138851107 Fiber Optics Lecture123

8/12/2019 138851107 Fiber Optics Lecture123

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Fiber Optics

Getting Started in Fibre Optics - You need tools, test equipment and -most of all - training!

This guide will help you get started by providing very basic information(we will also point you to more advanced studies) and demonstratingthat you don't need to brea the ban to brea into the field

What is "Fibre Optics"? And a short history"t's the communications technology that wors by sending signals downhair thin strands of glass #ibre (and sometimes plastic #ibre) "t beganabout $% years ago in the & labs (orning, *ell +abs, "TT , etc)and was first installed in hicago, "+, ./ in 0123 *y the early 014%s,#ibre networs connected the ma5or cities on each coast

*y the mid-4%s, #ibre was replacing all the telco copper, microwave andsatellite lins "n the 1%s, /T6 discovered #ibre and used it first toenhance the reliability of their networs, a big problem /long the way,the discovered they could offer phone and "nternet service on that same#ibre and greatly enlarged their maretsomputers and +/7s started using #ibre about the same time as thetelcos "ndustrial lins were among the first as the noise immunity of#ibre and its distance capability mae it ideal for the factory floor8ainframe storage networs came ne9t, the predecessors of today's#ibre ./7s (storage area networs):ther applications developed too; aircraft, ship and automobile databusses, T6 for security, even lins for consumer digital stereo! Today #ibre optics is either the dominant medium or a logical choice forevery communication system

Which Fibre Optics?


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Outside Plant (OSP)Telephone companies, /T6 and the "nternet all use lots of #ibreoptics, most of which is outside buildings "t hangs from poles, is buriedunderground, pulled through conduit or is even submerged underwater8ost of it goes relatively long distances, from a few thousand feet tohundreds of miles:utside plant installations are all singlemode#ibre (we'll define the #ibre types in the ne9tchapter), and cables often have very high#ibre counts, up to A44 fibres able designsare optimised for resisting moisture and rodentdamage "nstallation requires special pullers orploughs, and even trailers to carry giant spools of cable+ong distances mean cables are spliced together, since cables are notlonger than about B m (AC miles), and most splices are by fusionsplicing onnectors (., .T or # styles) on factory made pigtails arespliced onto the end of the cable /fter installation, every #ibre andevery splice is tested with an :T&"f this sounds lie big bucs, you are right! The installer usually has atemperature controlled van or trailer for splicing andDor a bucet truc"nvestments in fusion splicers and :T&s can add up to over E0%%,%%%aloneontractors doing outside plant wor are few and far between 8ostoutside plant telephone installs are done by the telco themselves, while

a small number of large, specialised installers do /T6 wor

Premises Cabling*y contrast, premises cabling- cabling installed in a building or campus -involves short lengths, rarely longer than a few hundred feet, with A toB4 fibres per cable typically The #ibre is mostly multimode, e9cept forthe enlightened user who installs hybrid cable with both multimode andsinglemode fibres.plicing is practically unnown in premisesapplications ables between buildings can be

bought with double 5acets, FG for outsideplant protection over F6 for buildingapplications requiring flame retardant cable

5acets, so cables can be run continuouslybetween buildings Today's connectors often have lower loss thansplices, and patch panels give more fle9ibility for moves, adds andchanges


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8ost connectors are .T style with a few .s here and thereTermination is by installing connectors directly on the ends of the fibres,primarily using adhesive technology or occasionally some other varietyof termination method Testing is done by a source and meter, but everyinstaller should have a flashlight type tracer to chec #ibre continuityand connectionnlie the outside plant technician, the premises cabler (who is oftenalso installing the power cable and at C for +/7s too!) probably has aninvestment of less than EA,%%% in tools and test equipmentThere are thousands of cabling installers who do #ibre optic worThey've found out it isn't =rocet science,= and their small initialinvestment in training, tools and test equipment is rapidly paid bac

he !nstallers#ew installers do both outside plant and premises cabling Thecompanies that do are usually very large and often have separatedivisions doing each with different personnel 8ost contractors donothing but premises cabling

Fibre s Copper .@YH you may be surprised by who wins thiscontest!

