all optical packet routing time wavelength...
TRANSCRIPT
ALL OPTICAL PACKET ROUTING TIME WAVELENGTH DIVISION
MULTIPLEXING PASSIVE OPTICAL NETWORK
MOHD SHAHRIL BIN SALLEH
A thesis submitted in fulfilment o f the
requirements for the award of the degree of
Doctor o f Philosophy (Electrical Engineering)
Faculty o f Electrical Engineering
Universiti Teknologi M alaysia
OCTOBER 2015
VI
ABSTRACT
Time Wavelength Division Multiplexing (TWDM) Passive Optical Network (PON) is a combination o f both Time Division Multiplexing (TDM) and Wavelength-Division Multiplexing (WDM) technologies. The TWDM PON system can provide scalable and efficient wavelength management in WDM-PON network and at the same time can reduce numbers o f aggregation node in metro network level. In this study, a new All-Optical Packet Routing (AOPR) TWDM PON system is designed to provide more flexibility o f data delivery for each PON port and more bandwidth to each subscriber at multiple PON Optical Distribution Network (ODN) link. By proposing broadcasting, multicasting, and multiplexing technique in downstream signal, the system is capable to support full degree of flexibility in managing efficient dynamic bandwidth allocation. To achieve flexible packet routing between multiple PON ports and multiple PON ODN links TWDM PON architecture, most o f the proposed system used tunable transceiver in optical line terminal. This design w ill cause the attractiveness o f the PON system, which is able to broadcast and multicast packet within the entire PON system limited only at single PON link. The proposed AOPR module was designed to incorporate fixed-type wavelength Optical Line Terminal (OLT) transmitter with Continuous Wave (CW) Pump Probe Signal (PPS) module. This design used high-speed wavelength selective switch (WSS) or ALL ON method to support high speed wavelength switching or all broadcast signal to replace a wavelength tuning feature in tunable OLT transmitter. The proposed architecture has been designed using the multicasting cross-gain modulation (XGM) method. In this proposed design. XGM function located in the OLT system becomes a part o f the AOPR OLT transmitter. The arrangement o f this design aims to generate single or multiple wavelengths in a downstream direction in each OLT PON port. The system is designed and simulated using VPI photonic software followed by experimental verification in the laboratory. This design showed the ability o f the system to perform flexible packet routing function by using WSS method with 38 dB allowable link loss margin in the system at 10 Gbps at Bit Error Rate (BER) o f 1 O'3. By using I6X. lOGbps downstream bandwidth can serve up to 2000 users at 20km. In regard to handling the broadcasting or multicasting flexible function with ALL ON method in the system, the result revealed that the proposed system can support 160Gbps broadcast downstream bandwidth to serve up to 16 PON links using I6X. The proposed architecture shows this method will minimise an inventory issue and reduce point o f error caused by different OLT PON port transmitter wavelength during system installation and maintenance. The proposed AOPR OLT module has high potential to be used in the future extended TWDM PON access network.
ABSTRAK
Pembahagian Kombinasi Masa dan Panjang Gelombang (TWDM) Rangkaian Optik Pasif(PON) adalah gabungan teknologi Pembahagian Kombinasi Masa (TDM) dan Pembahagian Kombinasi Panjang Gelombang (WDM). Sistem TWDM PON berupaya memberikan skalabiIiti dan amat berkesan dalam fungsi pengurusan panjang gelombang dalam rangkaian WDM-PON serta pada masa yang sama boleh mengurangkan bilangan pengagregatan nod di peringkat rangkaian metro. Dalam kajian ini, sistem Aliran Paket Optik Menyeluruh (AOPR) TWDM PON direka untuk memberi fleksibiliti dan jalur lebar tambahan dalam penghantaran data dari setiap liang PON kepada setiap pelanggan dalam berbilang Rangkaian Agihan Optik (ODN). Dengan mencadangkan teknik siaran, siaran terpi I ill dan penggabungan isyarat halaan menurun dari Terminal Talian Optik (OLT) ke Unit Rangkaian Optik (ONU), sistem ini mampu untuk memberikan fleksibiliti dalam pengurusan peruntukan jalur lebar yang lebih dinamik dan berkesan. Kebanyakan sistem TWDM PON yang dicadangkan mengunakan pemancar boleh laras pada OLT untuk mencapai fleksibiliti pada aliran data diantara setiap liang PON dan ODN. Namun, reka bentuk ini akan menghadkan kelebihan kepada sistem PON, di mana ia tidak mampu melaksanakan fungsi siaran secara sepenuhnya di dalam keseluruhan sistem PON. Modul AOPR yang dicadangkan telah direka untuk menggabungkan panjang gelombang bernilai tetap pada pemancar OLT bersama modul Gelombang Berterusan (CW) Isyarat Pam Kuar (PPS). Reka bentuk ini menggunakan kaedah suis pilihan panjang gelombang pada kelajuan tinggi (WSS) atau SBMUA AKTIF untuk menyokong pensuisan panjang gelombang pada kelajuan tinggi serta semua isyarat siaran untuk menggantikan fungsi pelarasan panjang gelombang pada pemancar OLT. Seni bina yang dicadangkan ini menggunakan kaedah siaran terpilih modulasi gandaan silang (XGM) di mana fungsi ini menjadi sebahagian daripada pemancar AOPR OLT. Susunan reka bentuk ini bertujuan menghasilkan panjang gelombang tunggal atau berbilang mengikut arah aliran isyarat menurun dari setiap liang PON OLT. Sistem ini direka dan disimulasi dengan menggunakan perisian VPI dan diikuti oleh pengesahan melalui ujikaji di dalam makmal. Keputusan menunjukkan keupayaannya untuk melaksanakan fungsi aliran paket yang fleksibel dengan menggunakan kaedah WSS dengan nilai kehilangan kuasa optik dalam talian sebanyak 38 dB pada kelajuan 10 Gbps dengan Kadar Ralat Bit (BER) sebanyak 10" . Dengan menggunakan 16̂ ., isyarat jalur lebar dari OLT ke ONU dengan kelajuan lOGbp boleh memberi perkhidmatan kepada pengguna seramai 2000 orang dalam jarak 20km. Merujuk kepada pengendalian fungsi fleksibel pada siaran penuh dan terpilih dengan menggunakan kaedah SEMUA AKTIF. hasilnya menunjukkan sistem ini boleh menyokong siaran penuh aliran menurun dengan kelajuan l60Gbps untuk memberi perkhidmatan kepada 16 PON dengan menggunakan 16).. Daripada hasil yang diperolehi, sistem yang dicadangkan ini mampu mengurangkan kelambatan masa yang disebabkan oleh pelarasan panjang gelombang dari OLT ke ONU. Di samping itu. kaedah ini akan mengurangkan isu inventori dan dapat mengurangkan kesilapan yang disebabkan oleh perbezaan panjang gelombang pada liang PON OLT yang boleh berlaku semasa proses pemasangan clan penyelenggaraan. Modul AOPR OLT yang dicadangkan mempunyai potensi yang tinggi untuk digunakan sebagai nilai tambah kepada sistem TWDM PON dalam rangkaian capaian pada masa akan datang.
TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT vi
ABSTRAK vii
TABLE OF CONTENTS viii
LIST OF TABLES xiv
LIST OF FIGURES xvi
LIST OF ABBREVIATIONS xxiv
LIST OF SYMBOLS xxviii
LIST OF APPENDICES XXX
1 INTRODUCTION 1
1.1 Background o f the study 1
1.2 Problem Statement 3
1.3 Motivation 4
1.4 Research Objectives 5
1.5 Scope o f Works 6
1.6 Research Methodology 9
1.7 Thesis Outline 11
2 REVIEW ON PON SYSTEM ARCHITECTURE 14
2.1 Introduction 14
2.2 PON System 15
2.3 TDM/WDM PON 16
ix
2.3.1 Previous work on flexible WDM and
WDM/TDM PON system architecture
2.3.2 Previous work on wavelength conversion
using Cross Gain Modulation to support
flexible WDM and WDM/TDM PON
system architecture
2.3.3 Previous reported work specifically based
on tunable laser source and wavelength
tuning in OLT module to support flexible
WDM and WDM/TDM PON systems
2.3.4 Previous reported work specifically based
on high power budget in WDM and
WDM/TDM PON systems
2.4 Flexible Hybrid WDM/TDM (TWDM) PON
System Architecture Design
2.4.1 Introduction
2.4.2 Types o f flexible TWDM PON system
architecture design
2.4.3 Type 1: Flexible TWDM PON system with
single PON link
2.4.4 Type 2: Flexible TWDM PON system with
multiple PON links
2.5 All-Optical Packet Routing TWDM PON
Proposed Design
2.5.1 AOPR TWDM PON system architecture
2.6 Enabling technology in flexible AOPR TWDM
PON system
2.6.1 Semiconductor optical amplifier
2.6.2 Theory and design SOA
2.6.3 XGM and multicasting XGM using SOA
2.7 Noise contribution within the optical link
2.8 Summary
18
21
22
24
25
25
28
28
34
41
42
43
43
44
45
47
48
X
3 FLEXIBLE TWDM PON SYSTEM DESIGN 51
3.1 Introduction 51
3.2 Flexible AOPR TWDM PON System
Functionality 53
3.2.1 Flexible all-optical packet routing function
system design 53
3.2.2 Flexible all-optical packet routing function
process flow 55
3.2.3 AOPR TWDM PON system with packet
broadcasting and the multicasting function 55
3.2.4 Packet broadcasting and multicasting
function system design 56
3.2.5 Packet broadcasting and multicasting
function process flow 59
3.3 AOPR OLT Subsystem Module Design 60
3.3.1 AOPR OLT module 61
3.3.2 Multi-wavelength pump probe signal
module 62
3.3.3 Wavelength select switch pump probe
signal module 63
3.3.4 All ON pump probe signal module 66
3.4 AOPR TWDM PON Simulation Model 68
3.5 Related simulation design 69
3.5.1 Optical spectrum of OLT transmit signal 69
3.5.2 Optical spectrum of pump probe signal 71
3.5.3 Optical spectrum after 1x2 optical coupler 72
3.5.4 Optical spectrum after SOA 73
3.5.5 Optical spectrum after AWG 76
3.6 Related simulation and experimental parameter
and measurement 77
3.7 Summary 82
xi
4 DESIGN AND SIMULATION AOPR TWDM PON
SYSTEM 84
4.1 Introduction 84
4.2 Flexible packet routing function in AOPR
TWDM PON System 85
4.2.1 AOPR TWDM PON System modelling 85
4.2.2 System design o f AOPR TWDM PON
system 89
4.2.3 Simulation result and discussion 91
4.2.4 System design optimisation 95
4.2.5 System design of AOPR TWDM PON
system with post-amplifier 103
4.2.6 Simulation result and discussion 103
4.3 Flexible Packet Multicasting function in AOPR
TWDM PON System 106
4.3.1 System design AOPR TWDM PON system
with broadcasting and multicasting
function 106
4.3.2 Simulation result and discussion 108
4.4 Fiber dispersion effect toward the proposed
system 114
4.5 Summary 118
5 DEVELOPMENT OF AOPR OLT SYSTEM 119
5.1 Introduction 119
5.2 Experimental Arrangement 120
5.3 Experimental setup 120
5.4 All Optical Wavelength Routing 122
5.4.1 Optical spectrum OLT PON port transmit
signal 122
5.4.2 Optical spectrum OLT PON port transmit
signal after SOA 123
5.4.3 SOA gain profile 123
5.4.4 Optical spectrum of amplified OLT
transmit signal
Optical Spectrum OLT PON Port Transmit
Signal After AWG
5.5.1 Performance study of wavelength routing
using TLS
Experimental Arrangement of Flexible Packet
Routing Function
5.6.1 Wavelength routing using XGM
5.6.2 XGM system design optimisation
5.6.3 System design comparison between
simulation and experiment
5.6.4 System design amplification to support 3R
(re-conversion, re-routing and re
amplification)
5.6.5 High-performance system design at 10
Gbps
Experimental Arrangement o f Flexible Packet
Broadcasting and Multicasting XGM Function
5.7.1 System design optimisation of multiple-
wavelength XGM
5.7.2 High performance of multichannel packet
broadcasting and multicasting downstream
signal at 10 Gbps
5.7.3 Four-channel multicast/broadcast
wavelengths
5.7.4 16-Channel multicast/broadcast
wavelength
5.7.5 Comparison of multichannel
multicast/broadcast wavelength
Comparison of Flexible TWDM PON System
Proposed by others with AOPR TWDM PON
System Architecture
Summary
6 CONCUSION AND FUTURE WORK 172
6.1 Conclusion 172
6.2 Contribution of Works 173
6.3 Suggestion for Future Works 174
REFERENCES
Appendices A-E
176
182-201
XIV
LIST OF TABLES
TABLE NO. TITLE
2.1 Comparison of NG-PON 2 technology selection.
2.2 Previous reported work specifically based on different
TWDM PON systems
2.3 Previous reported work specifically based on wavelength
conversion in WDM and TWDM PON system
2.4 Previous reported work specifically based on wavelength
tuning in TWDM PON system
2.5 Previous reported work specifically based on the power
budget in TWDM PON system
2.6 Variants for (a) fully flexible, (b) fully static and (c)
partially flexible hybrid TWDM PON by Dixit et al.
