At its core, an Optical Ground Wire (OPGW) is a composite cable that integrates the functions of a traditional ground wire with a fiber optic data transmission medium. It is engineered with a central tubular unit, typically made of stainless steel or aluminum, which houses the optical fibers. This core is then surrounded by layers of metallic wires, such as aluminum-clad steel or aluminum alloys. This design provides robust mechanical strength and electrical conductivity for grounding, while the inner core protects the sensitive optical fibers from environmental and mechanical stresses.