为了分析影响光纤机械可靠性和寿命的主要因素，通过模拟试验条件对比分析了引起光纤断裂的原因；将试验光纤断裂表面形貌与在实际工作状态下出现的光纤断裂源形貌特征进行对比，定性分析了引起光纤断裂形成的主要原因。分析认为是在外加应力的作用下，工作环境中水分或水汽的存在加速了光纤表面裂纹的生长、扩展，最终导致光纤断裂。

In order to analyze the main factors that affect the mechanical reliability and lifespan of optical fiber, through the simulating test conditions, the causes of optical fiber fracture are analyzed. The surface morphology of the experimental fiber fracture was compared with the morphology characteristics of the optical fiber fracture source that appeared in actual working conditions, and the main reasons for the formation of optical fiber fracture were qualitatively analyzed. Analysis suggests that the presence of water or vapor in the working environment under external stress accelerates the growth and propagation of surface cracks on the optical fiber, ultimately leading to fiber fracture.