The structure of GYTC8S 53 optical cable is to sleeve single mode or multimode optical fibers into a loose tube filled with waterproof compound made of high modulus plastic. The center of the cable core is a metal reinforced core, and for certain numbers of fiber optic cables, a layer of polyethylene (PE) is extruded outside the non-metallic reinforced core. The loose sleeve is twisted around the center strengthening core to form a compact and circular cable core, and the gaps inside the cable core are filled with water blocking compounds. After being longitudinally wrapped with plastic coated steel strips, a layer of polyethylene inner sheath is extruded, and after being longitudinally wrapped with double-sided plastic coated steel strips, a polyethylene outer sheath is extruded to form a cable. Double sheathed and double armored structure, with better water blocking effect.