What Can CATV Systems Benefit from EDFA Optical Amplifiers?

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As long-distance transmissions are
always required in the CATV systems, it is very necessary to make the quality
of visual and audio signals in high levels after the long transmissions, so
that the performance of the CATV systems can be ensured. To serve this aim, the
CATV EDFA optical amplifiers are come up with and widely used in the CATV
systems. Why the EDFA
optical amplifier is needed in CATV system? How does it work for the
long CATV application? The following text will give you the answers and simply
introduce two typical CATV EDFA amplifier applications for your reference.

 

What’s CATV EDFA Amplifier?

 

CATV EDFA is a kind of optical
amplifier, most commonly used in the long-haul CATV system for boosting the
damped CATV signals, with the aim of compensating the signal loss. Since it
mostly works as booster optical amplifier in the CATV system, so that it can be
also called CATV booster amplifier. By utilizing the CATV EDFA optical
amplifier, the CATV signals can be enhanced to meet the system requirement and
then be sent to the users. However, when the signal power is improved by the
CATV EDFA, the noise existing in the transmission link would also boosted and
some return loss would also occur at the same time. Considering that, it is
very necessary to choose quality CATV EDFA optical amplifier for ensuring the
performance of CATV system, even if it may be cost a little higher than common
optical amplifier.

 

Why CATV EDFA Optical Amplifier is
Used?

 

CATV is a multi-channel TV system
transmitting visual and audio signals from digital or analog television and
radio channel to many users via fiber or copper patch cable. As the signals should
be finally separated by optical splitter to serve more than one users and many
loss has occurred in the long transmission, the overall speed and quality of
the CATV signals would become too weak to meet the receiver requirements. Under
this condition, the CATV EDFA optical amplifier is very essential for CATV
system with the function of amplifying CATV signals and giving high performance
systems to the users.

 

How Does CATV EDFA Work for Long CATV
Applications?

 

A long CATV system is always composed of
head end, transmitter, receiver, CATV booster amplifier and optical splitter.
When the system runs, the CATV signals are provided by the head end, and need
to be split into several signals by the optical splitter to serve the users.
When the signals pass through the optical splitter, the signal power would be
in a very low level. Hence, the CATV EDFA optical amplifier should be deployed
after the receiver to improve the signal power, and the users can finally
receive quality signals.

 

From the figure above, we can learn a
simple point-to-multipoint CATV network design as mentioned above. The CATV
signals are provided by the RF combiner and should be connected with four
receivers by the optical splitter. In order to compensating the signal loss
caused by the optical splitter, CATV EDFA optical amplifier is required before
sending the weak signals to the users.

 

Except for this simple kind of CATV
network using CATV EDFA optical amplifier, here also offers a complex CATV
network, as designed in the figure below. In this CATV network, the CATV EDFA
optical amplifier is deploy behind the 8 channel DWDM Mux Demux to amplify the
signals while the 8 channel DWDM Mux Demux allows for higher capacity
transmission. Hence, a long CATV network with big capacity can be achieved.

 

Conclusion

 

When deploying a long CATV system, we
should pay attention to the loss caused by long transmission distance and CATV
components. When the loss is very high, CATV EDFA optical amplifier would be an
ideal device deployed in the long CATV system for improving the quality of CATV
signals, so that the users can receive high speed and reliability of the
services.