vii
TABLE OF CONTENTS
CHAPTER
1
2
TITLE
PAGE
TITLE PAGE
i
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
xi
LIST OF FIGURES
xii
LIST OF SYMBOLS
xv
LIST OF ABBREVIATIONS
xvi
LIST OF APPENDICES
xvii
INTRODUCTION
1
1.1
Historical Perspective
1
1.2
Project Background
2
1.3
Objectives
4
1.4
Scope of work
4
1.5
Methodologies
5
1.6
Thesis Outline
7
LITERATURE REVIEW
9
viii
2.1
Radio over Fiber
9
2.2
Sub Carrier Multiplexing
10
2.7.1
Analog SCM System
13
2.7.2
Digital SCM System
13
2.3
2.3.1
Mach-Zender Modulator
14
2.3.2
Electrooptic Phase Modulator
15
Light Source
20
2.5
Fiber Link
22
2.7.1
Step-Index Fiber
22
2.7.2
Graded-Index Fiber
25
2.7
4
14
2.4
2.6
3
Optical Modulator
Optical Amplifier
26
2.7.1
Noise
29
2.7.2
Gain Saturation
30
2.7.3
Inhomogeneous Broadening Effects
30
2.7.4
Polarization Effects
31
Receiver Part
32
2.7.1
Receiver Sensitivity
33
2.7.2
Dynamic Range
34
2.7.3
PIN Photodetector
36
2.7.4
Avalanche Photodetector
39
2.7.5
Photodetector Noise
42
SCM – ROF MODELLING
43
3.1
The Transmitter Model
45
3.2
The Transmission Link Model
49
3.3
The Receiver Model
51
SIMULATION RESULT
54
4.1
The Transmitter Simulation Results
55
4.2
The Transmission Link Simulation Results
58
4.3
The Receiver Simulation Results
59
4.4
The Eye Diagram
62
ix
5
PERFORMANCES ANALYSIS
65
5.1
Analysis on Fiber Length without EDFA Introduced
65
5.1.1
The Bit Error Rate Performances
66
5.1.2
The Carrier to Noise Ratio Performances
68
5.1.3
The Eye Diagram
69
5.2
5.3
5.4
5.5
6
Analysis on EDFA Length
70
5.2.1
The Carrier to Noise Ration Performances
71
5.2.2
The Bit Error Rate Performances
72
5.2.3
Quality Factor
73
5.2.4
The Eye Diagram
74
Analysis on Fiber Length with EDFA
74
5.3.1
The Carrier to Noise Ratio Performances
75
5.3.2
The Bit Error Rate Performances
76
5.3.3
Quality Factor
77
5.3.4
The Eye Diagram
78
Analysis on nonlinearity due to optical power level
79
5.4.1
The Bit Error Rate Performances
80
5.4.2
The Carrier to Noise Ratio
81
5.4.3
Quality Factor
82
5.4.4
The Eye Diagram
83
Analysis on number of channels in the system.
83
5.5.1
The Bit Error Rate Performances
84
5.5.2
The Carrier to Noise Ratio
85
5.5.3
The Eye Diagram
86
CONCLUSION AND RECOMMENDATION
87
6.1
Conclusion
87
6.2
Recommendation
89
6.3
Future Work
90
6.4
Publication
91
x
REFERENCES
89
APPENDIX A
94
APPENDIX B
96
xi
LIST OF TABLES
TABLE NO
TITLE
PAGE
2.1
Typical Step-Index Fiber characteristic
22
3.1
Global simulation setup
44
3.2
Subcarrier frequency allocation
45
3.3
Spectrum frequency
45
3.4
Simulation setup for EDFA
48
3.5
Simulation setup for Single Mode Fiber
48
3.6
Simulation setup for APD Photo detector
51
5.1
Basic Simulation Specification for Analysis on
Fiber Length
64
5.2
Basic simulation setup for Analysis on EDFA length
68
5.3
Basic simulation setup for SCM_ROF with EDFA
73
5.4
Basic simulation setup for nonlinearity of power levels
77
5.5
Frequency allocation for 8 channels
81
6.1
Length of fiber with reasonable BER
86
xii
LIST OF FIGURE
NO
TITLE
PAGE
1.1
Basic architecture of a single end-to-end SCM system
3
1.2
The project flow chart
6
2.1
A basic configuration of SCM system.
8
2.2
Basic configuration of RF modulation
10
2.3
Basic configuration of Optical modulator
12
2.4
The spectrum of Optical Double Side Band (ODSB)
12
2.5
The spectrum of Optical Single Side Band (OSSB)
13
2.6
Basic configuration of Optical Modulator for OSSB
14
2.7
The optical signals modulated by a single wavelength.
