1. Further Fibre Capacity Increase for Accommodation of New Services
TERENA Networking Conferrence 2013
Maastricht, Netherlands June 2-6, 2013
Josef Vojtěch
Miloslav Hůla, Jan Radil, Vladimír Smotlacha, Pavel Škoda, Stanislav Šíma

2. Fibre Capacity Increase for New Services
Work was partially supported by Czech Institutional funding of research by project Large Infrastructure CESNET ( and in GN3 project ( under EU FP7
Maastricht, June 2-6, 2013
TNC 2013

3. Outline Motivation - New types of applications
Fibre Capacity Increase for New Services
Outline
Motivation - New types of applications
Ways of information transport
Parallel transport with coherent 100 Gbps
L band practical experiences
S band and 2µm
Observations
Q&A
Maastricht, June 2-6, 2013
TNC 2013

4. Fibre Capacity Increase for New Services
Motivation
Some types of applications - statistical multiplex not suitable or even usable
Applications interacting with external processes (processes outside network) timing of interaction limits quality or even the acceptability of results
Metrology (basic quantities transmission: time, frequency)
Remote access to / control of unique instruments (e.g. telescopes, medical instruments)
Remote real-time data collection (sensors, early warning)
Enormous data flows
Maastricht, June 2-6, 2013
TNC 2013

5. Fibre Capacity Increase for New Services
Photonic Service
End-to-end connection between two or more places in network
Described by allocated bandwidth and photonic-path
Maximal transparency - minimal impact of network on transmitted content
Path all-optical, no OEO except special cases
Maastricht, June 2-6, 2013
TNC 2013

6. Photonic Service Photonic service can transport real time data
Fibre Capacity Increase for New Services
Photonic Service
Photonic service can transport real time data
Dedicated bandwidth with no or only special OEO
Transparency to transmitted signals
Only transport latency shortest photonic path
Constant latency (i.e. negligible jitter), non or only specially tailored electrical processing
Stable service availability (due allocated bandwidth)
Maastricht, June 2-6, 2013
TNC 2013

7. Available Transport Signals can be untypical (slow, non-modulated)
Fibre Capacity Increase for New Services
Available Transport
Signals can be untypical (slow, non-modulated)
Dedicated fibre – OK, but price of rental
Annualized avg. cost of fibre rental: cf = 0.5 €/m/year [1]
Long distances - Dedicated lambda – OK
Annualized costs of 10Gbps transmission
system: ct = 0.12 €/m/year [1]
[1] S. Sima et al.: Deliverable D3.2v3 of Porta Optica project: Economic analysis, dark fibre usage cost model and model of operations
Maastricht, June 2-6, 2013
TNC 2013

8. Fibre Capacity Increase for New Services
Long-haul Transport
Alien wavelength – lot of parallel lambdas posibly with 100G
Indicated: (slow) OOK (amplitude modulated) signals have negative impact on coherent DP-QPSK through non-linear interactions, but precise numbers difficult to find
Vendors typically don’t give any warranties on system performance with parallel transmission with PSs
Guard-bands generally improve the situation but consume system bandwidth (200GHz)
Maastricht, June 2-6, 2013
TNC 2013

9. Influence of Slow OOK Signals on 100G
Fibre Capacity Increase for New Services
Influence of Slow OOK Signals on 100G
Lab tested 100G DP-QPSK systems vendors 2 and 3
Interaction with slow signals – 1 Mb, 100 Mb and 1Gb
100Mb/s signals similar to PS accurate time transfer (comparison of atomic slocks)
1Mb/s tested as the worst alternative, on 50GHz spacing
preFEC was very slightly different but probably due to changes in power per channel (lab EDFAs)
Over 450km of fibre (G.652 and G.655) non principal harmful effects, when 100G ‚surrounded‘ by slow signals
May be different on 2000km
Maastricht, June 2-6, 2013
TNC 2013

10. Influence of slow OOK signals on 100G
Fibre Capacity Increase for New Services
Influence of slow OOK signals on 100G
Field verification 2011 vendor 1
Over 300km of G.655 fibre
Full operation Feb 2013 vendor 2
Same line as above + spectral displacement from coherent used
No observable influence
Maastricht, June 2-6, 2013
TNC 2013

