FTTx Architecture
Technical Trainer College
ICT Department
Bachelor Thesis: FTTx Architecture
First Supervisor: Dr. Wolfgang Frohberg.
Second Supervisor: Dr. Salem Lepaja.
ID.NO. 202302103 - Moayad AlZoghiby
Submission Date: 28.4.2012
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Bachelor Thesis: FTTx Architecture
Moayad AlZoghaiby
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Abstract
The growing of telecom companies and the popularity of the Internet service is the
key beyond the development of new access methods, which enables a customer
to use high speed Internet connection. Fiber optic technology is the technology of
the modern era by offering an ultimate solution to the customer premises. There
are several reasons to motivate telecom business use the fiber cables rather than
the copper cables. The inexpensive material used to make optical fiber cables
where the high bandwidth that fibers can offer over long distance. Also, fiber is not
attracted to interference, because the optical source is laser. The different
technical aspects of fiber optics have been presented on this thesis to describe
how the rollout of the Fiber To The x (FTTx) is applied including its equipment.
In this paper we present a brief overview of optical fiber cable including the
concept, types, operating wavelengths, advantages and disadvantages, the signal
transmission mechanism, transmission characteristics and the different optical
architectures passive/active networks which are related to the general architecture
FTTx. In our analysis the comparison of the different architecture methods is
presented of all FTTx types. The applications of each system are looked at
different viewpoints from their advantages and disadvantages are mentioned.
However, there is series factor should be taken on consideration as telecom
providers of deploying these kind of architectures. By deciding which method is
appropriate to deliver services to subscribers and the best budget to maintain it.
Also, which best for them is by deploying AON network that is point-to-point, or
passive network point-to-multipoint?
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1 FTTx Abstract
2 Introduction ................................................................................................................... 5
3 Fiber Optic Overview ................................................................................................ 7
3.1 Definition ............................................................................................................................. 7 3.2 Fiber Structure .................................................................................................................. 7 3.3 Decibel Unit ........................................................................................................................ 8 3.4 Electromagnetic Spectrum .......................................................................................... 9 3.5 Optical communication bands ................................................................................. 11 3.6 Operating Wavelength Windows ............................................................................ 12 3.7 Basic Concept of Fiber Optic Communication System ................................ 12 3.8 Advantages of Communication systems ............................................................ 14
4 Fiber Optic Cable Types ....................................................................................... 15
4.1 Based on refractive index profile ........................................................................... 15 4.2 Based on Fiber Modes ................................................................................................. 17 4.3 Mode Field diameter ..................................................................................................... 19 4.4 Based on the material used ...................................................................................... 20 4.5 Signal Transmission Mechanism ........................................................................... 20 4.6 Snell’s Law ....................................................................................................................... 20 4.7 Critical Angle (Øc) ......................................................................................................... 21 4.8 Total Internal reflection ............................................................................................... 21 4.9 Acceptance Angle ......................................................................................................... 22
5 Transmission Characteristics FO ..................................................................... 23
5.1 Attenuation ....................................................................................................................... 23 5.2 Fiber Dispersion ............................................................................................................. 26 5.3 Signal Multiplexing ....................................................................................................... 28 5.4 PON-WDM Components ............................................................................................. 29
6 Access technologies .............................................................................................. 30
6.1 Network Architecture Concept ................................................................................ 30 6.2 Types of Network ........................................................................................................... 31 6.3 Network Terminology................................................................................................... 31 6.4 Premises Terminology ................................................................................................ 32
7 FTTx overview ........................................................................................................... 33
7.1 FTTx Concept .................................................................................................................. 33 7.2 Why FTTx? ........................................................................................................................ 33 7.3 Features and benefits .................................................................................................. 34 7.4 FTTx scenarios ............................................................................................................... 34 7.5 FITL ...................................................................................................................................... 36
8 Optical Part ............................................................................................................... 37
8.1 Direct Fiber ......................................................................................................... 37
8.2 Shared Fiber ....................................................................................................... 38
8.2.1 Active Optical Network (AON) ............................................................. 39
8.2.2 Advantages and disadvantages of AON ......................................... 40
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8.2.3 Passive Optical Network (PON) .......................................................... 40
8.2.4 Types of PONs ........................................................................................... 42
8.2.5 Advantages and disadvantages of PONs ................................................ 43 8.3 Comparison AON Vs. PON ........................................................................................ 44
9 FTTx Architecture .................................................................................................... 45
9.1 FTTH Architecture ......................................................................................................... 45 9.2 FTTC Architecture ......................................................................................................... 47 9.3 FTTB Architecture. ........................................................................................................ 48 9.4 FTTP Architecture ......................................................................................................... 49 9.5 Advantages and Disadvantages of all FTTx ...................................................... 52
10 FTTx issues ................................................................................................................ 53
10.1 FTTx design issues .................................................................................................... 53 10.2 FTTx Installation Issues ........................................................................................... 54 10.3 FTTx Testing Issues ................................................................................................... 54 10.4 FTTx Safety issues ..................................................................................................... 55
11 Conclusion ................................................................................................................. 56
12 Vocational Pedagogy part: (FTTx Concept 50min) ................................... 58
12.1 Curriculum analysis. .................................................................................................. 58 12.2 Content analysis .......................................................................................................... 60 12.3 Didactic analysis ......................................................................................................... 61 12.4 Learning objectives .................................................................................................... 63 12.5 Process Overview of a lesson plan ..................................................................... 63
13 Bibliography .............................................................................................................. 66
14 Annex ............................................................................................................................ 68
15 Statutory declaration ............................................................................................. 70
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2 Introduction
Using light to transmit information is not exactly new; in1870 AD Tyndall was the
first scientist who introduced the principle of optical transmission in light of internal
reflection to follow desired path or specific path that is called as “Tyndall
Hypothesis”. The first person that used an optical medium to send an AM audio
link was Alexander Graham Bell in 1880 AD and the modulation of sunlight to send
that message over 200km. However, The development of optical fiber started in
1960s by the invention of Laser, and the real use of optical fiber began in 1980s by
transmitting video message at Lake Placid.
In this thesis on chapter three; presents the fundamental understanding of optical
fiber cables by defining the fiber structure, the unit used to measure fiber power.
Also, the basic concept of fiber optic system is explained with their equivalent
equipment. Operating wavelengths and its spectral bands were touched and finally
the advantages of using fiber as a modern communication system. On chapter
four; the types of optical fiber based on their materials, modes, and the refractive
index were thoroughly mentioned. Also, the technique used in fiber that shows
how does the light rays propagated through fiber?
The last chapter of optical fiber fundamental the fifth; concerns about the fiber
characteristics, which rather dealing with defects of fiber whether caused by long
distance transmission or by manufacturers.
The type of network is important to design the FTTx, In FTTx we on MAN network
and the geographical area is about 20km long. Each of the premises has the own
name, which is to identify the needs of the data rate.
FITL fiber in the loop is the old name of FTTx it was used in the past, its carry the
POTS telephone line from the central offices to the premises. FITL today is much
more components between the CO to the premises it contains of OLT, ONT, ONU
and Box splicing and PON or AON network technology, each of these elements
has the own functions and its will coming in chapter seven.
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Since that year, the development of fiber grows continuously until the
telecommunication network based on fiber optic technology dominating the
transmission communication systems.
Optical fiber plays a vital role of the infrastructure of communication system due to
the high capacity, the security, and the long life span that fiber cables can offer
compared to any other communication link. In modern communication network
there are several architectures has been introduced, in order to provide services to
customers. These communication networks are depending on the terminology, as
the following:
1. FTTP, which refers to all type of premises.
2. FTTH, which refers to homes and small business.
3. FTTC, which refers to the nearest curb of premise (from the curb to premises
using the copper cable).
4. FTTB, which similar to FTTC but copper cable is located at the entrance of
building without using curb. Types of FTTx architecture will introduce in
chapter nine.
At the end of the thesis the explaining of which steps are taken to build the full
type of FTTx network and the requirement for that starting from Designing the
network (in which network topology is?), Installing the whole FTTx equipment in
FITL and the Testing after implemented the FTTx network and finally the Safety
part. All that will be in chapter ten.
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3 Fiber Optic Overview
3.1 Definition
Optical fiber is a type of medium that carries information from one point to another
in form of light pulses. Optical fiber cable uses smooth, thin hair strands that made
of glass or plastic to transmit data as a pulse of light, and the cable’s diameter
around the human hair in size. Optical fiber communication technology uses light
as a signal carrier, which is an electromagnetic radiation. The light is transmitted
using laser, or LED as a transmitter that encodes frequency signals into light
pulses (ones and zeros) along the fiber. The receiving end has a detector, which
converts the light pulses back into data through fiber optic. Optic fiber cable
consists of three main components, which play a role of transmitting the signal see
the following figure.
3.2 Fiber Structure
Fiber optic cable mainly consists of core and cladding, which are made up of fused
silica. Germanium dopant is added to the core to raise the refraction index. Figure
3.1: FO structure.
Core
The central part of the fiber cable where the light is transmitted, and is made of
silica glass. The core diameter is 8 µm for single mode fiber, and 50 µm or 62.5
µm for multi mode fiber.
Cladding
The second layer of the fiber cable that surrounds the core where the light is
trapped in the core and guides it along the fiber. The typical cladding diameter is
125 µm.
Figure3.1: Construction of optical fiber.
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Primary Coating
Primary coating or buffer coating is a plastic coating that provides protection to the
glass from physical damages of both core and cladding.
Strength Members (Kevlar)
The benefit of Kevlar is to pull out the fiberglass during installation, also to protect
the fiberglass from damages.
3.3 Decibel Unit
In communication systems decibel is often used to measure the power, which
gives the ratio of the input power (Pin) to the output power (Pout). The ratio is
expressed in a logarithmic unit (based on power 10). For power measurement, dB
is defined as: dB = 10 x log (output power/input power). For example, the signal
strength in fiber results from loss mechanism (attenuation) in a transmission where
the output power level becomes (50%) of its input, therefore the loss of the cable
is expressed by this formula 10 x log (0.5) = -0.3 dB. (Which is the reduction of the
signal).
Decibel unit is used in two cases:
To express fiber and component loss.
To express power quantities in various points of optical cable that are called
`(power level).
The benefit of using decibel unit is to convert high values to small ones, which
converts multiplications to addition and division to subtraction.
Metric Prefixes
The metric prefixes define units, terms and the real size of units with their
corresponding symbols, which are used in optical fiber communications. These
prefixes show the measurements of data of very big and very small values. In the
metric prefixes table below, prefixes are defined to the power of ten factor; where
the positive units represent the number of zeros after figure it out, whereas the
negative units represent the number of decimal places after the decimal point. For
instance one Kilowatt = 10x10x10 = 103 (10 to the power of three is ten multiplied
by itself three times), one mill watt is 1 x 10-3 = 0.001W).
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3.4 Electromagnetic Spectrum
Telecommunication systems transmit signals in the form of electromagnetic
energy, which contains radio waves, microwaves, infrared light, and ultra light, x-
rays, Gama rays, and visible light portions of spectrum can all be used for
transmitting information by modulating various measurements that related to
electromagnetic waves.
