Jacklyn Dias Reis – Aveiro University

1. Jacklyn D. Reis, PhD
CPqD, Campinas, São Paulo, Brazil 27-28 May 2013
Day 2
High-Capacity Optical Access Networks
© 2005, it - instituto de telecomunicações. Todos os direitos reservados.
Jacklyn D. Reis, PhD
Ali Shahpari, Ricardo Ferreira, Darlene M. Neves, Mário
Lima, António L. Teixeira
University of Aveiro, Instituto de Telecomunicações

2. Next Generation PONs
Internet data traffic has been continuously increasing
Next generation PONs have been investigated to
– support several users with bit rates of 1 to 100 Gb/s
– flexible, extended reach and reduced cost
2
Source: Cisco, 2012
27-28 May 2013, Campinas, Brazil
Tb/s, 100 km,
1000 users
R. Yadav, "Passive-Optical-Network- (PON-) Based Converged Access Network [Invited]," J.
Opt. Commun. Netw. 4(11), B124-B130 (2012).
http://www.opticsinfobase.org/figure.cfm?uri=jocn-4-11-B124-g004

3. Outline
1. Future Optical Access Networks:
Coherent WDM-PON
– architectures
– transceiver configuration
– fiber impairments
2. Convergence Scenarios
I. UDWDM
III. Nyquist
II. Convergence
3
2. Convergence Scenarios
– WDM and XG-PON, G-PON, TWDM or Video
3. High-Capacity PON
– Nyquist shaped WDM-PON under different capacities
27-28 May 2013, Campinas, Brazil

4. 4
FUTURE OPTICAL ACCESS
NETWORKS
PART I
27-28 May 2013, Campinas, Brazil

5. Ultra-Dense WDM based Passive Optical Networks
Goal
up to 1000 users at 1Gb/s (up/down) in a single ODN
Allocate 1000 users efficiently?
Narrow channel spacing; coherent detection; advanced modulation
formats;
Benefits
High wavelength selective
High receiver sensitivity
Simple users’ data rate upgrade
DSP eases implementation of equalizers / FEC
I. UDWDM
III. Nyquist
II. Convergence
5
DSP eases implementation of equalizers / FEC
Challenges
Architecture
Transceiver configuration
Fiber effects
27-28 May 2013, Campinas, Brazil

6. UDWDM: Architectures
Fully transparent: Splitter
– Homogeneous network: coherent channels only
– Heterogeneous network: coherent + IMDD channels
Hybrid: AWG + splitter
Filtered: AWG
I. UDWDM
III. Nyquist
II. Convergence
6 27-28 May 2013, Campinas, Brazil

7. Homogeneous ODN only one technology;
Heterogeneous ODN convergence scenarios;
CW laser source modulated via an optical IQ modulator fed with
random symbols;
Transmission through Standard Single-Mode Fiber;
1:N Transparent Power Splitter
ONU: Direct Detection or Coherent Rx
UDWDM: Transceiver Configurations
I. UDWDM
III. Nyquist
II. Convergence
7
ONU: Direct Detection or Coherent Rx
27-28 May 2013, Campinas, Brazil

8. UDWDM: Fiber Impairments
Fully transparent UDWDM-PON
(3.125 GHz grid): Splitter
a) Homogeneous network: coherent channels only
b) Heterogeneous network: coherent + legacy (NRZ or Video)
I. UDWDM
III. Nyquist
II. Convergence
8 27-28 May 2013, Campinas, Brazil

9. 32x625 Mbaud @ 3.125 GHz
Volterra Series to estimate FWM / XPM
in coherent UDWDM-PON
MPSK: SPM/XPM negligible; FWM is dominant
MQAM: FWM and XPM are dominant;
FWM
I. UDWDM
III. Nyquist
II. Convergence
9
J.D. Reis et al JLT’2012(30), 234-241
27-28 May 2013, Campinas, Brazil
FWM+XPM

