Introduction of Optical Communication old data

introduction

1. 1
Prof. Z Ghassemlooy
Optic
al Fiber
Communications
Lecture 1: Introduction
Dr. Syed Baqar Hussain
[email protected]
[email protected]

2. 2
Prof. Z Ghassemlooy
Reading List
– John M. Senior “Optical FiberCommunications:
Principles and Practice”, Prentice Hall
Optional Reading List – J.R. Dutton “Understanding Optical Communications”,
Prentice Hall
– GovindP. Agarwal, “Light Wave Technology:
Telecommunication Systems”, Wiley and Sons
– Ramasawami, R and Sivarajan, K.N, “Optical network:
A practical perspective”, Elesevier
–Roger L. Freeman, “FiberOptic Systems for
Telecommunications”, Wiley Series
(if available)
i
Essential Reading List
(other than web sources)

3. 3
Prof. Z Ghassemlooy
Transmission Media iTransmission Medium, or channel, is the actual physical
path that data follows from the transmitter to the
receiver.
iCopper cable is the oldest, cheapest, and the most
common form of transmission medium to date.
iOptical Fiber is being used increasingly for high-speed
applications.

4. 4
Prof. Z Ghassemlooy
Transmission by Light: why? iGrowing demand for faster and more efficient
communication systems
iInternet traffic is tripling each year
iIt enables the provision of Ultra-high bandwidth to
meet the growing demand
iIncreased transmission length
iImproved performance
ietc.

5. 5
Prof. Z Ghassemlooy
Demand for Bandwidth
Bandwidth
Demand
1990 2000 2010
•
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
Typical data bandwidth requirement 20,000 x

6. 6
Prof. Z Ghassemlooy
Historical Developments
•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 photophoneby Alexander Graham Bell

7. 7
Prof. Z Ghassemlooy
Historical Developments -
contd.
•1930 Experiments with silica fibres, by Lamb (Germany)
•1950-55 The birth of clad optical fibre, Kapanyet 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 Kaoand Hockham(UL) was a break
through
-
Loss < 20 dB/km b
-Glass fibre rather than crystal (because of high viscosity)
-Strength: 14000 kg /m
2
.
Contd.

8. 8
Prof. Z Ghassemlooy
Historical Developments -
contd.
•1970 Low attenuation fibre, by Apron and Keck (USA) from 1000
dB/km -to -20 dB/km
-Dopentadded 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

9. 9
Prof. Z Ghassemlooy
Historical Developments -
contd.
•1990’s
-Solitontransmission (exp.):
10 Gbpsover 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
Š~ 50 THz transmission window
Š> 1000 Channels WDM
Š> 100 GbpsOTDM
ŠPolarisation multiplexing
-Intelligent networks

10. 10
Prof. Z Ghassemlooy
LightwaveEvolution
Single Channel (ETDM)
Multi-Channel (WDM)
Single Channel (OTDM)
WDM + OTDM
WDM + Polarization Mux
*
Soliton WDM
Capacity (Gb/s)
10,000
300
100
30
10
3
1
0.3
0.1
0.03
1000
3000
84 868890
Year
92 94 96 98 8082
*
00
02
*
04
Systems
Research
Experiments
Courtesy:
A. Chraplyvy

11. 11
Prof. Z Ghassemlooy
System Evolution
cisco
Fiberization
Digitization
SONET rings and
DWDM linear
systems
Optical networking
Wavelength Switching
TOTDM
Research Systems
Commercial Systems
0.1
1
10
100
1000
10000
1985 1990 1995 2000
Year
Capacity (Gb/s)
2004

12. 12
Prof. Z Ghassemlooy
Existing Systems -1.2 Tbps WDM •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)
DWDMDWDM
OTDM
OTDM
•Typical bit rate 6.3 Gbps / channel
•~ 400 Amplifier bandwidth
•16 channels with 1 ps pulse width

13. 13
Prof. Z Ghassemlooy
Commercial Systems
H. Kogelnik, ECOC 2004
System Year
WDM
chan -
nels
Bit rate/
channel
Bit rate/
Fibre
Voice
channels
per fibre
Regen
spans
FT3 1980 1 45 Mb/s 45 Mb/s 672 7 km
FTG -1.7 1987 1
1.7
Gb/s
1.7 Gb/s 24,192 50 km FT-2000 1992 1
2.5
Gb/s
2.5 Gb/s 32,256 50 km
NGLN 1995 8
2.5
Gb/s
20 Gb/s 258,000 360 km
WaveStar
TM
400G
1999
80
40
2.5
Gb/s
10 Gb/s
200 Gb/s
400 Gb/s
2,580,000
5,160,000
640 km
640 km
WaveStar
TM
1.6T
2001 160 10 Gb/s 1.6 Tb/s 20,640,000 640 km
LambdaXtreme 2003
128
64
10 Gb/s
40 Gb/s
1.28 Tb/s
2.56 Tb/s
16,512,000
33,0 24,000
4000 km
1000 km