"f you are already terminating copper wire then you are well along inlearning to install #ibre

Twenty years ago, #ibre was 5ust being introduced and required Fh'sfrom *ell +abs to install it while copper wire was easy to install Today itis often the opposite *ecause #ibre is so powerful, at today's networspeeds #ibre is hardly woring hard at all and can loo to the future often gigabit speeds with confidence opper on the other hand, canhandle gigabit Gthernet but only if it is carefully installed and tested withvery e9pensive test equipment and components Gven the e9perts haveto be very careful because it has little =headroom=

/lso, if you are currently woring with copper, you also have to nowthat +/7 copper cable is delicate "t only has a AC pound pulling tensionlimit and ins will ruin the high speed performance


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:, you might say, " can buy everything you've said so far, but isn't#ibre more e9pensive>Telcos and /T6 operators use #ibre because it's much cheaper Theyoptimise their networ to tae advantage of fibre's speed and distanceadvantages "n +/7s, you need to follow the new G"/DT"/ C34 *$standard to optimise the #ibre usage, and then it can be cheaper thancopper @ow about test equipment> Iuess again .@YH #ibre optic testequipment costs lots less than at CeD3 testers .ee 7etworswherewe will show you how the setup for a #ibre networ has some surprisingsavings

he Secret o Success !n Fibre Optics !s raining#You wouldn't try to drive a truc or fly a plane without taing lessons+iewise for improving your golf or tennis game


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you need to now to install a standard premises cabling networ aregood guidelines for designs, but 5ust guidelines - they are notmandatory .tandards for #ibre optic components and testing havebeen set by several groups, but most in the . follow the G"/DT"/developed #:TF's (#ibre optic test procedures) for testing .ome of theG"/ procedures are also called :#.TF (optical #ibre system testprocedures) lie :#.TF-0B for the installed cable plant.tandards for optical power measurements are set by 7".T (the .7ational "nstitute of .tandards and Technology)The only common mandatory standard is the 7G 22% (7ationalGlectrical ode) The 7G specifies fire prevention standards for #ibreoptic cables "f a cable doesn't have a 7G rating - don't install it - itwon't pass inspection!

/ complete listing of the G"/DT"/ standards is on the website of The#ibre :ptic /ssociation "nformation on the G"/DT"/ standards can befound on the website of most of he suppliers of structured cablinghardware

$e%ore &e get started ' Sa%ety First#

You might thin that eye damage from woring with lasers would be thebig concern in #ibre optic installations The reality is that high power

lasers burning holes in metal or burning off warts mostly have littlerelevance to your typical #ibre optic installation :ptical sources used in#ibre optics are of much lower power levels (The e9ception is highpower


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/lways follow these rules when woring with #ibre0 ispose of all scraps properlyA /lways use a properly mared container to dispose of later and woron a blac pad which maes the slivers of glass easier to spot$ o not drop them on the floor where they will stic in carpets or shoesand be carried elsewhereB o not eat or drin anywhere near the wor area

#ibre optic splicing and termination use various chemical adhesives andcleaners as part of the processes #ollow the instructions for usecarefully &emember, even simple isopropyl alcohol, used as a cleaner,is flammable

ero olerance %or irt


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Fibre Speci%ications

The usual fibre specifications you will see aresiJe, attenuation and bandwidth


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the various modes .tep inde9 #ibre is rare - only F:# uses a stepinde9 design today

Graded inde, multimodefibre uses variations in the composition ofthe glass in the core to compensate for the different path lengths of the

modes "t offers hundreds of times more bandwidth than step inde9 fibre- up to about A gigahertJ over 0 m

Singlemodefibre shrins the core down so small that the light can onlytravel in one ray This increases the bandwidth to almost infinity - but it'spractically limited to about 0%%,%%% gigahertJ - that's still a lot! #ind outmore about abled #ibre .pecifications

Si-e *atters#ibre, as we said, comes in two types, singlemode and multimodeG9cept for fibres used in specialty applications, singlemode fibre can beconsidered as one siJe and type "f you deal with long haul telecom orsubmarine cables, you may have to wor with specialty singlemodefibres