10. Different Channel Count
QPSK
minimal variation with distance
FWM increases up to 32 channels
support 1000 users limited to ~5 Gb/s
16/256QAM
higher dependence on distance
XPM increases further than 32 channels
support ~10-25 Gb/s per user limited to ~64 users
I. UDWDM
III. Nyquist
II. Convergence
10 27-28 May 2013, Campinas, Brazil

11. 11
CONVERGENCE SCENARIOS
PART II
27-28 May 2013, Campinas, Brazil

12. Coexistence with XG-PON / RF Video Overlay
Fully transparent UDWDM-PON
(3.125 GHz grid): Splitter
a) Homogeneous network: coherent channels only
b)Heterogeneous network: coherent + legacy (NRZ or Video)
I. UDWDM
III. Nyquist
II. Convergence
12 27-28 May 2013, Campinas, Brazil

13. UDWMD-PON + Legacy PONs
16x1.25 Gb/s-QPSK spaced by 3.125
GHz plus 10 Gb/s NRZ or RF Video
I. UDWDM
III. Nyquist
II. Convergence
13 27-28 May 2013, Campinas, Brazil
UDWDM Comb
OSA
10G NRZ
Fiber
Coherent Rx
DSP
IMDD Rx
Video

14. Coexistence with XG-PON
SSF simulations accurate up to 16.5 dBm
10G-NRZ Power≤10 dBm
FWM between QPSK (-3 dBm/ch)
10G-NRZ Power>10 dBm
XTalk due NRZ (XPM and possibly FWM)
EVM2 or 1/SNR P2 (2 dB higher every 1 dB of power)
I. UDWDM
III. Nyquist
II. Convergence
14 27-28 May 2013, Campinas, Brazil

15. Coexistence with XG-PON
Fixed 10G-NRZ Power (15 dBm) with variable
guard band
Nonlinear Xtalk decreases for GB≥1.6 nm (~200
GHz)
I. UDWDM
III. Nyquist
II. Convergence
15 27-28 May 2013, Campinas, Brazil

16. Coexistence with Video overlay
Video Power≤10 dBm
FWM between QPSK (-3 dBm/ch)
Video Power>10 dBm
XTalk due Video (XPM and possibly FWM)
EVM2 or 1/SNR P2 (2 dB higher every 1 dB of power)
I. UDWDM
III. Nyquist
II. Convergence
16 27-28 May 2013, Campinas, Brazil

17. Coexistence with Video overlay
Fixed Video Power (16.5 dBm) with variable guard
band
Nonlinear Xtalk decreases for GB>2 nm (~250 GHz)
I. UDWDM
III. Nyquist
II. Convergence
17 27-28 May 2013, Campinas, Brazil

18. Does UDWDM impact on the other technologies?
IMDD based*
I. UDWDM
III. Nyquist
II. Convergence
18
RF Video**
*GLOBECOM’11, **OFC’13
27-28 May 2013, Campinas, Brazil

19. 19
HIGH-CAPACITY PON
PART III
27-28 May 2013, Campinas, Brazil

20. “Terabit+ (192××××10 Gb/s) Nyquist Shaped UDWDM
Coherent PON with Upstream and Downstream
over a 12.8 nm Band”, OFC’13, PDP5B3
Previous work
N. Cvijetic et al “1.92Tb/s coherent DWDM-
OFDMA-PON with no high-speed ONU-side
electronics over 100km SSMF and 1:64
passive split”, Optics Express, 19(24), 2011.
I. UDWDM
III. Nyquist
II. Convergence
20
passive split”, Optics Express, 19(24), 2011.
48 Gb/s per wavelength ~16 nm (2 THz)
In this work
80 Gb/s – 120 Gb/s per channel group ~13
nm (1.6 THz)
Nyquist shaped UDWDM over DWDM
27-28 May 2013, Campinas, Brazil

21. I. UDWDM
III. Nyquist
II. Convergence
How to go further in density keep the ODN budget?
Spectral efficiency ~3 GHz optical band / user
Mitigation of back-reflections
OM2A6 – “Spectral Shaping for Mitigating Backreflections in a Bidirectional 10
Gbit/s Coherent WDM-PON” by D. Lavery; M. Paskov; S.J. Savory
Mitigation of FWM
2BB
21
……
27-28 May 2013, Campinas, Brazil
2BB

