基于光栅平面相位调控反馈机理的芯片化电泵浦垂直外腔面发射半导体激光器模式控制研究

The Chip-Scale Electrically-Pumped Vertical External Cavity Surface Emitting Lasers (VECSEL) has showed immense potential as light sources in the applications of chip-scale optical interconnection, precise medical imaging and chip-scale atomic sensor, due to their advantages of narrow linewidth, high output power and excellent beam quality. However, the traditional cold-cavity model of VECSEL couldn’t realize the precise analysis of the mode destabilization within the active region. Except for this, the control of the output optical mode and the pattern of optical feedback field couldn’t be realized stably. And these deficiencies lead to the poor stability of the optical field mode and its polarization, restricting the application field of EP-VECSEL seriously. .Based on the interaction between the carrier and optical field, the mechanism of mode control within the chip-scale EP-VECSEL would be proposed. And the way to control the optical-field mode would be defined. The mechanism of the phase modulation of planar grating would also be investigated simultaneously. The structure of planar-focusing grating would be proposed, and the distribution of its feedback optical field along the active region would be controlled precisely. The stable control of the polarization of output optical field would also be realized. The output power of more than 3mW for the EP-VECSEL with the single-mode operation was expected. And more than 25dB OPSR (Orthogonal Polarization Suppression Ratio) would be also gained.

电泵浦垂直外腔面发射半导体激光器（EP-VECSEL）具有窄线宽、高功率及优越的光束质量等优点，其单芯片化制备是现阶段新型芯片光互联、精准医疗成像及芯片级原子导航系统的关键核心技术。但现阶段VECSEL的外腔冷腔模型无法准确分析芯片化器件发光区的模式扰动效应，同时现有的集成微纳结构对反馈光场形貌及模式控制效果不理想，导致器件输出光的模式及偏振稳定性差，严重限制了其实际应用。本项目提出开展基于发光区光场及载流子相互作用机制的EP-VECSEL模式控制机理研究，通过明确EP-VECSEL的模式控制机理提出有效抑制模式扰动的方法；同时开展平面光栅相位调制机理研究，通过提出平面聚焦光栅集成化EP-VECSEL结构，实现对器件内部反馈光模式场分布形貌的精确控制以及偏振特性的稳定控制，最终实现980nm波段EP-VECSEL芯片单模输出功率大于3mW，偏振抑制比大于25dB。

电泵浦面发射半导体激光器（EP-VCSEL）具有窄线宽、高功率及优越的光束质量等优点，其单芯片化制备是现阶段新型芯片光互联、精准医疗成像及芯片级原子导航系统的关键核心技术。本项目拟通过通过明确电泵浦面发射激光的模式控制机理提出有效抑制模式扰动的方法，同时开展平面光栅相位调制机理研究，通过提出平面聚焦光栅集成化EP-VECSEL结构，实现对器件内部反馈光模式场分布形貌的精确控制以及偏振特性的稳定控制。建立起基于载流子-光子相互作用的有源区光电热综合模型，并用于分析面发射激光的内部多模式激射机制，证实高阶多模式激射与载流子聚集效应直接相关，通过优化载流子分布，可改善激光器模式特性；利用氧化孔尺寸与台面尺寸的相对优化，实现了有源区的载流子均匀分布。基于FDTD solutions软件，建立了表面光栅相位调制模型，对光栅的模式及偏振控制特性进行了深入分析，建立基于光栅调制的不同偏振模式阈值电流分析模型，得出不同偏振模式的阈值差异引起了偏振选择性；提出了非对称相位分布的光栅模型，理论证实该结构可以有效调控光束出射方向，出光方向调控角度超过30°。优化了光栅集成面发射激光器制备工艺，提出二次曝光制备完整光栅结构的方法，并对光栅的干法刻蚀技术进行技术优化，得到高陡直度的光栅侧壁形貌，实现表面微纳光栅的精准制备。所制备的光栅集成VCSEL激光器，激光波长980.7nm，单模功率达到3.5mW@300K，偏振抑制比26.5dB；相关研究发表论文21篇，申请发明专利5项；培养博士生3名。