In the structure of Model GYXTW optical cable, the single mode or multimode optical fibers are jacketed by loose tube and the tube is made of high modulus polyester. Inside the tube, it is full of waterproof filling compound, in which no elemental hydrogen could be detected. Outside the loose tube, it is wrapped longitudinally by a layer of both sides plastic coated ripple steeltape and the waterproof material between th steel tape and loose tube is used to ensure compact optical cable structure and longitudinal waterproof. There are two parallel steel wires on the two sides of the loose tube and they are sheathed by PE to form an optical cable.