Fiber Optic Communications TE-504 Department of TE

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Fiber Optic CommunicationsTE-504Department of
TECE IIU Islamabd

• Instructor Engr. Muhammad Ashraf Bhutta

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Lecture 1 - outline

• Course info
• Fiber optic introduction
• fiber basics
• history
• modulation formats
• digital/analog modulation
• ray optics description of fibers
• Relevant chapters in the book1-2.1

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Course outline

• week.1 Introduction, Optical fibers - geometrical
  description
• week.2Optical fibers - waveguiding, Maxwells
  equations
• week 3 Optical fibers - dispersion, pulse
  broadening, attenuation
• week 4 Optical fibers - nonlinearities
• Week 5 Solitons, nonlinear phenomena
• week 6 Light emitting diodes, semiconductor
  lasers

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Course outline

• week 7 Photodetectors, receivers
• Week 8 Optical amplifiers
• Week 9 Optical amplifiers
• Week 10 Receiver performance
• Week 11 System design
• Week 12 Dispersion compensation
• Week 13 Multi-channel systems, WDM / OTDM
• Week 14 Coherent systems, Microwave Photonics
• NOTE Each week we,ll have two
  lectures(02hrs01hrs)

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Home assignment, Research papers

• 4 Assignments
• Three quizez
• Two research Papers on the topics covered in the
  course
• Text books
• Fiber Optic Communications Technology 3rd edition
  By Djafar K.
• Optical fiber communications Third edition by
  Gerd Keiser
• Fiber Optic Communication systems Third Edition
  by Govind p. Agrawal

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A definition of Fiber Optics

• Utilization of electromagnetic waves in
  dielectric, circular waveguides combined with
  optoelectronic devices (LEDs, lasers,
  photodiodes, amplifiers, etc.)
• Applications of fiber optics
• communication
• medical applications
• optical sensing
• power distribution
• welding, drilling...

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Some definitions

• Visible spectrum 0.4 to 0.7 micrometer
• Optical (guided light) communication field
  700-1600 nm
• Reflection and refraction
• refractive index nc/v
• Dispersion process of separating light into each
  of its component frequencies.

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• Diffractionbending of light as it passes through
  an openong in an obstacle
• Absorptionconversion of light into heat
• Amount of energy contained in light is determined
  by wavelength or frequency
• Ehf(joules per photon)
• Light passing from a lower refractive index to a
  higher one is bent toward the normal

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Fresnel reflection

• Independentof the index of the two media , a
  small portion of light will always be reflected
  when light passes from one index to another
  ,this is called fresnel reflecton(p)
• P(n-1/n1)2
• dB10log10(1-p)

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The electromagnetic spectrum
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Fiber Optic Commnication Link
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Optical Fibers
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A multi-disciplinary technology
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Undersea systems
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Fiber basics
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Optical Fibers
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Fiber advantages

• Low attenuation (0.2 dB/km)
• Large bandwidth (35 THz)
• Wavelength independent attenuation in the
  transmission window
• The enormous capacity of an installed fiber can
  be utilized in future as the demand increases
• Small geometry and low weight
• Flexible
• Easy to install

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Fiber advantages

• Low sensitivity to moisture
• The fiber endpoints handle large differences in
  voltage
• Immune to electromagnetic interference
• No crosstalk between fibers
• Damage can not cause sparking
• Potentially low cost
• Well suited for future broadband services

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WDM-OTDM
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Progress in Lightwave communication (2)
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Direct detection digital and analog systems
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Analog and digital signals
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The dB units
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Fiber types
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Ray-optics description of step-index fiber (1)
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Numerical apereture