(201 la) and Dixit el al. (2011 b)
2.7 Wavelength broadcast-and-select TWDM PON system
(Li et al., 2012. 2013; Luo. Sui. & Effenberger. 2012: Ma
et al.. 2012: Yi. Li. Bi. Wei. & Hu, 2013)
2.8 Wavelength routed TWDM PON system (Chae & Oh,
1998: Feng. Chae. & Tran. 2011: Segarra, Sales, & Prat.
2008: Talli & Townsend. 2006)
2.9 Hybrid wavelength routed and broadcast-and-select
TWDM PON system (Calabretta et al.. 2007: Dixit et
al.,2012; Liu. Zhang, & Li. 2011; Mitsui. Hara, &
Fujiwara, 2011: Oh et al.,2008:)
2.10 Wavelength routed flexible TWDM PON system (K..-E.
Han et al.. 2007)(K. Han, He, & Lee. 2005)
PAGE
17
19
21
23
24
27
29
31
33
35
XV
37
39
40
49
50
74
91
102
131
146
156
163
Wavelength routed with broadcast-and-select Flex-
TWDM PON system (Bock, Prat, & Walker, 2005;
Glatty, Guignard, & Chanclou, 2007; Hsueh & Shaw,
2005; Jun-ichi Kani, 2013; Nakamura, 2012; Senoo &
Kaneko, 2012)
Wavelength broadcast-and-select flexible TWDM PON
system (Fujiwara et al., 2011; Kimura, 2010)
Wavelength multiplex and routing with broadcast-and-
select flexible TWDM PON system (Cheng, Wang, Liu,
& Gao, 2013)
Summary of previous work on flexible architecture
TWDM PON system with single PON link
Summary of previous work on flexible architecture
TWDM PON system with Multiple PON link
SOA (SAC 2Or)
Parameters o f major components in simulation design
Summary of maximum link loss margin and minimum
received sensitivity at BER of 1 O'9 and 1 O'3
Major component parameters in experimental design
Type o f loss for each component
Optical spectrum at different point
OSNR value at different numbers o f CW PPS at different
point of the transmission signal
LIST OF FIGURES
xvi
FIGURE NO. TITLE PAGE
1.1
1.2
2.1
2.2
2.3
2.4
2.5
3.1
3.2
*■> *■> J.J
3.4
3.5
3.6
3.7
Scope of work to be carried out in this thesis 8
Flow chart o f the research methodology 9
PON architecture 15
Proposed AOPR WDM/TDM PON system architecture 42
SOA building block (Said and Rezig. 2011) 44
XGM wavelength converter in SOA 46
Noise contribution within the optical link 47
Exploratory method using simulation and experimental
setup to support research objective 52
Flexible all-optical packet routing design to support (a)
low bandwidth traffic demand, (b) high bandwidth traffic
demand (c) multi-rate traffic design
Process flow for AOPR TWDM PON system to support
flexible all-optical packet routing function
Flexible all-optical packet broadcast and multicast
function to support (a) low bandwidth demand with single
PON port active and (b) high bandwidth demand with all
PON ports active 58
Process flow for AOPR TWDM PON system to support
flexible all-optical broadcasting and multicasting routing
function 60
AOPR OLT module design 61
XGM module that comprises pump probe signal. SOA
and electrical controller 63
54
56
3.8
3.9
3.10
3.11
3.12
3.13
3.14
3.15
3.16
3.17
3.18
3.19
3.20
3.21
XVll
All-optical wavelength routing using (a) TLS and (b)
WSS design 64
Proposed high-speed WSS signal as a probe for XGM
module 65
Dynamic routing with nanosecond switching windows for
an SOA cyclic router (Rohit et al., 2010). (a) The
microscope photograph for the SOA gate array and
arrayed waveguide cyclic router, (b) The waveguide
arrangement for a single input, multiple, (c) Time traces
showing the selecting and routing o f wavelength channels 66
Wavelength broadcasting using always ON PPS design
concept 67
Proposed All ON design as a probe for XGM module 67
Schematic diagram of AOPR TWDM PON system
simulation model 68
Schematic diagram of OLT transmitter simulation model 70
Optical spectrum of OLT transmit laser at +2 dBm 70
Optical spectrum of multiple CW transmit lasers at +7
dBm: single wavelength at 1554.13 nm 71
Optical spectrum of multiple CW transmit lasers at +1.2
dBm: multiple CW transmit laser with different
wavelengths at 1546.89, 1546.09, 1547.69 and 1548.49
nm. 72
Optical spectrum of OLT transmit signal and CW PPS
after coupling by 1x2 optical coupler 73
Power input versus (a) gain and (b) noise figure profile
for SAC20r 74
SOA black box simulation design using VPI System
based on real SOA data sheet 75
Comparison between data sheet and simulation result of
gain versus input power profile and noise figure versus
input power profile in SAC20r at 360 mA, 1554 nm. 76
3.22
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
Optical spectrum of the signal for both OLT transmit
signal and CW PPS routed from PON port 1 to output
AWG port 1 (PON ODN Link number 1)
AOPR TWDM PON system
AOPR TWDM PON system design
Optical spectrum OLT downstream signal and CW PPS
signal before XGM
Optical spectrum OLT downstream signal and CW PPS
signal after XGM
Optical spectrum downstream signal after filtered by
AWG
10 Gbps downstream BER performance of ONU received
sensitivity using OLT Tx at +2 dBm and CW PPS
transmit power at +7 dBm with different OLT transmit
wavelengths (a) received sensitivity and (b) link loss
BER performance at 2.5 Gbps after 25 dB link loss
margin and the OSNR value o f OLT and CW PPS signals
after XGM with different CW PPS transmit powers and
OLT transmit power fixed at +2 dBm.
