This document provides an overview of optical communications and optical fiber maintenance. It discusses the history of communication technologies leading up to optical communications. Key topics covered include the fundamentals of optical fibers, how light is transmitted through total internal reflection, fiber types, fiber attenuation and dispersion. Networking fundamentals such as protocols, layers, components and configurations are explained. The document concludes with a section on optical fiber maintenance, specifically fusion splicing and the tools used.

1. Optical communications
fundamentals and optical
fiber maintenance
EARTHLINK Telecommunications
Lec. Mohammed Adel Shitiat
Al-Ayen University
Technical engineering college
continuous education center

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Course
Content
03
01
02
04
05
Introduction
View the history development
of network communication
Optical Fiber
Principal of the Optical fiber
communication
Network Fundamental
Network System and its basic
component
Network configuration
Basic network command and
configuration concept
Optical fiber Maintenance
Optical fiber Maintenance devices
and equipment

3. Introduction
01

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Introduction
• Connection between people is very important to share knowledge,
experience and to make the world more easy to live.
• People first start to communicate through signals and then develop this
signals to written language.
• After that people started to communicate through distances by using
either smoke signal or sending messages through animals.

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Introduction
Communication with
smoke
Communication by using
animals
Communication by using
rising flag or canon
Pre-Electric Communication

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Introduction
Communication with
telegraph
Landline telephone Communication satellite
Electrical Communication

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Introduction
Why we use Optical Communication?
1. Electrical wire Bandwidth limitation (Connection Speed):
Copper-based transmissions currently max out at 40 Gbps
2. Fiber optic transmission can cover further distances:
Both copper and fiber-based signaling suffers from attenuation, or a weakening of the waveform signal
over distance. However, fiber optic cables can transmit data over much longer distances.
Copper cables are limited to 100 meters lengths.
3. Save space and enhance cable management
Fiber optic strands are extremely narrow, the most common fiber optic strand is the same
diameter as a human hair.

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Introduction
Why we use Optical Communication?

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Introduction
Why we use Optical Communication?

10. Optical Fiber
02

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Optical Fiber
Optical fiber consist of
1. Core: is the light transmission area of the fiber,
either glass or plastic , high refractive index
2. Cladding : function of the cladding is to provide a
lower refractive index at the core interface in order
to cause reflection
3. Coating : Coatings are usually multi-layers of plastics
applied to preserve fiber strength, absorb shock and
provide extra fiber protection.

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Optical Fiber

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Optical Fiber
How does Light Transfer inside
the Optical Fiber?

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Optical Fiber
Light Transfer inside the Optical Fiber by using Total internal
reflection technique
Light when hit medium with higher refractive index than the its
travel medium, light either refract or reflect back to the same
medium.
This can be determine using Snells Law
𝜃1 = incident angel
𝜃2 = refraction angel
At specific value of 𝜃𝑖 the 𝜃𝑟 = 90
𝜃𝑖 will called critical angle = 𝜃𝑐
At angle of 𝜃1 greater than the critical angle the light will total
reflect inside the incident medium

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Optical Fiber

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Optical Fiber

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Optical Fiber
Total internal reflectance inside the Optical fiber:
𝑛1 𝑠𝑖𝑛𝜃1 = 𝑛2 𝑠𝑖𝑛𝜃2 −−− − 1
We need 90 degree or above to make total internal reflection form 𝜃3
𝑛2 𝑠𝑖𝑛𝜃3 = 𝑛4
sin 𝜃3 =
𝑛4
𝑛2
−−−−− − 2
𝑛1 sin 𝜃1 = 𝑛2 cos 𝜃3 = (𝑛12 − 𝑛22)
1
2
𝑛1 𝑠𝑖𝑛𝜃1 𝑖𝑠 𝑐𝑎𝑙𝑙𝑒𝑑 𝑁𝑢𝑚𝑒𝑟𝑖𝑐𝑎𝑙 𝐴𝑝𝑒𝑟𝑡𝑢𝑟𝑒

