Check out the slides that ADVA Optical Networking's Stephan Pachnicke presented at OFC 2014.

1. S. Pachnicke, J. Zhu, M. Lawin, A. Wonfor, M. Eiselt, R. V. Penty, R. Cush,
R. Turner, P. Firth, M. J. Wale, I. H. White, J.-P. Elbers
First Demonstration of a Full C-Band Tunable
WDM-PON System with Novel High-Temperature
DS-DBR Lasers

2. © 2014 ADVA Optical Networking. All rights reserved.2
Outline
• Motivation
• Experimental Setup of Tunable WDM-PON
• Results
• Automatic Wavelength Tuning
• 1.25 Gb/s Transmission
• 10.3 Gb/s Transmission
• Conclusion

3. © 2014 ADVA Optical Networking. All rights reserved.3
Motivation
Low-cost components are essential for tunable laser based WDM-PON
Requirements for customer premises equipment:
• Reduce tunable laser componentry
• No thermo-electric cooler (TEC)
• No wavelength locker
• Network-based wavelength control with single wave locker for all ONUs located at central office (OLT)
• Avoid calibration of each laser
• Generic tuning algorithm, laser currents adapted based on current wavelength tuning feedback
OLT
Tx
...
1
RN
L
C
N
AWG
Rx
...
1
N
AWG
AWG
L-Band 97.15 GHz
C-Band 100 GHz
ONU N
Rx
ONU 1
Rx
T-LD
T-LD
C
L
C
L
ITU-T
698.3

4. © 2014 ADVA Optical Networking. All rights reserved.4
Experimental Setup
• Multi-user setup; novel high-temperature DS-DBR laser as central channel;
used laser was not equipped for modulation ( use of external MZM)
• Upstream data transmission with 1.25 Gb/s and 10.3 Gb/s; Downstream data transmission with 1.25 Gb/s
• Demonstration of pilot-tone based overhead channel and centralized wavelength locking both realized in
embedded hardware
OLT: optical line terminal; RN: remote node;
ONU: optical network unit; PT: pilot tone generator; FPGA: field
programmable gate array; MZM: Mach-Zehnder modulator;
PRBS: pseudo-random bit sequence data source

5. © 2014 ADVA Optical Networking. All rights reserved.5
Tuning with Central Wave Locker
• AM tone powers are extracted by FFT on the received optical signal;
multiple channels can be measured with a single etalon
• Wavelength error is calculated by comparing the etalon output power with the reference AM tone power
• Received power and wavelength error are communicated to ONU via tone channel
ONUOLT
iTLA
RN
AWG
FPGA
ECC Detection
DBR
Heater
MZM
AM Tone
µC
Wave
Locker
FPGA: Data &
ECC Generation
RXFPGA: FFT &
Feedback Gen.
L
C C
L
Etalon

6. © 2014 ADVA Optical Networking. All rights reserved.6
Wavelength Tuning Results
• After 20 s the right frequency slot has been identified
• Long-term frequency stability within ±10 GHz (limited by DAC resolution driving laser currents)
• Laser case temperature can vary between 70°C-90°C without any mode-jumps;
operation with heater envisioned (here results are shown for 70°C)
194.40
194.45
194.50
194.55
194.60
194.65
194.70
194.75
194.80
194.85
194.90
0 10 20 30 40 50 60 70 80 90 100
Frequency[THz]
Time [s]
194.70
194.75
194.80
194.85
194.90
0 2000 4000 6000
Frequency[THz]
Time [s]
Phase 1
(Power Feedback)
Phase 2
(Wavelength & Power Feedback)

7. © 2014 ADVA Optical Networking. All rights reserved.7
1.25 Gb/s Transmission Results
• Up to 80 km reach data
transmitted error-free
• EDFA used at OLT only for
80 km reach (gain  20 dB)
 approx. 2 dB penalty due
to ASE noise

8. © 2014 ADVA Optical Networking. All rights reserved.8
10.3 Gb/s Transmission Results
• An EDFA has been used at the OLT
at all times (Pout  2 dBm)
• Up to 40 km reach error-free
transmission
(longer reach possible by using
EDFA with higher gain)

9. © 2014 ADVA Optical Networking. All rights reserved.9
Summary & Conclusion
• First demonstration of ONU with high-temperature DS-DBR laser
• First demonstration of automatic tuning on turn-on and long-term frequency stability
(all realized in embedded hardware)
• Centralized wavelength locking & communication between ONUs and OLT by pilot-tone
based communication channels
• Operation of tunable laser without wavelength locker and without thermo-electric cooler
Proves feasibility of using low-cost uncooled tunable lasers in ONUs
for up to 10 Gb/s transmission rates

10. spachnicke@advaoptical.com
Thank you!
IMPORTANT NOTICE
The content of this presentation is strictly confidential. ADVA Optical Networking is the exclusive owner or licensee of the content, material, and information in this
presentation. Any reproduction, publication or reprint, in whole or in part, is strictly prohibited.
The information in this presentation may not be accurate, complete or up to date, and is provided without warranties or representations of any kind, either
express or implied. ADVA Optical Networking shall not be responsible for and disclaims any liability for any loss or damages, including without limitation, direct,
indirect, incidental, consequential and special damages,
alleged to have been caused by or in connection with using and/or relying on the information contained in this presentation.
Copyright © for the entire content of this presentation: ADVA Optical Networking.