Download All-optical Header Processing in Optical Communication Networks

Simulations of All-Optical Multiple-Input ANDGate Based on Four Wave Mixing in a Single
Semiconductor Optical Amplifier
H. Le Minh, Z. Ghassemlooy, Wai Pang Ng and M. F. Chiang
Optical Communications Research Group, NCRLab
Northumbria University, Newcastle, UK
14th IEEE International Conference on Telecommunications
8th IEEE Malaysia International Conference on Telecommunications
Penang, Malaysia, 14th - 17th May 2007
Presentation Outline
1. Introduction
2. SOA nonlinearities and FWM
3. Three-input AND gate based on SOA-FWM
4. Simulations
5. Summary
ICT-MICC 2007
Presentation Outline
1. Introduction
2. SOA nonlinearities and FWM
3. Three-input AND gate based on SOA-FWM
4. Simulations
5. Summary
ICT-MICC 2007
Introduction
Client
Network
0111
Low-speed packet
High-speed
packet
Low-speed
packet
1011
Core Network
Client
Network
1001
1010
0110
Edge Router (Ingress/Egress)
with 4-bit address XXXX
Core Router
XXXX
Photonic Network Transparency
 High-speed all-optical core router
Processing, switching and routing in optical domain  high throughput
Solution: All-optical Boolean logic gates (AND, OR, XOR…)
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Presentation Outline
1. Introduction
2. SOA nonlinearities and FWM
3. Three-input AND gate based on SOA-FWM
4. Simulations
5. Summary
ICT-MICC 2007
SOA Nonlinearities
Data
1
SOA
BPF (2)
Inverted data at 2
1. Cross gain modulation
2
CW
2
SOA1
1
2
CW
2
2. Cross phase
modulation
1
Data
1 – 2
BPF (2)
SOA2
1
SOA
21 – 2
1
2
22 – 1
3. Four-wave mixing
2
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Presentation Outline
1. Introduction
2. SOA nonlinearities and FWM
3. Three-input AND gate based on SOA-FWM
4. Simulations
5. Summary
ICT-MICC 2007
3-inputs AND gate based on SOA-FWM (1)
X1
1
X2
2
XM
M
Y
o
Ein
Eout
SOA
WDM
multiplexer
M-input AND gate
X1
X2
…
XM
Y
0
x
…
x
1
x
0
…
x
1
…
…
…
…
…
x
x
…
0
1
0
0
0
0
1
x: 0 or 1
Operation Principle
 M different inputs Xm at different M frequencies m
 Output Y is “1” only when all the inputs are non-zeros
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3-inputs AND gate based on SOA-FWM (2)
X1
1
X2
2
XM
M
Y
o
Ein
Eout
SOA
WDM
multiplexer
M-input AND gate
X1
X2
…
XM
Y
0
x
…
x
1
x
0
…
x
1
…
…
…
…
…
x
x
…
0
1
0
0
0
0
1
x: 0 or 1
Multi-tone Output
M 2 ( M  1)
 N frequency components are generated: N 
2

Output Y is selected at o such that the component consists of
all m contributions
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3-inputs AND gate based on SOA-FWM (3)
1
2
3
2S
1+2– 3
1+1–3
1+1– 2
2+2–3
2r
3+1–2
2+2– 1
2+3–1
3+3–2 3+3–1
Frequency component generation from 3 input wavelengths
 Signal beatings 3 – 2, 3 – 1 and 2 – 1 will modulate signals
at 1, 2 and 3, thus resulting in 9 new frequency components

However, only three components contain information of all 1, 2
and 3. Those are: 1 + 2 – 3, 3 + 1 – 2 and 2 + 3 – 1.
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3-input AND gate based on SOA-FWM (4)
o
Eout
Y
X1
X2
…
XM
Y
0
x
…
x
1
x
0
…
x
1
…
…
…
…
…
x
x
…
0
1
0
0
0
0
1
x: 0 or 1
Filtering out o