Waves in electromagnetic spectrum are varying in size from very long radio waves
to very short radio waves. The electromagnetic spectrum is a sequence of
electromagnetic waves (electrical and magnetic fields) both fields have direction
and amplitude (strength). The electromagnetic spectrum from very low frequency
to optical frequencies is shown in figure 3.2.
Figure3.2: Spectrum of electromagnetic waves.
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Light has a wave nature, which propagates
through the space as much same as radio
waves. Light in fiber has different colors, and
each color has a specific wavelength in the
electromagnetic spectrum. The following
figure 3.3 shows the Different wavelengths
represent colors represents specific colors.
All electromagnetic waves shown above are travel at the speed of light, which is
around (3x108 m/s) or (1.8x105 miles/second) in a vacuum. The speed of light in a
material is less than the speed of light in a vacuum. The physical property of the
waves can be measured in different ways, by measuring the oscillating frequency
of the waves. Whereas electrical signal transmission tends to use frequency to
designates the signal operating bands. Optical communication uses wavelength to
designate the spectral operating region and photon energy waves (optical power).
So, there are three ways to measure various regions in the electromagnetic
spectrum. First the frequency (f) is equal to the speed of light (C) divided by the
wavelength (λ).
f = c / λ
Another way of measuring the propagated waves by using “Quantum Theory” that
light wave consists of many tiny particles. Each one of these particles represents
discrete quanta (packet of energy), or photons. The photons are uncharged
particles within a light and their energy content is determined by the frequency, or
the wavelength. This equation is known as Planck’s law.
E = h x f
Where the parameters, E = energy, and h = 6.63x10-34 J.s = 4.14 eV.s, which is
called Plank’s constant. J refers to the unit Joules, and eV refers to the electron
volts that is given by:
E (eV) =
Figure3.3: the visible lights in a rainbow
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3.5 Optical communication bands
Optical spectrum ranges from (5nm) ultraviolet to (1mm) infrared, and the visible
region begins from 400nm to 700nm bands. Optical fiber uses the spectral band
from 800nm to 1675nm. International Telecommunications Union (ITU) has
designated six spectral bands, which are used for intermediate range and long
distance range dedicated for optical fiber communications. These wavelength
ranges begin from 1260nm to 1675nm regions. These bands designations are
matching the physical characteristics of the optical fiber cable and the
performance of the optical amplifiers. These regions are known by (O, E, S, C, L
and U) letters, which are defined in the figure 3.4:
Each letter represents specific bands range, which defines the operation of its
wavelengths, as the follows of Table 3.2:
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3.6 Operating Wavelength Windows
Optical fiber transmission uses wavelengths, which are near located to the infrared
portion of the electromagnetic spectrums, and above the visible light. Hence, the
human eyes cannot see it. The typical optical transmission wavelength windows
are shown as the following:
o First Window
o Second Window
o Third Window
o For Plastic Fiber
Both lasers and Light Emitting Diodes (LEDs) are used to transmit optical light. In
practical lasers usually used for 1310nm and 1550nm in single mode applications,
and LEDs usually used for 850nm and 1310nm in multimode applications. But in
advanced communication systems operate at , because it has a
minimum attenuation at this wavelength. While Different wavelengths windows are
operating at different types of fibers, as the follows table 3.3.
3.7 Basic Concept of Fiber Optic Communication System
The following figure 3.5 shows a block diagram of a typical communication system
to transfer messages from the transmitter to the receiver.
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Optical communication system is different of any other communication system in
principle of carrying information signals, where the medium is completely digital;
therefore analog signals need to be converted into digital signal. The typical optical
carrier frequency is very large around 100 THz, which is exceeding other
communication systems. The following diagram shows the optical communication
system block diagram.
Transmitter Section: Transmitting information e.g. voice, video, or computer in
form light signal. As it shown above the circuit it’s an A/D (Analog to Digital
converter) by coder (converter) circuit. If the input signal is digital it’s directly
connected to the light source circuit, if the input signal is analog it’s first converted
into digital signal and passed the light source circuit.
The light source block either a Light Emitting Diode (LED) or a laser beam source,
or in some cases infrared beam is also used. The rate o light source at turns to
ON/OFF depends on the frequency of digital pulses. Once the signal is converted
into equivalent light pulses and focused at the fiber optic cable. Then it is received
at the other end of the fiber optic cable.
Fiber Optic Cable: When light pulses are fed into one end of the fiber optic cable
they passed onto the other end (at the receiver).
Passive Devices: Optical components are passive devices that do not require
electronic controlling of their operations. Optical connectors are used to connect
cables to the indoor/outdoor devices optical splices to join two optical cables
together. Also, optical isolators are used to prevent unwanted light to go in a back
Figure 3.6: Block diagram of typical optical system
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direction, and optical filters, which selects narrow band to pass through the fiber
cable these are work as passive devices.
Optical Amplifiers: When the signal becomes weakened (power loss) after the
signal has travelled along the fiber. At that point the light signal needs to be
regenerated or boost up. In fact, the signal is converted to electrical signal to be
amplified (regenerated), and then converted back into light optical signal.
Receiver Section: at the receiving end, the light detector, or a photodiode is used
to detect the light pulse, which called a (transducer). To convert light signals into
electrical signals, then gets amplified and reshaped into original digital pulses.
These units are used in optical communication system, however if the distance
between the transmitter and the receiver is very large, then Repeater units are
used. Once the repeaters are used the attenuation is recovered, thus light signals
at the far end are converted into electrical signals, amplified, and then
retransmitted.
3.8 Advantages of Communication systems
1. Large Transmission Capacity.
The carrier (optical frequency) is very high in the range of 1014 HZ, which is a high
bandwidth rate; hence the system transmission capacity is increased.
2. Immunity to Interference and Crosstalk.
Optical fibers are fabricated from dielectric materials; therefore, they are
completely immune to electrostatic and electromagnetic interference. They are
made from either glass or plastic, which are electrically isolated. This property
makes the optical fiber transmission ideal solution in electrical hazardous
environment.
3. Low Loss.
The development of optical fiber over the last ten years has come up to the
production of optical fiber with very low transmission loss (Attenuation) compared
to other types of transmission lines. Optical fibers have been fabricated with loss
around ≈ 0.2dB/km, which means greater distance between repeaters and
becomes the best transmission line for very long distance.
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4. Long Life span.
Optical fibers have longer life span between 20 to 30 years compared to the
conventional copper wires. The reason is that the core of optical fiber is made from
silica, therefore does not corrode as metal.
5. Optical transmission system is capable to be expanding.
Fiber optic systems can be upgraded to expand the system capability by replacing
the transmitter laser, LED, or using the Wavelength Division Multiplexing (WDM).
6. Wide temperature Range.
Optical fibers are manufactured to operate at low temperature degree around -40˚
to +85˚.
7. Large Bandwidth with small diameter and lightweight.
The amount of information that carried out in the fiber is very large compared to
the copper line. Optical fiber has very small diameter in the range of micrometers
[µm]. The demand of bandwidth is increased rapidly with advanced technology,
which makes the fiber paly a vital role for long distance and short distance with
high-speed interconnection applications. Therefore, this size is smaller and much
lighter than copper cables, and they can be used effectively in aircrafts, ships,
trains, and satellite. Also, they provide high quality transmission, thus will increase
the amount of bandwidth with high bit error rate (BER) ≈ 10-9.
4 Fiber Optic Cable Types
Optical fiber can be classified into three categories depending on; refractive index
profile, number of modes, and the materials used.
4.1 Based on refractive index profile
The different of them is the way of the light is travelling through the fiber. The
different main parts of the fiber are dedicated as the core and the cladding where
the cladding is surround the core. But in advance the cladding has a different
refractive index than in the core. Optical fibers can be divided into two major types
step-index fibers and graded-index fibers.
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Step-Index Fiber.
The fiber has a refractive index that steps from low to high and so on, which
bounces between the core and the cladding and the refractive index in the core
has a constant value slightly greater than the value for cladding and change at the
core-cladding interface. The physical parameters such as the refractive index,
differences at fiber index, core radius that determines the maximum number of
guided modes in both multimode and single mode fibers. In a multimode step
index fiber the core diameter is around 50µm, with multi propagation modes of
light waves are shown on figure 4.1.
Single mode fiber has a core diameter of the order of 2 to 10µm, and the relative
refractive index (∆) is about 0.001 with single propagation mode of light wave.
.
The parameters (n) refer to the core radius [µm], and the cladding radius referred
as (d) in [µm]. In multimode step-index fibers the number of propagating modes
(Ms) that is used to determine the propagated signal inside the fiber by using the
following formula:
Ms = v2/2
When the refractive index of the core is constant, and the velocity of all
propagated modes is constant and determine the rays inside by the following
equation:
V =
Here V is known as cut-off frequency, which is referred as V-number, but it is
related to the fiber size, or the refractive index.
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The distinct disadvantage of multimode step-index fiber is the rays that have
different paths due to the constant velocity. The rays will reach the fiber end at
different times, which leads to a time delay between the propagating modes
through the fiber. These modes are known as an intermodal dispersion that limits
the transmission bit rate and therefore the fiber transmission distance.
Graded-Index Fibers
Graded-index fibers decreasing the core index n(r) with a radial distance from the
maximum value of n1 at the axis of n2 beyond the core radius (a) in the cladding.
On this fiber the light is transmitted through the fiber either at the wavelength
1300nm, or at 850nm bands. The best design of optical propagation is for
multimode graded-index fiber near to the parabolic refractive index with
. The number of propagating modes Mg is supported by the graded index
Where is the parameter profile that gives the characteristics of refractive index
profile of the fiber core. When the fiber has the following profile values they
indicated to specific core shape:
o
o
o
The shape of refractive index profile is illustrated in Figure 4.2:
4.2 Based on Fiber Modes
Light inside the optical fiber propagates as different rays with specific propagating
angles. The different rays are called (Modes), and each mode propagates at
specific order such as smaller mode in propagation angle indicated to lower in
order of modes. Thus, the propagating modes in fiber in central axis is called
(zero-order mode), or the fundamental mode. However, when the propagation
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mode is transmitted at critical angle is indicating to the highest order mode for the
fiber. There are four different types of propagation modes:
1. Transverse electric (TE) modes.
2. Transverse magnetic (TM) modes.
3. HE modes.
4. EH modes.
Where, (E) indicated to denotes electric field, and (H) denotes magnetic field. The
propagating mode numbers are determined by the normalized frequency
parameter, which is called (V-number). However, there are two major types of
fiber optic cable, single-mode and multi-mode. See figure 4.3
Single-Mode - The core diameter of a single-mode is about 8-10 micron. The
small core size allows only one light mode to travel within the core. The higher the
bandwidth, the more information carrying, thus more capacity the cable has. This
type of cable is preferred used for long distance, and the telephone companies
use it for long haul transmissions. Single mode has a lower attenuation compared
to the multimode (about the half). The main advantage of single mode in optical
fiber is that intermodal dispersion might be avoided, because there is only one
propagated mode, therefore no time delay.
