Professor Z Ghassemlooy
Northumbria Communications Laboratory
School of Informatics, Engineering and
Technology
The University of Northumbria
U.K.
http://soe.unn.ac.uk/ocr
Prof. Z Ghassemlooy 1

 Reading List
 Lecture 1: Introduction
 Transmission Media
 History
 Communication Technologies
 Applications
 System
 Challenges Ahead
 Lecture 2: Components for Photonic Networks
 Lecture 3: Optical Amplifier
 Lecture 4: System Limitation and Non-linear effect
 Lecture 5: Transmission System Engineering Part 1
 Lecture 6: Transmission System Engineering Part 2
 Lecture 7: Photonic Networks
 Lecture 8: Photonic Switching
 Lecture 9: Wavelength Routing Networks Part 1
 Lecture 10: Wavelength Routing Networks Part 2
 Lecture 11: Access Network
 Lecture 12: Revision
 Tutorials and Solutions: Visit http://soe.unn.ac.uk/ocr
Prof. Z Ghassemlooy 2


Essential Reading List
– lyas, Mohammad and Mouftah, Hussien: The Handbook of Optical
Communication Networks, CRC Press, 2004, ISBN 0-84-931333-3
– Ramasawami, R and Sivarajan, K.N: Optical network: A practical perspective, Morgan Kaufmann, 2001, ISBN 1-55-860655-6
– Donati, Silvano: Photodetectors: Devices, Circuits and
Applications, Prentice Hall, 2000, ISBN 0-13-020337-8

Optional Reading List
– Stern, T.E. and Bala, K: Multiwavelength Optical Networks: A layered approach, Addison Wesley, 1999, ISBN 0-20-130967-X
– Sabella, R and Lugli, P:High speed optical communications,
Kluwer Academic, 1999, ISBN 0-41-280220-1
Prof. Z Ghassemlooy 3


Transmission Medium, or channel, is the actual physical path that data follows from the transmitter to the receiver.

Copper cable is the oldest, cheapest, and the most common form of transmission medium to date.

Optical Fiber is being used increasingly for high-speed applications.
Prof. Z Ghassemlooy 4

why?
 Growing demand for faster and more efficient communication systems
 Internet traffic is tripling each year

It enables the provision of Ultra-high bandwidth to meet the growing demand
 Increased transmission length
 Improved performance
 etc.
Prof. Z Ghassemlooy 5

Bandwidth
Demand
1990 2000 2010
20,000 x
Typical data bandwidth requirement
•
Raw text = 0.0017 Mb
•
Word document = 0.023 Mb
•
Word document with picture = 0.12 Mb
•
Radio-quality sound = 0.43 Mb
•
Low-grade desktop video = 2.6 Mb
•
CD-quality sound = 17 Mb
•
Good compressed (MPEG1) video = 38 Mb
Prof. Z Ghassemlooy 6

• 800 BC Use of fire signal by the Greeks
• 400 BC Fire relay technique to increase transmission distance
• 150 BC Encoded message
• 1880
Invention of the photophone by Alexander Graham Bell
Prof. Z Ghassemlooy 7

contd.
• 1930 Experiments with silica fibres, by Lamb (Germany)
• 1950-55 The birth of clad optical fibre, Kapany et al (USA)
• 1962 The semiconductor laser, by Natan, Holynal et al (USA)
• 1960 Line of sight optical transmission using laser:
- Beam diameter: 5 m
- Temperature change will effect the laser beam
Therefore, not a viable option
•1966- A paper by C K Kao and Hockham (UL) was a break through
Loss < 20 dB/km

- Glass fibre rather than crystal (because of high viscosity)
- Strength: 14000 kg /m 2 .
Contd.
Prof. Z Ghassemlooy 8

contd.
• 1970 Low attenuation fibre, by Apron and Keck (USA) from 1000 dB/km - to - 20 dB/km
- Dopent added to the silica to in/decrease fibre refractive index.
• Late 1976 Japan,
Graded index multi-mode fibre
- Bandwidth: 20 GHz, but only 2 GHz/km
Start of fibre deployment.
• 1976 800 nm Graded multimode fibre @ 2 Gbps/km.
• 1980’s
- 1300 nm Single mode fibre @ 100 Gbps/km
- 1500 nm Single mode fibre @ 1000 Gbps/km
- Erbium Doped Fibre Amplifier
Prof. Z Ghassemlooy 9

contd.
• 1990’s
- Soliton transmission (exp.): 10 Gbps over 10 6 km with no error
- Optical amplifiers
- Wavelength division multiplexing,
- Optical time division multiplexing (experimental) OTDM
• 2000 and beyond
- Optical Networking
- Dense WDM, @ 40 Gbps/channel, 10 channels
- Hybrid DWDM/OTDM

~ 50 THz transmission window

> 1000 Channels WDM

> 100 Gbps OTDM

Polarisation multiplexing
- Intelligent networks
Prof. Z Ghassemlooy 10

10,000
3000
1000
300
100
30
10
0.3
0.1
3
1
0.03
*
*
80 82
*
Single Channel (ETDM)
Multi-Channel (WDM)
Single Channel (OTDM)
WDM + OTDM
WDM + Polarization Mux
Soliton WDM
84 86 88 90 92 94 96 98 00 02 04
Systems
Research
Experiments
Courtesy:
A. Chraplyvy
11

10000
1000
100
10
1
0.1
1985
Research Systems
Fiberization
Digitization
Optical networking
Wavelength Switching
TOTDM
Commercial Systems
SONET rings and
DWDM linear systems
2000 2004 1990 1995
Year
Prof. Z Ghassemlooy cisco
12

