The ground wire composite optical cable is referred to as OPGW (=Optical Power Grounded Wave-guide), also known as the optical fiber overhead ground wire. The ground wire in the power transmission line contains an optical fiber unit for communication. This kind of optical cable achieves both, that is, the electrical and mechanical properties of the ground wire will not be damaged due to the installation of optical fibers, and the optical fiber unit should be properly protected from damage. There are several types such as lead skeleton type, stainless steel tube type and submarine optical cable type.
Submarine optical cable is an optical cable laid on the seabed, which has shallow sea and deep sea applications. The characteristics of this kind of optical cable, one is to withstand a lot of hydrostatic pressure dark depth 10m increase pressure is 1 ton. ) and the drag force during the release process; the second is to prevent hydrogen from invading the optical fiber. It has been confirmed that hydrogen will increase the attenuation of the optical fiber; the third is that the span of the relay section is large. In the submarine cable the optical fiber unit is placed in the center of the cable and in a special stainless steel tube. The tube is wound with high-strength arched steel wires. The steel wire layer is wrapped with copper tubes for remote supply, and it prevents micro/macro bending when the optical cable is laid. The outer sheath is then extruded. It may also be pinned to protect against sharp objects, including shark bites. In my country's Shanghai, Qingdao, and Shantou, there are already inter-oceanic submarine optical cables landing.