Laser-induced damage threshold (LIDT) is investigated at several wavelengths in the high-purity silica optical fiber. The finite element method (FEM) is used to study transmission mode, LIDT, temperature distribution, and thermal stress distribution of the fiber. Our results show that the center of the front surface is subjected to severe thermal effects under laser irradiation and consequently, and it is susceptible damage. The variations in temperature and thermal stress are identified as increasing with laser fluences, which show a similar tendency. When laser fluences surpass the LIDT, such as 35 GW / cm2, the temperature at the front surface center shows a sudden growth and the melting damage appears, and no stress damage occurs at this time. Notably, the melting effect of high purity fused silica optical fiber is simulated by numerical calculation based on ray optics for the first time. Our research can provide systematic FEM simulations for the LIDT of silica optical fibers.

中文翻译：

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基于热效应的高纯石英光纤激光损伤阈值

在高纯度石英光纤的多个波长下研究了激光诱导损伤阈值 (LIDT)。采用有限元法（FEM）研究光纤的传输模式、LIDT、温度分布和热应力分布。我们的结果表明，前表面中心在激光照射下受到严重的热效应，因此很容易损坏。温度和热应力的变化被认为随着激光能量密度的增加而增加，这显示出类似的趋势。当激光能量密度超过LIDT时，如35 GW/cm2，前表面中心温度呈现突然增长并出现熔化损伤，此时不发生应力损伤。尤其，首次基于射线光学数值计算模拟高纯熔融石英光纤的熔化效应。我们的研究可以为石英光纤的LIDT提供系统的FEM模拟。