17
2.8
Basic architecture of using Phase Modulator.
17
2.9:
Step-Index Fiber. (a) Refractive index profile.
(b) End view.(c) Cross-sectional side view.
2.10
21
Graded-Index Fiber. (a) Refractive index profile.
(b) End view.(c) Cross-sectional side view.
24
2.11
Schematic diagram of a simple Doped Fiber Amplifier
25
2.12
A basic structure of PIN diode
26
2.13
Cross-sectional view of PIN diode
35
2.14
Energy-band diagram under reserve bias
35
2.15
Structure of an APD
38
2.16
Gain versus reverse bias characteristic of APD
39
3.1
Model of four channels SCM-ROF system.
42
3.2
Transmitter for electrical domain
43
xiii
3.3
Transmitter for optical domain.
46
3.4
Transmission link
50
3.5
The receiver for optical domain.
51
4.1
Signal wave modulated by PSK
53
4.2
(a) RF spectrum for data signal on first channel
(3.6 GHz).
54
(b) RF spectrum for data signal on second
channel (7.2 GHz).
54
(c) RF spectrum for data signal on third
channel (10.8 GHz).
54
(d) RF spectrum for data signal on fourth
channel (18.0 GHz).
54
4.3
RF spectrum for adding four channels.
55
4.4
Amplified composite signal
55
4.5
Spectrum of the signal after Mach Zender modulator.
56
4.6
Optical spectrum after EDFA.
57
4.7
Optical spectrum after propagated 65km in fiber.
57
4.8
RF spectrum detected by photo detector
58
4.9
Amplified received RF spectrum
58
4.10
RF spectrum for channel 1
59
4.11
Received electrical signal wave
59
4.12
Eye Diagram for the channel 1.
60
4.13
Eye Diagram for the channel 2.
61
4.14
Eye Diagram for the channel 3.
61
4.15
Eye Diagram for the channel 4.
61
5.1
BER Performance for channel 1.
65
5.2
BER Performance for channel 4.
65
5.3
CNR for the all channels.
66
5.4
Eye diagram for channel 1
67
5.5
CNR for 4 channels
69
5.6
Log of BER for 4 channels
70
5.7
Q factor versus EDFA length.
71
5.8
Eye Diagram for channel 1
72
xiv
5.9
CNR performance for 4 channels
74
5.10
BER performance for 4 channels
75
5.11
Quality factor for 4 channels.
75
5.12
Eye diagram for fiber length 1 km to 150 km
76
5.13
BER for channel 1 versus optical power.
78
5.14
BER for channel 2
79
5.15
CNR for versus optical power
79
5.16
Q factor for channel 1 and 2.
80
5.17
The eye diagram for channel 1
80
5.18
BER performance for 8 channels
82
5.19
CNR performance for 8 channels
83
5.20
The eye diagram for channel 5
84
5.21
Eye diagram for channel 6
84
xv
LIST OF SYMBOLS
f
:
Frequency
λ
:
Lambda
P0
:
Input optical power
Lis
:
Insertion loss
φBias
:
Bias phase shift
Vл
:
Half wave voltage
c
:
Critical angle,
∆
:
Refractive index change
n1
:
Refractive index
Er+3
:
Erbium ion
J
:
Quantum number
dB
:
Decibel
N
:
Average number of electrons
T
:
Bit interval of time
m
:
Number of electrons generated
η
:
Quantum efficiency
ρ
:
Resistivity
Ω
:
Ohm
GHz
:
Giga Hertz
xvi
LIST OF ABBREAVIATIONS
TDM
:
Time Division Multiplexed
FDM
:
Frequency Division Multiplexed
SCM
:
Sub Carrier Multiplexed
WDM
:
Wavelength Division Multiplexed
SCM-ROF
:
Sub Carrier Multiplexed Radio over Fiber
CNR
:
Carrier to Noise Ratio
BER
:
Bit Error Rate
EDFA
:
Erbium Doped Fiber Amplifier
MZM
:
Mach Zehnder modulator
FM
:
Frequency modulation
AM-VSB
:
Amplitude modulation with vestigial sideband
IMD
:
Intermodulation distortion
ODSB
:
Optical Double Side Band
OSSB
:
Optical Single Side Band
SCM/WDM
:
Sub Carrier Multiplexed and wavelength-division
multiplexing
LO
:
Local Oscillator
DFB LD
:
Distributed-feedback laser diode
ASE
:
Amplified Spontaneous Emission
PSC
:
Plastic-cladded silica fiber
PDG
:
Polarization Dependent Gain
LNA
:
Low noise amplifier
RMS
:
Root-mean-square
xvii
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A
Graph for Extended Performances Analysis
94
B
Published Conference Papers
96