22. Mitigation of Back-Reflections
8x10G down + 8x10G up
configuration (6.25 GHz): interleaved
by 3.125 GHz
I. UDWDM
III. Nyquist
II. Convergence
22 27-28 May 2013, Campinas, Brazil

23. Mitigation of FWM
16 16QAM channels at 3.125 GHz
I. UDWDM
III. Nyquist
II. Convergence
23 27-28 May 2013, Campinas, Brazil

24. Outline
Coherent UDWDM-PON setup
Nyquist shaped optical spectra
I. UDWDM
III. Nyquist
II. Convergence
24
Experimental results
5 Gb/s per channel or user
10 Gb/s per channel or user
Conclusions
27-28 May 2013, Campinas, Brazil

25. Experimental setup
Bi-directional Nyquist Shaped 16QAM
UDWDM over DWDM (100 GHz)
I. UDWDM
III. Nyquist
II. Convergence
25 27-28 May 2013, Campinas, Brazil
UDWDM Comb
OSA
Fiber
Coherent Rx
DSP
AWG DRTO
DWDM
Upstream
MZM

26. Optical Spectra: UDWDM Nyquist Shaped
12x10 Gb/s at 5 GHz
14x10 Gb/s at 3.125 GHz
16x5 Gb/s at 2.5 GHz
I. UDWDM
III. Nyquist
II. Convergence
26 27-28 May 2013, Campinas, Brazil

27. EVM: 5 Gb/s per channel
Sensitivity -35 dBm (single), -30 dBm (UDWDM)
Optimum power 40 km -10 dBm (1 UDWDM), -15
dBm (16 UDWDM)
I. UDWDM
III. Nyquist
II. Convergence
27 27-28 May 2013, Campinas, Brazil

28. EVM: 5 Gb/s per channel
EVM per channel at optimum power for
the 1550 nm UDWDM channel group
I. UDWDM
III. Nyquist
II. Convergence
28 27-28 May 2013, Campinas, Brazil

29. BER: 5 Gb/s per channel
Power margin around 10 dB
I. UDWDM
III. Nyquist
II. Convergence
29 27-28 May 2013, Campinas, Brazil

30. EVM: 10 Gb/s per channel
Sensitivity -32 dBm (single), -27 dBm (UDWDM)
Optimum power 40 km -11 dBm (1 UDWDM), -14
dBm (16 UDWDM)
I. UDWDM
III. Nyquist
II. Convergence
30 27-28 May 2013, Campinas, Brazil

31. EVM: 10 Gb/s per channel
EVM per channel at optimum power for
the 1550 nm UDWDM channel group
I. UDWDM
III. Nyquist
II. Convergence
31 27-28 May 2013, Campinas, Brazil

32. BER: 10 Gb/s per channel
I. UDWDM
III. Nyquist
II. Convergence
32 27-28 May 2013, Campinas, Brazil

33. Conclusions
Coherent detection plays an important
role on Future Optical Access Networks
Coherent Optical solutions better exploit
the full capacity of OANs
Convergence
33
Convergence
Simple bandwidth upgrade
Optical filter-free ONUs
T/Rx Sensitivity
symmetric and dedicated bandwidth
Performance optimization
Advanced modulations
Digital Signal Processing
Advanced filtering
27-28 May 2013, Campinas, Brazil

34. Acknowledgements
Funding
NG-PON2: ADI 30370
34
Collaborators
27-28 May 2013, Campinas, Brazil

35. Implementation of Nyquist Shaping
Implementation
– 4096 16QAM random symbols 16392 bits (Gray Coding)
– 10 GSa/s 1.25 Gbaud (8 Samples per symbol, 32784 samples)
– 10 GSa/s 2.5 Gbaud (4 Samples per symbol, 16392 samples)
– Roll-off factor 0
– Pre-emphasis filter: 1st Gaussian ~3 GHz
35 27-28 May 2013, Campinas, Brazil