Reach extension of passive optical networks
using semiconductor optical amplifiers
A E Kelly, C. Michie, I. Andonovic, J. McGeough, S Kariaganopoulos
Standard Passive Optical Networks
GPON 1:32
Reach 10-20km
Extended Reach Passive Optical
Networks
Electronic regeneration cannot be used as it results in
Preamble erosion due to burst mode locking time
Passive Optical Networks
1300nm backhaul
Significant ASE levels
VOA1
transmitter
1310nm
VOA2
SOA
20 nm
filter
insertion
loss α
receiver
1310nm
•VOA1 represents access loss – split plus some link loss
•VOA2 predominately trunk loss
•1300 nm and 1.25/2.5 Gbit/s; dispersion neglected
Power Budget
Simple linear model
2
SNR 
2
R Pin
 tot
2
Pin
PIN or APD
pin
2
2
SNR 
IP
 TOT
2
2
R Pin

2 e ( RP rec  I D ) B  4 (
shot noise terms
kT
RL
.
receiver Noise Figure
) FN B
thermal noise
Power Budget
2
Simple linear model
SNR 
2
R Pin
 tot
2
Pin
PIN or APD
APD
2
2
SNR 
IP
 TOT
2
2
2
M R Pin

2 eM F A ( RP in  I D ) B  4 (
2
kT
RL
) FN B
receiver Noise Figure
shot noise terms
thermal noise
APD Multiplication and Noise Factor
Power Budget
SNR modified to account for ER of transmitter
– at best 10 dB
Q 
P AVE
1 0
2
2
 1  re 


 1  re 
Baseline calculations
1.E-06
-36.00
-34.00
-32.00
-30.00
-28.00
-26.00
1.E-07
data modelled for commercial
pin/APD
1.E-05
1.E-08
BER
BTB
10dB ER
1.E-06
1.E-09
1.E-07
BTB
BTB ER 10 dB
BER
1.E-10
1.E-08
1.E-11
Receiver Power, dBm
APD
Neo Photonics
PTB3J88-5638T-SC/PC+
1.E-09
1.E-10
1.E-11
-30.00
-28.00
-26.00
-24.00
-22.00
Receiver Power, dBm
pin – OCP- TRXAG1M
-20.00
Inclusion of Amplifier
Build upon a model of the SNR to include the noise terms
associated with amplifier
1  T  S 
2
2
2
0 T 
2
2
2
ASE
2
ASE
  S  ASE  

2
ASE  ASE
2
2
ASE  ASE
Extinction Ratio further degraded due to
ASE
Significant ASE levels
VOA1
transmitter
1310nm
Q 
20 nm
filter
PAVE

