University of São Paulo
Engineering School of São Carlos
Department of Electrical Engineering
University of São Paulo
Engineering School of São Carlos
Department of Electrical Engineering
University of São Paulo
Engineering School of São Carlos
Department of Electrical Engineering
POSTDOCTORAL RESEARCHER: PH....
› Metamaterials
› Chiral Metamaterials
› Cavity sensors
› Plasmonic lenses
› SOI/SPP based devices
› Supercontinuum genera...
 OCDMA encoding technologies
 SPECTS-OCDMA systems
 Optimal code-set selection
 Concluding remarks
P. L. L. BERTARINI ...
 Multiple access technologies
WDMA TDMA CDMA
f
...
1
n
t
B
f
B ... ...
1 n 1 n
T
f
B
t
c
t
1
n
6P. L. L. BERTARINI - Cohe...
 Encoding -> to spread in one or more
dimensions:
 Time
 Frequency
 Space
 Polarization
 Maximize
› Cardinality (num...
 OCDMA technologies:
› Incoherent OCDMA systems
 Manipulates intensity of optical field
› Coherent OCDMA systems
 Manip...
DataLight
Source
Phase Mask – A(w)
Prism or grating SLM
Star
Couple
and
Optical
Channel
Data
Modulator
 Spectral Phase-Co...
10
Fourier
Transform
Inverse
Fourier
Transform
Spetral Phase
Code – user K
Gaussian
Optical
Pulse Encoder
Encoded
Signal
...
 System Performance
› Walsh-Hadamard and m-sequence codes
› “1” and “-1” represent phase shifts of “0” and “π”
› Synchron...
 A bit “1” is encoded with a given user's
code, and then is imposed to all other users'
decoders.
 We are able to get th...
 We showed for the first time in OCDMA
literature that each user differently interferes in
all other users in the system
...
 Interference level caused by users (a) #12 and (b) #15 on other
users when a bit "1“ is sent.
 The dashed lines indicat...
 BER evaluation
› based on the interference level between active user
› each user has a different performance depending
o...
 W-H 32 optimal code-set
3 simultaneous users:
992 (20%) out of 4960 → BER<10-12
1120 (22.6%) out of 4960 → BER<10-9
4 si...
 W-H 64 optimal code-set
6 simultaneous users :
409600 (0.543%) out of almost 75
million → BER<10-12
7 simultaneous users...
 The code-set selection is necessary in order to
implement optical networks based on OCDMA
technology
 Code-set selectio...
University of São Paulo
Engineering School of São Carlos
Department of Electrical Engineering
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Coherent Optical Code Division Multiple Access (OCDMA) Systems Pedro Bertarini

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Coherent Optical Code Division Multiple Access (OCDMA) Systems Pedro Bertarini

