FIBER Class
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Transcript of FIBER Class
8/6/2019 FIBER Class
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Fiber Optics Technology
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I ntroduction to Optical Fibers.
Fibers of glass
Usually 120 micrometers in diameterUsed to carry signals in the form of light over distances up to 50 km.
No repeaters needed.
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I ntroduction (Cont«)
Core thin glass center of the fiber
where light travels.Cladding outer optical materialsurrounding the core
Buffer Coating
plasticcoating that protects
the fiber.
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Evolution of Fiber 1880 A lexander Graham Bell
1930 Patents on tubing
1950 Patent for two-layer glass wave-guide1960 Laser first used as light source
1965 High loss of light discovered
1970s R
efining of manufacturing process1980s OF technology becomes backbone of long distance telephone networks in N A .
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Ad vantages of Optical Fibre
Thinner
Less ExpensiveHigher Carrying Capacity
Less Signal Degradation& Digital Signals
Light Signals
Non-Flammable
Light Weight
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Areas of A pplication
Telecommunications
Local A rea Networks
Cable TV
CCTV
Optical Fiber Sensors
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Type of FibersOptical fibers come in two types:
Single-mode fibers used to transmit one signal
per fiber (used in telephone and cable TV). Theyhave small cores(9 microns in diameter) andtransmit infra-red light from laser.
Multi-mode fibers used to transmit manysignals per fiber (used in computer networks). Theyhave larger cores(62.5 microns in diameter) andtransmit infra-red light from LED.
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H ow Does Optical FibreTransmit Light??Total Internal Reflection.
Fibre Optics Relay Systems has-Transmitter
-Optical Fibre
-Optical Regenerator-Optical Receiver
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P roperties of optical fibersFiber has to have two important properties:Total internal reflection, so that light is containedwithin fiberLow attenuation, so that light can be carried over
long distances with minimal lossStructure
Inner core glass: high refractive index (contains light )Cladding glass: lower refractive indexO
uter polymer coating: adds strength & protects fiber
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Light ray must enter the fiber within a certain acceptance angle. If not, light will get refracted out as condition for total internalreflection will be violated; this becomes important when a fiberbendsThe way to avoid losing light is to make fibers with small diameters;thinner fibers also better from a flexibility and weight point of view
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Total I nternal Reflection in Fiber
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SEEFIRE workshop ±
Sofia, 14-15 July 2005
12
Fiber Types
Multi-Mode: supports
hundreds paths for light.
Single-Mode: supports asingle path for light
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SEEFIRE workshop ± Sofia, 14-15 July 2005 13
Attenuation
It is the reduction of light power over the length of the fiber.
Its mainly caused by scattering.
It depends on the transmission frequency.
Its measured in dB/km ( ))(log10 10 inout dB !
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H ow are Optical Fibre¶s made??
Three Steps are Involved
-Making a Preform Glass Cylinder-Drawing the Fibres from the preform
-Testing the Fibre
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Testing of Optical Fiber
Tensile Strength
Refractive Index ProfileFiber Geometry
Information Carrying Capacity
Operating temperature/humidity range A bility to conduct light under water
A ttenuation
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Optical Fiber Laying Mechanical Linking
Includes coupling of two connectors end to end
Optical distribution frames allow cross connect fibersfrom by means of connection leads and opticalconnectors
Soldering: This operation is done with automatic soldering machine that
ensures: A lignment of fibers core along the 3 axis
Visual display in real-time of the fibers soldering
Traction test after soldering (50 g to 500 g)
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Optical Fiber Laying (Cont«)
Blowing
Used in laying optical cables in roadways.Cables can be blown in a tube high densityPoly Ethylene
Optical fiber is then blown in the tube
using an air compressor which can propel it up to 2 kilometers away.
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Tools of TradeCleaning fluid and rags
Buffer tube cutter
Reagent-grade isopropyl alcohol
Canned air
Tape (masking or scotch)
Coating strip
Microscope or cleaver checkerSplicer
Connector supplies
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Fiber Optics Test Kit Features
Includes Smart FO Power Meter and Mini LED orlaser source
FO test lite software for data logging
Tests all networks and cable plants
New versions of Gigabit Ethernet
Low Cost
A pplications
Measure optical power or loss
Trouble shooting networks
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P rotecting FibersTougher than copper wires
Designed in three concentric layers
Core Cladding Buffer
Two basic buffer types
Tight buffer Loose tubes
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I mplementation of Different L
AN s
IEEE 802.3
FOIRL Fiber optic inter repeater link
Defines remote repeaters using fiber optics
Maximum length 1000 meters between any two
repeaters.
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IEEE 802.3 (Cont«)10B A SEF Star topology with hub in the center
Passive hub:
Short cables No cascading
Reliable
A ctive hum:
Synchronous May be cascaded
Do not count as one repeater
A ny 10B A SEF active hub must have at least two FOIRL ports
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Token Ring (Cont«)Disadvantages
Relatively expensive cable cost and installation cost
Requires specialist knowledge and test equipment
No IEEE 802.5 standard published yet
Relatively small installed base.
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Fiber Distributed Data I nterface
Stations are connected in a dual ring
Transmission rate is 100 mbps
Total ring length up to 100s of kms.
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ConclusionThis concludes our study of Fiber Optics. We have
looked at how they work and how they are made. We have
examined the properties of fibers, and how fibers are
joined together. Although this presentation does notcover all the aspects of optical fiber work it will have
equipped you knowledge and skills essential to the fiber
optic industry.