8ultimode fibres originally came in several siJes, optimised for variousnetwors and sources, but the data industry standardised on 3AC corefibre in the mid-4%s (3ACD0AC fibre has a 3AC micron core and a 0AC

micron cladding) &ecently, as gigabit and 0% gigabit networs havebecome widely used, an old fibre has been revived The C%D0AC fibrewas used from the late 2%s with lasers for telecom applications beforesinglemode fibre became available "t offers higher bandwidth with thelaser sources used in the gigabit +/7s and can go longer distances


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C%D0AC mOM2 $D0 d*Dm C%%DC%% 8@J-m +aser-rated forIbG +/7s

C%D0AC m OM3 $D0 d*Dm0C%%DC%% 8@J-m

optimised for 4C%nm 6.G+s

3ACD0AC mOM1

$D0 d*Dm 03%DC%% 8@J-m 8ost common+/7 #ibre

0%%D0B% microns $D0 d*Dm 0C%D$%% 8@J-mG9pensive D littleuse

.inglemode

K0$0%D0CC%nm

4-1D0AC microns %BD%AC d*Dm@"I@!L0%% TerahertJ

TelcoD/T6Dlonghigh speed +/7s

8ultimode .tep-"nde9

K4C% nm K4C% nm

A%%DAB% microns B-3 d*Dm C% 8@J-m .low +/7s lins

F:# (plastic optical #ibre)

K 3C% nm K 3C% nm

0 mm L 0 d*Dm LC 8@J-m .hort +ins ars

/T":7; You cannot mi9 and match fibres! Trying to connect

multimode to singlemode fibre can cause A% d* loss - that's 11M of thepower Gven connections between 3ACD0AC and C%D0AC can cause lossof $ d* or more - over half the power

#ibre optic =cable= refers to the complete assembly of fibres, strengthmembers and 5acet #ibre optic cables come in lots of different types,depending on the number of fibres and how and where it will beinstalled hoose cable carefully as the choice will affect how easy it isto install, splice or terminate and, most important, what it will cost!


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Choosing a cable - what haJards will it face>

able's 5ob is to protect the fibres from the haJards encountered in aninstallation "nside buildings, cables don't have to be sostrong to protect the fibres, but they have to meet all fire codeprovisions :utside the building, it depends on whether the cable isburied directly, pulled in conduit, strung aerially or whatever

.ince the plan will call for a certain number of fibres, consider addingspare fibres to the cable - fibres are cheap! That way, you won't be introuble if you brea a fibre or two when splicing, breaing-out orterminating fibres /nd request the end user consider their futuree9pansion needs 8ost users install lots more fibres than needed,

especially adding singlemode fibre to multimode fibre cables for campusor bacbone applications

Cable ypes

ables (+N&); Oipcord, istribution, +oose Tube, *reaout

Simple, and -ip cord; .imple9 cables are one fibre, tight-buffered

(coated with a 1%% micron buffer over the primary buffer coating) withevlar (aramid yarn) strength members and 5aceted for indoor useThe 5acet is usually $mm (0D4 in) diameter Oipcord is simply two ofthese 5oined with a thin web "t's used mostly for patch cord andbacplane applications, but Jipcord can also be used for destopconnections lic her for more details
http://www.techoptics.com/pages/p19cable.htmlhttp://www.techoptics.com/pages/p19cable.html


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istribution cables; They contain several tight-buffered fibres bundledunder the same 5acet with evlar strength members and sometimesfibreglass rod reinforcement to stiffen the cable and prevent iningThese cables are small in siJe, and used for short, dry conduit runs,riser and plenum applications The fibres are double buffered and canbe directly terminated, but because their fibres are not individuallyreinforced, these cables need to be broen out with a =breaout bo9= orterminated inside a patch panel or 5unction bo9 lic here for moredetails

$rea.out cables; They are made of several simple9 cables bundledtogether This is a strong, rugged design, but is larger and moree9pensive than the distribution cables "t is suitable for conduit runs,riser and plenum applications *ecause each fibre is individuallyreinforced, this design allows for quic termination to connectors anddoes not require patch panels or bo9es *reaout cable can be moreeconomic where #ibre count isn't too large and distances too long,because is requires so much less labour to terminate lic here formore details

