Presentation on theme: "Introduction to Fiber Optics"— Presentation transcript:
1Introduction to Fiber Optics Presented by: James CarterSales Engineer – Cox Business
2Scope This presentation is designed to give a general overview of fiber optic theory, its construction,the two basic types of fibers, and the benefitsof fiber networks over traditional copper basednetworks.
3Content Terms Definition Quick history Wavelengths of light Anatomy of a fiberTypes of fiberModel of a simple fiber optic linkBenefits over copper-based networksFiber optic applicationsCATV applications
4Terms 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 acommunication 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 fiberoptics, the decibel is combined with the kilometer (dB/km) to formthe unit for measuring attenuation (signal loss) in a section of fiber.Electromagnetic Spectrum (EMS): This is a term that scientistsuse when they want to talk about the vast range of energythat radiates in every corner of the universe.
5Terms - cont.Electromagnetic Interference (EMI): A disturbance that affectselectrical circuits. It can degrade AM/FM radios, cell phones,television reception…. It can occur naturally – sun flares, orartificially. Any electronic device ever invented has the potentialto generate interference.Fiber-to-the-X (FTTX): A catch all acronym for all of the variationson the use of fiber between the service and the customer. TheseInclude 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 thenumber For example, a kilometer = 1000 meters.
6Terms – 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 usedto convert electrical signals (radio frequencies), into light signals.Master Telecommunications Center (MTC): The central location where Cox Communications, acquires and combines, all theservices that are offered to our customers. The MTC is alsoknown as a “headend”.Metropolitan Area Network (MAN): A large LAN that typically canspan up to 50km.
7Terms – 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 iscommonly 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 thatreceives the light signals from a LASER and converts the lightsignals back to electrical signals (radio frequencies).
8Terms – cont.Radio frequencies (RF): That part of the vast electromagnetic spectrumthat can be harnessed for such purposes as
9Terms – 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 encompassnetworks across a state, the country as a whole, or the world.
10DefinitionAn 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 incommunications because they permit transmissions over longerdistances and at higher bandwidths (data rates) than traditional copper-based networks.With very low attenuation ( signal loss), immunity from all electricalinterference, and high bandwidth capacity, optical fibers are almostthe perfect medium for communications.
11Quick History Though the use of fiber optics is common in modern communication networks, theguiding of light through a clearmedium is a fairly simple concept.Using a container of water, and asimple light source, Daniel Colladonand Jacques Babinet demonstratedthe guiding of light in Paris in theearly 1840s.LightsourceWaterreservoirLight carriedby waterstream
12Quick History – cont.In more modern times, scientists worked on developing a fiber so pure thatwhen a light source was introduced at one end, after a distance of onekilometer, one per cent of the light remained. In terms of attenuation (signalloss), this was equal to 20 decibels – the existing transmission distance for acopper-based telephone system.The crucial attenuation level of 20 decibel per kilometer was first achieved in1970 by Drs. Robert Maurer, Donald Beck, and Peter Schultz, of glass maker CorningIncorporated. 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. Thisenabled General Telephone & Electronics to sent the first live telephone trafficon April 22, 1977, in Long Beach, California.Today, the purity of glass enables attenuation levels of 1310nm, and1550nm. Combined with improvements in LASERs, optical receivers,and other optical components, optical networks can transmit digitized signals longdistances – in many cases without the need of optical amplifiers.
13Wavelengths of lightYou may not be aware of it, but the electromagneticspectrum is quite familiar to you: The microwaveyou heat your food with, the cell phone you keep intouch with, your favorite television show, the light fromthe sun that both warms and burns, plus the light your eyesuse to see; it is all part of the electromagnetic spectrum.
14Wavelengths of light – cont. Visible light:650nm400700Light not visible to the naked eye:wavelength1310 nm1550 nm
15Anatomy of an optical fiber Three functional components:CoreSilica glass with GermaniaPurpose – signal transmissionCladdingSilica glassPurpose – signal containmentCoatingDual-layer, UV cured acrylatePurpose – mechanical protection
16Types 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.
18Types of fibers – cont. Multimode fibers Disadvantages Advantages Optimized for distancesless than 2KmHigher attenuation thansingle-mode fiberMultimode fibersAdvantagesUses inexpensive light sourcesUses low cost connectorsthat are easy to installEasier and cheaper to installWorks well for LAN,college campus networksEasier to splice when cutCan handle high data rates
19Types of fibers – cont. Single-mode fiber Disadvantages Uses expensive LASERsas a light sourceDifficult to install connectorsHigher installation costsMore susceptible to damageduring installationMore difficult to splice whencutAdvantagesOptimized for longhaul applicationsVery low attenuationLight can reach distances50 miles without theneed of optical amplifiersCan handle high data rates
20Types of fibers – cont. Attenuation: Single-mode vs. Multimode
21Types of fibers – cont. Single bare fiber 250μmSingle bare fiber900μmSingle fiber strand with additionalwhite plastic coating
22Types of fibers – cont. Up to 432 fibers for Fiber glass support Buffer tubesRip cordIndividual fibersArmorMylar wrapPlasticUp to 432 fibers forsingle-mode cable
23Fiber optic link Model of "simple" fiber optic data link fiber InformationSourceOpticalReceiverInformationTo CustomerLASERModel of "simple" fiber optic data link
24Benefits vs. traditional networks Not susceptible to electro-magnetic or other types ofelectrical interferenceNot affected by temperatureNo amplification required up to@ 50 milesGreater information carrying capacityLightweightMore secureLess attenuation than copper-based cablesImproved quality of the signalstransmitted
25Benefits vs. traditional networks - cont. Why use fiber?Capacity of 2400 pair copper telephone cable:- 1 call per copper pairCapacity of a single fiber:- > 500,000 callsSize and weightTo transmit equivalent information 1 mileSingle fiber cable =28 lbsEquivalent capacity copper cable = 33 tons