OPTICAL COMMUNICATION NETWORK Passive Optical Networks Active Optical Networks Supervised by:

1. OPTICAL
COMMUNICATION
NETWORK
Passive Optical Networks
Active Optical Networks
Supervised by: -
DR. Samy S. Soliman
Prepared by: -
Mohamed Sewailam
November 2020

2. Optical Communication Network
Optical means using the light as a carrier.
So Optical Communication Network, using the light as a carrier to
transfer various types of information from place to another in various types
of telecommunication network.
The optical network consists of an optical line terminal (OLT) at the service
provider's central office (hub) and a number of optical network
units (ONUs) or optical network terminals (ONTs), near end users.
Optical network Example, In the central office of the network’s core each
fiber is carrying shared information of multiple end-users, so how to send
and splitting each user’s information correctly. here two common ways of
optical technologies (network), both of them based on the way of splitting
the signals
The two methods are called Active Optical Networks (AON) or Passive
Optical Networks (PON), AON and PON offer a way to separate data and
set it upon its intended route to arrive at the proper place. The key
difference between AON and PON is how the signal is split between the
multiple fibers going to each customer.
Active Optical Network (AON): -
Active means using devices which are working depending on its connection
to electrical power source.
Active optical network, also called point-to-point network, usually uses
electrically powered switching equipment such as a router or switch
aggregator, to manage signal distribution and direct signals to specific user.
This switch directs the incoming and outgoing signals to the proper place or
to user. Customers can have a dedicate fiber running to his or her home.
You can see this below in the diagram. a switching device will typically route
signals to each user correctly as each user will receive his/her information
only and switch device can route up to about 500 customers.

3. Normally, signals need an optical-electrical-optical transformation in the
AON. Each signal leaving the central office is directed only to the customer
for whom it is intended.
Passive Optical Network (PON)
Passive means using devices which are working normally without having
any connection to electrical power source.
Different from AON, PON doesn’t contain electrically powered switching
equipment, instead it uses fiber optic splitters to guide traffic signals
contained in specific wavelengths. The optical splitters can split and collect
optical signals when they run through the network.
Powered equipment is needed only at the signal source and the receiving
ends of the signals. Usually, the PON network can distribute signals into 16,
32 and 64 customers.
You can see from the diagram that each customer receives signals intended
for someone else, so encryption/addressing ensures privacy is maintained.

4. The downstream signal coming from the central office is broadcast to each
customer premises sharing a fiber.
AON vs. PON
As data travel across the fiber connection, it needs a way to be directed so
that the correct information can arrive at its intended destination.
these two networks are widely applied in FTTH systems. However, each
system has their own disadvantages and advantages. Here is a simple
comparison between them.
Signal Distribution
In AON networks, users have a dedicated fiber optic cable, as each user gets
the same bandwidth that doesn’t be shared. While the users share the fiber
optic cable for a portion of the network. In PON there is no fiber optic cable
dedication all fiber cables carry multiple signals of multiple users.
Equipment
AON directs optical signals mainly by powered equipment while PON has no
powered equipment is needed in guiding signals except for two ends of the
system.

5. Cost
When running an existing network, it’s known to us that the main source of
cost is the maintenance and powering equipment. However, PON uses
passive components that only need less maintenance and do not need
power, which contributes to that PON building is cheaper than that of AON.
Coverage Distance
AON networks can cover a range to about 100 km, a PON is typically limited
to fiber cable runs of up to 20 km. That is to say, subscribers must be
geographically closer to the central source of the data.
Conclusion
In summary, AON and PON have their own advantages and disadvantages,
but both of them provide practical solutions for FTTH network connection.
During design there are many trade of between many elements and factors
(Less cost & coverage area & distance between central office and users and
between users each other & complexity, maintenance, ….), So when it
comes to choose which one of them, there is no right or wrong answers.
Index
FTTH Fiber To The Home
FTTX Fiber To The X
PON Passive Optical network
AON Active Optical network
OLT Optical Line Terminal
ONU Optical Network Units
ONT Optical Network Terminals
References
https://en.wikipedia.org/wiki/Fiber_to_the_x#Active_optical_network
https://en.wikipedia.org/wiki/Passive_optical_network
https://www.headendinfo.com/aon-pon-difference/
https://en.wikipedia.org/wiki/Fiber_to_the_x