/oose tube cables; These cables are composed of several fibrestogether inside a small polymeric buffer tube or tubes, which are in turnwound around a central strength member and 5aceted, providing asmall, high fibre count cable This type of cable is ideal for outside planttruning applications, as it can be made with the loose tubes filled withgel or water absorbent powder to prevent harm to the fibres from water"t can be used in conduits, strung overhead or buried directly into theground .ince the fibres have only a thin buffer coating, they must becarefully handled and protected to prevent damage lic here for moredetails

0ibbon Cable; This cable offers the highest pacing density, since allthe fibres are laid out in rows, typically of 0A fibres, and laid on top ofeach other This way 0BB fibres only has a cross section of about 0DB

inch or 3 mm! .ome cable designs use a =slotted core= with up to 3 ofthese 0BB fibre ribbon assemblies for 43B fibres in one cable! .ince it'soutside plant cable, it's gel-filled for water blocing

Armoured Cable; able installed by direct burial in areas whererodents are a problem usually have metal armouring between two

5acets to prevent rodent penetration This means the cable isconductive, so it must be grounded properly lic here for more details
http://www.techoptics.com/pages/p20cable.htmlhttp://www.techoptics.com/pages/p21cable.htmlhttp://www.techoptics.com/pages/p23cable.htmlhttp://www.techoptics.com/pages/p28cable.htmlhttp://www.techoptics.com/pages/p20cable.htmlhttp://www.techoptics.com/pages/p21cable.htmlhttp://www.techoptics.com/pages/p23cable.htmlhttp://www.techoptics.com/pages/p28cable.html


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Aerial cable; /erial cables are for outside installation on poles Theycan be lashed to a messenger or another cable (common in /T6) orhave metal or aramid strength members to mae them self supporting

Gven 8ore Types /re /vailable; Gvery manufacturer has it's own

favourites, so it's a good idea to get literature from as many cablemaers as possible /nd chec out the little guysH often they can saveyou a bundle by maing special cable 5ust for you, even in relative smallquantities

Cable esign Criteria

Pulling Strength; .ome cable is simply laid into cable trays or ditches,so pull strength is not too important *ut other cable may be pulledthorough A m or more of conduit Gven with lots of cable lubricant,

pulling tension can be high 8ost cables get their strength from anaramid #ibre (evlar is the duFont trade name), a unique polymer #ibrethat is very strong but does not stretch - so pulling on it will not stressthe other components in the cable The simplest simple9 cable has apull strength of 0%%-A%% pounds, while outside plant cable may have aspecification of over 4%% pounds

Water Protection; :utdoors, every cable must be protected from wateror moisture "t starts with a moisture resistant 5acet, usually FG(polyethylene), and a filling of water-blocing material The usual way is

to flood the cable with a water-blocing gel "t's effective but messy -requiring a gel remover (use the commercial stuff - it's best- -but bottledlemon 5uice wors in a pinch!) / newer alternative is dry water blocingusing a miracle powder - the stuff developed to absorb moisture indisposable diapers hec with your cable supplier to see if they offer it

Fire Code 0atings; Gvery cable installed indoors must meet fire codesThat means the 5acet must be rated for fire resistance, with ratings forgeneral use, riser (a vertical cable feeds flames more than horiJontal)and plenum (for installation in air-handling areas 8ost indoor cables usF6 (polyvinyl chloride) 5aceting for fire retardance "n the nited.tates, all premises cables must carry identification and flammabilityratings per the 7G (7ational Glectrical ode) paragraph 22% Theseratings are;

7G &ating escription


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:#7 :ptical #ibre 7on-conductive

:# :ptical #ibre onductive

:#7I or :#I general purpose

:#7& or :#& riser rated cable for vertical runs

:#7F or :#Fplenum rated cables for use in air-handling plenums

:#7-+. low smoe density

ables without marings should never be installed as they will not passinspections! :utdoor cables are not fire-rated and can only be used up

to C% feet indoors "f you need to bring an outdoor cable indoors,consider a double-5aceted cable with FG 5acet over a F6 +-ratedindoor 5acet .imply remove the outdoor 5acet when you come indoorsand you will not have to terminate at the entry point You can use an"ndoorD:utdoor rated product with a +ow .moe Oero @alogen 5acet