10 Gbps downstream BER performance (a) ONU
received power (b) total link loss margin using OLT Tx
at +2 dBm with different CW PPS transmit powers
10 Gbps downstream BER performance of (a) ONU
received power (b) total link loss margin using OLT Tx at
+8 dBm with different CW PPS transmit power
Summary of 10 Gbps downstream BER performance of
total link loss margin and ONU received sensitivity at
different CW PPS transmit powers and different OLT
transmit powers
Simulation design o f flexible all-optical packets routing in
TWDM PON system with post-amplifier in the system
2.5 Gbps downstream BER performance of total link loss
margin using OLT Tx at +8 dBm and CW PPS transmit
77
86
90
92
93
94
96
98
99
101
102
xviii
103
4.13
4.14
4.15
4.16
4.17
4.18
4.19
4.20
4.21
4.22
xix
power at 0 dBm with and without post-amplifier in the
system 104
Optical spectrum downstream signal: (i) After AWG, (ii)
after SOA (amplified) and (iii) ONU received signal after
38 dB attenuation 105
Eye diagram of downstream signal at (a) 35 dB link loss
and (b) 38 dB link loss 105
Simulation design of flexible multicasting and all-optical
packet routing in TWDM PON system 107
Optical spectrum of four channel CW PPS downstream
signal: (a) multiplexing four-channel CW PPS signal, (b)
four-channel CW PPS signal and OLT PON port transmit
signal, (c) four-channel CW PPS signal after XGM, (d)
four-channel CW PPS signal after XGM signal filtered by
AWG 109
Optical spectrum of four channel CW PPS downstream
signal (a) Channel 1 (Ch 1) to support PON link 1 after
amplified by post-amplifier and (b) ONU received signal. 110
Ch 1 optical signal at PON link 1: (a) comparison of
signal after XGM before and after filter by AWG: (b)
comparison signal between output signal AOPR OLT and
ONU received signal after 33 dB link loss 111
BER performance of different multicast signals with
different attenuation power levels to maintain better BER
performance o f the system at 10 Gbps downstream signal 112
BER performance at different total link loss margin of
different number o f CW PPS signals to support multicast
downstream signal at 10 Gbps using OLT Tx +10 dBm
and CW +8 dBm 113
Linear and Nonlinear system with dispersion effect at
different fiber distance 115
performance o f AOPR WSS using single wavelength at
different fiber distance 116
4.23
4.24
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
5.14
xx
performance o f AOPR B&M using 4 wavelengths at
different fiber distance 117
Performance of AOPR B&M using 16 wavelengths at
different fiber distance 117
Experimental setup of (a) TLS transceiver back-to-back
system, (b) TLS with SOA and (c) TLS with SOA and
AWG 121
Optical spectrum of TLS transmit signal 123
Comparison experiment and data sheet inline amplifier
gain versus input power profile at 1554nm and 360mA. 124
Optical spectrum of TLS after amplified by SOA 125
Optical spectrum of TLS transmit signal 126
Optical spectrum of TLS transmit signal at different
transmit power 127
Comparison BER performance o f the TLS system using
SOA, with AWG and with TLS back-to-back system at
transmit power 2 dBm 128
Experimental set-up of the AOPR TWDM PON system 130
Comparison signal before and after XGM 135
BER performance of back-to-back system compared with
XGM signal with and without AWG filter at 2.5 Gbps 136
Comparison of eye diagram of 2.5 Gbps B2B system: (a)
TLS B2B system at 20 dB link loss compared with (b)
XGM signal with AWG filter at 20 dB link loss, (c) XGM
signal with AWG filter at 29 dB link loss and (d) XGM
without AWG filter at 20 dB link loss 137
Performance of BER versus ONU received sensitivity at
2.5 Gbps OLT Tx power at +2 dBm using single transmit
PPS at different CW Tx powers. 139
Summary of BER performance versus ONU received
sensitivity and BER versus link loss margin at different
OLT transmit powers and CW PPS transmit powers: 140
Comparison of experimental and simulation results at +8
dBm with different CW PPS transmit powers at 2.5 Gbps 142
5.15
5.16
5.17
5.18
5.19
5.20
5.21
5.22
5.23
5.24
5.25
5.26
xxi
Optical spectrum of AOPR TWDM OLT signal before
and after using post-amplifier (SAC20r) and ONU
received signal 143
Result of AOPR TWDM PON system captured with post
amplifier using single CW PPS at 2.5 Gbps with CW PPS
transmit power at -4 dBm and OLT Tx power at +8 dBm 144
BER performance of the system at different output
channels to determine W/> value in WSS method 145
Typical power attenuation loss in PON system 145
Total number of users at different distances and different
number of wavelengths at (a) total user per PON link and
(b) total user per system using WSS method 147
Different values of attenuation level versus total power o f
CW PPS at different numbers of CW PPS transmit
wavelength 149
Different values of attenuation level versus BER
performance of the system at different numbers of CW
PPS transmit wavelength 150
Block diagram of experimental set-up for AOPR TWDM
PON system 152
Optical spectrum of AOPR OLT downstream transmit
signal with multiplexing four-channel CW PPS 153
Optical spectrum of AOPR OLT downstream transmit
signal with four-channel CW PPS before and after XGM 154
Optical spectrum of AOPR OLT downstream transmit
signal at single-channel CW PPS selected after filtered by
AWG 155
Optical spectrum of AOPR OLT downstream transmit
signal with four-channel CW PPS at different points
(original CW PPS, spectrum after XGM, spectrum after
filtered by AWG, and the spectrum after post-amplifier)
in AOPR OLT module. 156
5.27
5.28
5.29
5.30
5.31
5.32
5.33
5.34
5.35
5.36
Optical spectrum of AOPR OLT downstream transmit
signal at output transmit AOPR OLT signal and ONU
received signal
Optical spectrum of AOPR OLT downstream transmit
signal at Channel 1 (1546.23 nm) CW PPS optical
spectrum at different points
BER performance of four downstream channels at 10
Gbps to determine W/> value in All ON method
Result captured by optical spectrum analyser: (a) total 16
CW probe signal and OLT downstream signal; (b) signal
after XGM; (c) total 16 probe signal after XGM; (d)
comparison before and after all 16 probe signals entered
AWG; (e) signal filtered by AWG and post amplifier and
(f) comparison of signal after post SOA and ONU
receiver.