Multi-Mode - The core diameter of a multimode is about 50-100 micron. The large
core allows many light modes to travel through the core simultaneously. Mode
overlap can occur over longer distances and may cause bit errors. Multimode is
often used for short distance transmission. Multimode fiber provides high
bandwidth at high speeds (10 to 100 Mbps - Gigabits to 275m to 2km) over
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medium distances. For long distance fiber link can carry light signal (up to 2 km),
with multi-paths of signal can cause signal distortion at the receiving end.
Which type of fiber is in use for FTTx?
Well, both of them are used for FTTx and the decision depends on the distance
and the bandwidth used. However, the most common type used in Saudi Arabia is
single-mode fiber due to the high bandwidth that can carry over long distance.
4.3 Mode Field diameter
Is a parameter for classifying single mode fiber properties that takes into the partial
field penetration into the fiber cladding. It is a rather a measurement for the fiber
core. It can be regarded as the single analog mode of the fiber core diameter in
multimode fibers and is a little bit larger than single mode fiber in the core diameter.
Gaussian Function expresses the distribution filed
through single mode optical fiber, also called (bell
shapes, or bell curve). Gaussian function
approximates the shapes of the output light signal
of the normalized frequency. See figure 4.4.
Where w is the mode field radius or the stop size by
the following formula:
MFD = 2wc
Figure4.4: Gaussian distribution of single mode fiber.
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4.4 Based on the material used
Fiber cables are manufactured by either plastic, or glass. See operating
wavelength. Where the wavelength of plastic fiber is only used at 650nm, whereas
glass fiber uses three different wavelengths that are 850nm, 1300nm and 1550nm.
4.5 Signal Transmission Mechanism
The light propagation and the transmission of light along the fiber is described
by two theories:
1. The light rays propagated at different refractive index (n) and different
velocities and this is called (Ray Theory). Also, describes the two types of rays
can be propagated through the fiber.
Meridional rays: Defines the passing rays through the axis of the fiber. It is
used to show how the light in optical fiber is transmitted.
Skew rays: Defines the transmitted rays along the fiber by bouncing through
the line, instead of passing its axis.
While Ray theory is used to gives the approximate amount of acceptance light
and the guide of light in optical light and can be defined as:
n =
Where, c is the light velocity in the medium, and co is the speed of light in free
space. If n = 1 is indicated to the air, n = 1.33 is indicated to the water, and n =
1.5 is indicated to glass.
2. The light is described as an electromagnetic wave, which is called (Mode
theory). It describes the light wave modes of optical fiber by giving the
characteristics of optical fiber transmission of absorption, attenuation, and
dispersion. The propagated light rays through the fiber are based on three
parameters, total reflection, Acceptance angle, and numerical aperture.
4.6 Snell’s Law
Snell’s law defines the link between the incident and refracted rays and their
angles; the following figure 4.5 shows the Snell’s law.
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The Snell’s law applied in fiber optic as follows:
n1 sin Ø 1 = n2 sin Ø 2 or
=
Where:
n1 and n2: are the refractive index of first and second media.
Ø1: is the incident angle.
Ø2: is the refraction angle.
Ø3: is the reflection angle.
And n1 > n2, therefore Ø2 > Ø1
4.7 Critical Angle (Øc)
If the incident angle of Ø1 is increased where the
light rays in air are vertical to the glass surface
this is known as “Critical angle”. When the
incidence angle is high where the refraction angle
is (90˚) then it is called critical angle. If the light
ray of incident angle is greater than the critical
angle the light rays are completely reflected back
into the glass and that is called “total internal
reflection”. Figure 4.6: shows Critical Angle.
4.8 Total Internal reflection
The light rays propagate between two different media at different refractive index
n1 and n2. When Ø1 > Øc the light is totally reflected, and the total internal
Figure 4.6: Critical case if incidence angle.
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reflection is obtained when the incident light on the dielectric is at lower refractive
index (n2), and from dielectric to higher refractive index (n1). The transmission of
light along the fiber is based on the total internal reflection. Total internal reflection
occurs when n1 > n2 and the incident ray of light is makes an angle Øc, when this
occurs it doesn’t enter the medium it is rather transmit along the interface and this
is called “Critical angle” as it shown on figure4.7.
4.9 Acceptance Angle
Acceptance angle is the maximum angle where the light is enter the fiber axis to
be propagated and is expressed as “Øa”. Where the light can enter the fiber within
a certain range of angle. There is a relation between the acceptance angle and the
refractive indices including; core, cladding and the surrounding medium. The
relation is between the acceptance angle and the refractive indices angle is that
the refractive index of the fiber core is n1. And refractive index of the fiber cladding
is n2, and the refractive index of the surrounding medium is n0. Figure 4.8: shown
the light goes from the Emitter to the fiber core.
Figure 4.8: Acceptance angle to the fiber core
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5 Transmission Characteristics FO
5.1 Attenuation
Optical fiber communication system has two critical transmission characteristics
Attenuation and Dispersion, which play a major role of determining the
maximum distance that optical fiber cable can reach, or in other word can
determine the performance optical communication system. Fiber loss falls into two
categories Attenuation and Bandwidth (dispersion). Material absorption,
scattering, and bending loss are caused by attenuation; whereas bandwidth is the
amount of bits that can be transmitted that causes signal dispersion.
Attenuation is the loss of optical power due to the distance of travelling along the
fiber. Where the signal attenuation is defined as the ratio of input (Pin) power to
the output power (Pout). The general formula to measure the attenuation:
Attenuation (dB) = 10 / L * Log (Pin / Pout)
Attenuation values are vary depending on the fiber type and the wavelength,
where the higher the wavelengths the lower the attenuation as it shown on figure
5.1:
“Water peak” fiber refers to the manufacturing of single-mode fiber by reducing the
water mixed in fiber (H2O- ions) that causes higher spectral attenuation at
wavelengths 1244nm and 1383nm. At the water peaks the attenuation is around 2
dB/km while low water peak attenuation is around 0.4 dB/km. However,
attenuation is a wavelength dependent and is determined in decibel per kilometer
(dB/km) by the following formula:
Figure5.1: Attenuation Spectrum of optical fiber.
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Loss in decibel (dB) = 10 log₁ ₀ (
)
Where, Pin is the input power, and Pout is the output power. There are three
factors in fiber that can cause attenuation, as follows:
1. Material Absorption.
2. Scattering.
3. Bending Loss.
1. Material Absorption: This type of attenuation causes an absorption of light
signal, which occurs when both molecular and electronic excitation of
impurities in the fiber core i.e. metal particles and moisture. Metal particle is no
longer available due to the good manufacturing of very pure glass. However,
attenuation due to moisture is very common in fiber and it is called “Water
Peak”, which is located at the wavelength 1990nm. This wavelength region of
optical fiber is not used, but manufacturer struggling to reach the “Zero water
peak” region where the optical fiber eliminates the moisture absorption. Single
mode works in most of wavelength spectrum providing large bandwidth by
using coarse wavelength division multiplexing (CWDM) to avoid such an
attenuation that caused by moisture. Absorption is based on the manufacture
of optical fiber and controlling the amount of impurities during the manufacture
process can easily solve this issue.
Absorption losses can be classified into two main categories:
1.1. Intrinsic Attenuation occurs inside the fiber, which is caused by the
impurity in the glass while the manufacture.
1.2. Extrinsic Attenuation occurs due to both micro bending and macro
bending and is called “Bending loss”, which cause reduction in optical
power.
2. Scattering losses are caused by the interaction of light with density
fluctuations (interactions) within a fiber. It is divided into two categories, which
are Mie scattering and Rayleigh scattering.
2.1. Mie Scattering: occurs when the imperfection of manufacturing the
core, or the cladding diameter of when the light signal is propagating in
optical fiber.
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2.2. Rayleigh Scattering: Rayleigh scattering occurs when the light is
interacted with the atoms in the glass, therefore the light is scatter. Also,
when the size of the density fluctuation (fiber defect) of the core is less than
(λ/10). Loss caused by Rayleigh scattering is proportional to the fourth
power of the wavelength (λ/4). If the size of the defect is greater than
(λ/10), scattering is called Mie scattering (Insignificant).
Rayleigh scattering is the most common type of attenuation of optical fiber
and is counted as 96% of all types of attenuation. Some lights inside the
core are reflected back to the fiber input, and the electronic device used is
Optical Time Domain Reflectometer (OTDR) to test the fiber.
3. Bending Loss: Bending loss is classified according to the bend radius of
the curvature of fiber where the light signal is propagated at the bend and
gets lost. There are two main types of bending losses; Micro bending and
Macro bending.
3.1. Micro-bending loss: occurs when the light gets distorted along the
fiber that indicated by pressure on the fiber. Micro bending is very
localized and a small-scale bend and sometimes it cannot be seen, thus
special equipment is needed to test the power. Micro bending is a
wavelength dependent, hence in single mode fiber micro bend
sensitivity increases when the wavelength at 1550nm and higher. While
in multimode fiber the micro bend sensitivity is constant according the
wavelength such as in 50 µm core diameter the micro bend sensitivity is
more than 62 µm.
3.2. Macro-bending loss:
occurs when the fiber has a
large radius of curvature,
which is relative to the fiber
diameter. When the light is
exceeds the core and run
along the cladding and that
causes a “Critical angle”.
The bending radius affects the refractive index on the bending region
and reflects the light signal back to the core and then causes
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attenuation. The optical power will be increased when the radius of the
curvature is decreased less than 1dB, as it shown on figure 5.2.
Macro bending is a large-scale bending where the bending can be seen.
Optical fiber with minimum radius specification, and large numerical
aperture with low core and cladding has a less sensitivity to the macro
bending. See figure 5.3.
5.2 Fiber Dispersion
Fiber dispersion is the spreading out (broadening) of the light pulses as they
propagated through the fiber. Dispersion occurs when some components of input
signal i.e. numerical aperture, refractive index profile, core diameter, laser or LED
line width and wavelength are causes the pulse broadening. In attenuation the
power becomes weaker with distance that reduces the amplitude of the output
waveform, and it does not alter the shape of the output signal as on the following
figure 5.4:
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Dispersion on fiber has three types:
A. Chromatic dispersion (Material dispersion).
B. Modal dispersion.
C. Intermodal dispersion.
1. Chromatic Dispersion (Material Dispersion): Refractive index (n) of
Silica is a function of wavelength, exists in all fibers, function of the source
line width. Occurs as a product of the spectral width of the source (Laser or
LED), which consist different range of wavelengths that has different
velocities. In laser the spectral width is very small and carries few numbers
of wavelengths, because shorter wavelengths transmitted slower than
longer wavelengths (short frequency). Different light modes travel at
different velocities with different time, exist only in multimode fiber as it
shown on the following figure 5.5:
2. Modal Dispersion: The spread effect caused by using multimode fiber
where the time delay occurs and the fiber has different modes (Lower order
and higher order) and the light signals are propagated at different velocities.
Some of these light rays are transmitted through out the core (lower order
of modes) and higher order modes (those rays are bouncing between
cladding and core). See Figure 5.6:
Figure 5.6: Model Dispersion Propagation
Figure 5.5: Chromatic dispersion.
