An in situ and nondestructive technique is developed to image the formation and evolution of dark line defects in the cavity of a high-power diode laser. The technique uses broadband near infrared emission that originates in the laser's core layers and enables defects to be imaged with high spatial resolution through the substrate. In particular, it enables defect imaging through the substrate of shorter wavelength lasers, even when the substrate is opaque near the lasing wavelength. The evolution of dark line defects during aging is studied in several devices, with correlations established between the observed characteristics of defect growth and changes in device parameters such as optical power, operating wavelength, threshold current, and slope efficiency. Gradual degradation is found to be associated with dark line defects that slowly propagate from dark spots that are present in the device interior in its fresh (unaged) condition, rather than propagating from spots that are formed during aging, suggesting a strategy to screen fresh devices for expected reliability. This defect growth phenomenon is found to be particularly evident in the dark spots near the output facet.

中文翻译：

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使用激光腔的宽带近红外光发射对高功率二极管激光腔中暗线缺陷生长进行成像


开发了一种原位无损技术，用于对高功率二极管激光器腔中暗线缺陷的形成和演变进行成像。该技术使用源自激光器核心层的宽带近红外发射，使缺陷能够通过基板以高空间分辨率成像。特别是，它能够通过较短波长激光器的衬底进行缺陷成像，即使衬底在激光波长附近不透明。在几种器件中研究了老化过程中暗线缺陷的演变，并在观察到的缺陷增长特性与器件参数（如光功率、工作波长、阈值电流和斜率效率）的变化之间建立了相关性。发现逐渐退化与暗线缺陷有关，这些暗线缺陷从存在于新鲜（未老化）状态下存在于设备内部的黑点缓慢传播，而不是从老化过程中形成的斑点传播，这表明了一种筛选新设备以获得预期可靠性的策略。这种缺陷增长现象在输出刻面附近的黑点中尤为明显。