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Introduction to Fiber Optics

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1 Introduction to Fiber Optics
Presented by: James Carter Sales Engineer – Cox Business

2 Scope This presentation is designed to give a general
overview of fiber optic theory, its construction, the two basic types of fibers, and the benefits of fiber networks over traditional copper based networks.

3 Content Terms Definition Quick history Wavelengths of light
Anatomy of a fiber Types of fiber Model of a simple fiber optic link Benefits over copper-based networks Fiber optic applications CATV applications

4 Terms Attenuation: Attenuation is a general term that refers to
any reduction in the strength of a signal. Bandwidth: The amount of data that can be passed along a communication medium in a given period of time. Decibel (dB): A unit used to express the difference in intensity, usually between two acoustic, light, or electrical signals. In fiber optics, the decibel is combined with the kilometer (dB/km) to form the unit for measuring attenuation (signal loss) in a section of fiber. Electromagnetic Spectrum (EMS): This is a term that scientists use when they want to talk about the vast range of energy that radiates in every corner of the universe.

5 Terms - cont. Electromagnetic Interference (EMI): A disturbance that affects electrical circuits. It can degrade AM/FM radios, cell phones, television reception…. It can occur naturally – sun flares, or artificially. Any electronic device ever invented has the potential to generate interference. Fiber-to-the-X (FTTX): A catch all acronym for all of the variations on the use of fiber between the service and the customer. These Include fiber-to-the-node (FTTN), fiber-to-the-curb (FTTC), fiber-to- the-home (FTTH), and fiber-to-the-premise (FTTP). Kilo (k): A prefix in the International System of Units denoting the number For example, a kilometer = 1000 meters.

6 Terms – cont. Local Area Network (LAN): A local area network is a computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport. LASER: A laser is a device that emits light through a process called stimulated emission. In communication networks, a LASER is used to convert electrical signals (radio frequencies), into light signals. Master Telecommunications Center (MTC): The central location where Cox Communications, acquires and combines, all the services that are offered to our customers. The MTC is also known as a “headend”. Metropolitan Area Network (MAN): A large LAN that typically can span up to 50km.

7 Terms – cont. Micron (μ): A unit of length equal to one millionth of a meter. Nano (n): A unit of length equal to one billionth of a meter. It is commonly used in fiber optics to differentiate between the various wavelengths of light. For example, the color blue has a wavelength of 475 nanometers. Optical receiver: In communication networks, it is the device that receives the light signals from a LASER and converts the light signals back to electrical signals (radio frequencies).

8 Terms – cont. Radio frequencies (RF): That part of the vast electromagnetic spectrum that can be harnessed for such purposes as

9 Terms – cont Secondary Telecommunications Center (STC): The STC is a
smaller version of the MTC. The STC is also referred to as a “hub”. Wide Area Network (WAN): Whereas a LAN (local area network) is a network that links computers, printers and other devices located in an office, a building or even a campus , a WAN (wide area network) is a system that extends for greater distances and is used to connect LANs (local area networks) together. A WAN can encompass networks across a state, the country as a whole, or the world.

10 Definition An optical fiber is a glass or plastic strand that can carry information - in the form of light, along its length. Optical fibers are widely used in communications because they permit transmissions over longer distances and at higher bandwidths (data rates) than traditional copper- based networks. With very low attenuation ( signal loss), immunity from all electrical interference, and high bandwidth capacity, optical fibers are almost the perfect medium for communications.

11 Quick History Though the use of fiber optics is common in modern
communication networks, the guiding of light through a clear medium is a fairly simple concept. Using a container of water, and a simple light source, Daniel Colladon and Jacques Babinet demonstrated the guiding of light in Paris in the early 1840s. Light source Water reservoir Light carried by water stream

12 Quick History – cont. In more modern times, scientists worked on developing a fiber so pure that when a light source was introduced at one end, after a distance of one kilometer, one per cent of the light remained. In terms of attenuation (signal loss), this was equal to 20 decibels – the existing transmission distance for a copper-based telephone system. The crucial attenuation level of 20 decibel per kilometer was first achieved in 1970 by Drs. Robert Maurer, Donald Beck, and Peter Schultz, of glass maker Corning Incorporated. They demonstrated a fiber with an attenuation of 17dB/km. A few years later they produced a fiber with an attenuation of only 4dB/km. This enabled General Telephone & Electronics to sent the first live telephone traffic on April 22, 1977, in Long Beach, California. Today, the purity of glass enables attenuation levels of 1310nm, and 1550nm. Combined with improvements in LASERs, optical receivers, and other optical components, optical networks can transmit digitized signals long distances – in many cases without the need of optical amplifiers.

