2.2.8 APPLICATION OF FIBER OPTIC
Medical Used as light guides, imaging tools and also as lasers
for surgeries Data Used for data transmission
Telecommunications Fiber is laid and used for transmitting and
receiving purposes Networking Used to connect users and servers in a variety of
network settings and help increase the speed and accuracy of data
transmission
Industrial/Commercial Used for imaging in hard to reach areas,
as wiring where EMI is an issue, as sensory devices to make temperature,
pressure and other measurements and as wiring in automobiles and in industrial
settings
Broadcast/CATV
Broadcast/cable companies are using fiber optic cables for wiring
CATV,HDTV, internet video on-demand and other applications.
2.2.9 FIBER OPTIC CONNECTION
In the establishment of fiber optic link the following
constraints are meeting:
> The transmitting source with optical fiber. > The optical
fiber to optical fiber.
> The optical fiber with the optical receiver.
2.2.10 THE PRINCIPLE STRUCTURE OF FIBER OPTIC
2.2.10.1. Fiber optical multiplexing
Optical multiplexing also called Wavelength Divided
Multiplexing (WDM) or Dense Wavelength Divisions Multiplexing (DWDM) as
presented on the following figure actual this technology of WDM was born from
the idea of simultaneously injection of several trains of numerical signals at
the same speed of modulation into same optical fiber each one with distinct
wavelength.
Figure 12 : Fiber optic multiplexing (WDM Point to Point).
The DWDM is the short form of Dense Wavelength Division
Multiplexing DWDM is an important technology in nowadays for fiber optic
network, DWDM use WDM technology to
arrange several fiber optic lights to transmit simultaneously via
the same single fiber optic cable, DWDM is usually used on fiber optic
backbones and long distance data.
2.2.10.2 Fiber optical modulation
We need a carrier signal high frequency for transmitting a
signal because a low level signal less power can not transmit over a long
distance, So modulation means to change some parameters (e.g phase, frequency
and amplitude) of the carrier in accordance to the message signal.
We have two types of modulation which are :
Analogue modulation( e.g Frequency modulation amplitude and phase
and Digital modulation(e.g pulse width modulation ,pulse code modulation...)
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