2Introduction to Optical Fibers. Fibers of glassUsually 120 micrometers in diameterUsed to carry signals in the form of light over distances up to 50 km.No repeaters needed.
3Introduction (Cont…)Core – thin glass center of the fiber where light travels.Cladding – outer optical material surrounding the coreBuffer Coating – plasticcoating that protectsthe fiber.
4Evolution of Fiber 1880 – Alexander Graham Bell 1930 – Patents on tubing1950 – Patent for two-layer glass wave-guide1960 – Laser first used as light source1965 – High loss of light discovered1970s – Refining of manufacturing process1980s – OF technology becomes backbone of long distance telephone networks in NA.
5Advantages of Optical Fibre ThinnerLess ExpensiveHigher Carrying CapacityLess Signal Degradation& Digital SignalsLight SignalsNon-FlammableLight Weight
6Areas of Application Telecommunications Local Area Networks Cable TV CCTVOptical Fiber Sensors
7Type of Fibers Optical fibers come in two types: Single-mode fibers – used to transmit one signal per fiber (used in telephone and cable TV). They have small cores(9 microns in diameter) and transmit infra-red light from laser.Multi-mode fibers – used to transmit many signals per fiber (used in computer networks). They have larger cores(62.5 microns in diameter) and transmit infra-red light from LED.
8How Does Optical Fibre Transmit Light?? Total Internal Reflection.Fibre Optics Relay Systems has-Transmitter-Optical Fibre-Optical Regenerator-Optical Receiver
10How are Optical Fibre’s made?? Three Steps are Involved-Making a Preform Glass Cylinder-Drawing the Fibre’s from the preform-Testing the Fibre
11Testing of Optical Fiber Tensile StrengthRefractive Index ProfileFiber GeometryInformation Carrying CapacityOperating temperature/humidity rangeAbility to conduct light under waterAttenuation
12Optical Fiber Laying Mechanical Linking Includes coupling of two connectors end to endOptical distribution frames allow cross connect fibers from by means of connection leads and optical connectorsSoldering:This operation is done with automatic soldering machine that ensures:Alignment of fiber’s core along the 3 axisVisual display in real-time of the fibers solderingTraction test after soldering (50 g to 500 g)
13Optical Fiber Laying (Cont…) BlowingUsed in laying optical cables in roadways.Cables can be blown in a tube high density Poly EthyleneOptical fiber is then blown in the tube using an air compressor which can propel it up to 2 kilometers away.
14Tools of Trade Cleaning fluid and rags Buffer tube cutter Reagent-grade isopropyl alcoholCanned airTape (masking or scotch)Coating stripMicroscope or cleaver checkerSplicerConnector supplies
15Fiber Optics Test Kit Features Applications Includes Smart FO Power Meter and Mini LED or laser sourceFO test lite software for data loggingTests all networks and cable plantsNew versions of Gigabit EthernetLow CostApplicationsMeasure optical power or lossTrouble shooting networks
16Protecting Fibers Tougher than copper wires Designed in three concentric layersCore – Cladding – BufferTwo basic buffer typesTight bufferLoose tubes
17Implementation of Different LANs IEEE 802.3FOIRLFiber optic inter repeater linkDefines remote repeaters using fiber opticsMaximum length – 1000 meters between any two repeaters.
18IEEE 802.3 (Cont…) 10BASEF Star topology with hub in the center Passive hub:Short cablesNo cascadingReliableActive hum:SynchronousMay be cascadedDo not count as one repeaterAny 10BASEF active hub must have at least two FOIRL ports
19Token Ring Advantages Long range Immunity to EMI/RFI Reliability SecuritySuitability to outdoor applicationsSmall sizeCompatible with future bandwidth requirements and future LAN standards
20Token Ring (Cont…) Disadvantages Relatively expensive cable cost and installation costRequires specialist knowledge and test equipmentNo IEEE standard published yetRelatively small installed base.
21Fiber Distributed Data Interface Stations are connected in a dual ringTransmission rate is 100 mbpsTotal ring length up to 100s of kms.
22ConclusionThis 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 not cover all the aspects of optical fiber work it will have equipped you knowledge and skills essential to the fiber optic industry.