- The document discusses fiber-to-x (FTTx) networks, including fiber-to-the-home (FTTH), fiber-to-the-building (FTTB), fiber-to-the-curb/cabinet (FTTC), and fiber-to-the-node (FTTN). It explains how fiber optic and copper connections are used depending on the distance from customer premises. - Key components of optical networks are described, including transmitters that encode signals onto laser light, multiplexers that combine signals, amplifiers to boost signal strength over long distances, switches to direct signals, demultiplexers to separate signals, and receivers to convert light back to electrical

1. Zulfidin Khodzhaev
​SUMMARY
- The connection between fiber and copper is used in today’s network systems. It is called
FFTx.
- FFTx has 4 categories: FTTH, FTTB, FTTC, FTTN. Based on distance from premises.
- We will call FTTH and FTTB as FTTP sometimes.
- FTTP fiber is near the house
- FTTC/FTTN fiber is far from house
- How fiber and copper are connected ?
-
The inside of a fiber cabinet. The left side contains the fiber, and the right side contains
the copper.
Also,​ there is ​transceiver​ than we can use for transmission :
A GBIC module: optical and electrical transceiver(11).

2. Zulfidin Khodzhaev
- How it reaches house ?
By direct fiber, shared fiber, active optical network, passive optical network, Ethernet
point to point
- How it converts the electrical signal optical signal ?
By Light Amplification by Stimulated Emission of Radiation (or laser)
- How it converts the optical signal to electrical one ?
Using thin fılm filter.
More: “The optical network terminal (ONT, an ITU-T term) or unit (ONU, an identical
IEEE term) converts the optical signal into an electrical signal using thin film filter
technology.”
- How does it work for FTTH and some forms of FTTB ?
It is common for the building's existing ethernet, phone, and cable TV systems to
connect directly to the optical network terminal or unit.
- How does it work for FTTC and FTTN ?
The combined internet, video and telephone signal travels to the building over existing
telephone or cable wiring until it reaches the end-user's living space.
And, ​ VDSL​ or ​DOCSIS​ modem converts data and video signals into ​ethernet ​protocol.

3. Zulfidin Khodzhaev
Now, below are more in depth information derived from various websites about FTTP, FTTC,
FTTN and connections or cables used in each case:
1. The type of connection​ we need for this journal is called: ​Fiber to x ​network(2):
Since on the paper it states:
The ability to offer gigabit speeds has been fueled by advances in digital signal
processing and by a steady migration towards fiber rich access networks where only the
last ‘mile’ into the homes remains copper based.
We can inference from (2) that it should be ​FTTN
● On the ​cost​ of the fiber: ​closer the fiber head, the higher the cost of construction
● On the ​speed​ of the fiber: closer the fiber head, higher the channel capacity
Comparison​ between ​Fiber​ and​ Copper​ cables:
● While fiber optic cables can carry data at high speeds over long distances, copper
cables used in traditional telephone lines and ADSL cannot
a. FTTP - FTTB/FTTH ?
FTTP (fiber-to-the-premises): This term is used either as a blanket term for both FTTH
and FTTB, or where the fiber network includes both homes and small businesses

4. Zulfidin Khodzhaev
Benefits of ​FTTP​:
FTTP has been selected by every major communications provider in the world to carry
data over long 1 Gbit/s symmetrical connections directly to consumer homes. FTTP
configurations that bring fiber directly into the building can offer the highest speeds since
the remaining segments can use standard Ethernet or coaxial cable.
What is Ethernet ?
Ethernet is a method of network communication that can be carried by many different cables,
including coaxial cables(3).
So, how we deliver this technology in FTTP, we know the fiber ends miles away from
premise ?
The signal is conveyed the final distance using any non-optical means, including twisted pair,
coaxial cable, wireless, or power line communication.[2]
■ What is Twisted Pair ?
Twisted pair cabling is a type of wiring in which two conductors of a single circuit
are twisted together for the purposes of improving electromagnetic
compatibility(4).
Types:
(5)

5. Zulfidin Khodzhaev
■ What is coaxial cable ?
Coaxial cable is a type of electrical cable that has an inner conductor surrounded
by a tubular insulating layer, surrounded by a tubular conducting shield(6).
(6)
■ What is Powerline Communication ?
Power Line Communication (PLC) is a communication technology that enables
sending data over existing power cables. This means that, with just power cables
running to an electronic device (for example) one can both power it up and at the
same time control/retrieve data from it in a half-duplex manner(7).
What ​other names​ used for this method of transmission ?
It is also known as power-line carrier, power-line digital subscriber line (​PDSL​),
mains communication, power-line telecommunications, or power-line networking
(​PLN​)(7).
How it works ?
Power-line communications systems operate by adding a modulated carrier
signal to the wiring system. Different types of power-line communications use
different frequency bands(7).
Can it carry higher frequency signal ?
Since the power distribution system was originally intended for transmission of
AC power at typical frequencies of 50 or 60 Hz, power wire circuits have only a
limited ability to carry higher frequencies. The propagation problem is a limiting
factor for each type of power-line communications(7).