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3. Waveguide Dispersion: Signal in the cladding travel with a different
velocity than the signal in the core, significant in single mode conditions. It
caused by power distribution. This type of dispersion caused by the effect of
the shape of core index, where the light in core propagates faster than in
the cladding. The light is propagated through out the fiber in an area that
exceeds the diameter of the core, which called “Mode field diameter”. It is a
function of the wavelength where longer wavelengths propagate in larger
mode field, as it shown on the following 5.7:
5.3 Signal Multiplexing
Multiplexing is an essential part of any communication systems where multiple
users are sharing the same medium, which is in our case is optical fiber link.
Multiplexing is used to increase the capability of the system to transmit more
signals, and decrease the system costs. There are two main types of multiplexing
techniques for optical fiber communication systems; Time Division Multiplexing
(TDM), and Wavelength Division Multiplexing (WDM). Where TDM is performed in
the electrical domain where the multiple input signals are transmitted through the
optical fiber in the same time. And WDM is the process of combining multiple input
signals are transmitted through the optical fiber at different wavelengths, and the
popular operating wavelengths are 1310nm and 1550nm.
However, the most common type of Wavelength Division Multiplexing is called
“Coarse Wavelength Division Multiplexing”. CWDM operates up to 18 wavelengths
in a metropolitan network between 1310nm and 1550nm, which applies greater
spacing at 20nm. In single-mode fiber CWDM operating wavelengths are 1270nm
to 1610nm, whereas multimode fiber CWDM operating wavelengths are 778nm,
800nm, 825nm, and 850nm. The devices use this type of multiplexing have large
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frequencies greater than 100GHz with different spectral bands. The following
figure 5.6 shows the spectrum bands of CWDM.
5.4 PON-WDM Components
First thing before explaining the components of WDM technology, there is some
equipment of WDM, which are electrical devices that play major role in
communication systems.
1. Two fibers are required and another two for backup, because the fiber ring is
two directional of data flow.
2. In AON technology, generators are important (so the data is not going out).
The functions of regenerators are to reshape and amplify the signal. These are
required from the electrical circuits to do first two makes conversion from the
electrical single into optical, then regenerate and amplification and back to
conversion from optical signal to electrical.
3. ADM (Add-Drop Multiplexer), does three things in on time which they are:
Passing the data along of fiber line equally.
In the receiver fiber, take the optical signal from the coming fiber and
converted into electrical signal, then De-Multiplexing (Downlink) the out
come signal to take out the portion and then transmitting the signal portion
to the premises.
In Sender fiber, take the electrical signal that was be converted from the
premise, then multiplexing (uplink) the signal with other premises single
around the network ring, and finally converting the electrical signal to the
optical light signal, so to e transmitted to the network ring.
Some times, In PON technology each of premises has to have the Ethernet
switching, because each of customers has the own fiber cable.
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6 Access technologies
6.1 Network Architecture Concept
The concept of network architectures is commonly use when the discussion for
design and implementation of telecommunication network. The Architectures of
Network are sets the rules and for sure they conventions. Here, the Architectures
of Network in telecommunication system describes the physical arrangement and
operational of two equipment together which we need a protocols. Architectures
make the rules, which the name it is “protocols” and protocols commonly use to
make the rules of each of controlling, formatting, exchanging and interpretations of
data that send from point to other point. For that international organization for
standardization creating an OSI (Open System Layers interconnect) model.
OSI model has the seven layers and it’s a main protocol of whose build the
network, OSI guiding the telecoms companies for what steps they should start and
end. OSI model starts from bottom to the top (as shown at the Figure 6.1), which
the layers are physical, data link, network, Transport, session, presentation and
finally the application.
Each of OSI layers has the own functionality such
like layer No.1 Physical layer: is for the transmitting
data into transmission medium (which the FTTx
network are). For layer No.2 Data link layer: is to
exchanging the data between two points. And layer
No.3 a Network is about the routing and switching
the information. For layer No.4 a Transport is to
providing end-to-end transmission of data. And
layer No.5 Session layer is for maintains dialog
between two devices. For layer No.6 Presentation
layer is for formation the data like (encrypt, and
encoding the data). And finally the layer No.7 is
Application layer it’s for users accessory and file transferring. Layers No.1, 2 and 3
is responsibility of network and Layers No, 4, 5, 6 and 7 it’s for host system or
provider.
Figure 6.1: OSI layers
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6.2 Types of Network
There are many types of network, and the most important for this project are :
WAN (Wide area network): is the largest area its common between two
cities or facilities.
MAN (Metropolitan area network): are covers most area of one city it’s
become between neighborhoods and three or five blocks, which the FTTx
Network are.
LAN (local area network): its localized area network for homes, building
and rooms.
6.3 Network Terminology
To understanding FTTx network we must define some terms of network
terminology, and the function of each elements before the fiber cable goes to the
customer. (Look at the Figure 6.2) the network terminologies are:
Central office (CO): Generally, Central office is a building of switching for the
telephones line in one facility and three or more neighborhoods in public
network they called it Co (central office) or other called it a point of presence
(POP) and the old name for CO is EXCH (Exchange) which that’s mean to
exchange the telephone between two subscriber line. The main function of
Central office is to carry out the all telephone subscriber line (with MDF
Switches), which should be a thousand of subscribers and it has another
function todays is used to connect with the main mobile stations. CO can be
cover of two or three area and neighborhood. Central office most connects
with other central offices by techniques of trunk which theses day connecting
with single mode fiber optic.
Figure 6.2: Different term of public network
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Long-haul network: The function of long haul network is to take the
information from the central offices in one city and interconnecting to the other
long-haul city (transmission links between cities), this procedure required a
long cable of single mode fiber (could be a thousand of miles), with using of
Dense Wave Division Multiplexing (DWDM) and many repeater between two
long-hauls.
Backbone network: A high capacity network which connecting different types
of network segment to each other like WAN, MAN and LAN. Backbone
responsible to interconnecting the traffic, traffics move from one segment to
other segment.
Metro interoffice network: The function of metropolitan or Metro is to connect
all central offices together in one city. The distance between two central offices
could be a ten of miles. And it’s connecting with each other by a single mode
fiber cable.
6.4 Premises Terminology
At the end of users for each customer,
the last mile network or FITL
(12miles/20Km long) can be
transferring and delivered the
information for different group of
customer like family houses, institute,
apartment and business work. And
each of these premises has a limited
of bandwidth demand and the services
order it from them (Figure6.3 showing the different term of end users), each of
these types has acronyms and function as the following:
SDU: A single dwelling unit, to serve a singles of houses.
MDU: A multiple dwelling unit, to serve full of building and apartment complex.
MHU: A multiple hospitality unit, to serve hospitals, hotels or airports.
MTU: A multiple tenant unit, to serve institutions universities and colleges.
MTU is the largest premises terminology.
Figure 6.3 the different term of end users
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SFU: A single-family unit, its alternative of SDU.
SOHO: small office/home office, to serve a small office and its look like SDU.
Each of premises terminologies require a limited bandwidth and data rate by
consideration with how its will be customized.
To distinguish between fiber flow, the term of upstream refers transmission from
end users to the central office and the term of downstream is refer to transmission
from central offices to the end-users. Access network is the best topic of
interesting a passive optical network (PON).
7 FTTx overview
7.1 FTTx Concept
Fiber to the x (FTTx) is techniques or methods of fiber installation between central
offices (CO) to the customer. FTTx “last mile” is a generic term of network
topology that’s to replace the copper cable into fiber optic. Structures of FTTx start
from central office CO to the end users, which is the customer. Most of FTTx
scenarios are PON (passive optical network) network and the main reason why
the need of this technology is to provide a large broadband access network data to
the end users.
Fiber Optic is already exists for a long distance specially between two cities and
two Exchange’s, but traditionally copper cable is exists between the central offices
and customer for that the needs to replace the copper cable to Fiber optic is
require. The main reason that we need a fiber optic between two points are to
cover the evolution of the technology and the needed of broadband capacity.
7.2 Why FTTx?
With the evolution of communication around the world, Telecom companies now
are suffering from copper cables specially in Saudi Arabia, companies which use
copper cable providing the internet and video communication they lose broadband
customers, today customers want a high speed of data, dependable voice service
and high quietly video. For that customers replace the copper cable to satellite
communications few years ago.
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Today we face a problem with copper cable and the last statistics around the
world is said the cable telephone bulk is 10% for long distance (fiber optic cable)
and 10% for a local loop(fiber optic cable) and 80% Subscriber loop(copper cable)
for that the companies is suffering. Telecoms now are losing a CATV broadband
customers, telephone provider and VOIP. Shortly the reasons why we need FTTx
network are: -
• Fiber optic will be the main transmission medium to provide a high capacity
of bandwidth for homes broadband network.
• Fiber optic is the best choose to carry a high data and to upgrading
unlimited data.
• The costs of Fiber optic and copper cable are almost the same, but with
more capability with the fiber.
• Fiber optic is much lower for maintenance and for operational costs.
• New technologies of passive optical network (PON) with cheaper
components, which makes FTTx technology much cheaper.
7.3 Features and benefits
There are many Features and benefits to use FTTx technologies like:
Quick to install and easy to maintenance.
Best performance comparison with twisted pair or coaxial cable.
Flexible design and consistently high performance levels.
Easy to absorb from a new users and technologies.
Matching with a selection of mini-cables
Tubes are available as single tube or multiple tubes, for maximum flexibility.
Lower costs for building the FTTX network.
7.4 FTTx scenarios
In General FTTx fiber to the x and x is the term of what the end is terminated, Here
X is indicating letter to how is fiber endpoint close to the end users. (Figure 7.1
shows scenarios of FTTx).
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The four main scenarios, in order of an increasingly longer fiber loop are:
1. FTTH: Fiber to the Home, using fiber optic between central office and customer
to delivered high downstream data rates and
unlimited bandwidth.
2. FTTB: Fiber to the building or business, Its
used a fiber between central office CO to the
entrance of building after that is usually copper
cable. It’s used for a high data upstream for
business work.
3. FTTC: Fiber to Curb or cabinet, fiber optic
between the central offices (CO) to the cabinet,
which is not more than 300m far from the
customer. From the cabinet to the customer is
copper cable. Used for high capacity trunks.
(E.g. for DSL). And other transmission medium is used the curbside to connect
the equipment the customer in the building.
4. FTTP: Fiber to the Premises, Generic terms that include both FTTH and FTTB.
#FTTN: Fiber to the Node or neighborhood, it’s like FTTC but the different is how
far the cabinet from the user end. Which is could be a few miles FTTN refers to a
PON (Passive Optical network). Most of telecom companies now are using FTTN
scenario.
The differences between FTTH and FTTB are FTTB is demand large data rate for
business work not like FTTH one or 4 users for one Fiber optic cable. The most
commonly used are FTTH (fiber to the home), FTTP (fiber to the premises) and
FTTC (fiber to the curb).
Today, FTTx is oreder from:
Homeowners: want FTTH for high speed internet and video downloads.
Buildiers: want FTTB to make pravet and add the value to they apartments.
Hardware Provider: want the FTTx to summetry with they hardware sales.