Choosing A Cable


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&ibbon :utside Flant@ighest #ibre count for smallsiJe

Pulling Fibre Optic Cable

"nstallation methods for both wire cables and optical fibre cables aresimilar #ibre cable can be pulled with much greater force than copperwire if you pull it correctly ?ust remember these rules;

o not pull on the fibres, pull on the strength members only! The cablemanufacturer gives you the perfect solution to pulling the cables, theyinstall special strength members, usually duFont evlar aramid yarn or

a fibreglass rod to pull on se it! /ny other method may put stress onthe fibres and harm them 8ost cables cannot be pulled by the 5aceto not pull on the 5acet unless it is specifically approved by the cablemanufacturers and you use an approved cable grip

o not e9ceed the ma9imum pulling load rating :n long runs, useproper lubricants and mae sure they are compatible with the cable

5acet :n really long runs, pull from the middle out to both ends "fpossible, use an automated puller with tension control or at least abreaaway pulling eye

o not e9ceed the cable bend radius #ibre is stronger than steel whenyou pull it straight, but it breas easily when bent too tightly These willharm the fibres, maybe immediately, maybe not for a few years, but youwill harm them and the cable must be removed and thrown away!

o not twist the cable Futting a twist in the cable can stress the fibrestoo /lways roll the cable off the spool instead of spinning it off the spoolend This will put a twist in the cable for every turn on the spool! "f youare laying cable out for a long pull, use a =figure 4= on the ground to

prevent twisting (the figure 4 puts a half twist in on one side of the 4 andtaes it out on the other, preventing twists) /nd always use a swivelpulling eye because pulling tension will cause twisting forces on thecable


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hec the length 8ae sure the cable is long enough for the run "t'snot easy or cheap to splice fibre and it needs special protection Try tomae it in one pull, possible up to about A-$ miles

onduit and "nnerduct; :utside plant cables are either installed in

conduit or innerduct or direct buried, depending on the cable type*uilding cables can be installed directly, but you might consider puttingthem inside plenum-rated innerduct This innerduct is bright orange andwill provide a good way to identify fibre optic cable and protect it fromdamage, generally a result of someone cutting it by mistae! Theinnerduct can speed installation and maybe even cut costs "t can beinstalled quicly by unsilled labour, then the fibre cable can be pulledthrough in seconds You can even get the innerduct with pulling tapealready installed

Cable Plant 1ard&are

6arious enclosures, cabinets, racs and panels are used to protect andorganise splice and termination points The networ designer shouldnow the type of networ, support systems, the routes to be taen Thenthe connectionDsplice locations can be determined and the hardwareplannedThere are lots of rules to follow, of course (the G"/DT"/ C31 has

something to say about all this)

@ere are some e9amples of fibre optic hardware;

$rea.out .its; They allow you to separate and protect individual fibresin a loose tube cable so it can be terminated

Splice enclosures- for long cable runs outside, the point where cablesare spliced, sealed up and buried in the ground, put in a vault of someind or hung off a pole

Splice panels- connect individual fibres from cables to pigtails

Patch panels- provides a centralised location for patching fibres,testing, monitoring and restoring cables


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0ac.s and cabinets; enclosures for patch panels and splice panelssually these also include cable management - without this the cablesstart looing lie spaghetti flying everywhere in a short time!

#or Froduct details lic @ere

There are tons of hardware and tons of manufacturers who mae them*e sure to choose panels that have the connections behind loceddoors, since the biggest problem we see is connectors broen bypeople messing around in communications closets! #ibre doesn't needmaintenance or inspection +oc 'em up and only unloc it when youhave to move something!


