So far we have studied the principles and characteristics of individual optical fibers.While they are certainly adequate for the job of carrying signals from one place to another, they are not rugged enough to withstand the rigors of handling,transportation, and installation.In addition, some installations require multiple optical fibers for sending and receiving or for routing to a number of locations.
For an optical fiber to be suitable for everyday everydays use, it must be incorporated into cables that provide standardized fiber groupings, protection from the environment, and suitable size for handling.We will describe standard and harsh environment fiber optic cables used in many types of installations.Such as Simplex Fiber Optic Cable . We will detail different types of fiber optic cables and the uses for which they were designed.We will also describe some of the basic requirements for handling and installation.
Fiber optic cables intended for aerial installation must also be designed to handle environmental extremes.Aerial installation involves stringing the cable from utility poles as illustrated.Generally, these cables are all dielectric.They contain no metal.This prevents ground loops and provides relevant cable with lightning immunity.Suspension between two poles is the classic installation method.Internal strength members must be strong enough in this installation to prevent sagging that would put excess stress on the fibers.In other cases, the cable is wound or lashed to a strong parallel length of the cable.Regardless of the actual installation method,all aerial cables have strength members and structures that isolate the fibers from the stress on the cable,and the outer jacket material offers UV protection from the sun in addition to protection from moisture and temperature extremes.
Another very demanding environment for fiber optic cable is the submarine environment where the cable is completely submerged in fresh or salt water.Submarine cables used for short distances are usually no more than ruggedized, waterproof versions of direct burial cable.Long-distance cables such as the one illustrated are more complex.Damage can occur from boat anchors, trawlers, fishermen,and sharks as well as water pressure in applications where the cable is laid in very deep water.Three types of submarine cable systems impact the actual construction of the cable, shower systems longer than 1000km require the use of repeaters or Fiber Optic Amplifiers ,transoceanic cables, as the name suggests, run thousands of kilometers across oceans from continent to continent.These Hybrid Cables use copper cables to power the repeaters as well as optical fiber for the signal transmission.High data rates, exploitation of the 1550nm window,and the developing EDFA, technology provide even greater distance capability for the optical signal and further reduce the need for repeaters in submarine systems.