Whose provideing the IPTV, HDTV and video demand(e.g. viewcast).
Any institue that using a high data rate.
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7.5 FITL
The old definition of FITL is to implement and upgrading the POTS (plain old
telephone service) of telephone line in the local loop to the customer premises by
using a components of FITL with a fiber optic technology.
Particularly the telephone carriers coming from central office and its remote to the
SAI (serving area interface) or the cabinet in the neighborhood to the ONU (optical
network unit), which is located at the customer premises. In FITL the fiber is the
base from central office to the ONT or depending on the type of FTTx (See figure
7.2).
The voice, Video and data it’s coming from central office in the neighborhood to
the customer premises, with the fiber Optic cable. Optical Line termination (OLT)
is placed in central office and the function of OLT to split the cables around the
network area that served, so its must be send in higher power because its send
the optical signal out, which is divide in several stream and the main function of
OLT is to take the incoming singles like voice, video or data from the MAN network
into the PON transport. After that its goes to the Optical Network Unit (ONU),
which is located at the nearest cabinet to the customer premises.
The function of Optical Network termination (OLT) is to divided the cables into the
customer premises, OLT and ONU is the same device but the OLT is located at
the customer premises and the ONU is located at the door of houses its usually
look like a small boxes, the function of these terms is to make an interfaces
between the customer premises and the PON network, then its goes directly to the
Figure 7.2: FITL NETWORK
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OLT in CO. ONT and ONU are receiving the light signal and converting into the
electrical signal to use at the premises ends. ONU is used when the fibers are
terminated out side of houses and ONT are used the fibers spreads to the
customer premises.
The function of PON splitters (usually, placed in outdoor of cabinet or at the end of
subscriber) are to split the single to the customer, 32 subscriber can be served in
two way of ATM, this way are not important to include an ATM (add-drop
multiplexer) or installing the OSP (Out side plant). The PON splitter can be in
many topologies of network like star, tree and or ring that’s help to increasing the
reliability. Fiber to the loop is the same techniques of FTTx but with different name,
it can use all the scenario of FTTx like FTTC, FTTN and FTTP.
8 Optical Part
In fiber optic technology there are many ways to distribute the fiber cable into
network area, for that why we use the technologies of each FTTx or FITL to tell
what method can we deployed the fiber to the premises. There is two ways to
deliver the cables to the customers by direct way or shared way and for
economical reason the telecoms companies preferred a shared way and for sure
each of these ways has a techniques to delivered the voice, video and data from
the CO (central office) to the customers.
Optical portion has two techniques to delivered the fiber cable to the customer,
which they are:
1. Direct Fiber.
2. Shared Fiber.
8.1 Direct Fiber
Generally, in direct fiber each of fiber cable coming up from central office and
goes directly to the premises, dedicated fiber (e.g. point to point links,
Ethernets link). Commonly a wavelength of downstream (coming from central
office to the premises) is 1550nm combined with voice, video and data service
in one glass fiber optic cable, and for upstream wavelength is 1330nm which is
back again to the central office with the same cable. This connection can be
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operating with 10Gbps for long up to 50 Kilometer distance. In this method it’s
required a large number of fiber optic cables, with each of one cable has own
transfer for one premises.
One of advantages in this method that is each of customers has own cable
that’s make greater bandwidth and larger data rate for last technologies of the
telecoms and information for next generation.
In unfortunately, to delivered one direct fiber to the customer a Provider ask at
least 1Gbps to operate this technology to the customer and its cost a lot of
money because each of customers has own fiber cable and that required the
companies to makes a hole along distance from the central office to the
premises, and for sure this method required own components like Ethernets
switch which is located in customer and transfer in customer all components
that needed.
The application of this technology is to deliver to the all kind of end users. A
Best example of direct fiber is FTTH technology, especially whose requesting
for high bandwidth and the largest data rate.
8.2 Shared Fiber
In this part, the fiber cables is going from the central office (CO) to the
customer in sharing way, the meaning of share is the customer can share with
other customer by using one cables or by using a splitter at the place of OSP
(out-side plant) to splitter the signal in sharing way the premises. An AON and
PON technologies are the best example of Shared fiber.
There are a lot of scenarios that can be help to deliver the single into the
customer premises. The type of FTTx that using the share fiber is FTTC and
FTTN. The cost of shared fiber is much lower than direct fiber. But it takes a
while to identify the problem and solve it. And for a bandwidth and data rate is
not greater like direct because the principle of this technique is a share network.
They are two main methods or techniques to distribute the fiber optic to the
network premises, which they are:
1. Active Optical Network (AON).
2. Passive Optical Network (PON).
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8.2.1 Active Optical Network (AON)
As I mentioned before, Active optical network
is could be a shared fiber, which that’s mean
point-to-point link, from central office CO to
the subscriber each of premises has own fiber
optic cable, which that’s terminated on an
optical concentrator (Access Node (AN)).
(Look at figure 8.1: Active optical network).
Here the Type of Access node (AN) can be
design in different way depending on
specification, Commonly its can be an IP-Edge, Multiple service access network
(MSAN) or Ethernet switching. In this case we refers to use an Ethernet switching.
Fiber optics can be terminated on optical network termination (ONT) but, its can be
also any of IP-route or Ethernet switches with an interface of uplink.
The biggest problem to makes a greater bandwidth in fiber optical, is the
conversion from electrical single to the optical and for receiver from optical to the
electrical by using an optical source and Photodetectors. For that reasons the
telecoms companies are building a huge Synchronous Optical Networking
(SONET), which is contains with long haul rings. These rings are same like a
freeways road, the problem is that the same as traffic of cars, Rings need to enter
and exit in ramps of data. But instead of that, a complex device is called ADM
(add-drop multiplexer).
Also need a repeater because a losses of fibers a long to the premises. And if
using a copper cable links a first mile to the premises, Digital subscriber line
Access network (DSLAM) or other MSAN are used. When MSANs are used, both
of optical lines and copper cables can be used for the first mile at the same access
node. The main problem with AON technology is that must to convert the signal
from electrical to optical (e.g. O-E-O conversion), which the equipment of this is
too highly expensive.
Figure.8.1: Active Optical Network
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8.2.2 Advantages and disadvantages of AON
Table 8.1: AON TECHNOLOGY: -
Advantages Disadvantages
1. Simple to install and Maintenance.
2. The highest bandwidth.
3. High Quality of service.
4. Much secure, because each of
subscriber has own fiber cables.
5. No port is shared any way.
6. Higher data rate and its can upgraded
easily.
7. Cost of equipment in subscriber
terminology.
8. Reliable for transmission.
9. No problem with the transmission,
because the signal is travel in optical.
1. An Expensive service.
2. Cost of network
components (e.g. O-E-
O conversion).
3. Needs to amplifying the
signal power at splitter
place.
8.2.3 Passive Optical Network (PON)
The concept of PON network is an attractive option
it’s reduce the operational cost and traffic signals.
The structure of PON network is from point to
multipoint point (PMP). (Figuer8.2: shows the
general structure of passive technology).
Only passive optical components are placed in the
transmission network, that’s to guide the single path
with specific wavelength to the customer premises
and back again to the central office. Because replacing the AON devices to the
passive components that’s help to save the money for telecoms companies. Since
there are no O-E-O conversion components or signal processing requirements,
that’s good for lower the cost of Maintenance especially for telecoms companies
that’s why more than 90% of network around the world are using PON network.
Generally, the function of splitter is to divide the light signal that’s coming from
Figure.8.2: Passive Optical Network
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OLT (Optical line terminology) in central office and communing them with the
signal coming from ONT (optical network terminology) in the nearest cabinet in
premises.
Here the signal is coming from CO, one signal fiber optic cable to run the passive
optical power to the nearest block of the premises in this point the function of
splitter is to spilt and divide the signal into separated path to the premises by
dividing the number of signals/power to be come for premises evenly, which that’s
mean in downlink is just to splits the power of optical signal to many fibers and for
uplink is doing TDM (time division multiplexing) or WDM (wavelength division
multiplexing, much advance) to protect intervals between time slots.
A PON is used for the first mile only, which the components of the first mile PON
are OLT, Fibers, splitter and ONT. In PON technique is similar to the switched, but
here is not required OSP (Out-side plant, in cabinet) because in PON technique is
replace the OSP with Optical splitter.
PON system has long way to delivered the signal from CO to the customer
premises, which a PON system consist of:
1. Optical terminal, which is located at the customer, premises it for
delivered the voice and data.
2. Switch at CO to send the PON protocols to the premises.
3. Splitter and passive couplers, which are located at the fiber, loop.
4. NMA: management of all PON system, located at OLT.
The distance between OLT to ONT is must be maximum 20km for 1:32 subscriber.
PON technology can have a multiple splitter for serve many types of terminologies
of premises, for example its can have a three splitter respectively. And for the
topologies of network the main three types of network topologies are ring, tree
(using one splitter) and bus. And the most advanced topology is tree-PON network.
Generally, the limit of subscribers are delivered to the central office is from 1:4, 1:8,
1:16 and 1:32 per fiber with 4, 8, 16 and 32 port splitter to serve multiple
customers. Here in PON, there are no active components between the central
office and the premises. Broadband PON (BPON), Ethernet PON (EPON), Gigabit
PON (GPON) and ATM PON (APON, subset of BPON) are the types of PON
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networks. Devices in PON loop is not much cost, but the problem with cost each of
SONET, ADM and power transmitter and because of splitter and PON couplers
are passive that’s mean is not required any power. PON technology doesn't have
much problem to maintain.
The most common applications in PON network are CATV (cable television) and
wireless provider. A PON network is grate solution for broadband access
technology x-DSL.
8.2.4 Types of PONs
1. Broadband-Passive Optical Network (BPON), ITU G.983.3:
BPON serve at maximum of 1:32 or 2:32 fiber to 32 subscriber, the
wavelength of fiber cable is 1550nm or 1490 for downstream and for
upstream is 1310nm, here the bandwidth is shared using an ATM protocol
and the type of multiplexing is WMD which is located at CO. 20Km is
maximum length between CO and the customer premises. The data rate
here are 622Mb/s for downstream and 155MB/s for the upstream. The
mains application services of this type are voice, data and IP video and its
possible to add CATV analog and digital channels.
2. Ethernet-Passive Optical Network (EPON), IEEE 802.3ah
EPON served maximum 1:32 and typically 1:16, 1 fiber to 16 or 32
subscriber, the wavelength of fiber cable is 1550nm or 1490 for
downstream and for upstream is 1310nm, here the bandwidth is shared
using an Ethernet protocols and the type of multiplexing is WMD which is
located at CO. 20Km is maximum length between CO and the customer
premises. The data rate here are 1Gb/s for downstream and 1GB/s for the
upstream. The mains application services of this type are voice, data and IP
video and its possible to add CATV analog and digital channels.