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Optical Fiber
Total internal reflectance inside the Optical fiber:
Numerical Aperture represent light gathering capacity of the fiber have another form is:
𝑁𝐴 = 𝑛2(2∆)
1
2
∆ =
𝑛2 − 𝑛4
𝑛2

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Optical Fiber
Total internal reflectance inside the Optical fiber:

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Optical Fiber
Optical fiber type:
3. Graded index multimode:
1. Large N.A.
2. Easy coupling
3. Less modal dispersion
4. Good compromise between
multimode and single-mode fiber
2. Step index Multi mode:
1. Large N.A.
2. Easy coupling
3. Modal dispersion
4. Lower data rates
5. Shorter distances
1. Step index single mode:
1. Small Na
2. Coupling more
difficult
3. No modal dispersion
4. High data rates
5. Long distance

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Optical Fiber
Optical fiber type:
Step index Single
Mode fiber
Step index Multi
Mode fiber
Graded index Multi
Mode fiber

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Optical Fiber
Optical fiber Losses:
1. Optical fiber Attenuation
2. Optical fiber Dispersion
Attenuation : attenuation of an optical fiber measures the amount of light lost between input and output.
Total attenuation is the sum of all losses.
Optical losses of a fiber are usually expressed in decibels per kilometer (dB/km). The expression is
called the fiber’s attenuation coefficient α and the expression is

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Optical Fiber
Optical fiber Attenuation :

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Optical Fiber
Optical fiber Attenuation :
• The different wavelength of light has
different effect inside the optical medium.
• Some medium pass only specific
wavelength range while absorbed the other
wavelength.
• Fused silica which use to make the optical
fiber that use in communication has
different low optical loss to specific
wavelength.

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Optical Fiber
Optical fiber Attenuation:
Fiber can carry different wavelength of light each wavelength has its on Attenuation.
for communication the most common use wavelength is 1310 nm and 1550 nm.

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Optical Fiber
Optical fiber Attenuation:
Type of Attenuation:
1. Intrinsic
1. Absorption
2. Scattering
2. extrinsic:
1. Splicing
2. Bending

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Optical Fiber
Optical fiber Attenuation:

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Optical Fiber
Optical fiber Attenuation:
How to solve Attenuation:
1. Use fiber with low Power loss.
2. Use Optical Amplifiers (or Repeaters )

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Optical Fiber
Optical fiber dispersion:
describes the process of how an input signal broadens/spreads out as it propagates/travels down the
fiber.

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Optical Fiber
Optical fiber dispersion:
After traveling a distance broaden pulses will over lap and create limit in data rate transfer.

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Optical Fiber
Optical fiber dispersion:
Type of dispersion in fiber:
1. Modal Dispersion:
Modal dispersion is a distortion mechanism occurring in multimode fibers and other waveguides, in
which the signal is spread in time because of different propagation velocity for all modes.

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Optical Fiber
Optical fiber dispersion:
Type of dispersion in fiber:
2. Chromatic Dispersion:
Chromatic dispersion is a phenomenon of signal spreading over time resulting from the different speeds
of light rays. The chromatic dispersion is the combination of the material and waveguide dispersion
effects.

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Optical Fiber
Optical fiber dispersion:
How to solve dispersion in Optical fiber?
By using Dispersion-shifted fiber
Dispersion-shifted fiber (DSF) is a type of optical fiber made to optimize both low dispersion and low
attenuation.
Dispersion Shifted Fiber is a type of single-mode optical fiber with a core-clad index profile tailored to
shift the zero-dispersion wavelength from the natural 1300 nm in silica-glass fibers to the minimum-loss
window at 1550 nm.

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Optical Fiber
Optical fiber Connectors:
There are many type of fiber connector but the most common use in optical communication is:
LC SC MPO

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Optical Fiber
Optical fiber Coupler:
Use to connect to pigtail together
LC SC MPO

36. Network Fundamentals
03

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Network Fundamental
Network Characteristic
1- Performance
2- Reliability
3- Security

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Network Fundamental
Network System
Transmitters Channel Receivers

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Network Fundamental
Network Protocols
A protocol is a set of rules that governs the communications between computers on a network. In order
for two computers to talk to each other, they must be speaking the same language.

