A A System view ofSystem view ofOptical Fiber CommunicationOptical Fiber Communication

Prepared byPrepared by

Ismail Ali Al-QaramIsmail Ali Al-Qaram

Zeyad Al-QabbaniZeyad Al-Qabbani

Ali Kamel Al-AwamiAli Kamel Al-Awami

Overview:Overview:

An optical fiber is a glass An optical fiber is a glass or plastic fiber designed to or plastic fiber designed to guide guide light along its length along its length by by total internal reflection

Optical fibers are widely used in Optical fibers are widely used in fiber-optic communication, which permits , which permits digital data transmission over longer distances and at higher data rates digital data transmission over longer distances and at higher data rates than electronic communication. than electronic communication.

Optical fiber was developed in Optical fiber was developed in 19701970 by by Corning Glass Works with with attenuation low enough for communication purposes (about attenuation low enough for communication purposes (about 2020dBdB//kmkm))

• 1st1st generation generation operated operated at a wavelength at a wavelength 0.8 0.8 µm

HistoryHistory

• 2nd2nd generation generation 1.31.3 µm

• 3rd3rd generation generation 1.551.55 µm

• 4th4th generation generation 1.61.6 µm

• 5th5th generation generation extending the extending the wavelength range over which a WDM wavelength range over which a WDM system can operate. system can operate.

Types of optical fiber:Types of optical fiber:

I.I. SINGLE-MODE FIBERSINGLE-MODE FIBER

- narrow core, diameter (- narrow core, diameter (8 microns8 microns or less). or less).

- Light travels parallel to the axis. - Light travels parallel to the axis.

- little pulse dispersion.- little pulse dispersion.

Uses:Uses:

Telephone & cable television networksTelephone & cable television networks

II.II. STEP-INDEX MULTIMODE FIBERSTEP-INDEX MULTIMODE FIBER

- large core, diameter: - large core, diameter: 100 microns100 microns

- travel in direct route, other rays zigzag as - travel in direct route, other rays zigzag as they bounce off the cladding they bounce off the cladding

- pulse, spread out, losing its well-defined shape - pulse, spread out, losing its well-defined shape

Uses:Uses:

short distances, for example an endoscopeshort distances, for example an endoscope

III.III. GRADED-INDEX MULTIMODE FIBERGRADED-INDEX MULTIMODE FIBER

- core has refractive index that diminishes gradually from - core has refractive index that diminishes gradually from the center axis out toward the cladding. the center axis out toward the cladding.

- the light rays move down the axis advance more slowly than - the light rays move down the axis advance more slowly than those near the cladding. those near the cladding.

- shortened path & higher speed less dispersion. - shortened path & higher speed less dispersion.

- light in the core curves helically.- light in the core curves helically.

ComparisonComparison

BASIC CABLE DESIGNBASIC CABLE DESIGN

• Two basic cable designs:Two basic cable designs:

1- Loose-Tube Cable:1- Loose-Tube Cable:

Uses:Uses:

- used in outside-plan installations. - used in outside-plan installations.

- holds up to - holds up to 1212 fibers per buffer tube. fibers per buffer tube.

- fibers are loosely packaged in gel filled buffer tubes to repel water. - fibers are loosely packaged in gel filled buffer tubes to repel water.

- endure outside temperatures and high moisture. - endure outside temperatures and high moisture.

- Typically, distance not to exceed - Typically, distance not to exceed 50 feet50 feet. .

Properties:Properties:

2-Tight-Buffered Cable2-Tight-Buffered Cable

- often used for intra-building - often used for intra-building

-no gel, connectors terminated no gel, connectors terminated directly onto the fiber without directly onto the fiber without difficult to use breakout kits difficult to use breakout kits

less expensive installation less expensive installation

- (Temperature rating - (Temperature rating -40ºC-40ºC to to +85ºC+85ºC). ).

- Typically, long distance- Typically, long distance

Uses:Uses:

Properties:Properties:

Communication ApplicationsCommunication Applications

• Fiber-optic cable is used by many Fiber-optic cable is used by many telecommunications companies to telecommunications companies to transmit telephone signals, internet transmit telephone signals, internet communication, and cable television communication, and cable television signals, sometimes all on the same signals, sometimes all on the same optical fiber

Communication System Using Optical FiberCommunication System Using Optical Fiber

Components of the Transmission System:Components of the Transmission System:

• TransmittersTransmitters

• AmplifiersAmplifiers

• ReceiversReceivers

- The most commonly used optical transmitters are - The most commonly used optical transmitters are semiconductor semiconductor devices such as devices such as Light emitting diodesLight emitting diodes (LEDs) (LEDs) and and laser diodeslaser diodes. .

I.I. Transmitters:Transmitters:

- A - A semiconductorsemiconductor laser emits light through laser emits light through stimulated emission rather than spontaneous emissionrather than spontaneous emission

high output power (~high output power (~100 mW100 mW) )

- efficiency (~- efficiency (~50%50%))

- wide spectral width of - wide spectral width of 30-60 nm30-60 nm

LEDs:LEDs:

- efficiency (~- efficiency (~1%1%))- Output power - Output power 100100 microwatts microwatts

- - wide spectral width ofwide spectral width of 0.81-0.87 0.81-0.87 µmµm - High data rates, long distances- High data rates, long distances

laser diodes:laser diodes:

II.II. Amplifiers:Amplifiers:

- Solution for fiber attenuation and fiber distortion.- Solution for fiber attenuation and fiber distortion.

