高功率半导体激光器结构研究

	高功率半导体激光器结构研究
	张金胜
学位类型	博士
导师	宁永强
	2014-07
学位授予单位	中国科学院大学
学位专业	凝聚态物理
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808nm 2×2 VCSEL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60n，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。
其他摘要	Experienced several decades of development, the performance of high power semiconductor laser has become more sophisticated and exuberant. The demand for high power semiconductor lasers is also increasing.Great development has taken place in high power semiconductor lasers in recent ten years with the improvement of domestic epitaxy chip level, but still far behind the foreign countries. The requst of optimization in semiconductor laser technology and semiconductor laser structure is in demand. In this paper, optimization of new structure high power semiconductor laser and process has bee deeply researched. The major contents and achievements of 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 the damage principle. The reflectance and electric field distribution is simulated with film thickness continuous changing using optical transmission matrix, the film damage is reduced at the interface by the optimization film. Higher Plasma density LaB6 is adopted as in situ plasma source, also the cleaning parameter of ion source is optimized. Facet de-oxidation is made with ion pre-cleaning in a high vacuum environment, 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 from 4.5W to 7W, operating current is raised from 5A to 8A in the case of the quasi-continuous operation with the optimized film and cleaning method. 2 × 2 VCSEL array is fabricated with non-closed ring structure. The peak power of the VCSEL array is tested under waveform analysis method. the peak power is 30W in 60ns pulse width and 100Hz repetition rate, and the slope efficiency is 0.27W/A; the peak power is 9W in 20ns pulse width and 100Hz repetition rate, and the slope efficiency is 0.3W/A. Also, the near-field and far-field of VCSEL array are measured, near-field is of 4 annular distribution singl emitter, the far field is nearly Gaussian distribution. The beam divergence with full-width at half maximum was 16.9° and 17.6° respectively in the vertical and lateral directions. High output power of 808nm VCSEL array is obtained，which provide a device basis for laser distance measuring and laserfuze. The InGaAlAs VCSEL temperature shift is calculated under the temperature-dependent Sellmeier equation. Each emitter diameter is 60 μm. Lasing wavelength, optical power and the threshold current are measured by changing the temperature of heat sink. The maximum output power reaches 56 mW in the pulse width of 50μs, and the repetition frequency of 100Hz in 20 ℃. The central wavelength is 808.38nm, and the full width at half maximum is 2.5nm, continuous output power reaches 22mW, the output power decreases rapidly above 50 ℃，the temperature shift is 0.055nm/K. Experimentally temperature shift is consistent with the 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 SiO2 dielectric film is optimized. Ion assisted deposition conditions is Optimized, The curvature change of SiO2 thin films is measured by step profiler, also the stress is calculated by Stoney theory. Finally, the deposition conditions is selected by Ar + ion assisted, thickness of 250 nm, growth rate of 0.8 nm/s.In which condition, the film stress is much smaller than the traditional method, and the changes of stress is small before and after annealing. The deposition conditions is obtained in preparing high quality , low stress dielectric film before and after annealing. The output power of VCSEL is 92 w with the optimized SiO2 dielectric film.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41499
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	张金胜. 高功率半导体激光器结构研究[D]. 中国科学院大学,2014.

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