We observe a drastic increase in propagation loss at visible wavelengths in PECVD silicon nitride waveguides after exposure to ultraviolet (UV) light. Low temperature annealing or high intensity optical exposure at visible wavelengths brings the propagation loss back toward the original value before UV exposure or even lower. We postulate that these effects can be explained by the population and depopulation of defect centers in the silicon nitride. We demonstrate the importance of defect depopulation before using waveguides in any silicon nitride based visible photonic application and provide a cleaning procedure that yields reproducible, low-loss, initial waveguide conditions.

中文翻译：

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减轻PECVD氮化硅光子波导中紫外线引起的传输损失

我们观察到暴露于紫外（UV）光后，PECVD氮化硅波导中可见波长处的传输损耗急剧增加。在可见光波长下的低温退火或高强度光学曝光可将传播损耗恢复至紫外线之前的原始值，甚至更低。我们假设这些影响可以用氮化硅中缺陷中心的增加和减少来解释。我们证明了在任何基于氮化硅的可见光子应用中使用波导之前，缺陷消除的重要性，并提供了一种可产生可再现的，低损耗的初始波导条件的清洁程序。