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May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 1
Optically Amplified Multigigabit Links in CESNET2 network
Jan RadilLeoš Boháč
Miroslav Karásek
www.cesnet.cz
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 2
Optically Amplified Multigigabit Links in CESNET2 network
OutlineMotivation for extending the span lengthNumerical simulations @10 GPractical results (single channel, DWDM) Conclusions
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 3
Experimental and theoretical results on extending the span length Repeaters for 1 GE, 10 GE or 10 G POS ?Repeater-less or nothing-in-line transmissions at 1 Gbit/s, 2.5 Gbit/s and 10 Gbit/s over standard G.652 SMFFibre on the top of high-voltage poles, coast-island links, power supplies, maintenance ? Using optical amplifiers (EDFA, Raman)
Optically Amplified Multigigabit Links in CESNET2 network
Motivations
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 4
To estimate the maximum span length @10Gb/s for single channel transmissionsCompensation of chromatic dispersion - DCFPost- and pre-compensation schemes Effect of self-phase modulation (SPM)For 1 G and 2.5 G - these effects negligibleTo keep the BER better than 10-12 (or Q > 7)
Optically Amplified Multigigabit Links in CESNET2 network
Numerical simulations
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 5
Different wavelengths propagate at different speedsIncreases as the square of the bit rate
Optically Amplified Multigigabit Links in CESNET2 network
Chromatic dispersion
100 km of SMF G.652, without compensation
100 km of SMF G.652, with compensation
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 6
Optically Amplified Multigigabit Links in CESNET2 network
Self-phase modulation
Signal modulates its own phase (Kerr effect) The effect increases with spectral density and the bit rate
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 7
Optically Amplified Multigigabit Links in CESNET2 network
Post and pre-compensation schemes, SMF 0,22 dB/km, DCF 0,55 dB/km
Post-compensation scheme
Pre-compensation scheme
High quality parameters for fibres and lasers Possible problems with „real“ componentsBetter - post-compensation
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 8
Optically Amplified Multigigabit Links in CESNET2 network
Post-compensation, optimalization of the degree of compensation
0.6 0.7 0.8 0.9 1.04
5
6
7
8
9
LSMF
= 270 km, PDCF
= 0 dBm
Q,
dB
DCR
PSMF
= 16 dBm
17dBm 18dBm 19dBm 20dBm 21dBm
DCR = |LDCF*DDCF|/(LSMF*DSMF), LSMF = 270 km, PDCF = 0 dBm
5.8
5.83.8
3.81.7
7.9
0.6 0.7 0.8 0.9 1.016
17
18
19
20
21
SM
F in
put
pow
er,
dBm
DCR
LSMF
= 270 km, PDCF
= 0 dBm
Q
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 9
Optically Amplified Multigigabit Links in CESNET2 network
Post-compensation, optimalization of input powers PSMF and PDCF
-15 -10 -5 0 5 10
-25
-20
-15
-10
-5
log
BE
R
DCF input power, dBm
PSMF
=16 dBm
17 dBm 18 dBm 19 dBm 20 dBm 21 dBm
LSMF
= 270 km, LDCF
= 45 km
DCR = 0.83, LSMF= 270 km, LDCF= 45 km
-6.3
-13
-6.3
-20
16 17 18 19 20 21
-15
-10
-5
0
5
10
DC
F in
put
pow
er,
dBm
SMF input power, dBm
LSMF
= 270 km, LDCF
= 45 km
BER
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 10
Optically Amplified Multigigabit Links in CESNET2 network
Post-compensation, 270 km SMF +45 km DCF, PSMF=19 dBm, PDCF=0 dBm
17 18 190
1
2
3
4
after SMF
pow
er, W
time, ns
17 18 190
5
10
15
20
25
after DCF
optic
al p
ower
, W
time, ns
17 18 190
5
10
15
20
25
after OBPF
optic
al p
ower
, W
time, ns17 18 19
0.0
0.2
0.4
0.6
0.8
1.0
after ELP
PD
vol
tage
, a.
u.
