The optical cable adopts a loose-tube layer-stranded structure. The optical fiber is inserted into a loose tube made of high-modulus polyester material, and the tube is filled with waterproof compound. Loose tubes (and filling ropes) are twisted around the metal central reinforcing core (phosphated steel wire) to form a compact cable. The gaps in the cable body are filled with water-blocking ointment, and a blue flame-retardant PVC sheath is extruded outside the cable core.