14. 14
Prof. Z Ghassemlooy
Communications Technologies
Year Service Bandwidth distance product 1900 Open wire telegraph 500 Hz-km
1940 Coaxial cable 60 kHz-km
1950 Microwave 400 kHz-km 1976 Optical fibre 700 MHz-km 1993 Erbium doped fibre amplifier 1 GHz-km 1998 EDFA + DWDM > 20 GHz-km 2001- EDFA + DWDM > 80 GHz-km 2001- OTDM > 100 GHz-km

15. 15
Prof. Z Ghassemlooy
Optical Technology -Advantages •High data rate, low transmission lossand 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
448 copper pairs
5500 kg/km
62 mm
21mm
648 optical fibres
363 kg/km

16. 16
Prof. Z Ghassemlooy
Applications
¾Optical Communication Systems
àHigh Speed Long Haul Networks 9
(Challenges are transmission type)
àMetropolitan Area Network (MAN) 9?
àAccess Network (AN)?
Challenges are:
-Protocol
-Multi-service capability
-Cost
¾Electronics and Computers
¾Broad Optoelectronic
¾Medical Application
¾Instrumentation
Optics is here to stay for
a long time.

17. 17
Prof. Z Ghassemlooy
Undersea Cables

18. 18
Prof. Z Ghassemlooy
System Block Diagram
Photonics Institute

19. 19
Prof. Z Ghassemlooy
Source Source
coding
Source
coding
Modulation
ModulationMultiplexing
MultiplexingModulation
Modulation
External
ExternalInternal
Internal
• Analogue
•Digital
• Analogue •Digital
• Frequency
•Time
• Frequency •Time
•Pulse shaping
• Channel coding
• Encryption
•etc.
•Pulse shaping • Channel coding • Encryption •etc.

20. 20
Prof. Z Ghassemlooy
Receiver
1
st
-stage
amplifier 1
st
-stage
amplifier
2
nd
-stage
amplifier 2
nd
-stage
amplifier
Pre-detection
filtering
Pre-detection
filtering
Sampler
&
detector
Sampler
&
detector
Demultiplexer Demultiplexer
•Equalizer
Demodulator
Demodulator
Output signal
Output signal
Decoder
Decryption
Decoder
Decryption

21. 21
Prof. Z Ghassemlooy
All Optical Network
SDH
ATM
IP
SDH
ATM
IP
Open Optical Interface
SDH
ATM
IP
Other
All Optical Networks
Challenges ahead:
• Network routing
• Network routing• True IP-over-optics
• True IP-over-optics • Network protection
• Network protection

22. 22
Prof. Z Ghassemlooy
Challenges Ahead àModulation and detection and a ssociated high speed electronics
àMultiplexer and demultiplexer
àFibre impairments:
. Loss
. Chromatic dispersion
. Polarization mode dispersion
. Optical non-linearity
. etc.
àOptical amplifier
. Low noise
. High power
. Wide bandwidth
. Longer wavelength band S

23. 23
Prof. Z Ghassemlooy
Challenges Ahead -
contd.
àDedicated active and passive components
àOptical switches
àAll optical regenerators
àNetwork protection
àInstrumentation to monitor QoS

24. 24
Prof. Z Ghassemlooy
Chromatic Dispersion
60 Km SMF-28
4 Km SMF-28
10 Gbps
40 Gbps
t
t
•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
cisco

25. 25
Prof. Z Ghassemlooy
Dispersion Compensating Fibre
iBy joining fibreswith 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

26. 26
Prof. Z Ghassemlooy
Polarization Mode Dispersion (PMD)
iThe optical pulse tends to broaden as it travels down the
fibre; this is a much weakerphenomenon than chromatic
dispersion and it is of some relevance at bit rates of 10Gb/s
or more
n
x
n
y
Ex
Ey
Input pulse
Spreaded output pulse
cisco

27. 27
Prof. Z Ghassemlooy
Combating PMD iFactors contributing to PMD
– Bit Rate
– Fiber core symmetry
– Environmental factors
– Bends/stress in fiber
– Imperfections in fiber
iSolutions for PMD
– Improved fibers
– Regeneration
– Follow manufacturer’s recommended installation
techniques for the fiber cable

28. 28
Prof. Z Ghassemlooy
Optical Transport Network Global Network
Wide Area
Network
Metropolitan/Regional
Area Optical Network
Corporate/
Enterprise Clients
Cable modem
Networks
Client/Access
Networks
FTTH
Mobile
SDH/
SONET
ATM
PSTN/IP
ISP
Gigabit
Ethernet
Cable
FTTB
ATM
< 10000 km
< 10 Tbit/s
< 100 km
< 1 Tbit/s
< 20 km
100M - 10 Gbit/s
Courtesy: A.M.J. Koonen