Fiber optic cables have a shielding layer

Fiber optic cables generally do not have a traditional electromagnetic shielding layer, but they include protective coatings, strength members, and optional armor for mechanical protection.

Fiber optic cables are primarily designed to transmit light signals through a glass or plastic core, so they are inherently immune to electromagnetic interference and do not require metallic shielding like copper cables . The core is surrounded by cladding, which keeps the light contained, and then by a polymer coating that protects the fiber from moisture, micro-bends, and physical damage . This coating is typically around 250 micrometers thick and acts as a cushioning layer for the delicate glass fiber . Beyond the coating, fiber optic cables include additional layers for mechanical protection. These may consist of aramid yarn (e.g., Kevlar) to absorb tensile stress, central or peripheral strength members to prevent buckling, water-blocking elements, and an outer jacket that shields the cable from environmental factors such as abrasion, chemicals, and UV exposure . In some applications, especially outdoor or industrial environments, cables may include a metallic armor layer made of steel or aluminum to provide extra mechanical protection, but this is not for electromagnetic shielding—it is purely for physical durability . In summary, fiber optic cables rely on coatings, strength members, and jackets for protection rather than traditional shielding, because the optical signal is not affected by electromagnetic interference. Optional armor layers may be added for mechanical robustness in harsh environments, but they do not serve the same purpose as the shielding in copper cables .