Simulations of All-Optical Multiple-Input AND-Gate Based on Four Wave Mixing in a Single Semiconductor Optical Amplifier

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Simulations of All-Optical Multiple-Input
AND-Gate 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 Pen
ang, Malaysia, 14th - 17th May 2007
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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

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Presentation Outline

• Introduction
• SOA nonlinearities and FWM
• Three-input AND gate based on SOA-FWM
• Simulations
• Summary

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Introduction

• 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

• Introduction
• SOA nonlinearities and FWM
• Three-input AND gate based on SOA-FWM
• Simulations
• Summary

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SOA Nonlinearities

• 1. Cross gain modulation
• 2. Cross phase modulation
• 3. Four-wave mixing

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Presentation Outline

• Introduction
• SOA nonlinearities and FWM
• Three-input AND gate based on SOA-FWM
• Simulations
• Summary

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3-inputs AND gate based on SOA-FWM (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)

• Multi-tone Output
• N frequency components are generated
• 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)

• 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)

• 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
• 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
• Output On/Off Contrast Ratio the ratio of the
  minimum value of output bits 1 and the maximum
  of output bit 0

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Presentation Outline

• Introduction
• SOA nonlinearities and FWM
• Three-input AND gate based on SOA-FWM
• Simulations
• Summary

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Simulations (1)
Simulation parameters
SOA parameters
Parameters 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
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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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

- - - 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

- - - 2-input AND gate ?? 3-input AND
gate ? Pout ? rAM
? ron/off
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Presentation Outline

• Introduction
• SOA nonlinearities and FWM
• Three-input AND gate based on SOA-FWM
• Simulations
• Summary

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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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