- amplifies the optical signal directly without having to convert the signal - amplifies the optical signal directly without having to convert the signal into the electrical domain. into the electrical domain.

- Made by - Made by doping a length of fiber with an rare-earth mineral ( a length of fiber with an rare-earth mineral (erbium), ), and and pumping it with light from a it with light from a laser with a shorter wavelength than with a shorter wavelength than the communications signal (typically the communications signal (typically 980 nm980 nm))

- The main component of an optical receiver is a photo detector - The main component of an optical receiver is a photo detector that converts light into electricity through the photoelectric effect.that converts light into electricity through the photoelectric effect.

- detectors are also used due to their suitability for circuit - detectors are also used due to their suitability for circuit integration in regenerators and wavelength-division multiplexersintegration in regenerators and wavelength-division multiplexers

III. Recivers:Recivers:

WDM is dividing the wavelength WDM is dividing the wavelength capacity of an optical fiber into capacity of an optical fiber into multiple channels.multiple channels.

Requirements:Requirements:

- - multiplixermultiplixer in the transmition. in the transmition. - - demultiplexerdemultiplexer in the receiving. in the receiving.

-bandwidth can be divided up to bandwidth can be divided up to 8080 channels channels

- carry information at around - carry information at around 14 Terabits/s14 Terabits/s over over 160 km160 km of fiber. of fiber.

Wavelength-Division Multiplexing (WDM) :Wavelength-Division Multiplexing (WDM) :

- attenuation is caused by a - attenuation is caused by a combination of material absorption, combination of material absorption, and connection losses. and connection losses.

-attenuation in modern fiber is attenuation in modern fiber is about about 1000 db/km1000 db/km. .

- other causes of attenuation are - other causes of attenuation are physical stressesphysical stresses to the fiber, to the fiber, microscopic fluctuationsmicroscopic fluctuations in density, in density, and and imperfect splicingimperfect splicing techniques. techniques.

AttenuationAttenuation

Comparison between electrical transmissionComparison between electrical transmission and fiber opticsand fiber optics

ElectricalElectrical Fiber opticsFiber optics

Low bandwidthLow bandwidth high bandwidthhigh bandwidth

High lossHigh loss Low lossLow loss

Easy installationEasy installation Difficult installationDifficult installation

Low costLow cost High costHigh cost

Affected by Affected by electromagnetic interferenceelectromagnetic interference Not affected by Not affected by electromagnetic electromagnetic interferenceinterference

Heavy & big cable sizeHeavy & big cable size Lighter weight & smaller cable Lighter weight & smaller cable sizesize

Low electrical resistanceLow electrical resistance High electrical resistanceHigh electrical resistance

sparkssparks No sparksNo sparks

Application Wavelength

Max distance (m)for fiber type

Link Margin (dB)for fiber type

62.5 50 SM 62.5 50 SM

  10Base-F10Base-F 850 2000 2000 NS 12.5 7.8 NS

  FOIRLFOIRL 850 2000 NS NS 8 NS NS

Token Ring 4/16Token Ring 4/16 850 2000 2000 NS 13 8.3 NS

  Demand Priority Demand Priority (100VG-AnyLAN) (100VG-AnyLAN)

850 500 500 NS 7.5 2.8 NS

  Demand Priority Demand Priority (100VG-AnyLAN) (100VG-AnyLAN)

1300 2000 2000 NS 7.0 2.3 NS

  100Base-FX 100Base-FX (Fast Ethernet) (Fast Ethernet)

1300 2000 2000 NS 11 6.3 NS

  100Base-SX100Base-SX 850 300 300 NS 4.0 4.0 NS

  FDDIFDDI 1300 2000 2000 40000 11.0 6.3 10-32

  FDDI (low cost)FDDI (low cost) 1300 500 500 NA 7.0 2.3 NA

  ATM 52ATM 52 1300 3000 3000 15000 10 5.3 7-12

  ATM 155ATM 155 1300 2000 2000 15000 10 5.3 7-12

  ATM 155ATM 155 850(laser) 1000 1000 NA 7.2 7.2 NA

  ATM 622ATM 622 1300 500 500 15000 6.0 1.3 7-12

  ATM 622ATM 622 850(laser) 300 300 NA 4.0 4.0 NA

  Fiber Channel 266Fiber Channel 266 1300 1500 1500 10000 6.0 5.5 6-14

  Fiber Channel 266Fiber Channel 266 850(laser) 700 2000 NA 12.0 12.0 NA

  Fiber Channel 1062Fiber Channel 1062 850(laser) 300 500 NA 4.0 4.0 NA

  Fiber Channel 1062Fiber Channel 1062 1300 NA NA 10000 NA NA 6-14

  1000Base-SX1000Base-SX 850(laser) 220 550 NA 3.2 3.9 NA

  1000Base-LX1000Base-LX 1300 550 550 5000 4.0 3.5 4.7

  ESCONESCON 1300 3000 NS 20000 11 NS 16

THE ENDTHE END

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