3. Gigabit-Passive Optical Network (GPON): ITU G.984.2
GPON served maximum 1:64 or 2:64 and typically 1:32 or 2:36, 1 fiber to
32 or 64 subscriber, the wavelength of fiber cable is 1550nm or 1490 for
downstream and for upstream is 1310nm, here the bandwidth is shared
using an ATM or Ethernet protocols and the type of multiplexing is WMD
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which is located at CO. 20Km is maximum length between CO and the
customer premises and it’s could serve at 60Km without analog video. The
data rate here are 1.2Gb/s or 2.4Gb/s for downstream and 155MB/s or
2.4Gb/s for the upstream. The mains application services of this type are
voice, data and IP video and its possible to add CATV analog and digital
channels. GPON is the best PONs system.
8.2.5 Advantages and disadvantages of PONs
Table 8.2: PON TECHNOLOGY: -
Advantages Disadvantages
1. Quality of service for GPON.
2. Cost to get this service.
3. Range.
4. Cost of network components (e.g.
because no O-E-O conversion).
5. No need to amplifying the signal
power at splitter place.
6. Good for ISDN and high speed
Internet and CATV.
7. Prioritisting service.
1. Hard to install and
Maintenance.
2. Bandwidth is shared.
3. Cost of subscriber equipment.
4. Cannot upgrade the service
easily.
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8.3 Comparison AON Vs. PON
Table 8.3 AON Vs. PON
Bandwidth
High Bandwidth,
because each of
subscriber has own fiber
cable.
Average bandwidth, but its
could be high with GPON
technology.
Data rate
High data rate. And the
speed can upgrade
easily.
Average data rate, but with
GPON technology is good. For
Speed most of PONs is hard to
hard to upgrade.
Fiber consumption
Each subscriber has the
own fibers.
The signal fiber to the passive
splitter, after that is could be
shared or directly from the
splitter.
Testing
Testing is simple.
Testing is difficult. For example
testing each of connectors,
which located from CO to the
customers.
Trouble shooting
Very simple to identify
the problem and maintain
it.
Hard to identify the problem,
because the process between
the CO and the subscriber.
Cost
Very high price for
subscriber to have such
like this system. And the
components of network
are high.
Average price for the
subscriber. And for the
components much bitter
because of passive splitter.
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Geographical
Coverage
For small area.
It’s covered a large area of
network by using a multiple
splitter. And its use for long
distance. Mostly using a MAN
network.
Quality & Security High quality and much
secure. Because each
subscriber has own fiber.
Average quality and secure
depends on the types of PON.
The quality is good for GPON.
Energy
consumption
High energy, because
the number of laser
interface.
Low energy, because of
passive splitter doesn’t have a
amplifier or repeater.
Ranges
Good, Can be
transmitted for long of
70km without any
repeater.
Low, Because it’s dependable
of passive splitter. 20km as
Maximum.
9 FTTx Architecture
9.1 FTTH Architecture
Fiber To The Home FTTH, from the name of this type tells the fiber cable is used
from the central office to the customer, here there are a three methods to deliver a
fiber optic cable to the premises which they’re: Point to point (active fiber network),
Switched (Active Ethernet switched) and PONs. With FTTH technology can
service a long of independent fiber to the subscriber at least 450 subscriber.
In FTTH architectures all three methods that’s delivered the fiber are required a
aggregation devices in OLT (located at central office) and required an optical to
electrical device which is located in the ONT or the boxes in outdoor of houses its
depend on how far the OLT from customers and how many customers are served.
The most common about the FTTH fiber cables are the one cable allowed to be
bidirectional transceivers (BIDI), so one signal mode fiber can serve for upstream
and downstream, which usually the wavelength of downstream is 1550nm and for
upstream is 1310nm, the good about these wavelengths are to protect from
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attenuation and dispersion (the higher or longer the wavelength, the lower the
attenuation).
The main benefits of using BIDI are to reduce the quantity of fiber cables and
specially reducing the splicing labor. But that makes the cost of optical
transmission mush higher.
Point-to-Point (P2P or Active fiber)
architecture, one fiber cable from the
CO to the subscriber, P2P links is the
simplest architecture of FTTH and the
highest bandwidth and data rate, the
main advantages of P2P can operate,
upgrade, identify or maintain the
problem easily and specially is doesn’t
have any port in OLT to share (one
port for one subscriber). Here the
problem just with the quantities of fibers cables. From 32 to 64 subscribers the
distance is long 70Km without any repeaters. P2P is an expensive service to get.
(Figure.9.1 shows the Point-to-Point links).
Active Ethernet architecture,
Its same to the P2P link but the main
different is that from CO to the
customers there is an OSP cabinet, An
OSPs help to serve in big area or large
customer, the single fiber coming from
the CO to the OSP and divide the
cables to the customers with
bidirectional fibers. One fiber from OLT to
the OSP cabinet to serve 64subscribers.
Figure.9.1: Point to Point links
Figure.9.2: Active Ethernet Network
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PON Architecture:
This architecture is to serve a high
data rate with a large number of
premises, here From OLT to the
customer there are WDM multiplexer
and Passive splitter, the maximum
length from OLT to the premise is
20Km. In FTTH, here we use a GPON
system. Here the number o subscriber and the length depend on the type of PONs
system. (Figure 9.3: shows the general PON network).
As in chapter five, the different between AON (with didactic fiber cable to many
customers) and PON with many advantages in AON compared with PON
technologies. With no splitter in AON, along of distance to the customer premises
its good be a sustainable and for the base for of customers requirements for the
future. For that AON technology is the best service for each of subscriber or
network provider. With the high quality and bandwidth of FTTH, FTTH can be
serving to any services that have today. And to met the revolution of future
technologies.
9.2 FTTC Architecture
Fiber to the curb is based on fiber optic cable to the curb, from the CO to the
nearest cainet of premises. And each of these caninet to the customers is used for
transmession a coaxiel cable or twisted pair. The idea of fiber to the curb FTTC
architecture is to solve the problem with bandwidth and speed of broadband
Internet access network with a copper cable network.
FTTC helps to solve the broadband internet problem by building a full a single
mode fiber optic (two directional) from CO to the distribution hub and the function
of distribution hub is to distribute the fiber cable to the nearest ONU which the
called it “electronic cabinet”, and from FTTC electronic cabinet the cables goes
direct or share to the premise with copper cable. (Figure 9.4: shows the network of
FTTC).
Figure.9.3: General PON Network
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This methods help the telecoms companies to provide high broadband Internet to
the customer, but the distance from the electronic cabinet to the customers its
should be 300m. The big different of FTTC from the other types of FTTx like FTTN
or FTTP is the FTTC placed in the nearest cabinet of the customers, which FTTN
placed far a from the customers and FTTP is placed at the serving location. From
the using of copper cable in the last mile FTTC costs less to deploy but with the
lower bandwidth. The bandwidth and the speed of data rate in FTTC depend on
how far the cabinet from the customers.
FTTC can deliver a broadband service xDSL and CATV. FTTC is a good method
to serve small business and houses, especially for whose require a not more than
40Mbps speed.
9.3 FTTB Architecture.
Fiber to the building or business, here the fiber it’s goes directly or in share way to
the customer building, Fiber cable goes from CO to the entrance of building
premises and after that its goes directly with copper cable to the premises. The
main reason why we need FTTB is the most of Internal connections of building is
in copper cable and its cost very much to replace the copper cables into the fibers
cables that are the main reason why we need an FTTB.
The idea of FTTB is to cover the demand of high bandwidth; the solution is to have
a fiber optic cable connected from the CO to the building or business, and its
usually goes to the customer in copper cable for that reason of not loss the
bandwidth we used a DSLAM from the entrance to the subscriber by copper cable.
Figure.9.4: FTTC network
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Each of subscribers can get not less than 100Mbps in short distance of copper
cable by using a VDSL2 transmission. So the telecoms companies can provide the
subscribers many services such as VOIP, ISDN telephone, IPTV, CATV and high
access of broadband Internet with minimal costs of other services without losing
the bandwidth or the access speed.
Mile gates is a compact DSLAM, It’s connecting the subscribers in multiple
apartment or small business to the FTTB. Mile gates offer 8 VDSL-2 with
maximum bandwidth over distance of up 100m. Mile gates give the optional to
converting each of analogue and digital CATV signals. The mile gates is the
solution to have a large bandwidth with high data rate for a large building to serve
man customers without losing of the signal because of Copper cable problem and
losing broad band services.
9.4 FTTP Architecture
Fiber to the premises is a generic term of FTTH and FTTB. The idea of this
scenario is to cover a large MAN area with high quality and bandwidth of services
to the premises. FTTP can use two or more distribution hub (MAN splitter) and
other splitters to serve the premises at one area, the number of splitter depending
on the number of subscribers at each area.
FTTP can deliver to multiple premises terminologies such like MDU, MHU, MTU
and SDU all that are for serve to the business, building and houses. The
differences between FTTP and other FTTx scenarios, Is FTTP is multiple that can
serve to many premises terminologies and its can delivered a high bandwidth such
like FTTH and high quality of services and much secure. (Figure 9.5 shows the
FTTP network).
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FTTP includes the uses of ONTs at the FTTH and FTTB implementation and the
uses of ONU for FTTC and FTTN applications. The processes of FTTP from CO to
the customers are:
1. Distribution cable (distribution hubs): from CO to the optical splitter with
fiber cables, the distance from the CO to the optical splitter its usually 10km.
here the optical splitter can splits 1:2 or 1:4 or 1:8 1:32 one feeder cable
from CO to 2, 4, 8 or 32 splitter to serve a 32, 64, or 128 subscriber in one
area (the number of subscribers depends on the methodologies (E.g.
BPON, APON and GPON). From the optical splitter to the premises its can
connects directly to the customer or run a local splice box, which is located
at the nearest cabinet to the premises.
2. Local splice box: from splice box to the premises its connected with fiber
cable, and for cooper cable its just use to the business or building such as
FTTB. The distance between splice box to the premises normally its should
be 1-km long. The maximum distance from CO to the Premises 20km.
For the designing of FTTP network, must consider on two important thing, which
they are:
a. Type of optical splitter: the type of splitter it’s depend on how splitter can
split the fiber (how much?) and how many subscriber can serve in one big
area.
Figure.9.5: FTTP network.
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b. Location of optical power splitter: the location is important when the
demand of the bandwidth and the data rate of each customer, for example
the premises of building or business requires high bandwidth to serve them,
here the locate of optical power splitter should be nearest to whose
requesting the largest bandwidth.
FTTP includes all kind of methodologies to deliver the voice; video and data to the
premises and the popular methodology are BPON, EPON or GPON from PONs
system and includes WDM-PON system or WDM multiplexing and active optical
network (AON) or active Ethernet. With WDM-PON, which installed at the feeders
distribution hubs with other possible splitter at the cabinet, here each of customer
has specified a wavelength. And for active Ethernet the OSP located at the
distribution hubs. And finally with AON only one-fiber cables goes from CO directly
to the premises. The Conclusion of FTTP methodologies, each of one
methodology can serve depending on the bandwidth and the speed of data rate
requesting from the type of premises terminologies.
FTTP is the most expansive scenarios of FTTx, because its serve for big area and
can work with multiple methodologies which each of that required the own
components and elements. FTTP is the most popular scenarios at these days and
its can provide the same application services for all kind of FTTx. FTTP is the
solution of everything.
