1) using the CVD method tube when there is damage in the the initial quartz tube itself.

(2) The drawing furnace dust, temperature changes of the environmental conditions.

(3) The surface of the optic fiber cable is in contact with other objects.

Fiber surface damage will be gradually expanded over time which is a fiber break.

Expanding the main factor of the optical fiber damage including: stress, water, temperature, and so on. Quartz-based optical fiber, compared to the water and air the the basic rupture time and the load stress of these two properties will decline. And we must not neglect the decrease in strength of the optical fiber in the water when the no-load state; 80oC under load stress, the fiber strength decreased significantly.