11. Transmission Channels Shortage
Fibre Capacity Increase for New Services
Transmission Channels Shortage
2.5G systems able of operation over 25GHz grid ~ 160ch in 35nm of C band
Typical 10G systems with 50GHz offered 88 (92) channels, undersea systems over 33GHz grid ~ 120 channels
Present 100G DP-QPSK fits into 50GHz
Probably no chance to fit 400G or 1T streams into 50GHz
Maastricht, June 2-6, 2013
TNC 2013

12. Possible Solutions Spectral savings:
Fibre Capacity Increase for New Services
Possible Solutions
Spectral savings:
More advanced signals modulations – higher spectral efficiency and spacing reduction (e.g. 100Gps into 33GHz grid)
Use of flexible grid together with adaptive transponders, indicated savings up to 30%
Both leads into higher channels density
Can be in contradiction with demand for spectral separation
Maastricht, June 2-6, 2013
TNC 2013

13. Available Bandwidth in SSMF
Fibre Capacity Increase for New Services
Available Bandwidth in SSMF
L band
S band
Maastricht, June 2-6, 2013
TNC 2013

14. Practical Results with L Band
Fibre Capacity Increase for New Services
Practical Results with L Band
C + L band lab verification
Single span 150 and 200km G.652 fibre on spools
High launched power about +8.5 and dBm/ch
Power transfer (Raman effect) from lower to higher wavelengths
0.58/0.38 dB
Maastricht, June 2-6, 2013
TNC 2013

15. Practical Results Field deployment – C + L
Fibre Capacity Increase for New Services
Practical Results
Field deployment – C + L
EF line Praha-Brno 300km, mixture of G.655 fibre with G.652 local loops
Maastricht, June 2-6, 2013
TNC 2013

16. Fibre Capacity Increase for New Services
S band
Suitable rare earth Thulium, but poor efficiency in silica, due to high non-radiative decays
TDFAs based on fluoride fibres commercially available
nm 19dB gain and 19dBm output
Can’t be spliced with silica fibres, hydroscopic
Double pumped TDFA in silica with dopants – not commercially available
Er Tm
Maastricht, June 2-6, 2013
TNC 2013

17. S band cont. Modified EDFA
Fibre Capacity Increase for New Services
S band cont.
Modified EDFA
Can handle region about nm, 20dB gain, commercially available, NF higher that TDFA
Commercially unavailability of DWDM transceivers for this region
Maastricht, June 2-6, 2013
TNC 2013

18. 2um (2000nm) band Experimental TDFA operation Bandwidth 1910-2020nm
Fibre Capacity Increase for New Services
2um (2000nm) band
Experimental TDFA operation
Bandwidth nm
Small signal gain 35dB
NF 5-7dB
Silica glass
Li Y. et al,”Thulium-doped Fiber Amplifier for Optical Communications at 2μm”, OFC2013
Maastricht, June 2-6, 2013
TNC 2013

19. 2um (2000nm) band cont. Hollow core photonic bandgap fibers
Fibre Capacity Increase for New Services
2um (2000nm) band cont.
Hollow core photonic bandgap fibers
Minimal latency, neff close to 1, propagation speed almost c, not 2/3c
Nonlinear coefficient 0.07% of SSMF
Losses still in order of 4.5dB/km in 2um
Theoretically losses can go down to 0.15 dB/km
1966 Charles K. Kao fiber
1000dB/km
Source: NKT Photonic
Maastricht, June 2-6, 2013
TNC 2013

20. Fibre Capacity Increase for New Services
Observations
Parallel operation of coherent signals and PS needs to be more verified
Building blocks for L band are available, curiously biggest issue were transceivers
Well known issues
Bending losses especially from 1600nm to higher wavelengths
Power transfer from C to L
Plans to deployment of S band in EF abandoned due to commercial unavailability of equipment
Maastricht, June 2-6, 2013
TNC 2013

21. Miroslav Karásek (In memoriam)
Fibre Capacity Increase for New Services
Acknowledgement
Lada Altmannová, Jan Gruntorád, Martin Míchal, Jan Nejman, Václav Novák, Karel Slavíček
Miroslav Karásek (In memoriam)
Maastricht, June 2-6, 2013
TNC 2013

22. Thank you for kind attention! Questions?
Fibre Capacity Increase for New Services
Thank you for kind attention!
Questions?
josef.vojtech(salamander)cesnet.cz
Maastricht, June 2-6, 2013
TNC 2013

23. HC PBGF losses prediction
Fibre Capacity Increase for New Services
Source: Richardson D.” Fiber Amplifiers for SDM Systems”, OTu3.G1, OFC2013
Maastricht, June 2-6, 2013
TNC 2013