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Digital non-linear equalization for flexible capacity ultradense WDM channels for metro core networking
Valeria Arlunno1, Xu Zhang, Knud J Larsen
1DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kgs. Lygnby, Denmark. vaar@fotonik.dtu.dk
Optics Express
|January 26, 2012
Summary
This study demonstrates ultradense wavelength division multiplexing (WDM) using digital signal processing to mitigate interference in flexible capacity metro core networks. The advanced digital non-linear equalization improves optical signal-to-noise ratio (OSNR) for closely spaced carriers.
Area of Science:
- Optical communication systems
- Digital signal processing
- Photonics
Background:
- Metro core networks require higher capacity and flexibility.
- Ultradense wavelength division multiplexing (WDM) is a key technology for increasing optical network capacity.
- Managing interference between closely spaced WDM channels is a significant challenge.
Purpose of the Study:
- To experimentally demonstrate an ultradense WDM scheme using independent tunable distributed feedback (DFB) lasers.
- To investigate the use of digital non-linear equalization for mitigating inter-channel interference.
- To evaluate the performance improvement in terms of optical signal-to-noise ratio (OSNR) and compare it with a single-laser system.
Main Methods:
- Utilizing independent tunable DFB lasers with a 12.5 GHz spacing for generating ultradense WDM channels.
- Implementing advanced digital non-linear equalization algorithms to compensate for impairments.
- Employing polarization-multiplexed quadrature phase-shift keying (PM-QPSK) modulation for flexible capacity.
- Comparing system performance against a baseline ultradense WDM system with carriers from a single laser.
Main Results:
- Successful demonstration of ultradense WDM with 12.5 GHz channel spacing.
- Digital non-linear equalization effectively mitigated inter-channel interference.
- Significant improvement in OSNR was achieved, enabling denser channel packing.
- The proposed scheme shows advantages over traditional single-laser based ultradense WDM systems.
Conclusions:
- Advanced digital signal processing, specifically non-linear equalization, is crucial for enabling ultradense WDM systems with closely spaced carriers.
- The proposed scheme offers a viable solution for flexible capacity enhancement in metro core networks.
- This approach improves spectral efficiency and overall system performance, paving the way for future optical communication advancements.
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