13 Wavelengths of light You may not be aware of it, but the electromagnetic spectrum is quite familiar to you: The microwave you heat your food with, the cell phone you keep in touch with, your favorite television show, the light from the sun that both warms and burns, plus the light your eyes use to see; it is all part of the electromagnetic spectrum.

14 Wavelengths of light – cont.
Visible light: 650nm 400 700 Light not visible to the naked eye: wavelength 1310 nm 1550 nm

15 Anatomy of an optical fiber
Three functional components: Core Silica glass with Germania Purpose – signal transmission Cladding Silica glass Purpose – signal containment Coating Dual-layer, UV cured acrylate Purpose – mechanical protection

16 Types of fibers Putting the micron (μ) in perspective
A human red blood cell is 10 microns across. A human hair ranges from 40 – 120 microns wide. The period at the end of this sentence is about 397 microns. The eye of a typical needle is 749 microns wide. A postage stamp 25,400 microns long.

17 Types of fibers – cont. 50 & 62.5 microns Cladding 125 microns Plastic
Coating 250 microns Multimode 8 – 10 microns 125μm μm Single-mode

18 Types of fibers – cont. Multimode fibers Disadvantages Advantages
Optimized for distances less than 2Km Higher attenuation than single-mode fiber Multimode fibers Advantages Uses inexpensive light sources Uses low cost connectors that are easy to install Easier and cheaper to install Works well for LAN, college campus networks Easier to splice when cut Can handle high data rates

19 Types of fibers – cont. Single-mode fiber Disadvantages
Uses expensive LASERs as a light source Difficult to install connectors Higher installation costs More susceptible to damage during installation More difficult to splice when cut Advantages Optimized for long haul applications Very low attenuation Light can reach distances 50 miles without the need of optical amplifiers Can handle high data rates

20 Types of fibers – cont. Attenuation: Single-mode vs. Multimode

21 Types of fibers – cont. Single bare fiber
250μm Single bare fiber 900μm Single fiber strand with additional white plastic coating

22 Types of fibers – cont. Up to 432 fibers for Fiber glass support
Buffer tubes Rip cord Individual fibers Armor Mylar wrap Plastic Up to 432 fibers for single-mode cable

23 Fiber optic link Model of "simple" fiber optic data link fiber
Information Source Optical Receiver Information To Customer LASER Model of "simple" fiber optic data link

24 Benefits vs. traditional networks
Not susceptible to electro- magnetic or other types of electrical interference Not affected by temperature No amplification required up to @ 50 miles Greater information carrying capacity Lightweight More secure Less attenuation than copper- based cables Improved quality of the signals transmitted

25 Benefits vs. traditional networks - cont.
Why use fiber? Capacity of 2400 pair copper telephone cable: - 1 call per copper pair Capacity of a single fiber: - > 500,000 calls Size and weight To transmit equivalent information 1 mile Single fiber cable =28 lbs Equivalent capacity copper cable = 33 tons

26 Fiber optic applications
LAN B A Access Metro Long Haul -WAN -Cross-country/Intercontinent -Submarine >200 km MAN/city rings km Fiber-to-the-X (curb, building, home) 0-10 km LAN 0-2 km

27 Cable applications Cable Networks MTC Tree-and-Branch Microwave
Service Area                                                                         Long cascade of amplifiers Service Area Microwave HUB Hybrid-Fiber-Coaxial Service Area

28 Cable applications – cont.
Ring-in-ring HFC Network Fiber Access Network Fiber Transport Network Distribution Amplifier Line Extender Amplifier Coaxial Access Network MTC Hub/STC                                                                        


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