VOA2
SOA
2
1

2
0
insertion
loss α
receiver
1310nm
1   


1   
  ( P1  PASE ) / PASE
0v
APD based Receiver
Assumptions
– -28 dBm sensitivity for BTB un amplified with 10 dB ER
– M=10
– thermal noise estimated to give sensitivity of -28dBm for
10-10 BER (value specified on data sheets)
– Psat of SOA +13 dBm
– NF 7 dB
Amplified APD Receiver
20 nm filter
10 nm filter
Baseline
0.8nm filter
1.E-03
1.E-04
1.E-05
1.E-06
BTB infinite ER
BTB 10 dB ER
0.8 nm filter
10 nm filter
20 nm filter
20 nm no ER deg
BER
1.E-07
20 nm filter
ER not considered
1.E-08
1.E-09
1.E-10
1.E-11
1.E-12
1.E-13
-45.00
-40.00
-35.00
Signal Power, dBm
-30.00
-25.00
-30.00
10
-31.00
9
-32.00
8
-33.00
7
-34.00
6
-35.00
5
-36.00
4
-37.00
3
Prec pin
-38.00
2
Prec APD
-39.00
1
pin ext dB
APD ext dB
-40.00
0
5
10
Optical Filter Bandwidth, nm
15
0
20
Extinction Ratio, dB
Receiver Power, dBm ( BER10e-10)
Influence of Optical Filtering
Post Amplifier Losses
Splitter
(Access)
loss
ONT
Backhaul
SOA
insertion
loss α
20 nm
filter
Position amplifier to compensate for
splitting and reach losses
SOA Psat limited to +13 dBm
Gain adjusted accordingly
G 
G max
1
GP in
G max
OLT
receiver
1310nm
40
10
35
9
booster margin
30
8
7
25
6
20
5
mid span
margin benefit
15
10
Post Amplifier Loss
Unamplified Signal
Ppenalty
ext dB
GPON
5
4
3
2
1
0
Extinction Ratio, Power penalty, dB
Loss after amplifier, dB
System Power Margins
0
0
5
10
15
20
Loss into Amplifier, dB
25
30
35
pre-amp margin
Margin Enhancement for Amplified GPON
System Margin Enhancement, dB
30
25
20
15
128 split
10
5
0
0
5
10
15
20
25
Loss into Amplifier, dB
30
35
40
Backhaul Distance, km
Distance versus number of users for each
case
100
Amplified Reach
Unamplified Signal
Psat limited
80
Gain limited
60
3264
Split
Split
512 Split
40
20
NF limited
GPON: 32 split
64128
split
split
0
1
10
100
-20
SplitRatio
1000
10000
Experiment
VOA
1300 tx
VOAl
SOA
Channel Drop
OSA
(filter)
1300 nm
receiver
Experimental Validation
1.E-05
1.E-06
BTB Theory
10 nm theory
20 nm theory
20nm
BTB
10 nm
BER
1.E-07
1.E-08
1.E-09
1.E-10
-40.00 -38.00 -36.00 -34.00 -32.00 -30.00 -28.00 -26.00
Signal Power, dBm
-30
9
-31
8
-32
7
-33
6
-34
5
-35
4
-36
3
-37
2
-38
Prec APD
-39
1
Sens
APD ext dB
-40
0
5
10
Optical Filter Bandwidth, nm
15
0
20
Extinction Ratio, dB
Receiver Power, dBm ( BER10e-10)
Constant BER curve with filter width
Experimental Margin Enhancement
Loss Post Amp Theory
Loss Post Amp Expt
Unamplified
P BER10-9 EXPT
P 10-9 theory
50
Post Amplifier Margin, dB
40
0
-5
-10
30
20
-15
10
-20
0
0
5
10
15
20
25
30
35 -25
-10
-30
-20
-30
-35
Loss into Amplifier, dB
Power at Receiver, dBm
60
Conclusions
• Number of users and backhaul distance can be considerably
increased by using SOA based amplification
• Required SOA specification depends on placement within
network
• A single SOA cannot meet these requirements
• Variable gain clamping schemes?
Key Publications
Russell P. Davey, Daniel B. Grossman, Michael Rasztovits-Wiech, David B. Payne, Derek Nesset,
A. E. Kelly, Albert Rafel, Shamil Appathurai, and Sheng-Hui Yang “Long-Reach Passive Optical
Networks” Journal of Lightwave Technology, Vol. 27, Issue 3, pp. 273-291 February 2009 (invited
tutorial paper)
High Performance Semiconductor Optical Amplifier Modules at 1300nm”A.E.Kelly, C.Michie,
I.Armstrong, I.Andonovic, C. Tombling, J.McGeough and B.C.Thomsen, Photon.Tech.Lett, Vol.18,
No.24, pp 2674-2676, 2006
“The Dynamic Gain Modulation Performance of Adjustable Gain-Clamped Semiconductor Optical
Amplifiers (AGC-SOA)” Liu, L. Michie, C. Kelly, A. E. Andonovic, I., Journal of Lightwave
Technology , Volume: 29 Issue: 22 pp 3483 – 3489, 2011.