Optical Cross Connect OXC Simulation

1
Optical Cross Connect(OXC) Simulation

• David Chan
• Kai Song
• Wen De Zhong
• Michael Cahill

2
Outline

• Objective of OXC simulation
• Issues in modelling an OXC
• Development of OXC simulation module
• Preliminary Results
• Future Work

3
Objective of OXC Simulator

• Develop a module that will extend Kai Songs
  Matlab-based simulation tool to model OXCs
• calculation of system impairments for traffic
  streams passing through OXC
• comparison of OXC architectures using
  user-specified or generic models
• analysis of OXC performance and dependence on
  component specifications using user-defined
  values

4
Calculation of System Impairments

• system impairments for traffic streams passing
  through OXC may be calculated
• e.g. heterodyne and homodyne crosstalk, switch
  leakage etc.

5
Comparison of OXC Architecture

• OXC architecture may be specified, e.g.

(i)
(ii)
(iii)
6
Component Specification

• basic component specifications may be specified,
  e.g.
• also filters, optical amplifiers, gratings,
  couplers, etc.

(iii) MUX
(i) 2X2 WXC
(ii) DMUX
(iv) Splitter
7
(Ultimate) Objective of OXC Simulator

• Useful component in the suite of WDM system
  simulator tools

8
OXC Modelling Issues

• Number of input fibres and wavelength channels
  per fibre
• Architectural and Component Issues
• OXC DEMUX and MUX
• WDM demux, splitter plus filters
• OXC switching fabric
• splitters plus gates, NN opto-mechanical
  switches, Clos network of 22 switches, broadcast
  select (star coupler plus tunable filters or
  wavelength converters), FBGs plus circulators
• Connection between DEMUX/MUX and switching fabric
• conventional (see figures in slide 5), loop back
• Each of the above will have an impact on the
  performance of the OXC

9
Development of OXC Simulation Module

• As a first cut, choose the following
  implementation
• any number of input fibres (assume same number of
  outputs)
• any number of wavelength channels per fibre
• WDM DEMUX and MUX, conventionally connected to
  switches
• NN space switches for any value of N
• Outputs power spectra, eye diagrams and Q values

10
OXC Simulation Module

• module generates the OXC switching fabric based
  on
• number of input fibres, N (determines dimension
  of switches)
• number of channels per fibre, M (determines
  number of switches)

11
Preliminary Results

• An OXC with 4 input fibres and 4 channels per
  fibre
• Four 4 4 switches required
• Each 4 4 switch has 4! or 24 possible switching
  states
• Switches 1 3 totally crossed, 2 4 totally
  barred

Input Source Average Power Input Fibre
Output Input Source Average Power Input
Fibre Output 1 0 dBm 1 4
9 -5 dBm 3 2 2
0 dBm 1 1 10 -5 dBm 3 3
3 0 dBm 1 4 11
-5 dBm 3 2 4 0 dBm 1 1
12 -5 dBm 3 3 5
5 dBm 2 3 13 10 dBm 4 1
6 5 dBm 2 2 14
10 dBm 4 4 7 5 dBm 2 3
15 10 dBm 4 1 8 5
dBm 2 2 16 10 dBm 4 4
12
Preliminary Results Input Power Spectra
Web note Fibres 2-4 available in full download
version
13
Preliminary Results Output Power Spectra
Web note Fibres 2-4 available in full download
version
14
Preliminary Results (II)

• An OXC with 5 input fibres and 3 channels per
  fibre
• Three 5 5 switches required
• Each 5 5 switch has 5! possible switching
  states
• Switches 1 3 totally crossed, 2 totally
  barred

Input Source Average Power Input Fibre
Output Input Source Average Power Input
Fibre Output 1 0 dBm 1 5
9 -5 dBm 3 3 2
0 dBm 1 1 10 -5 dBm 4 2
3 0 dBm 1 5 11
-5 dBm 4 4 4 0 dBm 2 4
12 -5 dBm 4 2 5
5 dBm 2 2 13 10 dBm 5 1
6 5 dBm 2 4 14
10 dBm 5 5 7 5 dBm 3 3
15 10 dBm 5 1 8 5
dBm 3 3
15
Preliminary Results (II) Input Power Spectra
Web note Fibres 2-4 available in full download
version
16
Preliminary Results (II) Output Power Spectra
Web note Fibres 2-4 available in full download
version
17
Future Work

• Develop more detailed models of OXC
• increase complexity of OXC architecture
• incorporate more detailed component models
• Verification and comparison with analytical
  results
• Improve module and optimise code for speed
• Investigate effect of cascading OXCs

18
References
1) T. Gyselings et al., Crosstalk analysis of
multiwavelength optical cross connects, JLT,
vol. 17 no. 8, pp. 1273 - 1283, 1999. 2) P.
Ohlen, Noise and crosstalk limitations in
optical cross-connects with reshaping wavelength
converters, JLT, vol. 17 no. 8, pp. 1295 - 1301,
1999. 3) N. Antoniades et. al., An architecture
for a wavelength interchanging cross-connect
utilizing parametric wavelength converters, JLT,
vol. 17 no. 7, pp. 1113 - 1125. 4) C. Herben et
al., Crosstalk performance of integrated optical
cross connects, JLT, vol. 17 no. 7, pp. 1126 -
1134, 1999. 5) E. Iannone et. al., Modelling of
in-band crosstalk in WDM optical networks, JLT,
vol. 17 no. 7, pp. 1135 - 1141, 1999. 6) Y. Shen
et al., Coherent and incoherent crosstalk in WDM
optical networks, JLT, vol. 17 no. 5, pp. 759 -
764, 1999. 7) L. Gillner et. al., Scalability
of optical multiwavelength switching networks
crosstalk analysis, JLT, vol. 17 no. 1, pp. 59 -
67, 1999. 8) S. Dods et. al., Homodyne
crosstalk in WDM ring and bus networks, IEEE
PTL, vol. 9, pp. 1285 - 1287, 1997.