  1. 1. University of São Paulo Engineering School of São Carlos Department of Electrical Engineering
  2. 2. University of São Paulo Engineering School of São Carlos Department of Electrical Engineering
  3. 3. University of São Paulo Engineering School of São Carlos Department of Electrical Engineering POSTDOCTORAL RESEARCHER: PH.D. PEDRO LUIZ LIMA BERTARINI PH.D. CANDIDATES: ANDERSON L. SANCHES DANIEL B. MAZULQUIM LEONE M. VEIGA JOSÉ V. REIS JR. THIAGO R. RADDO THIAGO VASCONCELOS (UFPE) MS.C. CANDIDATES: ACHILES F. MOTA DANIEL MARCHESI HEINZ SUADICANI LARISSA LIMA COLLABORATORS: PH.D. FREDERICO D. NUNES (UFPE) COLLABORATORS: PH.D. LUIZ G. NETO (SEL/USP)
  4. 4. › Metamaterials › Chiral Metamaterials › Cavity sensors › Plasmonic lenses › SOI/SPP based devices › Supercontinuum generation › Optical Code Division Multiple Access (OCDMA) P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems 4  Different Applications:  Antennas  Biosensors
  5. 5.  OCDMA encoding technologies  SPECTS-OCDMA systems  Optimal code-set selection  Concluding remarks P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems 5
  6. 6.  Multiple access technologies WDMA TDMA CDMA f ... 1 n t B f B ... ... 1 n 1 n T f B t c t 1 n 6P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  7. 7.  Encoding -> to spread in one or more dimensions:  Time  Frequency  Space  Polarization  Maximize › Cardinality (number of simultaneous users) › Orthogonality (differentiation between users) 7P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  8. 8.  OCDMA technologies: › Incoherent OCDMA systems  Manipulates intensity of optical field › Coherent OCDMA systems  Manipulates phase and amplitude of optical field  It appears to be the most viable technology for the implementation of OCDMA systems * 8P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems * Optical Access Seamless Evolution (OASE), “Survey of next-generation optical access system concepts,” FP7/2007–2013, deliv. D4.1; http://www.ict-oase.eu/.
  9. 9. DataLight Source Phase Mask – A(w) Prism or grating SLM Star Couple and Optical Channel Data Modulator  Spectral Phase-Coding Time Spreading Encoder Fourier Transform Inverse Fourier Transform Spetral Phase Code – user K Gaussian Optical Pulse Encoder 9P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  10. 10. 10 Fourier Transform Inverse Fourier Transform Spetral Phase Code – user K Gaussian Optical Pulse Encoder Encoded Signal  Encoding / decoding process › The pulse reconstruction, or decoding, requires a conjugate code to be used, otherwise it will remain spread out as multiple access interference (MAI) › Other devices are necessary to distinguish between correctly and incorrectly decoded users  Time gate devices – NOLM  Nonlinear thresholder P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  11. 11.  System Performance › Walsh-Hadamard and m-sequence codes › “1” and “-1” represent phase shifts of “0” and “π” › Synchronism between active users › Worst case scenario 11P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  12. 12.  A bit “1” is encoded with a given user's code, and then is imposed to all other users' decoders.  We are able to get the energy (interference) level received by each user.  This process is carried out for all possible code combinations. 12P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  13. 13.  We showed for the first time in OCDMA literature that each user differently interferes in all other users in the system › Ideal scenario → orthogonality between codes › Realistic scenario → the MAI produced by incorrectly decoded users coincide with the correctly decoded user’s signal 13P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  14. 14.  Interference level caused by users (a) #12 and (b) #15 on other users when a bit "1“ is sent.  The dashed lines indicate the average energy value, equal to 0.286 for W-H 32 (left) and 0.277 for m-sequence (rigth). 14P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  15. 15.  BER evaluation › based on the interference level between active user › each user has a different performance depending on the interference caused by others active users  Optimal code-set selection › The goal is to select the code-set that represents the best scenario for all possible code combinations › best scenario: code-set with lowest BER for all users 15P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  16. 16.  W-H 32 optimal code-set 3 simultaneous users: 992 (20%) out of 4960 → BER<10-12 1120 (22.6%) out of 4960 → BER<10-9 4 simultaneous users: 416 (1.16%) out of 35690 → BER<10-12 656 (1.82%) out of 35690 → BER<10-9 The maximum number of active users allowed to W-H 32 with satisfactory BER levels is only 4 16 BERTARINI , P. L. L., et al. - "Optimal Code Set Selection and Security Issues in Spectral Phase-Encoded Time Spreading (SPECTS) OCDMA Systems," Journal of Lightwave Technology, vol. 30, no. 12, June, 2012. P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  17. 17.  W-H 64 optimal code-set 6 simultaneous users : 409600 (0.543%) out of almost 75 million → BER<10-12 7 simultaneous users: 262144 (0.042%) out of almost more than 621 million → BER<10-12 8 simultaneous users: 65536 (0.0015%) out of more than 4 billion → BER<10-12 A random choice of the code-set will compromise the overall system performance 17 BERTARINI , P. L. L., et al. - "Optimal Code Set Selection and Security Issues in Spectral Phase-Encoded Time Spreading (SPECTS) OCDMA Systems," Journal of Lightwave Technology, vol. 30, no. 12, June, 2012. P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  18. 18.  The code-set selection is necessary in order to implement optical networks based on OCDMA technology  Code-set selection algorithm can be applied to any CDMA system, regardless the technology used  Some efforts have to be made to seek a STANDARD for CDMA technology in optical domain, such as G-PON for TDMA systems  We are currently working on security, robustness and scalability issues of coherent OCDMA networks 18P. L. L. BERTARINI - Coherent Optical Code Division Multiple Access (OCDMA) Systems
  19. 19. University of São Paulo Engineering School of São Carlos Department of Electrical Engineering

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