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Fort Worth Seminar 2001 - Trafficware Group Inc. · PDF file 1.40 1.60 1.80 2.00 Vacuum Air Water Fused Glass Fused Glass Material The ratio of the speed of light in a vacuum to the

Mar 27, 2020

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  • Fiber Optics

    Jim Sluss University of Oklahoma

    Electrical & Computer Engineering [email protected]

  • Outline

    • Part 1: Fiber Basics • Part 2: Fiber Optic Networks for Traffic and

    Transportation Systems • Part 3: Troubleshooting

    (Problems, Test & Measurement)

  • Part 1: Fiber Basics

  • Basic Communications Link

    ChannelSource Transmitter Receiver Destination

    Noise Interference

  • Basic Fiber Transmission Link

    Drive Circuit

    Signal Restorer

    Light Source

    AmpPhoto- detector

    Transmitter Channel Receiver

    Electrical Output Signal

    Electrical Input Signal

    Attenuation Distortion

  • Rays of Light Photons

    Light is Oscillating Electromagnetic Energy

    Smallest Particle of light is called a Photon

    A Photon is a quantum or bundle of energy

    Only exists if the particle is in motion

    Electromagnetic EnergyElectromagnetic Energy

  • Electromagnetic EnergyElectromagnetic Energy Magnetic

    Field

    Electric Field

    Direction of Propagation

    Travels through free space @ 300,000 Km/sec or 186,000 Miles/sec

    Consists of Oscillating Electric and Magnetic Waves at right angles to each other

    In free space the Velocity of an Electromagnetic Wave is the Speed of Light 300,000 Km/sec

    Wavelength

    Sine-Wave

    Cycle

    Frequency (Hertz’s) = The number of Cycles/sec

    WavelengthWavelength (Meters) = (Meters) = The distance between the same points on consecutive waves

    Positive Amplitude Negative Amplitude

    Electromagnetic Waves are Sinusoidal in shape

  • Electromagnetic EnergyElectromagnetic Energy Magnetic

    Field

    Electric Field

    Direction of Propagation

    Travels through free space @ 300,000 Km/sec or 186,000 Miles/sec

    Consists of Oscillating Electric and Magnetic Waves at right angles to each other

    In free space the velocity of an Electromagnetic Wave is the Speed of Light 300,000 Km/sec

    Wavelength

    Sine-Wave

    Cycle

    Frequency (Hertz’s) = The number of Cycles/sec

    WavelengthWavelength (Meters) = (Meters) = The distance between the same points on consecutive waves

    Positive Amplitude Negative Amplitude

    Electromagnetic Waves are Sinusoidal in shape

    Wavelength = Velocity

    Frequency Wavelength = Meters

    Velocity = 300,000Km/Sec.

    Frequency = Hertz

    What is the wavelength of 60 Hz ?

    Wavelength = 300,000 Km 60 Hz

    = 5000Km

    Los Angeles Boston 5000 Km

    60 Hz

    QuestionQuestion

  • Electromagnetic EnergyElectromagnetic Energy Magnetic

    Field

    Electric Field

    Direction of Propagation

    Travels through free space @ 300,000 Km/sec or 186,000 Miles/sec

    Consists of Oscillating Electric and Magnetic Waves at right angles to each other

    In free space the velocity of an Electromagnetic Wave is the Speed of Light 300,000 Km/sec

    Wavelength

    Sine-Wave

    Cycle

    Frequency (Hertz’s) = The number of Cycles/sec

    WavelengthWavelength (Meters) = (Meters) = The distance between the same points on consecutive waves

    Positive Amplitude Negative Amplitude

    Electromagnetic Waves are Sinusoidal in shape

    Wavelength = Velocity

    Frequency Wavelength = Meters

    Velocity = 300,000Km/Sec.

    Frequency = Hertz

    QuestionQuestion What is the wavelength of 2.4 GHz ?

    Wavelength = 300,000 Km 2.4 GHz

    = 125 microns

    Approximately the same diameter as a strand of human hair!

  • 10 0 Sub-sonic

    (1 MHz) 10 6 AM Radio

    10 4 10 5

    (1 KHz) 10 3 Sound 10 2

    (1 THz) 10 12

    10 8

    10 7

    (1 GHz) 10 9 Radar

    Television

    Short-wave Radio FM Radio

    10 10 10 11

    10 14

    10 16 Ultraviolet Rays

    Visible Light Infrared Light10 13

    10 15

    10 22

    10 18

    10 20

    Cosmic Rays

    Gamma Rays

    X-Rays

    10 17

    10 19

    10 21

    Electromagnetic SpectrumElectromagnetic Spectrum High Frequency

    Ultra- Short Wavelengths

    Low Frequency

    Long Wavelengths

    Sound

    18K Hertz

    20 Hertz

    Ultra Violet

    Violet

    Blue

    Green

    Yellow

    Orange

    Red

    Infrared

    400

    455

    490

    550

    580

    620

    750

    800

    850Far Infrared

    Wavelength (nm)