BER performance of 5 different downstream channels at
10 Gbps to determine W/j value in All ON method for 16
channel B&M system.
Comparison o f link loss margin at different BER
performance o f WSS, B&M 4 and B&M 16 wavelength at
10 Gbps
BER performance o f the proposed system with different
link loss margin at 10 Gbps to support up to 16-
wavelength multicast signal
Summary of the total number o f users at different
distances and different number of wavelengths at (a) total
user per PON link and (b) total user per AOPR TWDM
PON system using All ON method
BER performance of the proposed AOPR TWDM PON
system with flexible TWDM PON system based on
replotted data taken from the published articles (Cheng et
al., 2013; Cheng et al., 2014).
BER performance of the proposed AOPR TWDM PON
system with O/E/O WSS with and without SGC based on
157
158
159
xxii
161
162
164
165
166
169
on replotted data taken from the published articles
(Nakamura et al., 2013; Taguchi et al., 2014).
xxiv
LIST OF ABBREVIATIONS
A/W - Amperes per watt
AGC-SOA - Adjustable Gain-Clamped Semiconductor Optical Amplifier
ALC - Automatic level control
APON - ATM(-Based) Passive Optical Network
ASE - Amplified Spontaneous Emissions
AWG - Arrayed Waveguide Grating
B&M - Broadcasting and Multicasting
B&S - Broadcast and select
B2B - Back to Back
BER - Bit Error Rate/Ratio
BERT - Bit Error Rate Test (Or Tester)
BPON - Broadband Passive Optical Network
B-Tx - Burst Transmitter
CD - Chromatic Dispersion
CO - Central Office
CW - Continuous Wave
CW-PPS - Continuous Wave- Pump probe signal
DBA - Dynamic Bandwidth Allocation
DCA - Digital Communications Analyzer
DFB - Distributed Feedback Laser
DML - Directly Modulated Laser
DPSK - Differential Phase Shift Keying
DS - Downstream Signal
DS/US - Downstream Signal Upstream Signal
DWBA - Dynamic Wavelength and Bandwidth Allocation
DWDM - Dense Wavelength Division Multiplexing
EAM - Electro Absorb Modulation
XXV
EDFA - Erbium-Doped Fiber Amplifier
EML - Externally modulated laser
EPON - Ethernet (-Based) Passive Optical Network
ER - Extinction Ratio
FEC - Forward Error Correction
FLS - Fixed Laser Source
FMW - Four Wave Mixing
FSAN - Full Service Access Network
FSR - Free spectral range
GaAs - Gallium arsenide
Gbit/s - Gigabits per second
GHz - GigaHetz
GPON - Gigabit Passive Optical Network
GVD - Group velocity dispersion
ID - Identification
IEEE - Institute O f Electrical And Electronics Engineers
IL - Insertion Loss
InP - Indium phosphide
ISI - Intersymbol Interference
ITU-T - International Telecommunication Union-Telecommunications
L2 - Open Systems Interconnection (OSI) Layer 2
L3 - Open Systems Interconnection (OSI) Layer 3
LD - Laser Diode
M&R - Multiplexing and Routing
MAC - Media Access Control (IEEE 802)
MPOS - Multi- Protocol Optical Switch
MW - Multiple Wavelengths
NG-PON - Next Generation Passive Optical Network
NRZ - Non-Return To Zero
NTT - Nippon Telegraph and Telephone
O/E - Optical to Electrical conversion
O/E/O - Optical to Electrical to optical conversion
OA - Optical Amplifiers
OAN - Optical Access Network
OCM - Optical Channel Monitor
ODN - Optical Distribution Network
OFDM - Orthogonal Frequency Division Multiplexing
OLT - Optical Line Terminal
OMA - Optical Modulation Amplitude
ONT - Optical Network Terminal
ONU - Optical Node Unit
OOB - Out of band
OOK - On Off Keying
OPM - Optical Performance Monitor
OPS - Optical Passive Splitter
OSA - Optical Spectrum Analyzer
OSI - Open Systems Interconnection
OSNR - Optical signal to noise ratio
OTDM - Optical time domain multiplexing
P2P - Point to Point
PAYG - Pay As You Grow
PDL - Polarization Dependence Loss
PIC - Photonic in Circuit
PIN - Positive-Intrinsic-Negative
PL - PON link
PMD - Physical Media-Dependent
PON - Passive Optical Network
PPS - Pump Probe Signal
PRBS - Pseudo-Random Bit Sequence
QD-SOA - Quantum Dot SOA
R&D - Research and Development
RIN - Relative Intensity Noise
RN - Remote Node
RSOA - Reflective Semiconductor Optical Amplifier
RSOF - Red Shift Optical Filter
RX - Receive
xxvii
SGC - Synchronized gain-clamping
SMSR - Side mode suppression ratio
SOA - Semiconductor optical amplifier
SR - Short Range
TDM - Time Division Multiplexing
TDM/WDM - Time Domain Multiplexing Wavelength Division
Multiplexing
TDM-PON - Time Domain Multiplexing Passive Optical Network
TL - Tunable Laser
TLS - Tunable Laser Source
TWDM - Time Wavelength Division Multiplexing
TWLS - Tunable wavelength laser source
TX - Transmit
US - Upstream signal
VO A - Varying Optical Attenuator
VPN - Virtual Private Network
W&R - Wavelength routing
WB&M - Wavelength broadcasting and multicasting
WB&S - Wavelength broadcast and select
WDM - Wavelength-Division Multiplex
WDM-PON - Wavelength Division Multiplexing Passive Optical Network
WM - Wavelength Multiplexing
WM&B - Wavelength Multicast and Broadcast
WM&R - Wavelength multiplex and routing
WR - Wavelength routing
WS - Wavelength select
WSS - Wavelength select switch
WTF - Wavelength tuning free
XGM - Cross Gain Modulation
XG-PON - 10G Passive Optical Network
XPM - Cross Phase Modulation
xxviii
LIST OF SYMBOLS
Pin - Input power
Pout - Output power
Xs - Center Frequency OLT transmitter
Xt - Center Frequency CW PPS
h - Planck constant
v - Probe signal frequency
I,h - Current fluctuation is induced by thermal noise
q - Electron charge
nsp - Spontaneous emission factor
Av - Effective receiver bandwidth
fsr - Frequency spectral range
IL - Insertion loss
B - Bit rate
R - Responsivity
Be - Electrical bandwidth filter
Bo - Optical bandwidth filter
GSai - Saturation Gain
Gsai Muin - Saturation Gain for broadcasting/multicasting
crsho, - Shot noise
crsjsp - Signal spontaneous noise
o~sp sp - Spontaneous spontaneous noise
<r,h - Thermal noise
(?com - Wavelength conversion noise
G0 - Unsaturated material gain
r - Extinction ratio
rout - Extinction ratio output signal
Pprobe - Pump probe power (CW transmit power)
XXIX
Ppump - Pump power (OLT transmit power)
