Rb原子泵浦用高温工作面发射激光光源偏振转换机制及偏振控制研究

Vertical surface emitting lasers (VCSELs) are the special light source for chip-scale atomic sensing due to the low power consumption,narrow linewidth and high operating reliability. Owing to the inherent cubical symmetry of the VCSEL resonators, and the isotropic optical gain of the active QWs, VCSELs do not possesses a well defined state of polarization. In addition, the non-uniform distribution of carriers and the refractive index perturbation along orthogonal orientations caused by the high temperature lead to the frequent polarization switch, and these phenomenons affect its applications. As the premise of realizing the chip-scale atomic sensing, the polarization switching dynamics and its control of VCSELs should be investigated..Based on the temperature-dependent birefringence, the theoretical model of polarization dynamics was proposed, and the polarization modes would be investigated according to the refractive index difference between two orthogonal orientations; the optical gain distribution within the active region would be analyzed according to the temperature related carrier-photon interaction model. By these two method, the polarization switching dynamics was expected to be clarified. Then the sub-wavelength dielectric grating would be integrated on the output window of VCSEL. Thus the asymmetrical optical feedback would be built up inside the VCSEL resonator, and the polarization control would be realized. More than 25dB OPSR (Orthogonal Polarization Suppression Ratio) would be gained for the 795nm VCSEL operating at the temperature above 60℃.

垂直腔面发射半导体激光器(VCSEL)在高温环境下具有低功耗、窄线宽、高可靠性，是理想的芯片级原子传感泵浦光源。但VCSEL光源材料体系具有晶向对称性及增益各向同性，加之高温环境下载流子分布不均、晶向折射率扰动等引起出射光偏振态出现频繁转换，这给其应用带来了不良影响。探索高温工作VCSEL器件的偏振转换机制及偏振控制是实现芯片级原子传感技术的重要前提。.本项目研究VCSEL高温双折射现象，分析材料正交晶向折射率变化趋势，建立偏振波导模式分析模型，结合高温环境下载流子-光子相互作用模型，确立光模式增益分布，明确高温工作VCSEL的偏振转换机理；在出光窗口集成低损耗亚波长介质光栅，并优化偏振方向，使之与增益方向匹配，在VCSEL谐振腔内构造非均匀性的偏振反馈机制，实现偏振控制。实现Rb原子泵浦用795nm VCSEL光源高温工作（>60℃）高偏振抑制比（>25dB）激光输出。

垂直腔面发射半导体激光器（VCSEL）具有非常低的能耗，窄的激光线宽，低成本及高的稳定性，在通信、鼠标等领域得到广泛应用。近年来，由于新型原子传感技术的发展，VCSEL器件在芯片级的原子陀螺或者原子钟系统中得到广泛应用。为了满足芯片级原子陀螺及原子钟系统的应用需求，VCSEL输出光场必须具有非常稳定的偏振特性以及单模特性。在本项目中，我们全面完成了项目预定目标，实现795nm VCSEL器件在65℃下的激光偏振抑制比达到25.8dB。项目研制过程中相关研究发表SCI论文11 篇,其中标明资助的文章6篇，申请专利3项。