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Geneva, 12-13 May 2008
ITU-T Kaleidoscope ConferenceInnovations in NGN
Hiroshi Yamazaki1, Takashi Yamada1, Yohei Sakamaki1, Akimasa Kaneko1,
Akihide Sano2, Hiroji Masuda2, and Yutaka Miyamoto2
1. NTT Photonics Laboratories2. NTT Network Innovation Laboratories
NTT corporation
Advanced Optical Modulators withHybrid Configuration of Silica-based PLC
and LiNbO3 Phase-Shifter Arrayfor Ultra-High-Speed Transport Networks
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 2
Outline
IntroductionConcept of PLC-LN hybrid
PLC-LN hybrid modulatorsDQPSK modulator
2-subcarrier-OFDM-DQPSK modulator
Conclusion
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 3
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Symbol rate [Gsymbol/s]
Dat
a (lin
e) r
ate
[Gbit/s
]Trends in Transmission Schemes
for 100G/λ TransportReported transmission experiments
(Total capacity >1 Tb/s, distance >1,000 km )
0
20
40
60
80
100
120
0 20 40 60 80 100 120
Symbol rate [Gsymbol/s]
Dat
a (lin
e) r
ate
[Gbit/s
]
Limited by PMD,electronics BW ...
Multilevel mod.(DQPSK, QAM ...)
Carrier MUX(OFDM, PDM ...)
Multiple-bits/symbol
Complex Tx (& Rx)
required
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 4
Obstacle:
Chip size > wafer (4")
LiNbO3 (LN) Modulator Integration
Single MZM Nested Dual MZM Further integration?
OOK
DB
DPSK
...
DQPSK...
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 5
Concept of PLC-LN Hybrid Modulator
LN: Simple high-speed modulators
Silica PLC: Complex low-loss circuits
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 6
1 bit/symbol: OOK, DPSK...
2 bit/symbol: DQPSK ...
4 bit/symbol: 2-carrier DQPSK, 16 QAM...
Concept of PLC-LN Hybrid Modulator
Large-scale integration withlow loss & practical chip size
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 7
DQPSK Modulator
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 8
PLC-R
Modulator Circuit
PLC-L LN
π/2phase shifter
I-ch mod.
Q-ch mod.
Module insertion loss: 6.5 dB
WFM Y-branch
Y. Sakamaki et al., Electron. Lett., vol. 43, no. 4, p. 217, 2007.
to (CS)RZpulse carver
T. Yamada et al., IPNRA2007, ITuC2
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 9
CSRZ-DQPSK (111G) Signal Spectrum
111 Gb/s with 166-GHz bandwidth
166 GHz
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 10
(Odd ch)(Even ch)
Setup for Transmission Experiment
LD1
DQPSK Mod. CSRZ
LD69
...
IL
111 Gb/s x 70λ Tx
160-km transmission line(w/o band-filtering nodes)
55.5GData1
55.5GData2
Differentialdirect-detection Rx
Pol. MUX
G.656 fiber80 km
G.656 fiber80 km
A. Sano et al., ECOC2006, Th4.1.1
Pol. DEMUX
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 11
Q-factor & Received Optical Spectra
Successful transmission of 14 Tb/s(111 Gb/s x 2 pol. x 70λ) over 160 km
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 12
Remaining Challenges
Greater distance (160 km → >1,000 km)
Tolerance to band filtering in ROADM nodes
Further decrease in symbol rate
(by increasing bits/symbol)
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 13
2-subcarrier(SC)-OFDM-DQPSK Modulator
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 14
All-Optical OFDM Modulation
Optical SC generatorLD
Mod. B
Mod. A
Symbol Rate= Δf= 25 Gbaudf
f0
f
Δf = 25 GHz
fA fB
ffA fB
Integrated Modulator
4 bit/symbol (100 Gb/s with 25 Gbaud)
A. Sano et al., ECOC2007 PD1.7
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 15
Modulator Circuit
PLC-L PLC-RLN
DEMUX filter
DQPSK mod. B
DQPSK mod. A
Total insertion loss: 6.5 dB
3-dB coupler
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 16
2-SC-OFDM-DQPSK Signal Spectra
100 Gb/s with 75-GHz bandwidth
10-node ROADM window
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 17
(Odd ch)(Even ch)
Setup for Transmission Experiment
LD12-SC-OFDMDQPSK Mod.
SCGen.
LD29
...
IL
100 Gb/s x 30λ Tx
1300-km transmission linew/ 10 ROADM nodes
25GData1
25GData4
...
x5
Differentialdirect-detection Rx
A. Sano et al., ECOC2007 PD1.7
ROADM ROADM
SW
SW
SMF 100 km
SMF 80 kmSMF 80 km
DCF
SC DEMUX(MZDI)
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 18
Q-factor & Received Optical Spectra
Successful transmission over1,300-km SMF with 10 ROADM nodes
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 19
Conclusion
PLC-LN hybrid modulatorsHigh-speed LN phase modulators
+ Low-loss Silica PLCs
High integration scalability
Promising for future 100G/λ-classtransport networks
Geneva, 12-13 May 2008 First ITU-T Kaleidoscope Conference – Innovations in NGN 20
Thank you.