DWDM
• Typical bit rate 40 Gbps / channel
• ~ 8 THz (or 60 nm) Amplifier bandwidth
• 32 channels (commercial) with 0.4 nm (50 GHz) spacing
• 2400 km, no regeneration (Alcatel)
Total bandwidth = (Number of channels) x (bit-rate/channel)
OTDM
• Typical bit rate 6.3 Gbps / channel
• ~ 400 Amplifier bandwidth
• 16 channels with 1 ps pulse width
Prof. Z Ghassemlooy 13

System
FT3
FTG -1.7
FT -2000
NGLN
WaveStar
400G
TM
WaveStar
1.6T
TM
LambdaXtreme
1980
1987
1992
1995
Year
1999
2001
2003
WDM chan nels
1
Bit rate/ channel
1
1
8
80
40
160
128
64
45 Mb/s
1.7
Gb/s
2.5
Gb/s
2.5
Gb/s
2.5
Gb/s
10 Gb/s
10 Gb/s
10 Gb/s
40 Gb/s
Bit rate/
Fibre
45 Mb/s
1.7 Gb/s
2.5 Gb/s
20 Gb/s
200 Gb/s
400 Gb/s
1.6 Tb/s
1.28 Tb/s
2.56 Tb/s
Voice channels per fibre
672
24,192
32,256
258,000
2,580,000
5,160,000
20,640,000
16,512,000
33,0 24,000
Regen spans
7 km
50 km
50 km
360 km
640 km
640 km
640 km
4000 km
1000 km
H. Kogelnik, ECOC 2004
Prof. Z Ghassemlooy 14

Year Service Bandwidth distance product
1900 Open wire telegraph
1940 Coaxial cable
1950
1976
Microwave
Optical fibre
1993 Erbium doped fibre amplifier
1998 EDFA + DWDM
2001-
2001-
EDFA + DWDM
OTDM
500 Hz-km
60 kHz-km
400 kHz-km
700 MHz-km
1 GHz-km
> 20 GHz-km
> 80 GHz-km
> 100 GHz-km
Prof. Z Ghassemlooy 15

• High data rate, l ow transmission loss and low bit error rates
• High immunity from electromagnetic interference
• Bi-directional signal transmission
• High temperature capability, and high reliability
• Avoidance of ground loop
•
Electrical isolation
•
Signal security
• Small size, light weight, and stronger
62 mm
21mm
648 optical fibres
363 kg/km
Prof. Z Ghassemlooy
448 copper pairs
5500 kg/km
16


Electronics and Computers

Broad Optoelectronic

Medical Application

Instrumentation

Optical Communication Systems

High Speed Long Haul Networks

(Challenges are transmission type)
 Metropolitan Area Network (MAN)  ?

Access Network (AN)?
Challenges are:
- Protocol
- Multi-service capability
- Cost
Prof. Z Ghassemlooy 17

Prof. Z Ghassemlooy 18

Photonics Institute
Prof. Z Ghassemlooy 19

Source coding
Modulation Multiplexing Modulation
• Analogue
• Digital
• Frequency
• Time
External Internal
• Pulse shaping
• Channel coding
• Encryption
• etc.
Prof. Z Ghassemlooy 20

1 st -stage amplifier
2 nd -stage amplifier
Pre-detection filtering
•
Equalizer
Sampler
& detector
Demultiplexer
Demodulator
Decoder
Decryption
Output signal
Prof. Z Ghassemlooy 21

IP IP
ATM
SDH
ATM
SDH
SDH ATM IP Other
Open Optical Interface
All Optical Networks
Challenges ahead:
• Network protection • Network routing • True IP-over-optics
Prof. Z Ghassemlooy 22


Modulation and detection and associated high speed electronics

Multiplexer and demultiplexer

Fibre impairments:
. Loss
. Chromatic dispersion
. Polarization mode dispersion
. Optical non-linearity
. etc.

Optical amplifier
. Low noise
. High power
. Wide bandwidth
. Longer wavelength band S
Prof. Z Ghassemlooy 23

contd.

Dedicated active and passive components

Optical switches

All optical regenerators

Network protection
 Instrumentation to monitor QoS
Prof. Z Ghassemlooy 24

• It causes pulse distortion, pulse "smearing" effects
• Higher bit-rates and shorter pulses are less robust to Chromatic Dispersion
• Limits " how fast “ and “ how far ” data can travel
10 Gbps t
60 Km SMF-28
40 Gbps cisco
4 Km SMF-28 t
Prof. Z Ghassemlooy 25


By joining fibres with CD of opposite signs (polarity) and suitable lengths an average dispersion close to zero can be obtained; the compensating fiber can be several kilometers and the reel can be inserted at any point in the link, at the receiver or at the transmitter
Prof. Z Ghassemlooy 26

Ey
Ex
Input pulse n x n y
Spreaded output pulse

The optical pulse tends to broaden as it travels down the fibre; this is a much weaker phenomenon than chromatic dispersion and it is of some relevance at bit rates of 10Gb/s or more
Prof. Z Ghassemlooy cisco
27


Factors contributing to PMD
– Bit Rate
– Fiber core symmetry
– Environmental factors
– Bends/stress in fiber
– Imperfections in fiber

Solutions for PMD
– Improved fibers
– Regeneration
– Follow manufacturer’s recommended installation techniques for the fiber cable
Prof. Z Ghassemlooy 28

Global Network
< 10000 km
< 10 Tbit/s
Wide Area
Network
< 100 km
< 1 Tbit/s
Metropolitan/Regional
Area Optical Network
Client/Access
Networks
Courtesy: A.M.J. Koonen
Cable modem
Networks
Cable
SDH/
SONET
ISP
ATM
FTTB
Gigabit
Ethernet
< 20 km
100M - 10 Gbit/s
ATM
FTTH
PSTN/IP
Prof. Z Ghassemlooy
Mobile
Corporate/
Enterprise Clients
29