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Network Fundamental
Network Layers

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Network Fundamental
Network Layers
Layer 7: Application layer network
Provides standard services such as virtual terminal, file, and job transfer and operations.
Protocols:
HTTP | FTP | SMTP | DNS | Telnet | SSH
Layer 6: Presentation layer network protocols
The presentation layer is responsible for the delivery and formatting of information to the application
layer for further processing or display.

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Network Fundamental
Network Layers
Layer 5: Session layer network
Manages user’s sessions and dialogues, establishes and terminates sessions between
users(Authorization, Authentication).
Layer 4: Transport layer network
The tasks of the transport layer (also end-to-end control, transport control) include the segmentation of
the data stream and in relieving congestion.
Protocols:
TCP | UDP

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Network Fundamental
Network Layers
Layer 3: Network layer network
Routes packets according to unique network device addresses , renders flow and congestion control to
prevent network resource depletion.
Protocols:
IPv4,IPv6 | ICMP
Layer 2: Data link layer network
Frames packets, detects and corrects packet transmit errors.
Protocols:
Ethernet | MPLS | ARP
Layer 1: Physical
Interfaces between network medium and devices. defines optical, electrical, and mechanical
characteristics.

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Network Fundamental
Network Layers

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Network Fundamental
Network Components
1. Devices (Nodes)
Intermediate Devices: represent the routers
and switches that carry the services
Examples: Switches, Wireless Access point,
Routers, Security Devices.
End Devices: Examples of end nodes are
computers, security, cameras, printers, and
many more.

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Network Fundamental
Network Components
Wireless Access point:

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Network Fundamental
Network Components
Router and Switch and Multi-Layer switch:
SFP Port
Ethernet
Port
Console Power cable
QSFP Port

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Network Fundamental
Network Components
SFP (Small form-factor pluggable transceiver):
Transceiver that plugs into an SFP port on a network switch or server.
Convert Optical Signal to electrical signals

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Network Fundamental
Network Components
QSFP (Quad small form-factor pluggable transceiver):
Transceiver that plugs into an SFP port on a network switch or server.
Convert Optical Signal to electrical signals

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Network Fundamental
Network Components
QSFP (Quad small form-factor pluggable transceiver):

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Network Fundamental
Network Components
Cables and fibers:
Ethernet Cable Optical Fibers

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Network Fundamental
Network type:

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Network Fundamental
Network topology :

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Network Fundamental
Network Cloud:
Cloud networking is a type of IT infrastructure in which some or all of an organization’s network
capabilities and resources are hosted in a public or private cloud platform
Instead of buying, owning, and maintaining physical data centers and servers, you can access a wide range
of technology services on an as-needed basis from a cloud provider like AWS , Microsoft Azure

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Network Fundamental
Network Cloud:

56. Network Configuration
04

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Network Configuration
IP addressing
IP is Internet Protocol
Represent in decimal and it has 4 octets
Start 0.0.0.0 and end 255.255.255.255
each device in the network must have it own IP
To find IP of your PC using the command ipconfig IN CMD
IP address
Subnet mask

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Network Configuration
IP addressing
Subnet Mask
Every device has an IP address with two pieces: the client or host address and the
server or network address. IP addresses are either configured by a DHCP server or
manually configured (static IP addresses). The subnet mask splits the IP address into
the host and network addresses.
192.168.0.1
255.255.255.0
Network.Host

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Network Configuration
Mac Address
• A media access control address (MAC address) is a
unique identifier assigned to a network interface
controller (NIC) to be used as a network address in
communications within a network segment.
• Each device has its own MAC address.
• To show your MAC address in your PC windows type in
CMD (ipconfig /all ).
Mac-Address of PC

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Network Configuration
Address Type
A unicast address is used to
refer to a single host. It
sends data to a single
destination.
A multicast address can be
used to deliver a package
to a group of destinations.
The broadcast addressing
involves a single sender
(source) and multiple
receivers (destinations).