time, ns
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 11
BER as a function of input power: post-compensation scheme
Eye diagram post-compensation
270 km SMF + 45 km DCF
PSMF= 19 dBm, PDCF = 0dBm
Optically Amplified Multigigabit Links in CESNET2 network
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 12
1 GE, 2.5 G POS and 10 GE with NILThree different configurations Booster, + preamp, + RamanFiber field test-beds 25, 50, 100, 200 kmTwo GE backbone lines (189 km and 170 km) are currently in use in CESNET2 network [1]
Optically Amplified Multigigabit Links in CESNET2 network
Practical results
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 13
Cisco Catalyst 6503 with 1 port 10 GE 1550 nm linecards, GSR 12008 for POSKeopsys High power booster 30 dBm, low noise preamplifier 13 dBmRaman pump 24 dBm, provided by IREESantec & JDS optical filtersOFS DCF
Optically Amplified Multigigabit Links in CESNET2 network
Practical results – equipment used
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 14
Scenario 1 – booster only
Scenario 2 – booster and preamplifier
Optically Amplified Multigigabit Links in CESNET2 network
Practical results – tested scenarios
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 15
Scenario 3 – booster, preamplifier and Raman pump
Scenario 1 – booster only for POS
Optically Amplified Multigigabit Links in CESNET2 network
Practical results – tested scenarios
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 16
Not DWDM lasers (chirp, linewidth, modulators)Fibre field test-beds – cables with patchcordsA lot of patchcords between lab and ODFRecalculating of length to more realistic figures…with attenuation 0,27 dB/km
Optically Amplified Multigigabit Links in CESNET2 network
Practical results – problems pt.1
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 17
Optically Amplified Multigigabit Links in CESNET2 network
Practical results – 1 GE and 2.5 G POSSpee
dLoopsLength
Scenario
DCF
OF EstimatedLength
Results
GE 200 km
BoosterPreamp
No No 220 km OK!
GE 200 km + 25 km
BoosterPreamp
No Yes
270 km Short packets
2.5 G
200 km
BoosterPreamp
No No 220 km OK!
2.5 G
200 km + 25 km
BoosterPreamp
No Yes
270 km Failed
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 18
Optically Amplified Multigigabit Links in CESNET2 network
Practical results – 10 GELoopsLength
Scenario
DCF OF EstimatedLength
Results
100 km Booster No No 125 km OK!
100 km + 50 km
BoosterPreamp
Yes Yes 180 km OK!
200 km BoosterPreampRaman
Yes Yes 220 km Failed
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 19
BER measurement ?No BERT equipment – we rely on PINGPOS line cards with BIP countersFor 1 GE even better situationDifficult for 10 GE, we still believe in our simulations and PING testing Billions of long packets with 0% drop-outs
Optically Amplified Multigigabit Links in CESNET2 network
Practical results – problems pt.2
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 20
Verify the possibility to use single channel EDFA with DWDM system (up to 8 lambdas)Three DWDM platforms: Cisco 15540, Cisco 15200 (together with Cisco EDFA 15501) and Pandatel Fomux 3000 Keopsys optical amplifiers
Optically Amplified Multigigabit Links in CESNET2 network
DWDM systems testing
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 21
Spectral diagram for 30 dBm input power, after EDFA.
Spectral diagram for 30 dBm input power, before receiver.
Optically Amplified Multigigabit Links in CESNET2 network
DWDM systems testing
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 22
Strong effects of SPM, CPM and FWMOSC mostly affectedSingle-channel EDFAs are OK for 5 channelsFor 16/32 channels you need really powerful booster (17 dBm for 1 channel corresponds to 2 dBm for 32 channels)
Optically Amplified Multigigabit Links in CESNET2 network
DWDM systems testing
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 23
We presented NIL solutions for multigigabit links „Better“ fibersBetter equipment (low noise amps, DWDM lasers)More precise compensation: DCF and/or FBGBER measurement, eye-mask testing
Optically Amplified Multigigabit Links in CESNET2 network
Conclusions
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 24
Thanks to Lada Altmanová, Stanislav Šíma and Martin Míchal from CESNET
Optically Amplified Multigigabit Links in CESNET2 network
Acknowledgements
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 25
[1] Šíma S., Altmanová L., „Development of the CESNET2 Optical Network“, TNC 2002
[2] Agrawal G.P., „Fiber-optic Communication systems“, J.Wiley, 2002
[3] Agrawal G.P., „Nonlinear Fiber Optics“, Academic Press, 2001
[4] Kartalopoulos S.V., „DWDM Networks, Devices and Technology“, J.Wiley, 2003
Optically Amplified Multigigabit Links in CESNET2 network
References
May 19-22, 2003 TERENA Networking
Conference Zagreb, Croatia 26
Thank you for your attention!
Optically Amplified Multigigabit Links in CESNET2 network