【作者】 张金胜；

【导师】 宁永强；

【作者基本信息】 中国科学院研究生院(长春光学精密机械与物理研究所) ， 凝聚态物理， 2014， 博士

【摘要】 经历了数十年的发展，高功率半导体激光器性能日益成熟化和多样化，人们对高功率半导体激光器的需求也在不断增加。随着国内芯片外延水平的提高，国内高功率半导体激光器研究在最近十年取得了长足的进步，但仍然明显落后于国外，对于半导体激光器结构和工艺的优化也提出了更高的要求，本文主要针对高功率半导体激光器新结构的优化制备工艺进行深入的研究。主要研究内容和成果如下：对激光器的灾变性光学镜面损伤产生的原因进行了探讨。针对腔面薄膜的损伤原理，将高反膜中场强最大处移出界面，采用光学传输矩阵，对厚度连续变化的界面场强和反射率进行了计算，得到优化高反膜系。采用改进后束流密度更大的LaB6作为阴极原位等离子源，对离子源清洗的参数进行了优化。薄膜制备前期使用离子清洗的方法在真空环境下对腔面进行去氧化，在制备过程中使用电子束蒸发离子源辅助沉积,并测试了薄膜在高温高湿环境下的稳定性。优化的膜系和清洗方法下制备的半导体激光器，在准连续输出情况下，功率由4.6W提升到了7W，工作电流由5A提升到了8A。通过非闭合环结构制备了808nm2×2VCSEL列阵。采用波形分析法对VCSEL列阵的功率进行了测量，在脉冲宽度为20ns，，重复频率为100Hz注入电流为110A的最大峰值功率为30W，斜率效率为0.27W/A，在脉冲宽度为60ns，重复频率为100Hz，注入电流为30A的最大功率为9W，斜率效率为0.3W/A。对列阵的近场和远场进行了测量，近场为4个环形分布的单管，远场为近高斯分布。激光器垂直发散角和水平发散角半高全宽分别为16.9°和17.6°。实现了808nm VCSEL列阵高峰值功率，为激光测距，激光引信等提供了器件基础。通过变温塞耳迈耶尔方程计算了InGaAlAs量子阱VCSEL的温度漂移系数。出光单元为60μm的VCSEL列阵通过热沉温度调节，对不同温度下的激射波长、光功率以及阈值电流进行了测量。在20℃，脉宽为50μs、重复频率100Hz的脉冲条件下，最大输出功率达到56mW，中心光谱值为808.38nm，光谱半宽为2.5nm，连续输出功率为达到22mW。通过变温测试，得到输出功率在50℃以上衰减剧烈，列阵的温漂系数为0.055nm/K，实验测得温漂系数与理论值保持一致。为了进一步增大注入电流，提高激光器的输出功率，防止漏电流的发生，对SiO2介质薄膜的制备工艺进行优化。优化了离子辅助沉积工艺条件，使用台阶仪测量了SiO2薄膜的曲率变化，通过Stoney理论计算了其应力大小，选取镀膜条件为Ar+离子辅助沉积，薄膜厚度为250nm，生长速率为0.8nm/s制备的SiO2薄膜的应力远小于常规工艺条件下沉积薄膜的应力，且退火前后应力变化小，得出了制备高质量、低应力和退火前后性质稳定的介质薄膜工艺条件。在此条件下制备的钝化层用于激光器，其输出功率达到92W。更多还原

【Abstract】 Experienced several decades of development, the performance of high powersemiconductor laser has become more sophisticated and exuberant. The demand forhigh power semiconductor lasers is also increasing.Great development has takenplace in high power semiconductor lasers in recent ten years with the improvementof domestic epitaxy chip level, but still far behind the foreign countries. The requstof optimization in semiconductor laser technology and semiconductor laser structureis in demand. In this paper, optimization of new structure high power semiconductorlaser and process has bee deeply researched. The major contents and achievementsof the study are as follows:The causes of the catastrophic optical mirror damage in the laser are discussed.The highest field intensity move out of the interface in the HR film against thedamage principle. The reflectance and electric field distribution is simulated withfilm thickness continuous changing using optical transmission matrix, the filmdamage is reduced at the interface by the optimization film. Higher Plasma densityLaB6is adopted as in situ plasma source, also the cleaning parameter of ion source isoptimized. Facet de-oxidation is made with ion pre-cleaning in a high vacuumenvironment, and the film is fabricated with ion-assisted electron beam evaporation.The stability of film is tested under high temperature and high humidity environment.The laser output power is raised from4.5W to7W, operating current is raised from 5A to8A in the case of the quasi-continuous operation with the optimized film andcleaning method.2×2VCSEL array is fabricated with non-closed ring structure. The peak powerof the VCSEL array is tested under waveform analysis method. the peak power is30W in60ns pulse width and100Hz repetition rate, and the slope efficiency is0.27W/A; the peak power is9W in20ns pulse width and100Hz repetition rate, andthe slope efficiency is0.3W/A. Also, the near-field and far-field of VCSEL array aremeasured, near-field is of4annular distribution singl emitter, the far field is nearlyGaussian distribution. The beam divergence with full-width at half maximum was16.9°and17.6°respectively in the vertical and lateral directions. High outputpower of808nm VCSEL array is obtained，which provide a device basis for laserdistance measuring and laserfuze.The InGaAlAs VCSEL temperature shift is calculated under thetemperature-dependent Sellmeier equation. Each emitter diameter is60μm. Lasingwavelength, optical power and the threshold current are measured by changing thetemperature of heat sink. The maximum output power reaches56mW in the pulsewidth of50μs, and the repetition frequency of100Hz in20℃. The centralwavelength is808.38nm, and the full width at half maximum is2.5nm, continuousoutput power reaches22mW, the output power decreases rapidly above50℃，thetemperature shift is0.055nm/K. Experimentally temperature shift is consistent withthe theoretical value.Inorder to increase the inject current for increasing the output power of laser,and prevent the occurrence of leakage current, the process of SiO2dielectric film isoptimized. Ion assisted deposition conditions is Optimized, The curvature change ofSiO2thin films is measured by step profiler, also the stress is calculated by Stoneytheory. Finally, the deposition conditions is selected by Ar+ion assisted, thicknessof250nm, growth rate of0.8nm/s.In which condition, the film stress is muchsmaller than the traditional method, and the changes of stress is small before andafter annealing. The deposition conditions is obtained in preparing high quality, low stress dielectric film before and after annealing. The output power of VCSEL is92wwith the optimized SiO2dielectric film.更多还原