GCYFTY [non-metallic reinforcing member, loose-layer stranded filled, polyethylene sheathed communication outdoor optical cable] The structure of the optical cable is to insert single-mode or multi-mode optical fiber into a high-modulus plastic and fill the loose tube with waterproof compound. Among them, the center of the cable core is a non-metallic strength member. For some fiber optic cables, the non-metallic center strength member is extruded with a layer of polyethylene. The loose tube (and filling rope) is twisted around the central strength member to form a compact and round cable core, and the inner gap of the cable core is filled with a water-blocking compound and an outer polyethylene sheath is extruded to form a cable.