What is the GYTY53 Fiber Cable? GYTY53 fiber optic cable structure is a singlemode or multimode fiber into a high-volume polyester material made of pine casing, the casing filled with waterproof compounds. At the center of the core is a metal-enhanced core, which for some fiber optic cables requires a layer of polyethylene (PE) to squeeze outside the metal-enhanced core. The loose sleeve (and filling rope) surrounds the center to strengthen the core to form a compact circular core, with gaps in the core filling up to block water fillers. Squeeze a layer of polyethylene inner sheath outside the cable core, and squeeze the polyethylene coat into a cable after a double-sided chrome-coated steel belt (PSP) is packed.