Page 28 - Optical Communications Essentials

Basic Concepts of Communication Systems

18 Chapter One

TABLE 1.6. Some Examples of Optical
Power Levels and Their dBm Equivalents
Power dBm equivalent
200mW 23
100mW 20
10mW 10
1mW 0
100µW 10
10µW 20
1µW 30
100nW 40
10nW 50
1nW 60
100pW 70
10pW 80
1pW 90

1.10. Simulation Programs
Computer-aided modeling and simulation software programs are essential tools
to predict how an optical communication component, link, or network will func-
tion and perform. These programs are able to integrate component, link, and
network functions, thereby making the design process more efficient, less
expensive, and faster. The tools typically are based on graphical interfaces that
include a library of icons containing the operational characteristics of devices
such as optical fibers, couplers, light sources, optical amplifiers, and optical filters,
plus the measurement characteristics of instruments such as optical spectrum
analyzers, power meters, and bit error rate testers. To check the capacity of the
network or the behavior of passive and active optical devices, network designers
invoke different optical power levels, transmission distances, data rates, and
possible performance impairments in the simulation programs.
An example of such programs is the suite of software-based modeling-tool
modules from VPIsystems, Inc. These design and planning tools are intended
for use across all levels of network analyses, performance evaluations, and tech-
nology comparisons ranging from components, to modules, to entire networks.
They are used extensively by component and system manufacturers, system
integrators, network operators, and access service providers for functions such
as capacity planning, comparative assessments of various technologies, optimiza-
tion of transport and service networks, syntheses and analyses of wavelength
division multiplexing (WDM) system and link designs, and component designs.

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