Fiber optics are the newest and fastest communication technology currently available, typically achieving speeds of 10 to 40 Gbit/s in most systems. Each optical fiber is made of very pure and carefully constructed glass. The innermost layer of the fiber, the ‘core’, is the part that mainly guides light down its length. The core is surrounded by the ‘cladding’, which acts to contain light within the core. There may also be a ‘buffer’ layer of resin or glass and a ‘jacket’ layer of plastic outside of that to further protect the fiber. Multi-mode fiber has a larger core and is usually used for short distance communication, while single-mode fiber has a much smaller core and is used for larger distances. While multi-mode fiber is a bit more expensive than single-mode fiber, single-mode fiber equipment is generally more expensive than its multi-mode eqivalent.
A fiber optic cable is one or more of these fibers bundled together in a plastic cover. Each end of the cable terminates in a connector which allows the cable to be easily connected or disconnected to fiber optic equipment. There are many types of cable configurations and optical connectors, and the kind that needs to be used depends on the equipment setup.