    Short

    Long

    Sight

  • Electromagnetic SpectrumElectromagnetic Spectrum

    Violet Blue Green Yellow Orange RedUltra-Violet Infrared

    Invisible Light

    400 455 490 550 580 620 750 800

    Wavelength (nm)

    10 – 9 m

    1m

    1,000,000,000

    1nm =

    850 1300 1550

    Visible Light

    Fiber Optics Transmission

  • The Speed Of LightThe Speed Of Light

    1 1.0003

    1.33 1.46 1.48

    0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00

    Vacuum Air Water Fused Glass

    Fused Glass

    Material

    The ratio of the speed of light in a vacuum to the speed of light in a specific medium

    CoreCladding

    IOR

    Index of Refraction

    Velocity

    300,000 Km/s

    205,000 Km/s

    225,000 Km/s

  • Journey of LightJourney of Light

    InterfaceInterface

    GlassGlass I.O.RI.O.R 1.481.48

    I.O.RI.O.R 1.461.46

    Angle ofAngle of Incidence Incidence

    RayRay

    Refracted Refracted RayRay

    NormalNormal

    Angle ofAngle of Incidence Incidence

    RayRay

    Angle ofAngle of RefractionRefraction

    CriticalCritical AngleAngle

    Angle ofAngle of IncidenceIncidence

    == Angle ofAngle of ReflectionReflection

  • Advantages of Optical FiberAdvantages of Optical Fiber ••Wide Bandwidth Wide Bandwidth

    ••Low Loss Low Loss

    ••Electromagnetic Immunity Electromagnetic Immunity

    ••Light Weight Light Weight

    ••Small Size Small Size

    ••Safety Safety

    ••Security Security

    Flat OC192 129,024 Voice ChannelsFlat OC192 129,024 Voice Channels

    Fiber is Dielectric, does not carry electricityFiber is Dielectric, does not carry electricity

    0.25dB/Km @ 1550nm0.25dB/Km @ 1550nm

  • Optical FiberOptical Fiber Two Types Of Fiber -

    MultimodeMultimode

    SinglemodeSinglemode

    • Used for Low Bandwidth (less than 650MHz), Short Haul Communications with distances of up to 3Km (850nm) & 10Km (1300nm)

    • Two operating wavelengths, 850nm and 1300nm

    • Used for High Bandwidth, Long Haul Communications with distances of up to 40Km (1310nm) and 100Km (1550nm) or more

    • Two operating wavelengths at 1310nm and 1550nm

    MMultimode & Singlemodeultimode & Singlemode

  • 125 / 62.5 125 / 62.5 micronsmicrons

    125 / 62.5 125 / 62.5 micronsmicrons

    MultimodeMultimode

    CoreCore

    FiberFiber BufferBuffer

    CladdingCladding

    Core / Cladding sizes 50/125, 62.5/125 and 100/140 microns

    FDDI Fiber Distributed Data Interface

    WavelengthWavelength

    850 & 1300nm850 & 1300nm

  • SinglemodeSinglemode

    FiberFiber BufferBuffer

    125 / 125 / 9/ 9micronsmicrons

    CladdingCladdingCoreCore125 / 125 / 99/ 9micronsmicrons

    Core less than 10 microns Cladding 125 micronsWavelengthWavelength

    1310 & 1550nm1310 & 1550nm

  • Attenuation vs. λ

  • MultimodeMultimode

  • Refractive Index Profiles

    • Multimode Stepped Index Fiber

    • Multimode Graded Index Fiber

    • Singlemode Stepped Index Fiber

  • Mode Time Scale

    Multimode Stepped Index Fiber

    ModalModal

    Input Input Output Output Bandwidth Limited to about Bandwidth Limited to about

    150Mhz/Km 150Mhz/Km Refractive Refractive

    Index Profile Index Profile

    Core 100 microns

    Cladding 140 microns

  • Mode Time Scale

    Multimode Graded Index Fiber

    ModalModal Refractive Refractive

    Index Profile Index Profile

    Input Input Output Output Bandwidth Limited to Bandwidth Limited to

    about 650Mhz/Km about 650Mhz/Km

  • Signal Distortion Important in determining the information capacity (bandwidth) of an optical fiber as a function of transmission distance.

  • Intermodal Dispersion Intermodal dispersion - pulse spreading (in time) in multimode fibers, due to varying arrival times at the RX because each mode travels with a slightly different velocity.

    core

    cladding

    cladding

    mode 1

    mode 2

    Axial Cross-Sectio

  • Refractive Refractive Index Profile Index Profile

    Stepped Index, Terahertz Bandwidth Stepped Index, Terahertz Bandwidth

    Singlemode Step Index Fiber

  • Dynamic Range Dynamic Range

    Wavelength / Att

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