structures are simulated by the concept of equivalent cavity. The results show that the zero-order light fed back to the active region can effectively reduce the external cavity loss of the Littman-Metcalf structure laser and improve the coupling efficiency of the system, thus reducing the threshold current and improving the output power of the laser. At the same time, the output linewidth of the laser is further narrowed by improving the reflection efficiency of the external cavity. The factors affecting the output linewidth and output power of low loss Littman-Metcalf external cavity laser(end reflectivity, internal and external cavity length, blazed grating diffraction efficiency and mirror reflectivity) are also simulated and analyzed. It improves the theoretical guidance for the later laser production.

关 键 词：外腔反馈 外腔损耗 阈值电流 外腔半导体激光器 线宽 

分 类 号：TN243[电子电信—物理电子学]