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9.5 Advantages and Disadvantages of all FTTx
Table
9.1
Advantages Disadvantages
FTTH
1. Today, the cost is low.
2. The highest Bandwidth of all FTTx.
And its can upgrade easily.
3. Highest quality of all FTTx.
4. Greater reliability of all FTTx, and
no interference at all.
5. The best of data speed, for both
upstream and downstream.
6. No active components between the
CO to the customers.
7. The only technology that keep pace
with developments in
communications evolution.
8. Serve a lot of subscriber, over 450
subscribers (just for P2P).
9. Easy to maintain.
10. The FTTH network is a future of
FTTx architectures.
1. Required a lot of fiber
cables.
2. Cost of cables, e.g.
P2P.
3. If the cable is cut for
P2P. take a lot of work
to solve it.
FTTP
1. Generic terms can use all
methodologies to provide the
signals. E.g. AON and PON.
2. High Bandwidth.
3. Reliable for transmission.
4. Can serve a lot of subscribers.
5. The best of data speed, for both
upstream and downstream for both
business and houses.
6. The best choose for large area.
1. Hard to install and
maintain.
2. Bandwidth is shared
with PON.
3. Cost of subscriber
equipment with PON.
4. Cannot upgrade it
easily with PON.
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7. Can do all methodologies to deliver
the signal.
8. The future proof.
FTTC
1. Low cost.
2. Flexible to deploy.
3. The idea is to deliver a high data to
the premises with copper cable
from the cabinet (good for).
1. Less Bandwidth.
2. Take the time to solve
the problem.
3. Requires a lot of
equipment’s, which
are expensive.
4. Can’t upgrade easily.
5. Loss of signal.
6. Needs to Maintain.
FTTB
1. Bandwidth.
2. The data rate.
3. High quality.
1. Need to convert the
optic signal.
2. Loss of signal (in
building area).
10 FTTx issues
FTTx has many benefits and advantages to use, but when establishing the
network of FTTx its must required a lot of thing (issue) to consider about such like
design, installation, testing and safety. These issues are helpful to identify the
problems and solve it. The FTTx issues that most consider about are:
10.1 FTTx design issues
Before the implementing or installing the FTTx technology. FTTx design issues
must consider several requirements, like:
1. Each of FTTx network is different, that’s required to study all factors and the
size of area for designing and installation.
2. Provider must consider about:
a. The geographical area and the current location of each FDH, OLT
and ONT.
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b. The current infrastructure, which kind of FTTx use?
c. Types of premises terminologies.
d. Types of services that have required from the customers, to be
chose which FTTx refer to use.
e. Provider requirements.
10.2 FTTx Installation Issues
There are many issues to consider about FTTx installation must be consider about
like:
1. Termination: The end of fiber cables, connecters, splicing pigtails (cabinet)
and splicing at the customers.
2. Location and cable placemat: is about how far to the customers from CO
(central office) or electronic cabinet and consideration of pulled in cabinet
and buried.
3. Hardware Mounting: the device in CO (central office) for basis, OLT
(optical line terminated) inside the CO.
4. Testing the fiber: testing for each cable for insert loses, testing for each
splicers location and testing in the customer cable.
5. Testing the equipment: Is the fiber work perfectly? Using the equipment to
testing the transmitting and receiving the data, voice and video.
6. Vendors Requirements: here use the specialized vendors to save the time
about the methods of installation and testing to save the design time.
10.3 FTTx Testing Issues
After the design and installation the one of FTTx type, the part of testing issues is
important to know if the job is done perfectly and for sure to keep the testing work
daily when the need of the testing. Here some issues must to considering about
which they are: -
Testing all components from CO to the premises with each equipment’s and
fiber cable flow.
Testing here with the same of old OSP, but the differences with each of
WDM and splitter (became more complex than old OSP, e.g. PONs)
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Intelligent ONT that allow to troubleshooting the easily and located inside
the FITL.
Testing of each splitter, couplers and splicing box cabinet.
The testing device should be operating of each 1310, 1490 and 1550 nm
wavelength.
With the using of optical loss test (EXFO is the best), testing of each OTDR,
insertion losses and reflectance.
Testing the link signal from CO to FDH (fiber distribution hubs) and from
FDH to the ONT, just for FTTP.
After the installation of FTTx make sure they testing of END to END that
include of connecters losses, fiber flow losses in each link and the splicing
box link.
10.4 FTTx Safety issues
Installing or maintaining fiber cables needs specific precautions to avoid
hazardous caused by optical fiber cables. As any other communication system
fiber has several factors, which are taken on consideration when dealing with fiber,
otherwise harmful damages could happen, these factors are:
Laser.
Bare Fibers.
Chemical Materials.
Optical Power.
Laser can damage the worker eyesight when direct views, and reflected lights
beams can cause fire, or skin injury. Therefore, there are several factors can
determine the precautions of optical fiber sources, in order to avoid harmful
damages, as the following:
Wearing safety glassware.
Do not throw fiber debris in the site.
Ethylene chloride.
Acetone.
Isopropyl or denatured alcohol.
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Epoxies.
Gel removers, cable gels.
The worker must turn the power off, whether installing or maintaining the
fiber in the workstation especially with EDFA.
11 Conclusion
Today many service are applied and the problem with the using of copper cable.
But with the capability and the advantages of fiber optic cable the fiber today is the
best solution of transmission media. With the evolution of broadband services,
FTTx methodology is the solution for everything with using the Fiber cable to
transfers the highest bandwidth with minimum losses. FTTx can cover all the
needs of customers and businesses demands from the bandwidth to the speed of
data rate.
The best technology to deliver the highest bandwidth is P2P and AON, but the
AON technology is to serve a small area with limited subscriber. PONs technology
is the best to deliver a high bandwidth with a large area (MAN), GPON today is the
popular network.
All FTTx scenarios can deliver high bandwidth with the speed of data rate, but
each of FTTx types has the own advantages like; FTTH is the best scenarios to
deliver a high bandwidth and the data rate, especially if the customer wants to
upgrade his service. FTTH use a three technology of delivered which they are:
P2P, Active switch and PONs (GPON) FTTH are required from houses or small
businesses. The good technique that’s delivered the fiber to the large area is
FTTP. FTTP is a generic term that’s including the three scenarios of FTTx, which
they are FTTH, FTTB and FTTC. FTTP is required from houses, businesses, and
big institute.
FTTC is good for unstructured area e.g. if the MAN area that’s service use an
Copper cable and the telecoms company are poor to establishing a fiber cable to
each customers then the best solution is to provide a FTTC methods and for FTTB
is same idea of FTTC but the main different with FTTB using an copper cable
inside the building.
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The most important thing in testing part is the designs issues, the question will be
are: -
Which types of network terminologies are?
Which types of premises terminologies are?
How many the customers in one area?
Which methods we used AON or PONs or better P2P?
Which kind of FTTx used?
Provider and customers requirements.
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12 Vocational Pedagogy part: (FTTx Concept 50min)
12.1 Curriculum analysis.
Department Major Course Name Code Prerequisites
Communication
Techniques Communications Fiber Optic Cable COM-240 COM-136
Trimesters 1 2 3 4 5 6
Credit Hours (Hours/Week) 5
Contact Hours
(Hours/Week)
L 4
W 2
T
Table 12.1
Prerequisites of FTTx (Thesis):
A basic knowledge of electric circuit-1 (COM-115) is needed. Also, some subjects those are
relevant to basic communications needed to complete this subject, or as a required in future
semester, as follows:
General Mathematics “MAT-113”
Electric Circuit-1 “COM-115”
Electric Circuit-2 “COM-116”
General Physics “PHY-115”
After finishing this course there’s no required courses for the next trimester.
However, there are some lessons are required before the topic (FTTx Concept), and lessons come
after finishing this topic. They are grouped and organized on the following chart
Course Description:
This course is designed to provide state-of-art information of different types of optical fiber and the new technologies available nowadays in communication system. Considering the broad meaning of FTTx concept including its features, the four scenarios, the installation issues, and the advantages of FTTx types compared to other types of communication network. Also, to deliver the reasons beyond the demands of large bandwidth that requires new loop installation, in order to deliver high-speed Internet services including IPTV, video-conference and voice over IP.
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The following topics will be addressed:
Related
tasks Duties Tasks detail
1A4
2A2
2C4
Knowledge of electrical
characteristics of transmission
lines like characteristic
impedance, propagation constant
and their dependence on
frequency and line length.
The trainees should follow the fault
repair, analyze the fault, and Examine the
devices after repair. And participate in
executing solutions.
1C3
2C3
1D2
Knowledge of Fresnel reflection
and misalignment loss (lateral,
angular).
The trainees should suggest suitable
solutions, and take readings from the
base transmitting stations.
This course will be given on the 5th trimester; it has five credit hours, four hours for lectures
(theories), and two hours for practice. It consists of eleven chapters with fifty-four sub-topics
within thirteen weeks. FTTx is located on the sixth chapter, and the total contact hours are
78hrs. This course has also different tasks “NOSS”, which specific skills, objectives,
knowledge, and duties that are required to complete this subject. These skills have taken
from the book of job analysis timetable, which is made by TVTC organization and published
on 2002.
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Bachelor Thesis: FTTx Architecture
Moayad AlZoghaiby
60
1E1
1E2
2E4
2E5
Ability to measure characteristic
impedance of transmission lines,
light source and photo-detector
characteristics and attenuation
for glass and plastic fibers.
The trainees should Collect faulty
information from the faulty controller, and
specify the type and location of faults.
Also, examine the devices after repair to
coordinate with the faults controller to
make sure of clearing all faults.
Table 12.2
12.2 Content analysis
Before we start the lecture, make an overview about the fiber optic (overview in
what we stop in last chapter). Then we start in new chapter.7 we define some
terms such like FTTx concept, why FTTx, FTTx features and benefits, FTTx
scenarios and the FITL functions. First, we define the FTTx in Generally; Fiber to
the x (FTTx) is techniques or methods of fiber installation between central offices
to the customer. FTTx “last mile” is a generic term of network topology that’s most
to replace the copper cable into fiber optic. Second, why we need FTTx today?
With the evolution of communication around the world, Telecom companies now
are suffering from copper cables especially in Saudi Arabia. Last statistics around
the world is said the cable telephone bulk is 10% for long distance (fiber optic
cable) and 10% for a local loop (fiber optic cable) and 80% Subscriber loop
(copper cable) for that the telecoms companies are suffering. Then, the features
and benefits of FTTx todays are with the performance of FTTx comparison with
twisted pair or coaxial cable, Quick to install and easy to maintenance, flexible to
design, Easy to absorb from a new users and technologies with low cost of
building FTTx networks. Last but not least, define the scenarios of FTTX like FTTH,
FTTP, FTTC, FTTB and FTTN. In short definitions of FTTx scenarios are:
FTTH: Fiber to the Home, using fiber optic between central office and customer
FTTB: Fiber to the building or business, Its used a fiber between central office
CO to the entrance of building after that is usually copper cable.to the cabinet,
which is not more than 300m far from the customer. From the cabinet to the
customer is copper cable.
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FTTP: Fiber to the Premises, Generic terms that include both FTTH and FTTB.
