半导体激光器腔面介质薄膜损伤机理研究

Semiconductor lasers have many applications such as laser printing, information storage, optical sensing, optical fiber communications, pumped solid state lasers, industrial processing, laser medical, military and so on. High power semiconductor lasers are embargo at abroad, while the most critical issue is facet dielectric film damage which can increase semiconductor laser power. Contraposing the issue of the facet dielectric films damage for semiconductor laser, we attempt to analysis the diffusion equation and photon rate equation of the semiconductor laser and use of three dimensional heat conduction equations to establish the facet heat distribution model. Then we selected facet dielectric film material and design facet dielectric film structure through analysis the heat distribution model and the inherent nature of the semiconductor laser epitaxial material. We manufacture facet dielectric film sample with different facet dielectric film manufacture method. Finally we analyzed the internal relations between the film absorbed, film stress, film structure, elemental ratio of film properties and damage threshold, and constantly optimize the design and manufacture method, at last the damage threshold achieved 5 MW/cm2.The innovation points are: (1) Establishing the semiconductor laser facet dielectric films damage physical model, to provide theoretical guidance for improve facet damage threshold. (2) The semiconductor laser facet dielectric film damage threshold is.reached 5 MW/cm2 by using high vacuum cleaving coating technology.

由于半导体激光器在激光打印、信息存储、光传感、光纤通信、泵浦固体激光器、工业加工、激光医疗、军事等领域有着非常广泛的应用。国外对高功率半导体激光器实行禁运，而制约其功率提高的最关键问题是腔面介质薄膜损伤问题。针对腔面介质薄膜损伤问题，我们拟通过分析半导体激光器扩散方程和光子速率方程，运用三维热传导方程建立腔面热量分布模型；再通过分析热量分布模型和半导体激光器外延材料固有性质选取腔面介质薄膜材料，进行膜系结构设计；再采用不同的腔面介质薄膜制备方法制备腔面介质薄膜样品；最后通过分析薄膜吸收、薄膜应力、薄膜结构以及元素比例等薄膜特性与损伤阈值的内在联系，不断优化设计制备方法，最终制备出损伤阈值达到5MW/cm2薄膜样品。项目的创新点为（1）建立半导体激光器腔面介质薄膜损伤物理模型，为提高腔面损伤阈值提供理论指导。（2）采用真空解理镀膜技术，使半导体激光器腔面介质质薄膜损伤阈值达到5MW/cm2。

由于高功率半导体激光器在激光加工、激光医疗、强激光武器等领域有着非常广泛的应用，并且国外对高功率半导体激光器实行禁运，而制约半导体激光器功率提高的最关键问题是腔面介质薄膜损伤问题。针对高功率半导体激光器腔面介质薄膜损伤问题，我们分析了半导体激光器失效机理和腔面介质薄膜损伤机理。通过分析半导体激光器腔面热特性理论，利用ANSYS有限元分析软件模拟了半导体激光器腔面热特性。针对半导体激光器外延材料固有性质，选取腔面钝化材料和高激光损伤阈值腔面介质薄膜材料。选取Si材料作为腔面钝化膜，并分析了不同Si钝化层厚度对GaAs表面生成氧化物的影响。针对半导体激光器输出特性，以及半导体激光器前后腔面膜反射率对器件输出特性的影响，运用光学薄膜设计软件Essential Macleod优化设计了不同剩余反射率（1%、2%、3%、4%、5%、10%、15%、20%）的前腔面增透膜和后腔面高反膜。利用1-on-1激光损伤测试方法测量单层HfO2、Ta2O5、Al2O3薄膜以及HfO2/Al2O3、Ta2O5/Al2O3、HfO2/Ta 2O5/Al2O3多层膜激光损伤阈值，采用组合膜堆HfO2/ Al2O3/Ta2O5/Al2O3的反射膜，其抗激光损伤阈值达到305MW/cm2，满足了在较少膜层数下同时获得高反射率和高损伤阈值激光反射膜的设计要求。最后利用高真空解离技术制备腔面钝化膜，全自动电子束镀膜机蒸镀半导体激光器前腔面膜和后腔面膜，前腔面膜采用HfO2/Al2O3增透膜，后腔面膜采用HfO2/Al2O3/Ta2O5/Al2O3组合高反射膜。利用半导体激光器综合参数测试仪测试，当连续电流达到8.00A时，半导体激光器连续输出功率达到8.08W,连续激光损伤阈值达4.04MW/cm2。当准连续占空比为2%，电流为9.30A时，半导体激光器准连续输出功率达到10.06W，准连续激光损伤阈值达5.03MW/cm2。