There are several types of fibers based both on the transmission modes and the refractive index profile. We won't discuss them in detail, but it is important to know that the design of an optical fiber depends on the needs it is supposed to meet.
Key parameters like attenuation , bandwidth , dispersion , and tensile strength are the most considered. Also the protection of the fiber from external factors like humidity, heat, cold, and water is contemplated. That's why plastic sheaths where the fiber is enclosed in, are used. The whole material comprising the single fiber or bundle of fibers, the sheaths, and the jacket, is usually referred as a fiber cable. Obviously these cables also must satisfy requirements such as high flexibility, resistance to kinks and crushing, and light weight.
If you're eager to know what and how many polymers are involved in the manufacture of fiber cables, take a look at these examples: Designing Your Own Fiber Cables. In the first example on the right we have a multi-layered system in which the fiber is firstly surrounded by a buffer tube. This buffer tube is usually a layer of silicone or epoxy resin , softer than the external jacket, and has no optical function. It keeps the fiber from "microbends" due to physical contact with the other components of the cable.
As relatively fragile materials, fibers need some mechanical reinforcement. Many materials in form of strands or filaments can play this role. One of them is fiberglass, and in the example, we can see a bunch of fiberglass strands surrounding the buffer tube. Of course, since fiberglass is a stiff material, another layer of polyurethane is added, to provide cushioning. If not, click here to learn something about it. Finally, you must think that your fiber cable may be placed in a number of different environments: in the air, into the water, or under ground.
Therefore an external protective jacket becomes essential. PVC and polyurethane are the most used materials for that purpose. But be careful with the choice: PVC is a better material than polyurethane when considering its resistance to: water, flame, acids, alkalis, hydrocarbons, and alcohol.
Conversely, polyurethane has certain advantages over PVC when dealing with its resistance to: abrasion, nuclear radiation, and low temperatures. This moisture barrier can be made of plastic often polyethylene , metal particularly aluminum , or both. Lastly, a PVC coating ensures the utility of this fiber cable to be installed in free air.
Only this time an underground fiber cable is shown. Don't get confused: Fiber optics FO is a science, by which electrical energy is converted into light or optical energy ; that light is transported through optical fibers to some other place, and finally is converted again in electrical energy. Sounds amazing that the waves along our telephone line or our cable television travel in form of light, which many times falls in the visible frequency spectrum.
The enormous advantages of the optical fiber telecommunications compared to metal wire or coaxial transmission may be summarized as follows: High bandwidth, completely independent of the cable size. Low attenuation, i. This makes them especially valuable for multimode optical fibers, which can transmit hundreds of discrete light wave signals concurrently. In a fiber optic cable, many individual optical fibers are bound together around a central steel cable or high-strength plastic carrier for support.
This core is then covered with protective layers of materials such as aluminum, Kevlar, and polyethylene the cladding.
Because the core and the cladding are constructed of slightly differing materials, light To make an optical fiber, layers of silicon dioxide are first deposited on the inside surface of a hollow substrate rod. This is done using Modified Chemical Vapor Deposition, in which a gaseous stream of pure oxygen combined with various chemical vapors is applied to the rod. As the gas contacts the hot surface of the rod, a glassy soot several layers thick forms inside the rod.
After the soot is built up to the desired thickness, the substrate rod is moved through other heating steps to drive out any moisture and bubbles trapped in the soot layers. During heating, the substrate rod and internal soot layers solidify to form the boule or preform of highly pure silicon dioxide.
As a light wave traveling in the fiber core reaches the boundary between the core and cladding, these compositional differences between the two cause the light wave to bend back into the core. Thus, as a pulse of light travels through an optical fiber, it is constantly bouncing away from the cladding. A pulse moves through the optical fiber at the speed of light—, miles per second , kilometers per second in a vacuum, somewhat slower in practice—losing energy only because of impurities in the glass and because of energy absorption by irregularities in the glass structure.
Energy losses attenuation in an optical fiber are measured in terms of loss in decibels, a unit of energy per distance of fiber.
Typically, an optical fiber has losses as low as 0. With current datalink technology, laser signal repeaters are necessary about every 30 kilometers However, on-going research in optical material purity is aimed at extending the distance between repeaters of an optical fiber up to kilometers 62 miles.
There are two types of optical fibers. In a single-mode fiber, the core is smaller, typically 10 micrometers a micrometer is one-millionth of a meter in diameter, and the cladding is micrometers in diameter. A single-mode fiber is used to carry just one light wave over very long distances. Bundles of single-mode optical fibers are used in long-distance telephone lines and undersea cables.
Multimode optical fibers, which have a core diameter of 50 micrometers and a cladding diameter of micrometers, can carry hundreds of separate light wave signals over shorter distances. This type of fiber is used in urban systems where many signals must be carried to central switching stations for distribution. After the solid glass preform is prepared, it is transferred to a vertical drawing system. In this system, the preform is first heated.
As it does so, a gob of molten glass forms at its end and then falls away, allowing the single optical fiber inside to be drawn out.
The fiber then proceeds through the machine, where its diameter is checked, a protective coating is applied, and it is cured by heat. Finally, it is wound on a spool. Both the core and the cladding of an optical fiber are made of highly purified silica glass. An optical fiber is manufactured from silicon dioxide by either of two methods. CABLExpress products are future-proof, and will last for generations of hardware. CABLExpress features several product lines for fiber jumpers and trunks.
As such, depending on the selected line, the cable parts will vary. However, rest assured that we have carefully selected the best components available to ultimately provide the most reliable and accurate fiber optic cables available. CABLExpress is dedicated to delivering quality in every product we provide — and every interaction you have with us. Just call us at We will respond as quickly as possible. For our data center infrastructure products, we have plenty of support available for you.
Our architects are happy to provide free design assistance for full scale data centers, colo-space, and upgrades. Learn more about how and why to buy from us here. Talk with an Expert Get a quote Contact Us. Data Center Cabling Solutions. Matt Warshal January, 24,
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