6. Zulfidin Khodzhaev
(8)
(9)
b. Fiber to the curb/cabinet/node FTTC/FTTN
Curb - pole-mounted device or communications closet or shed
FTTC - fiber to the neighbourhood
FTTC - fiber to the cabinet
A telecommunications system based on fiber-optic cables run to a platform that serves
several customers(2).
So, how we deliver this technology in FTTC/FTTN, we know the fiber ends miles
away from premise ?
Each of these customers has a connection to this platform via ​coaxial cable or ​twisted
pair.

7. Zulfidin Khodzhaev
What protocol is used between cabinet and customer ?
Generally, high-speed communications protocols such as broadband cable access
(typically ​DOCSIS​) or some form of digital subscriber line (​DSL​) are used between the
cabinet and the customers.
Benefits:
FTTN often uses existing coaxial or twisted-pair infrastructure to provide last mile service
and is thus less costly to deploy.
HOW OPTICAL NETWORKS WORK ?
The optical network consists of 6 principal systems:
1.Transmitter
2.Multiplexer
3.Amplifier
4.Switching/routing
5.De-Multiplexer
6.Receiver
(10)
1. Transmitter​: done by Light Amplification by Stimulated Emission of Radiation (or laser)
How exactly the signal is formed?
By turning each laser device ON to represent a digital 1 and turning it OFF to represent a
digital 0. Each optical signal has its own wavelength or frequency.
What are common devices for transmission?
Commonly used classes of semiconductor laser transmitters used in fiber optics include
VCSEL (Vertical-Cavity Surface-Emitting Laser), Fabry–Pérot and DFB (Distributed
Feed Back).
2. Multiplexer: ​aggregating of multiple wavelengths onto a single strand of fiber.
Done by use of optical devices called Wavelength Division Multiplexers (or WDMs)
There are different types of this device, for more info check (10).

8. Zulfidin Khodzhaev
3. Amplifier: ​when transferred in long distances, the signal loses strength, or excessive
attenuation. We use this to compensate for loss.
What device is used ?
Erbium Doped Fiber Amplifier (or EDFA) is the most widely deployed device
4. Switching/ Routing: ​Communication network must incorporate multiple points of
connectivity. Wavelengths must be added, dropped or redirected.
Common devices used to redirect signal ?
a. Opto-mechanical (or Prism) switches and Micro Electro-Mechanical Systems (or
MEMS) switches are two examples of devices that are commonly used to redirect
optical signals.
b. The Optical Add-Drop Multiplexer (or OADM) is a commonly used device to
provide the entrance and exit ramps for the individual wavelengths in a
multi-wavelength light signal.
5. De-multiplexer: ​dis-aggregate the multi-wavelength optical signal by splitting it back into
a series of the original wavelengths.
6. Converts an incoming optical signal into an equivalent electrical signal.

9. Zulfidin Khodzhaev
Some definitions:
Fixed line broadband
On the other hand, is what we usually mean when we use the word 'broadband' - an internet
connection in your home, delivered via your phone line or through the provider's network of
cables. You'll get it as either standard ADSL or superfast fibre optic. It connects to a router,
which you can then connect to all your devices through Wi-Fi or an Ethernet cable(1). Also,
benefits are listed in (1).
ADSL - Asymmetric Digital Subscriber Line
Is a type of digital subscriber line (DSL) technology, a data communications technology that
enables faster data transmission over copper telephone lines
It is mainly used to download(downstream) material(1).
“​Last Mile​”:
Phrase widely used in the telecommunications, cable television and internet industries to refer
to the final leg of the telecommunications networks that deliver telecommunication services to
retail end-users (customers).
In other words: refers to the portion of the telecommunications network chain that physically
reaches the end-user's premises.
REFERENCE
1. https://www.broadbandchoices.co.uk/reviews/mobile-broadband-vs-fixed-line-broadband
2. https://en.wikipedia.org/wiki/Fiber_to_the_x#FTTN_and_FTTC
3. https://protectionplus.ca/whats-difference-ethernet-coax/
4. https://en.wikipedia.org/wiki/Twisted_pair
5. https://goo.gl/images/3eZn7M
6. https://en.wikipedia.org/wiki/Coaxial_cable
7. https://en.wikipedia.org/wiki/Power-line_communication
8. https://goo.gl/images/cfJLih
9. https://goo.gl/images/TJhTaU
10. https://www.diconfiberoptics.com/company_fib.php?sec=2
11. https://en.wikipedia.org/wiki/Fiber-optic_communication#Transmitters