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onnector and splice loss is caused by a number of factors+oss is minimised when the two #ibre cores are identical andperfectly aligned, the connectors or splices are properly finishedand no dirt is present :nly the light that is coupled into thereceiving fibre's core will propagate, so all the rest of the lightbecomes the connector or splice loss

Gnd gaps cause two problems, insertion loss and return lossThe emerging cone of light from the connector will spill over thecore of the receiving #ibre and be lost "n addition, the air gapbetween the fibres causes a reflection when the light encountersthe change n refractive inde9 from the glass #ibre to the air inthe gap This reflection (called fresnel reflection) amounts toabout CM in typical flat polished connectors, and means that noconnector with an air gap can have less than %$ d* loss Thisreflection is also referred to as bac reflection or optical returnloss, which can be a problem in laser based systemsonnectors use a number of polishing techniques to insurephysical contact of the #ibre ends to minimise bac reflection:n mechanical splices, it is possible to reduce bac reflection byusing non-perpendicular cleaves, which cause bac reflections tobe absorbed in the cladding of the #ibre

The end finish of the #ibre must be properly polished to minimise loss /rough surface will scatter light and dirt can scatter and absorb light.ince the optical #ibre is so small, typical airborne dirt can be a ma5orsource of loss


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These fibre mismatches occur for two reasons The occasional need tointerconnect two dissimilar fibres and production variances in fibres ofthe same nominal dimensions


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#DF has been one of themost popular singlemodeconnectors for many years "tscrews on firmly, but mae sure

you have the ey aligned in theslot properly before tightening"t's being replaced by .s and+s

. is a snap-in connector thatis widely used in singlemodesystems for it's e9cellentperformance "t's a snap-inconnector that latches with asimple push-pull motion "t is

also available in a duple9configuration

*esides the . uple9, you may occasionally see the #" andG.:7P duple9 connectors which mate to their specificnetwors They are generally used to connect to the equipmentfrom a wall outlet, but the rest of the networ will have .T or .connectorsPG.:7 is an "*8 trademar

*elow are some of the new .mall #orm #actor (.##) connectors;

+ is a new connector thatuses a 0AC mm ferrule, half thesiJe of the .T :therwise, it's astandard ceramic ferruleconnector, easily terminatedwith any adhesive Ioodperformance, highly favouredfor singlemode


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8T-&? is a duple9 connectorwith both fibres in a singlepolymer ferrule "t uses pins foralignment and has male and

female versions 8ultimodeonly, field terminated only byprepolishedDsplice method

:pti-?ac is a neat, ruggedduple9 connector cleverlydesigned around two .T-typeferrules in a pacage the siJe ofa &?-BC "t has male and female(plug and 5ac) versions

6olition is a slic, ine9pensiveduple9 connector that uses noferrule at all "t aligns fibres in a6-groove lie a splice Flug and

5ac versions, but fieldterminate 5acs only

GA%%%D+Q-C is lie a + but witha shutter over the end of the#ibre


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8 loos a miniature . with a0AC mm ferrule "t's morepopular in ?apan

8T is a 0A #ibre connector forribbon cable "t's main use is forpreterminated cableassemblies

The .TD.D#D#"DG.:7 connectors have the same ferrule siJe -AC mm or about %0 inch - so they can be mi9ed and matched to eachother using hybrid mating adapters This maes it convenient to test,since you can have a set of multimode reference test cables with .Tconnectors and adapt to all these connectors +iewise, the +, 8 andGA%%%D+Q-C use the same ferrule but cross-mating adapters are noteasy to find

Connector ypesThe .T is still the most popular multimode connector because it ischeap and easy to install The . connector was specified as astandard by the old G"/DT"/ C34/ specification, but its higher cost anddifficulty of installation (until recently) has limited its popularity@owever, newer .s are much better in both cost and installation ease,so it has been growing in use The duple9 #", G.:7 and .connectors are used for patch cords to equipment and can be mated to.T or . connectors at wall outlets

.inglemode networs use # or . connectors in about the sameproportion as .T and . in multimode installations There are someBs out there tooG"/DT"/ C34 * allows any #ibre optic connector as long as it has a#:". (#ibre :ptic onnector "ntermateability .tandard) documentbehind it This opened the way to the use of several new connectors,which we call the =.mall #orm #actor= (.##) connectors, including