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Network Configuration
Ping (Packet Internet or Inter-Network Groper)
• Ping is a computer network administration software utility used to test the reachability of a host
on an Internet Protocol (IP) network.
• Ping measures the round-trip time for messages sent from the originating host to a destination
computer that are echoed back to the source.
• Ping operates by means of Internet Control Message Protocol (ICMP) packets.
• Pinging involves sending an ICMP echo request to the target host and waiting for an ICMP echo
reply.

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Network Configuration
ARP (Address Resolution Protocol)
Address Resolution Protocol (ARP) is a protocol or procedure that connects an ever-
changing Internet Protocol (IP) address to a fixed physical machine address, also known as
a media access control (MAC) address, in a local-area network (LAN).
HOW DOES ARP WORK ?
After sending ping Request the Arp protocol try to find where the MAC address related to
this destination by broadcasts an ARP request to all devices on the same subnet if the
destination IP in the same subnet or flood the broadcast to another network subnet throw
the router if destination IP not int the same subnet.
APR Command:
Apr –a to show arp table
Arp –d to clear arp table

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Network Configuration
ARP (Address Resolution Protocol)

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Network Configuration
ARP (Address Resolution Protocol)

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Network Configuration
Vlans
Virtual Lan:
A virtual local area network (VLAN) is any broadcast domain that is partitioned and
isolated in a computer network at the data link layer (OSI layer 2).

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Network Configuration
Vlans

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Network Configuration

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Network Configuration
Vlans
CONFIGURATION:
SW1(config-if)#switchport trunk allowed vlan 10,30
ACCESS
ACCESS
TRUNK

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Network Configuration
Ip ROUTING (Static Route)
You can configure static routes to direct packets to the destination network. A static route is
a pre-determined pathway that a packet must travel to reach a specific host or network

70. Fiber Maintenance
05

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Network Configuration
Fiber cut maintenance
Fusion splicing:
tools:
Fusion splicer

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Network Configuration
Fiber cut maintenance
Fusion splicing:
tools:
Cleaver

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Network Configuration
Fiber cut maintenance
Fusion splicing:
tools:
Stripper

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Network Configuration
Fiber cut maintenance
Fusion splicing:
tools:

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Network Configuration
Fiber cut maintenance
Fusion splicing:
tools:
Optical fiber cleaner cassette
Optical fiber cleaner

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Network Configuration
Fiber cut maintenance
Fusion splicing:
tools:

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Network Configuration
Fiber cut maintenance
Fusion splicing:
Steps:

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Network Configuration
Fiber cut maintenance
Fusion splicing:
Steps:
After stripping the fiber, we need to have a sharp end fiber cut before fusion splicer join step. The end
of the fiber should be 90 degree from both end of fiber this can be done by using cleaver.

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Network Configuration
Fiber cut maintenance
Fusion splicing:
Steps: using cleaver to cut the fiber at 90 degree

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Network Configuration
Fiber cut maintenance
Fusion splicing:

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Network Configuration
• Fiber Power Budget
• Each network design need to know how much the power of the fiber to design there network.
• To know what type of devices to use.
• How much devices along each path needed.
• And also what does the cost of the technology worth.

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Network Configuration
Fiber Power Budget
Optical Power Budget
=
Fiber loss
+
Splicing loss
+
Connector loss

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Network Configuration
Fiber Power Budget

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Network Configuration
Fiber Power Budget

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Network Configuration
How to measure fiber link or detect the fault?
By using OTDR (optical time domain reflectometer)

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Network Configuration
OTDR (Optical Time Domain Reflectometer)
An optical time-domain reflectometer (OTDR) is an optoelectronic instrument used to characterize an
optical fiber.
OTDR send Pulse of light and Receive the reflectance portion of the light measuring pulse power and
time to give accurate fiber characteristics.

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Network Configuration
OTDR (Optical Time Domain Reflectometer)

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Network Configuration
Power Meter
Device measure the optical receive power

89. Thank you