PSat - Saturation output power
Gmuiti - Saturation Gain for broadcasting or multicasting
n - No of PON link
ptotai - Total Noise per system
Psoa total - Total SOA noise
Prx totai - Total receiver Noise
Pb - Power budget
Prec - Received power
PSen - Received sensitivity power
Cl - Total loss
Ms - System margin
Wp - Wavelength penalty
ctf - Optical fiber loss
L - Total ODN loss
acon - Connector loss
a SpUce - Splice loss
czSpHi - Single optical splitter loss
& total_spUt - Maximum total optical splitter loss
5 - Numbers o f the optical splitter cascading
Smax - Maximum number of optical splitter cascading
k - Total number o f user / split ratio per optical splitter
kmax - Maximum number of user / split ratio per optical splitter
j - Total number o f users per PON link
m - Total number o f users per AOPR TWDM PON system
y - Number o f optical splitter stage
Ax - Band Gap delay
At - Tuning delay
XXX
LIST OF APPENDICES
APPENDIX TITLE PAGE
A Noise components in proposed system 182
B Experimental Setup AOPR TWDM PON system 185
C List of Test Equipment 187
D Datasheets 189
E List o f Publications and Awards 199
CHAPTER 1
INTRODUCTION
1.1 Background of the study
With the demand for higher bandwidth and high quality of services expected
to increase in the next few years (Cisco System, 2011; Cisco System, 2013;
Middleton, 2010), network operators are starting to migrate their system from legacy
system to new technology that is capable to support more bandwidth and offer more
reliable network. This system upgrade will affect the entire network from access,
metro to the core network. The migration o f system must also consider the
integration o f new and legacy system to ensure smooth upgrade planning and to
support the current as well as the future network demands. However, most
telecommunication service providers invest multimillion dollars to deploy passive
optical network (PON) system such as (Ethernet Passive Optical Network (EPON)/
Gigabit Passive Optical Network (GPON)) in their network. In order to maintain the
investment of the current network, the evolution of PON towards next-generation
PON must be able to coexist with the current EPON/GPON. This initiative was
further studied by Andrade et al. (2011); Kani et al. (2009); Kramer, (2009) and
Teixeira, (2010). It was found that the main factor that contributes to the coexistence
o f the network and system, is using the existing optical distribution network (ODN)
and avoiding the usage o f the same wavelength allocated by current PON
technology.
2
Full Service Access Network (FSAN) group has been studying next-
generation solutions to facilitate high bandwidth provision, large split ratio, and
extended reach (Kani and Nakamura, 2012). In addressing next generation passive
optical network 1 (NG-PON1), whose main focus is to develop a PON that is
compatible with an operational GPON, International Telecommunication Union-
Telecommunication (ITU-T) with FSAN has defined XG-PON1 as part of the NG-
PON1 standardization path, with its features elaborated in the ITU-T G.987
recommendations (Wong, 2012). There are two types o f NG-PON1 developed by
ITU-T standard. This technology is based on the upstream line rate: XG-PON1 and
XG-PON2, featuring a 2.5 and a 10 Gbit/s upstream path, respectively. After
finalizing the XG-PON1 basic specifications, which are being successfully adopted
by ITU-T and standardized in G.987 document series, the group is now focusing on
the additional features and tools for extending the applicability of the XG-PON
technologies. Moreover, under the generic term NG-PON2, the task group has
started an investigation on the upcoming technologies which are able to (i) increase
bandwidth further and (ii) solve the issues faced in the “1G” and “ 10G” PON
technology deployments. In 2010, FSAN began investigating such NG-PON2
technologies to address the user, services, and network requirements. NG-PON2 also
considers new fibre architectures to harness the benefits of the maturing WDM
technologies and their necessary adaptations for the access network (Andrade et al.,
2011; Kani et al., 2009; Kani and Nakamura, 2012; Luo et al., 2012; Wong, 2012)
Operators provide a general set of NG-PON2 requirements. The
requirements to support NG-PON2 come from several aspects including user
requirements, services requirements, and network requirements (Chanclou et al.,
2012; Effenberger et al., 2009; Effenberger et al., 2010; Kani et a l, 2009; Luo et
al., 2012). To support higher bandwidth demand in the future, telecommunications
companies expect NG-PON2 system to support at least 40 Gbit/s aggregate capacity
per feeder fibre in the downstream, and at least 10 Gbit/s in the upstream. On top of
that, to support a longer reach o f fibre distance between optical line terminal (OLT)
and optical network unit (ONU), the maximum fibre reach for NG-PON2 should be
at least 40 km, and a maximum differential fibre distance o f up to 60 km should also
be supported. Optical distribution networks (ODNs) that are typically deployed in
GPON today range between 16 and 128 ONUs. NG-PON2 should be (Chanclou et
3
al., 2012) capable to operate in available spectrums that are not used by legacy
PONs to allow coexistence, smooth migration network, and provide high level of
flexibility that makes the coexistence of GPON, XG-PON, and NG PON2 possible.
The legacy ONU and OLT must remain unchanged and do not require an additional
filter to protect against interference from NG-PON2 signals in any migration
scenario with coexistence. On the basis of the general requirements gathered from
major telco operators, there have been many different system configurations
proposed by research institutes and vendors to support aggregate data rate beyond 40
Gbit/s. In April 2012, FSAN selected TWDM PON system as a primary solution to
be deployed in NG-PON2 (Luo et al., 2013), supported with P2P WDM PON to
support mobile backhaul system.
