Fiber-Optic Technology

In recent years fiber optics has become apparent to be steadily replacing copper wire as an appropriate means of communication signal transmission. Fiber optic systems are currently used most extensively as the transmission link between terrestrial hardwired systems. They span the long distances between local phone systems as well as other system users which include cable television services, university campuses, office buildings, industrial plants, and electric utility companies.

Afiber-optic system can generally be seen as a system with three main components: a transmitter, a transmission medium and a receiver. As a model it is similar to the copper wire system to be replaced by fiber optics. The difference is that fiber optics uses light pulses to transmit information down fiber lines instead of using electronic pulses to transmit information down copper lines. Looking at the three main components in the fiber optic chain will give a better understanding of how the system works in conjunction with wire based systems.

At the head end of the chain is the transmitter. This is the place of origin for information coming on to fiber optic lines. The transmitter accepts coded electronic pulse information coming from copper wire. It then processes and translates that information into equivalently coded light pulses. A light-emitting diode (LED) or an injection-laser diode (ILD) can be used for generating the light pulses. Using a lens, the light pulses are tunneled into the fiber-optic medium where they transmit themselves down the line.

Light pulses move easily down the fiber-optic line because of a principle known as total internal reflection. This principle of total internal reflection states that when the angle of incidence exceeds a critical value, light cannot get out of the glass; instead, the light bounces back in. When this principle is applied to the construction of the fiber-optic strand, it is possible to transmit information down fiber lines in the form of light pulses.

There are generally five elements to make up the construction of a fiber-optic strand, or cable: the optic core, optic cladding, a buffer material, a strength material and the outer jacket. The optic core is the light carrying element at the center of the optical fiber. It is commonly made from a combination of silica and germanium. Surrounding the core is the optic cladding made of pure silica. It is this combination that makes the principle of total internal reflection possible. The difference in materials used in the making of the core and the cladding creates an extremely reflective surface at the point in which they interface. Light pulses entering the fiber core reflect in the core cladding interface and thus remain within the core as they move down the line.

Surrounding the cladding is a buffer material used to help shield the core and cladding from damage. A strength material surrounds the buffer, preventing stretch problems when the fiber cable is being pulled. The outer jacket is added to protect against abrasion, solvents, and other contaminants.

Once the light pulses reach their destination they are channeled into the optical receiver. The basic purpose of an optical receiver is to detect the received light incident on it and to convert it to an electrical signal containing the information impressed on the light at the transmitting end. To put it in other words the coded light pulse information is translated back into its original state as coded electronic information. The electronic information is then ready for input into electronic based communication devices such as a computer, telephone or TV.

Exercise 10. Give the English equivalents for the following words and word combinations.

Наземні електричні системи; електрична побутова компанія; середовище із здатністю передавати; приймач; світлодіод; інжекційний лазерний діод; кут падіння; критичне значення; серцевина оптичного волокна; оптичне покриття; буферний матеріал; покриття із високим відбиттям; зовнішнє покриття.

Exercise 11. Give synonyms from the text for the following words and word combinations.

On a large scale; a set of equipment used to generate electromagnetic waves carrying messages or signals; to pass data from one place to another; to force a passage through something; to return after meeting an obstacle; joining different parts or qualities; a certain area that has a property to reflect radiation, light etc.; to protect from danger, risk; not useful admixtures; contribution of information.

Exercise 12. Decide if the following statements are true, false or not stated. Prove you point of view.

1. Fiber optic systems are more effectively used in terrestrial systems than in any other medium.

2. Fiber systems are composed of two components – transmitter and receiver.

3. Copper wire systems use electronic impulses to transmit information.

4. Transmitter is always the beginning of any data-passing system.

5. A light emitting diode tunnels light pulses into the fiber optic medium.

6. Total internal reflection does not allow transmitting any information.

7. Germanium is more expensive than silica in producing optic cladding.

8. Optic core and optic cladding are made of completely different materials which makes data-passing easier.

9. Buffering material defends the internal part of fiber-optic cable from danger.

10. The coded information is translated in a reverse order which hinders its understanding.

Exercise 13. Do the following puzzle. Use the information from the text.

						1		2		3
														4
5				6								7
			8													9
10								11						12				13
					14
								15											16
			17
												18				19
										20
21		22								23
		24

Across:

2. Thick strong metal rope; a set of wires.

5. Injection-laser diode.

6. The act or process of sending out an electronic signal or message.

10. A material such as a rope that is made from a mass of natural or artificial threads.

11. Light-emitting diode.

12. A factory or place where power is produced.

17. A covering of a hard material, used as protection.

18. Article.

19. To last all through a period of time or to cover the whole of it.

21. The act of putting information.

23. The way in which light meets surface.

24. A system of talking to somebody else over long distance.

Down:

1. A series of connected things.

3. A structure such as a house.

4. Element.

5. Data.

7. A substance, especially a liquid, that can dissolve another substance.

8. An object or a piece of equipment that has been designed to do a particular job.

9. University area.

13. Television.

14. Condition of something or somebody.

15. Metal in the form of thin thread.

16. To dig through.

20. A long thin mark on the surface.

22. To move something on a particular place.

Exercise 14. Translate the following sentences into English.

1. Виявилось, що оптичне волокно швидше передає інформацію, ніж при використанні мідної проволоки і електричних імпульсів. 2. Було закладено особливий кабель, який складається з чотирьох електричних проводів, кожний з яких представляє собою, в свою чергу, жилу з семи мідних проводів. 3. Відомо, що буферний матеріал захищає серцевину оптичного волокна. 4. Розробники вкрили кабель зовнішньою оболонкою (покриттям), щоб запобігти його ушкодження від стирання, розчинників та інше. 5. Територія Харківського національного університету розподілена по всьому місту. 6. Для того щоб успішно провести дослідження, Ви повинні обрати відповідний метод. 7. За статистикою, наземні засоби пересування не такі безпечні, як повітряні. 8. Теорія вірогідності розповсюджується на всі області знання. 9. Ядро заліза складається переважно із залізо-нікелевого сплаву, при цьому його маса дорівнює 1,932·10²⁴ кг. 10. Під час броунівського руху атоми газів зіштовхуються і відскакують один від одного.

Study the following grammar rule