What do most fiber optic cables use to protect the fibers from environmental factors?

Most fiber optic cables utilize plastic sheathing as a primary means of protection for the fibers from environmental factors. This plastic sheath serves multiple crucial functions: it acts as a barrier against moisture, physical abrasion, chemicals, and other potentially damaging influences in the environment. The durability of the plastic sheathing ensures that the delicate glass fibers inside the cable are shielded from impacts that could cause fractures or signal loss.

Additionally, plastic materials can be engineered to meet specific requirements regarding flexibility, weight, and resistance to temperature variations, making them ideal for a wide range of installation scenarios, from indoor setups to outdoor applications.

Other materials, like metal conduits, might be used in some specialized installations to provide additional protection or mechanical strength, but they are not the predominant choice due to weight and flexibility concerns. Fiber-coated tubing and silica gel also serve specific purposes, such as moisture absorption or additional protective layers, but they are not the primary protective means in standard fiber optic cable constructions. Thus, plastic sheathing is the most widely used solution for safeguarding fiber optic cables against various environmental threats.