What is a fiber optic ?

Fiber optic fibers are made of pure glass is long and thin thickness does not exceed the thickness of the hair shaft that combines many of these fiber optic cables inside the packages used in signal transmission Optical very long distances.

Optical fiber components

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Optical Fiber Optical Fiber: It consists of concentric cylinders called the first heart-Core surrounded by other drum called Cover Cladding then the protective cover Buffer Coating the outer shell of the cable (jacket)

Heart (Core): It is a thin glass (cylindrical) travels light and is made from silica Silica grafted (Germanium example, Ge-Silica).

Brow (Cladding): material surrounding the core in the glass (DISC other ambient) and working on keeping the light in the center of the optical fiber is made of silica, in order to be the refractive index of the heart Larger than the refractive index of the cover, which is the condition required to get the process of total internal reflection Total Internal Reflection, which is the basis of direct light in the optical fiber, as reflected Light completely and repeat the reflection of light spreading inside the heart of the optical fiber and up to the other end of the fiber.

Protective cover (Buffer Coating): plastic casing protects the optical fiber from moisture and protect it from damage and breakage.

Hundreds or maybe thousands of these optical fibers are lined up together in a package to be rope light cover which protects so-called external jacket.

Divisions of the optical fiber

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1 . (single mode fiber) transmitted through which light signals coordinated and uniform pattern in each fiber optical fiber package is used in telephone networks and cable TV. This type of fiber Characterized by its small radius of the heart where the glass up to about micron 9 and pass through infrared laser with a wavelength of 1.3-1.55 nm.

2 . multi -mode fibers and are moved by the many types of optical signals through the fiber-optic one which makes the best use of computer networks. This type of fiber is Half the diameter of the largest in terms of up to 62.5 micron and transmitted through the infrared 0.2

Advantages of optical fiber

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We have created a fiber-optic revolution in the world of communications for excellence on the connecting wires are normal

1. most ability to carry information because fiber optic wiring Increase normal, it can put a large number of them into a single package which increases the number of phone lines or the number of broadcast channels TV in a single rope. Enough to know that the bandwidth of the optical fiber up to 50THZ while the largest bandwidth needs of broadcast television does not exceed 6Mhz.

2.oql ones where the radius is less than the radius of the traditional copper wires for example, can replace copper wire diameter of 7.62 cm by another from the optical fiber diameter does not exceed 0.635 cm and this is particularly important when extending the wires underground.

3.Light weight could replace copper wires weighing 94.5 kg to one of the optical fiber weighs only 3.6 kg.

4.Loss less of the signals transmitted

5.No the possibility of overlapping signals transmitted through the fiber rope in the adjacent one which ensures the clarity of the transmitted signal, whether a telephone conversation or TV broadcast. It is also not exposedTo electromagnetic interference which makes the signal transmitted confidentially, which is especially important for military purposes.

6.Non-flammable which reduces the risk of fires

7.The need for to less energy in the generator because the loss through the process of conduction few Because of these advantages, the fiber-optic entered in a lot of industries, especially telecommunications and computer networks. Also used in medical imaging, as well as different kinds of high-quality Sensors The change in temperature and pressure with its applications in exploration in the ground.

There are types of modern fiber optic discovered recently called photon crystal fiber, because it is made from photon crystals, which are characterized by the transfer of the less light loss ..

1. Data transfer at very high speeds, where up to more than 100 / mega bytes / second

Mechanism of Action

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Usually made of fiber-optic materials with large refractive index and be high so that he can not light that falls on the walls angle less than the critical angle, the light rays and fall The fall of the angle is greater than the critical angle total internal reflection Reflected in the tube even carried out from the other party.

Uses optical fiber

1. In the medical field, a surgical procedure minute and you can see the internal parts of the body such as (gastroscopy)

2. In the field of telecommunications. A broader area, which includes dozens of applications such as communications applications, televisions and others.

3. In the field of genetic engineering, where they can dismantle the genetic code and prevent genetic diseases such as diabetes, Down syndrome and anemia ....

4. in the military field, where it is difficult to spy them and drag signal ....

The use of fiber-optic communications

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The unit is made of optical-fiber communications:

• transmitter (Transmitter): sends optical signals encoded.

• optical fiber (Optical Fibers): These fibers to connect and transfer information light signals over long distances.

• renewed or enhanced optical signals (Optical Regenerator): This is necessary to enhance and strengthen the signals so as not to weaken and fade during its long journey across the optical cables.

• The receiver (Receiver): receives optical signals and solve encrypted.

Transmitter (Transmitter)

The managed devices to give a series of light gleams successive blades that generate or optical signals sent.

Enhanced optical signals (Optical Regenerator):

As mentioned earlier that there are some of the light signals that lose or weaken, especially when traveling long distances like that happens in the cables running beneath the surface of the sea, which are used for the purposes of Communications between ships and submarines, and thus address these optical cables Enhanced to these signals stretching along the cable and working to strengthen the optical signal boosters of this .Consists Optical fibers coated with a special material, and when it falls on weak optical signals particles of matter, they disturbed to give a strong light signals have the same characteristics of optical signals Fallen, any cover that does the work of the laser (magnification incident light), and so continue the process of light transmission over long distances without losing.

Future (Receiver):

These receptors are used in photovoltaic cells (Photocell) or light emitting diodes (Photodiode) that recognize and reveal the optical signals transmitted and decoded to replace electrical signals runs Different devices such as television, computer, telephone ... and others. The advantages and benefits of fiber optic

Brought about a revolution in fiber optic telecommunications world, what is the reason for this revolution? Why preferably used for traditional metal wire?

Characterized by optical fiber for metal wire has the following characteristics:

• Inexpensive:

Can make miles of optic cables at a lower cost compared to those made of metal cables as wires of copper.

high-fish:

Characterized by optical fiber as a high and accurate compared with Metal wire . that this high-fiber, it can be compiled many of them in bundles to stretch cables in small diameters and this can not be done with Copper wire.

• High efficiency:

There are only a few of the light signals that lose or weaken compared to metal wires.

• use light signals to transmit information:

Information is transmitted optical signals over fiber optic unlike copper wire that use electrical signals and optical signals of these passers-by in a fiber does not interfere with Signals with other fibers found in the same package within the cable, and that means there is no overlapping lines during telephone conversations where the sound is clear and pure.

• convey digital signals:

The optical fiber is ideal and convenient way to transfer digital signals and are used in computer networks.

• safe against fire:

Do not use any fiber optic electrical signals, and therefore is considered a safe way to transfer information and optical signals over long distances without fear of damage caused by the fires shipments Electrical.

• Lightweight:

The fiber optic light weight compared to copper wires, as it occupies a small space when the supply of underground Comparison space occupied by large metal wire cables.

• High flexibility:

What distinguishes it is flexible optical fiber and is therefore used in digital cameras for the following purposes:

- To capture medical images through the use of different perspectives (endoscope, laparoscope and bronchoscope).

- To examine the process of welding the pipes and aircraft engines, cars and The rocket and other.

Therefore, prefer to use fiber optic communications in industrial, wires and lines of computers.