Single jacket cables consist of a single protective layer, providing basic defense against environmental factors. It functions due to a phenomenon known as total internal reflection, which means that light in the Fiber core does not escape but reflects off the sides of. A typical armored fiber optic cable features a multi-layered protective structure, generally composed of the following layers from the outside to the inside: Outer Jacket: Usually made of polyethylene (PE) or polyvinyl chloride (PVC), it provides excellent resistance to weathering and abrasion. The typical components of an outdoor fiber optic cable include: Core: The core of the cable is the central part through which light travels.