Y could be selected from one of these components
1 + 2 – 3
3 + 1 – 2
2 + 3 – 1

However, for high conversion efficiency, 2 + 3 – 1 is selected
(positive detuning)
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3-input AND gate based on SOA-FWM (5)
Output power

Output power is given by
Pout  P1 P2 P3G R2  3  21 
3
X
where GX is the SOA gain in X-polarisation, R() is
the conversion efficiency function (nonlinear)
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3-input AND gate based on SOA-FWM (6)

Output Amplitude Modulation Ratio: the ratio of the
maximum value over the minimum value of the output
bits “1”

rAM 
P1,max
P1,min
Output On/Off Contrast Ratio: the ratio of the
minimum value of output bits “1” and the maximum of
output bit “0”
ICT-MICC 2007
ron/off 
P1,min
P0,max
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Presentation Outline
1. Introduction
2. SOA nonlinearities and FWM
3. Three-input AND gate based on SOA-FWM
4. Simulations
5. Summary
ICT-MICC 2007
Simulations (1)
Simulation parameters
SOA parameters
Parameters
Parameters
Values
X1 signal frequency - f1 193.1  1012 Hz
X2 signal frequency - f2 193.4  1012 Hz
X3 signal frequency - f3 194.1  1012 Hz
X1 pulse peak power - P1 2 mW
X2 pulse peak power - P2 2 mW
X3 pulse peak power - P3 2 mW
Pulse-width
5 ps
Output filter frequency – f0 194.4  1012 Hz
(at f0 = f2 + f3 – f1)
Filter bandwidth - B0
140  109 Hz
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Values
Laser chip length
600.0  10-6 m
Active region width
3.0  10-6 m
Active region thickness
40.0  10-9 m
Confinement factor
0.56
Group effective index
3.7
Material linewidth enhancement factor
3.0
Differential refractive index
-1.11  10-26 m3
Linear material gain coefficient
3.0  10-20 m2
Transparency carrier density
1.5  10-24 m-3
Nonlinear gain coefficient
1.0  10-23 m3
Nonlinear gain time constant
200.0  10-15 s
Carrier capture time constant
70.0  10-12 s
Carrier escape time constant
140.0  10-12 s
Gain peak frequency
196.0  1012 Hz
Gain coefficient spectral width
1.0  1013 Hz
Population inversion parameter
2.0
Initial carrier density
1.0  1024 m-3
Injection DC current
200 mA
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Simulations (2)
VPI simulation schematic
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Simulations (3)
AND operation
X1
(1 0 1 0 1 1 1 1 0 1 )
X2
(0 1 1 0 1 1 1 0 1 1 )
X3
(0 1 1 0 0 1 1 0 1 1 )
Y
(0 0 1 0 0 1 1 0 0 1 )
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Simulations (4)
Two/three-input AND gate performance (10 Gbit/s)
• Output power: linearly
dependent on the input
power
• Amp. modulation ratio
(rAM): the amplitude
variation is small ~ 2 dB
• On/off contrast ratio
(ron/off): in a range of 14 22 dB
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- - - 2-input AND gate
 3-input AND gate
 Pout
 rAM
 ron/off
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Simulations (5)
Two/three-input AND gate performance (10, 20 and 40 Gbit/s)
• Output power: being
reduced at high speed due
to slow SOA gain recovery
Therefore
• Amp. modulation ratio
and On/off contrast
ratio are reduced
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- - - 2-input AND gate
 3-input AND gate
 Pout
 rAM
 ron/off
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Presentation Outline
1. Introduction
2. SOA nonlinearities and FWM
3. Three-input AND gate based on SOA-FWM
4. Simulations
5. Summary
ICT-MICC 2007
Summary

SOA-FWM AND gate features
–
–
–
–

Multiple-input logic AND gates
Simple implementation
Low power consumption
Integration capability (SOA size ~ m)
SOA-FWM AND gate issues
–
–
Low wavelength conversion ratio
Speed is limited by SOA gain recovery
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Acknowledgement
Northumbria University for sponsoring this research
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Thank you!
Any Questions?
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