Sheathing has three core values for use in fiber optic design: Protect the fiber. Keep ambient or stray light from creating signal noise (for sensor applications). Many procurement decisions focus on fiber count, connector type, or price, while the outer jacket material is selected by default or copied from previous projects. While internal components transmit power or data, the sheath ensures the entire cable assembly can survive the environment in which it is placed. When a fire occurs in the data. fiber optic cable in general by the optical fiber core and cladding, coating, strengthening element, an outer sheath, outer sheath as protective layer of cables, such as fire prevention, moistureproof effect, when a fire starts in the data center had important effect on the performance of the outer.