Fiber Optic

F U N D AM E N T AL S
OF PHOTONICS

Module

1.8
Fiber Optic
Telecommunication
Nick Massa
Springfield Technical Community College
Springfield, Massachusetts
Fiber optics is a major building block in the telecommunication infrastructure. Its high
bandwidth capabilities and low attenuation characteristics make it ideal for gigabit transmission
and beyond. In this module, you will beintroduced to the building blocks that make up a fiber
optic communication system. You will learn about the different types of fiber and their
applications, light sources and detectors, couplers, splitters, wavelength-division multiplexers,
and state-of-the-art devices used in the latest high-bandwidth communication systems. Attention
will also be given to system performance criteria such aspower and rise-time budgets.

Prerequisites
Before you work through this module, you should have completed Module 1-7, Basic Principles
of Fiber Optics. In addition, you should be able to manipulate and use algebraic formulas, deal
with units, and use basic trigonometric functions such as sine, cosine, and tangent. A basic
understanding of wavelength, frequency, and the velocity of light isalso assumed.

© 2000 University of Connecticut

293

FUNDAMENTALS

OF

PHOTONICS

Objectives
When you finish this module, you will be able to:
•

Identify the basic components of a fiber optic communication system

•

Discuss light propagation in an optical fiber

•

Identify the various types of optical fibers

•

Determine the dispersion characteristics for thevarious types of optical fibersDescribe
the various connector types

•

Calculate decibel and dBm power

•

Calculate the power budget for a fiber optic system

•

Calculate the bandwidth of a fiber optic system

•

Describe the operation and applications of the various types of fiber optic couplers

•

Describe the operation and applications of light-emitting diodes (LEDs)

•Describe the operation and applications of laser diodes (LDs)

•

Describe the operation and applications of distributed-feedback (DFB) lasers

•

Discuss the differences between LEDs and laser diodes with respect to performance
characteristics

•

Discuss the differences between the various types of optical detectors with respect to
performance characteristics

•

Describehow pulse code modulation (PCM) is used in analog-to-digital conversion

•

Describe the operation North American Digital Hierarchy

•

Describe the difference between internal and external modulation

•

Discuss the principles of time-division multiplexing (TDM)

•

Discuss the principles of wavelength-division multiplexing (WDM)

•

Discuss the principles of densewavelength-division multiplexing (DWDM)

•

Discuss the significance of the International Telecom Union grid (ITU grid)

•

Discuss the use of erbium-doped fiber amplifiers (EDFA) for signal regeneration

•

Describe the operation and applications of fiber Bragg gratings

•

Describe the operation and application of fiber optic circulators

•

Describe the operation of a typical fiberoptic communication system and the
components that make it up

294

© 2000 University of Connecticut

FIBER OPTIC TELECOMMUNICATION

Scenario—Using Fiber Optics in Telecommunication
Michael recently completed an associate degree in laser electro-optics technology
at Springfield Technical Community College in Springfield, Massachusetts. Upon
graduation he accepted a position as anelectro-optics technician at JDS Uniphase
Corporation in Bloomfield, Connecticut. The company makes high-speed fiber optic
modulators and components that are used in transmitters for the
telecommunication and cable television industry.
The company’s main focus is on the precision manufacturing of these devices,
which requires not only an in-depth knowledge of how the devices work but also an...