Fiber optic cables are relatively thin, they are used as the current fastest medium for data transer and less likely to have interruptions due to extra cables around it (noise). Since it uses flashes of light to transmit the data, there is no need to worry about static noise on the line, however crimps/bends in the cable provide the most drawback for transmittal of data. This is also a costly way of wiring, as such it is seldom used in private residences.

1) "Optical fiber cables are widely used in the telecommunications field to transmit information. In general, an optical fiber cable can be classified into a single-core optical fiber cable and a multi-core optical fiber cable depending on the number of housed optical fibers. The multi-core optical fiber can also be classified into optical fiber ribbons and loose tube optical fiber cables. The former relying on optical fiber ribbons or multi-ribbons achieve optimum packing density in high fiber count cables by coating a plurality of optical fibers side-by-side, parallel to one another and substantially in the same plane. As the plurality of optical fibers is housed in this type of arrangement, optical-fiber ribbon cables achieve high packing density. Thus, the ribbon optical fiber cable is widely used as an optical transfer medium in an optical telecommunication system. Referring to FIG. 1, the ribbon optical fiber cables 100 according to an embodiment of the conventional art comprise a plurality of optical fibers 110 and ribbon coating layers 120 surrounding the external peripheries of these optical fibers. The conventional ribbon optical fiber cables 100 have a thickness between 0.28 mm and 0.40 mm, and a width of 1.1 mm when the optical fibers with four cores are provided, 2.1 mm when the optical fibers with eight cores are provided, and 3.1 mm when the optical fibers with twelve cores are provided. Furthermore, the conventional ribbon optical fiber cables 100 have a coating thickness of about 30-50 µm on both side surfaces thereof." Source and further information: http://www.patentstorm.us/patents/6519398-description.html 2) "An optical fiber cable is a cable containing one or more optical fibers. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed." "Modern cables come in a wide variety of sheathings and armor, designed for applications such as direct burial in trenches, dual use as power lines , installation in conduit, lashing to aerial telephone poles, submarine installation, or insertion in paved streets. In recent years the cost of small fiber-count pole-mounted cables has greatly decreased due to the high Japanese and South Korean demand for fiber to the home (FTTH) installations." Source and further information: http://en.wikipedia.org/wiki/Optical_fiber_cable 3) "An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length. Fiber optics is the overlap of applied science and engineering concerned with the design and application of optical fibers. Optical fibers are widely used in fiber-optic communication, which permits transmission over longer distances and at higher data rates than other forms of communications. Fibers are used instead of metal wires because signals travel along them with less loss, and they are immune to electromagnetic interference. Optical fibers are also used to form sensors, and in a variety of other applications. Light is kept in the "core" of the optical fiber by total internal reflection. This causes the fiber to act as a waveguide. Fibers which support many propagation paths or transverse modes are called multimode fibers (MMF). Fibers which support only a single mode are called singlemode fibers (SMF). Multimode fibers generally have a large-diameter core, and are used for short-distance communication links or for applications where high power must be transmitted. Singlemode fibers are used for most communication links longer than 200 meters. Joining lengths of optical fiber is more complex than joining electrical wire or cable. The ends of the fibers must be carefully cleaved, and then spliced together either mechanically or by fusing them together with an electric arc. Special connectors are used to make removable connections." Source and further information: http://en.wikipedia.org/wiki/Optical_fiber Further information: http://en.wikipedia.org/wiki/Optical_fiber_composite_overhead_ground_wire

They are mainly used for telephone conne connections. They aren't unually thick, but they won't snap if you trip on them. The thickness does vary though.

they transfer data. can be pretty thick . . .

A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves. Fiber optics has several advantages over traditional metal communications lines: Fiber optic cables have a much greater bandwidth than metal cables. This means that they can carry more data. Fiber optic cables are less susceptible than metal cables to interference. Fiber optic cables are much thinner and lighter than metal wires. Data can be transmitted digitally (the natural form for computer data) rather than analogically. The main disadvantage of fiber optics is that the cables are expensive to install. In addition, they are more fragile than wire and are difficult to splice. Fiber optics is a particularly popular technology for local-area networks. In addition, telephone companies are steadily replacing traditional telephone lines with fiber optic cables. In the future, almost all communications will employ fiber optics.

There are a number of types of fiber optic cables. And different types of Optical fibers. For short distance (tens of meters) such as stereo components, relative thick plastic fibers of about 400 micron diameter are used. Long distance, hundreds of miles, telecommunications, the glass fibers are about 125 microns diameter (roughly the thickness of a human hair), but the light carrying "core" (a region of special chemical composition in the center) is about 10 microns diameter. Fiber cables are of varying thicknesses depending on the number of fibers contained and the thickness of the protection elements around the glass or plastic fibers. Plastic waterproofing, fiberglass or kevlar strength elements, and UV protective sheaths. A single fiber cable might be 1 to 3 mm in diameter. A high count 864 fiber cable, might be almost 3 inches in diameter.

When we talked about telecommunications, fiber optics is one of the best telecommunications equipment used in internet due its fast transmission of digital information. Fiber optics also used in telephones. Its cable is somehow made out of thin glass just like a human hair strand.