Presentation: Methods & Limits of Wet Plant Tilt Correction to Mitigate Wet Plant Aging [SubOptic 2016

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Wet Plant Tilt Correction

Methods and Limits

Loren Berg Ciena

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Contents

Presenter Profile

Loren Berg has been working in the fiber optic transmission business since graduating with a B Sc and M Sc in Electrical Engineering from Queen’s University in Kingston Ontario, Canada in 1991. Loren began working at Bell Northern Research upon graduation in the area of electro-optics. Since then, he has been involved in the design of many generations of optical transmission systems starting with early un-amplified WDM systems at OC-48 rates, early optical amplifier based WDM systems and onto DWDM systems with Layer 0 agility with Nortel and eventually Ciena. Currently Loren is an Advisor for Photonics and Submarine Systems Applications for Ciena.

Loren Berg Submarine Optical Systems R&D [email protected]


Contents

1.  Baseline System 2.  Types of Degradation

•  Distributed Losses •  Lumped Losses

3. Conclusions


5000km Lab System Specifications Parameter Value Units Wavelength Range 1535 - 1563 nm

Output Power 15.0 dBm Average Span Loss 15.0 dB

Number of spans 70

Total Distance 4877 km Number of EQs 10

5000km Linear System Baseline System – 5000km Dispersion Managed


• Old cables can have shady pasts •  Information on repairs and locations may not be readily available •  Supervisory information especially over time can fill in gaps in

information. •  Black box characterization gives: - End to end gain over wavelength - Delivered OSNR over wavelength

The Performance of Old Cables Degradations


5000km Linear System Baseline Performance


Distributed Loss: 4x4dB No SLTE Pre-emphasis


Distributed Loss: 4x4dB SLTE Pre-emphasis


Distributed Loss: 4x4dB Average Power Per Channel

4x4dB loss with NO SLTE Pre-emphasis 4x4dB loss with SLTE Pre-emphasis

The SLTE Pre-emphasis equalizes the average launch power per channel of the link. This is very important in the case of phase modulation such as QPSK because of the deleterious effects of fiber non-linearities.


Lumped Loss: 15dB Head End No SLTE Pre-emphasis


Lumped Loss: 15dB Tail End No SLTE Pre-emphasis


Lumped Loss: 15dB Head End SLTE Pre-emphasis


Lumped Loss: 15dB Head End Average Power Per Channel

15dB loss with NO SLTE Pre-emphasis 15 dB loss with SLTE Pre-emphasis

The SLTE Pre-emphasis equalizes the average launch power per channel of the link. This is very important in the case of phase modulation such as QPSK because of the deleterious effects of fiber non-linearities.


Conclusions

•  Conclusions -  Distributed and lumped degradations show different

signatures from a black box perspective. -  SLTE pre-emphasis is more effective at addressing

distributed loss degradations. -  Spectral hole burning (SHB) actually works to mitigate tilt

effects.

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Presentation: Methods & Limits of Wet Plant Tilt Correction to Mitigate Wet Plant Aging [SubOptic 2016