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/TT +, the 8T-&?, the Fanduit =:pti-?ac,= $8's 6olition,the GA%%%D+Q-C and 8 The + has been particularlysuccessful in the .Connector Ferrule Shapes + Polishes#ibre optic connectors can have several different ferrule

shapes or finishes, usually referred to as polishes early connectors,because they did not have eyed ferrules and could rotate in matingadapters, always had an air gap between the connectors to preventthem rotating and grinding scratches into the ends of the fibres*eginning with the .T and # which had eyed ferrules, the connectorswere designed to contact tightly, what we now call physical contact (F)connectors &educing the air gap reduced the loss and bac reflection(very important to laser-based singlemode systems ), since light has aloss of about CM (L%AC d*) at each air gap and light is reflected bacup the #ibre


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cable length .econdly, the connectors must be protected .ome cableand connector manufacturers offer protective sleeves to cover theconnectors, but you must still be much more careful in pulling cablesYou might consider terminating one end and pulling the unterminatedend to not ris the connectorsThere is a growing movement to install preterminated systems but withthe 8T 0A multifibre connector "t's tiny .@YH not much bigger than a.T or ., but has up to 0A fibres 8anufactures sell multifibre cableswith 8Ts on them that connect to preterminated patch panels with .Tsor .s


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the epo9y type, it has become the favourite of lots of contractors whoinstall relatively small quantities of connectors

/naerobic /dhesives; These connectors use a quic setting adhesive toreplace the epo9y They wor well if your technique is good, but often

they do not have the wide temperature range of epo9ies, so only usethem indoors / lot of installers are using +octite 3B4, with or without theaccelerator solution, that is neat and easy to use

rimpDFolish; &ather than glue the #ibre in the connector, theseconnectors use a crimp on the #ibre to hold it in Garly types offered=iffy= performance, but today they are pretty good, if you practice a lotG9pect to trade higher losses for the faster termination speed /nd theyare more costly than epo9y polish types / good choice if you onlyinstall small quantities and your customer will accept them

FrepolishedDsplice; .ome manufacturers offer connectors that have ashort stub #ibre already epo9ied into the ferrule and polished perfectly,so you 5ust cleave a #ibre and insert it lie a splice (.ee ne9t section forsplicing info)


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includes all the termination tools, cable tools and test equipment oyou now your test cables are good>


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usually based on cost or location 8ost splicing is on long haul outsideplant .8 cables, not multimode +/7s, so if you do outside plant .8

5obs, you will want to learn how to fusion splice "f you do mostly 88+/7s, you may never see a splice

#usion .plices are made by =welding= the two fibres together usually byan electric arc :bviously, you don't do that in an e9plosive atmosphere(at least not more than once!), so fusion splicing is usually done aboveground in a truc or trailer set up for the purpose Iood fusion splicerscost E0C,%%% to EB%,%%%, but the splices only cost a few dollars eachToday's singlemode fusion splicers are automated and you have a hardtime maing a bad splice The biggest application is singlemode fibresin outside plant installations

8echanical .plices are alignment

gadgets that hold the ends of two fibrestogether with some inde9 matching gelor glue between them There are anumber of types of mechanical splices,lie little glass tubes or 6-shaped metalclamps The tools to mae mechanicalsplices are cheap, but the splicesthemselves are e9pensive 8anymechanical splices are used forrestoration, but they can wor well withboth singlemode and multimode #ibre, with practice

Which Splice ?"f cost is the issue, we've given you the clues to mae a choice; fusion ise9pensive equipment and cheap splices, while mechanical is cheapequipment and e9pensive splices .o if you mae a lot of splices (liethousands in an big telco or /T6 networ) use fusion splices "f youneed 5ust a few, use mechanical splices#usion splices give very low bac reflections and are preferred for

singlemode high speed digital or /T6 networs @owever, they don'twor too well on multimode splices, so mechanical splices are preferredfor 88, unless it is an underwater or aerial application, where thegreater reliability of the fusion splice is preferred

138851107 Fiber Optics Lecture123

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Transcript of 138851107 Fiber Optics Lecture123