1.2 Problem Statement
The main challenge of the architecture is to have the flexibility and
scalability of the time and wavelength division multiplexed passive optical network
(TWDM) PON to support more numbers o f users and manage the burst and
fluctuation o f low and high bandwidth traffic in access network. There are many
approaches used to support high numbers o f users and long-reach system (Shea and
Mitchell, 2009; Taguchi et al., 2010; Talli and Townsend, 2006). One of the
approaches is to design the system by managing multiple PON link interconnects
with multiple PON ports within a single TWDM PON system (Feng et al., 2011;
Taguchi et al., 2013; Cheng et al., 2013). Nevertheless, the problems of this
architecture are the following:
• Flexibility o f the system to handle full function of broadcasting or
multicasting and at the same time to handle multiplexing o f multiple
wavelengths with different PON ports at different PON links within a single
TWDM PON system decreases.
• High cost of fibre deployment to support an existing ODN and fibre
infrastructure.
4
• Complex design of the system to handle multiple access technologies thereby
GPON, XG-PON, and TWDM PON at different PONs.
In designing a flexible TWDM PON system, most o f the proposed
architectures use tunable laser source (TLS) (Bock et al., 2005; Nakamura et al.,
2013) or multiple fixed multi-wavelength (FMW) (Cheng et al., 2013; Cheng et al.,
2014) transmitter in OLT PON port that allows flexible wavelength routing (WR)
and multiplexing of the signal in downstream signal. However, tunable laser source
(TLS) signals have the following limitations:
• In providing full broadcast or multicast within entire TWDM PON system as
TLS will transmit only single wavelength and this signal will be routed only
to a certain single PON link.
• To re-route certain packet at a different PON link, TLS requires certain time
to tune the wavelength (Buus and Murphy, 2006; Fabrega et al., 2011),
which will cause wavelength tuning delay in the system, thereby affecting
the performance of the system.
However, adopting a multi-channel wavelength transmitter, the following problems
are encountered:
• High numbers o f OLT transmitter connected to a single PON port, which
will incur an additional cost to the system.
• Different types of transmitter will introduce inventory issues and will add the
possibility o f human error during the system installation or maintenance.
1.3 Motivation
Motivated by the benefit of flexible TWDM PON system architecture, this
study discusses the development of flexible TWDM PON system to support multiple
PON link interconnects with multiple PON ports. This will allow the scalable
system to support high numbers o f users and large coverage area in the access
network. In addition this will support full degree of flexibility to manage highly
efficient dynamic bandwidth allocation and to support burst and fluctuation traffic at
5
low- and high-bandwidth demand in the access network. Subsequently, to reduce the
capital expense and operational expense, by leveraging an existing fibre cable and
maintaining the optical splitter in the remote node, a service provider is able to use
the existing fibre and ODN deployment in access network, which will reduce the
cost of system and the deployment time in brown field network. This method will
allow coexistence of TWDM PON system with legacy GPON and XG-PON systems
and provide a smooth migration from legacy to TWDM PON. Besides maintaining
an existing infrastructure, pay-as-you-go (PAYG) design concept will reduce an
initial investment of the service provider by allowing the system to work with
minimum numbers of PON ports and making it scalable to increase the number of
PON ports according to the demand of the users. Meanwhile, using fixed
wavelength and minimum number of PON port transmitters in OLT system will
reduce the system cost, inventory issue, and chances o f error in the system during
fibre installation. In addition, to support green system initiative, the capability of the
OLT system to turn OFF certain OLT PON ports while the total bandwidth usage is
low will allow power-saving mode to be implemented in the OLT module.
Moreover, the flexible design of TWDM PON architecture to integrate with
aggregation and routing functions in PON system will reduce the numbers of
aggregation ports in the metro network, which will reduce the capacity of layer 2
metro switch that turns to power saving for overall system in the network.
1.4 Research Objectives
The main objectives of this research was to design an all-optical packet
routing (AOPR) TWDM PON system architecture to support full degree of flexible
function in TWDM PON system to support flexible packet routing, packet
multiplexing, packet broadcasting and multicasting functions, and to combine both
multiplexing and broadcasting functions.
6
There are several goals to achieve this objective.
1. To design and develop AOPR OLT module using all-optical wavelength
conversion with cross-gain modulation (XGM) and multicasting XGM to
support up to 2000 users with 160Gbps downstream bandwidth
2. To design and develop 3R (re-routing, re-convert, and re-amplified) function
in AOPR OLT module to support high allowable link loss margin in the
system
3. To design free (zero) wavelength tuning delay in the downstream system by
implementing the high-speed wavelength select switch as a pump probe
signal (PPS) in AOPR OLT module
1.5 Scope of Works
The objective o f this work is to concentrate at PON system technology for
hybrid TWDM PON. Figure 1.1 shows the scope of work to be carried out in this
study. The previous work of flexible design of TWDM PON will be reviewed and
investigated to support and align it with NG-PON2 system requirements. Two
designs o f proposed TWDM PON architecture have been reviewed in this study: the
first is static and the second is dynamic TWDM PON system architecture. To
support flexible and scalable system design architecture, the study will focus and
exploit dynamic-type PON architecture supported with multiple PON links
interconnected with multiple PON ports in the TWDM PON system; this design will
be used as a base design in this proposed system architecture. On the basis of the
literature review, flexible multiple PON links are classified into four categories of
flexible TWDM PON system architecture: (i) broadcast and select (B&S), (ii)
wavelength-routed (WR) and B&S (W&R and B&S), (iii) wavelength multiplexing
7
and routing and broadcast and select (WM&R and B&S), and (iv) W&R system
architecture. This work will focus on WM&R and B&S system design architecture.
Two types of transmitter were used in OLT PON port to support full flexible design
in TWDM PON architecture,: TWLS and fixed-wavelength laser source (FWLS). In
this proposed design, the system applies single OLT transmitter FWLS in OLT PON
port to eliminate the problems discuss earlier. This proposed system architecture had
full degree of flexibility to support four functions o f wavelength multiplexing
(WM), WR, wavelength broadcasting and multicasting (WB&M), and hybrid WM
and WB&M functions. To design all-optical WR and WB&M, it is suggested that
XGM technique instead o f XPM or FWM should be used to reduce the complexity
of the system design to support the required function. In managing single or multiple
wavelengths to support WR and WB&M functions, WSS PPS and All ON PPS
modules were design in this study. All the experimental and simulation analyses of
the system will be focused on downstream signal in this study, and physical
performance will be examined.