FTTN: Fiber to the Node or neighborhood, it’s like FTTC but the different is
how far the cabinet from the user ends.
Finally, with FITL (fiber in the loop) The idea of FITL is to implement and
upgrading the POTS (plain old telephone service) of telephone line in the local
loop to the customer premises by using a components of FITL with a fiber optic
technology. And define the elements that’re between CO to the premsis of all
FTTx senairos.
12.3 Didactic analysis
This is a 50-minute lecture, which is about an overview of FTTx concept to
everyone who would benefit from a broad knowledge of the fundamentals
concepts of FTTx of Fiber Optic Cables. Also, to provide information about how
does fiber cable installation from CO to the premises. Introduction as examples of
reality of all FTTx scenarios would be included that will be delivered in the
classroom. Then, the lesson will be define of FTTx concepts, and what the major
types FTTx. After that, these types will be explained with details including the
Pictures and drawing in the WB telling the different of all FTTX scenarios and fiber
performance.
First, in the opening phase, the trainer will start attracting the trainee's intention by
reviewing the last lecture’s topic to make a connection between them, and simply
explain the definition of FTTX Concept. The method at the beginning will be (in
front of the class), this is the only way to encourage the trainees to be more active.
Also, to motivate them to concentrate as a beginning, the media that the trainer
will use are:
Whiteboard.
Projector (presentation).
Second, in the body phase the social form will be (Demonstration, or in other word
in front of the class). I will explain about one if the all FTTx scenarios such like
FTTH, FTTP, FTTC, FTTB, and which is the important of dominating the telecom
business nowadays. So, it needs to be taken step-by-step to be understandable
from the trainee’s side. The media will be used are (whiteboard, PowerPoint
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Bachelor Thesis: FTTx Architecture
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62
slides) besides the trainees will be given handouts to follow the trainer where the
important points are included. Also, useful for the present time and the future as
well, overview and defining FTTx types using the following media:
Whiteboard.
Projector (presentation).
This lecture is seemed to be (deductive approach), because there’s no practical
part it just about architectures.
Then, the important part of the topic is (Why we need FTTx Toady), and the
method the trainer will use is (demonstrating). The media will be used are:
Whiteboard.
Projector (presentation).
After that the trainer will explain the types of FTTx including the effects of labour
marketing today and which is better and the media are:
Whiteboard.
Projector (presentation).
After that, the general and the total formulas of FITL technology and tell what the
function of each elements between central office and the premises. The method
that will be used is (Demonstrating), and the media are:
Whiteboard.
Projector (presentation).
Finally, at the end of the lesson the trainer will give a short explaining of one
example of FTTx, which is FTTH architecture. The suitable methods for this phase
are (in front of the class and classroom conversation). The media that will be used
are (Whiteboard and Projector (presentation).
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12.4 Learning objectives
General objectives:
o Review of last lecture.
o Are encouraged to improve technical English.
o Get further knowledge beyond demands of FTTx Networks.
o Get further knowledge about the benefits and features of FTTx.
o Are getting more proficiency to work in-group.
o Are encouraged to take note with the trainer.
o Finishing the task that’s given on the time.
Specific objectives:
The trainees:
o Are able to define the FTTx Concept. (Reproduction)
o Are able to define the four main Types of FTTx. (Reorganization)
o Are able to compare with different FTTx scenarios. (Transfer).
o Are able o describe the functions of elements in FITL loop.
(Reproduction)
o Are able to distinguish which FTTx methodologies are better.
(Reproduction)
o Are able to identify the FITL network components. (Reproduction)
12.5 Process Overview of a lesson plan
Opening/Entrance/Motivation Methodology Media Time
Expected Trainer-action Expected Trainee-
action
Reviewing in what we
toke the last chapter and
make the link it with this
lesson. Questioning
them about last lecture.
Give the trainees
Motivation And
Expecting form
them some
answers.
Question/Disc
ussion.
WB
3 min.
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Bachelor Thesis: FTTx Architecture
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Close (Reflection, Exercises, Homework,
Feedback
Methodology Media Time
Expected Trainer-
action
Expected Trainee-
action
Starting on the topic to
define the FTTx concept
and the meaning of last-
mile.
Trainees listen.
Frontal,
Classroom
conversion.
PPT,
WB
5 min.
Explaining Why we
need the FTTx and tells
the benefits and
features. And whose
wants the FTTx?
Trainees listen.
Frontal,
Classroom
conversion.
Work.
PPT,
WB
5 min.
Explaining The main
four types of FTTx and
which the popular and
important. And
explaining the services
of FTTx.
Trainees listen, and
asking some
questions.
Frontal,
Classroom
conversion.
PPT
(PICs),
WB
12 min
Group work; the
questions about “ what
the advantages and
disadvantages of the all
FTTx scenarios and
what the best type?”
Trainees listen. And
accepting from them
some questions.
And they will do
group work
perfectly.
Group Work
PPT,
WB
10 min
Explaining the elements
of FITL loop such like
OLT, ONT and ONU.
And distinguish between
the active and the
passive splitter.
Trainees listen.
Frontal,
Classroom
conversion.
PPT
12 min
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Bachelor Thesis: FTTx Architecture
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Close (Reflection, Exercises, Homework,
Feedback)
Methodology Media Time
Expected Trainer-
action
Expected Trainee-
action
At the END of the class.
Review What we
learned today. Giving
them as concluding.
Should be
answering, if they
understood the
lesson
Classroom
conversion.
Question/Disc
ussion
----------
---------
Pre-assessment; Which
type of fiber cable use in
FITL.
Trainees listen and
try to answer the
assessment.
Classroom
conversion.
PPT
3 min
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Bachelor Thesis: FTTx Architecture
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13 Bibliography
Main references Books:
Gerd Keiser, FTTx Concept and application ©2006.
FuruKawa Company, Understanding Fiber Optic ©2007.
Ivan P.Kainow, Tingy Li, Alan Willner, Optical Fiber Telecommunications,
Elsevier Inc. ©2008.
Moh. Yasin, Sulaiiman Harun, Hamszah Arof, Optical Fiber Communcations
and Devices, InTech ©2012.
FTTx System Catalogue, fibreflow System, Emtelle ©2011.
Gwenn AMICE, PPT of FTTx and xDSL testing, EXFO ©2008.
Jim Hayes, FTTx (Current Status of Fiber To The User), Fiber Optic
Association and VDV Academy ©2006.
Andre Girard, FTTx PON Technology and Testing, EXFO Electro-Optical
Engineering ©2005.
PDF project of AON and PONs network, KeyMile company.
List of Figures:
Fig 3.1: (http://olabstech.com/pdf/construction.pdf)
Fig 3.2: (http://nuclearfootprints.com/?attachment_id=1973)
Fig 3.3: (http://science.hq.nasa.gov/kids/imagers/ems/index.html)
Fig 3.4: FTTx concept and Application, Gerd Keiser ©200
Fig 4.1: (http://etd.lib.fsu.edu/theses/available/etd-11202003-
060632/unrestricted/09_psm_Chapter2.pdf)
Fig 4.3: (http://www.sensornet.co.uk/)
Fig 4.4: (http://www4.nau.edu/microanalysis/Microprobe-SEM/Statistics.html)
Fig 4.5: (http://aaronmiemban.blogspot.com/2009/11/basic-block-diagram-of-
communication.html )
Fig 4.6: (http://physicsnet.co.uk/a-level-physics-as-a2/waves/refraction/)
Fig 4.7: (http://physicsnet.co.uk/a-level-physics-as-a2/waves/refraction/)
Fig 4.8: PPT, Partner
Fig 5.1: FuruKawa Company, Understanding Fiber Optic ©2007.
Fig 5.2: FTTx concept and Application, Gerd Keiser ©2006.
Fig 5.3: (http://www.muxtronics.com/pressure-and-level-measurement-
Technical Trainer College
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Bachelor Thesis: FTTx Architecture
Moayad AlZoghaiby
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systems/)
Fig 5.5: (http://www.thefoa.org/tech/)
Fig 5.6: (http://www.fiberoptics4sale.com/wordpress/)
Fig 5.7: (http://www.thefoa.org/tech/)
Fig 6.1: FTTx concept and Application, Gerd Keiser ©2006.
Fig 6.2: FTTx concept and Application, Gerd Keiser ©2006.
Fig 6.3: FTTx concept and Application, Gerd Keiser ©2006.
Fig 7.1: Wikipedia web. FTTx.
Fig 7.2: Course of Advanced comm. System with Dr. Frohberg, TTC.
Fig 8.1: AON Vs. PON Project, KeyMile company, Germany.
(http://www.keymile.com)
Fig 8.2: AON Vs. PON Project, KeyMile company, Germany.
(http://www.keymile.com)
Fig 9.1: Multicomm. Marketing company, America.
(http://www.multicominc.com)
Fig 9.4: Multicomm. Marketing company, America.
(http://www.multicominc.com)
Fig 9.5: Multicomm. Marketing company, America.
(http://www.multicominc.com)
Fig 9.6: Multicomm. Marketing company, America.
(http://www.multicominc.com)
Technical Trainer College
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Bachelor Thesis: FTTx Architecture
Moayad AlZoghaiby
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14 Annex
Glossary
FTTx Fiber to the Terminated x.
OSI Open System Layers interconnect
WAN Wide area network
MAN Metropolitan area network
LAN Local area network
CO Central Office
POP Point of presence
MDF Main distribution frame
EXCH Exchange
DWDM Dense Wave Division Multiplexing
FITL Fiber in the loop
SDU A single dwelling unit
MDU: A multiple dwelling unit
MHU A multiple hospitality unit
MTU: A multiple tenant unit
SFU: A single-family unit
SOHO Small office/home office
AON Active Optical Network
PON Passive optical network
CATV Community access television
VOIP Voice over IP
FTTH Fiber to the home
FTTB Fiber to the building
FTTC Fiber to the curb
FTTP Fiber to the premises
FTTN Fiber to the node
IPTV Internet Protocol television
HDTV High definition television.
OLT Optical line termination
ONT Optical Network termination
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OLD Optical line distributor
SU Service Unit
ATM Asynchronous Transfer Mod
OSP Out side plant
P2P Point to Point
AN Access node
MSAN Multiple service access network
SONET Synchronous Optical Networking
ADM Add-drop multiplexer
DSLAM Digital subscriber line Access network
O-E-O Optical to Electrical to optical
PMP Point to multipoint point
TDM Time division multiplexing
WDM Wavelength division multiplexing
BPON Broadband Passive optical network
EPON Ethernet Passive optical network
APON ATM Asynchronous Transfer Mod -Passive optical network
GPON Gigabit Passive optical network
ITU International telecommunication union
IEEE Institute of Electrical and Electronics Engineers
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15 Statutory declaration
We declare within the meaning of 1.43/1.45 of Examination and Study Regulations and TTC’s Code of Conduct and Honor: This bachelor thesis has been completed by our group independently without outside help and only the defined sources and study aids were used. Sections that reflect the thoughts or works of others are made known through detailed references.
1. Moayad Al Zoghiby:
City, Date Trainee name Trainee ID
Signature
2 0 2 3 0 2 1 0 3
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