8
Figure 1.1 Scope of work to be carried out in this thesis
9
1.6 Research Methodology
This section will cover all the issues and approach considerations towards
this project. To address the research objectives, a work flow diagram of the research
is constructed and presented in Figure 1.2.
Figure 1.2 Flow chart o f the research methodology
10
This work is basically divided into three main stages, and each stage
addresses all the issues encountered in completing this research. This flow-chart
shows the development o f the system and covers all the issues that have to be
considered throughout this project. At the initial stage, investigation on the current
research and technology of selection in NG-PON2 system is conducted. This
involves studying the literature on TWDM PON system as well as all the related
research works. It is important to study and comprehend the concept o f TWDM
PON system to support future requirement o f PON system. This stage also covers
the investigation on the architecture of the enhanced TWDM PON, which is called
flexible TWDM PON system, to support more users with more dynamic and flexible
design architecture. In this literature, the system architecture is differentiated from
the previous works proposed by the other research institutions including the
university, telecommunication vendors, and telecommunication providers. In the
second stage, the proposed AOPR TWDM PON system architecture with different
flexibility is designed. In this stage, the proposed design focuses on developing
AOPR OLT module to support packet routing and packet multicasting and
broadcasting. This phase provides the detail about the design scenario and event
trace flow of both flexible functions. In this stage, the proposed AOPR TWDM PON
system architecture is also designed. This architecture consists of subsystem of OLT,
ONO, and ODN systems. In OLT system, a new module, called AOPR OLT
module, is designed to integrate with semiconductor optical amplifier (SOA), multi
wavelength PPS, and cyclic arrayed waveguide grating (AWG). The main
components involved in supporting the proposed design such as SOA and AWG will
be discussed.
The third stage is the system characterization and performance study. In this
stage, the best correlation between OLT PON port transmitting power and multiple
wavelength PPS to support packet routing and packet multicasting and broadcasting
is obtained. Each component is characterized and each parameter is obtained to get
the best performance to support the proposed system. Using the (VPIphotonics)
simulation result as a reference design, each o f the subsystem of OLT, AOPR and
ONU, and ODN will be constructed. Each subsystem has a different design and
parameter, and results o f simulation performance and experimental characterization
11
are compared. Using subsystem characterization result as a reference, each
subsystem is integrated for a complete end-to-end system testing. Result analysis is
the last phase in this study. This phase provides results to support the physical layer
performance study. Physical performance of the system is measured by analyzing
the quality o f signal through bit-error rate (BER) optical signal-to-noise ratio and
ONU-received sensitivity. This stage is the most crucial stage because it is where the
entire study is analyzed thoroughly. It is important to get the best input parameter
setup so that an optimum design can be determined. In addition, should there be any
problems or limitations on the design, it will then be rectified and further
implications, suggestions, and possible recommendations will be given.
1.7 Thesis Outline
In Chapter 1, an overview o f the research, aims, motivation, problems, and
reasoning of the study are discussed. The objectives of the research work are also
presented accordingly. Methodology of the research work that covers the matters in
completing the work is thoroughly discussed.
Chapter 2 broadens the discussion and provides more detailed background
and reviews of the optical access technology focusing on PON system technology.
Each PON evolution will be reviewed and the requirements to support future PON
are identified. Technology selection to support NG-PON2 is reviewed and studied
based on its pros and cons. As proposed by FSAN and ITU-T standardization,
TWDM PON technology has been selected by most of the major telecommunication
companies and vendors for deployment in NG-PON2. In this study, the enhanced
TWDM PON system (called flexible TWDM PON system), which was proposed to
support more users and more flexible in allocating bandwidth to all users in all ODN
links, gains the main focus in the literature. In this chapter, the development of the
AOPR TWDM PON system is also proposed and each of the main module and
components to support the proposed architecture will be discussed in detail.
12
In Chapter 3, system design of the proposed architecture to support different
functions in AOPR TWDM PON system is elaborated, with algorithm o f each
function proposed and discussed. The chapter focuses at the first and second flexible
functions, which are flexible packet routing and flexible multicast and broadcasting
functions. This chapter also presents the developments of subsystem module to
support AOPR OLT. The characterization of SOA as main components to support
AOPR used in XGM module is studied in detail. The design of multi-wavelength
pump probe signal module is proposed to reduce the wavelength tuning delay in the
system by using high-speed wavelength select switch PPS design and Always ON
design. The performance of the fundamental method used in each sub module design
is assessed using simulation design and the effect of performance parameter on each
of the input parameter is measured.
Chapter 4 presents the simulation setup and performance study of the
proposed AOPR TWDM PON system. On the basis of the subsystem reference
result in Chapter 3, the overall performance o f the proposed architecture is
measured; each o f submodules will be integrated and BER performance to support
maximum total link loss and ONU-received sensitivity is measured. To achieve the
research objective o f supporting high-power budget to enhance the number of users
and area o f system coverage, system optimization and signal amplification are
introduce in AOPR OLT module design. All these activities are measured using
commercial VPI simulation tools.
Chapter 5 presents the development o f AOPR OLT module in the proposed
system; design consideration and experimental setup. The effect o f different input
power from two input signals on the performance of the model is also highlighted.
Later, the performance of wavelength-tuning-free design module using fixed type of
wavelength in OLT transmitter to support both WSS and All ON method is
discussed and compared with the conventional method using TLS to support
wavelength conversion. Also, the development of high-performance AOPR TWDM
PON system is presented by integrating each sub module such as OLT AOPR,
multiple ODN link, and ONU module. This model acts as a whole proposed system
that emulates functions in AOPR TWDM PON system. The physical performance
13
studies such as BER, optical signal-to-noise ratio, and ONU-received sensitivity of
the system are also obtained. Finally, analysis results based on the simulation and
measurement are compared, discussed, and concluded.
Finally, in Chapter 6, concluding remarks and recommendations for future
prospects for this work are given and the original contributions are highlighted.
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