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Munchen, Germany

Rafique D.,Coriant GmbH
Journal of Lightwave Technology | Year: 2016

Fiber nonlinearities define the ultimate performance bound for optical communication systems. Todays 100 Gb/s commercial products employ advanced digital signal processing (DSP) algorithms, capable to adequately address linear channel impairments, leaving fiber nonlinearity compensation (NLC) as the next logical step to improve transmission performance, and consequently diminish the need for signal regeneration. Over the last few decades, several techniques have been presented to minimize or mitigate channel nonlinearities, ranging from specialized link designs in direct-detect legacy networks to advanced DSP algorithms in coherent systems. However, specifically in the coherent age, NLC has always been perceived as an extremely complex approach, allowing insignificant gains when practical implementations are considered. In this paper, we focus on the real-world commercial use cases and complexity tradeoffs for NLC, and review several application scenarios, including homogeneous and heterogeneous networks, dispersion unmanaged and dispersion managed link infrastructures, flex-grid networks, and short reach to ultra long-haul transmission applications. We establish that in various practical use cases, NLC may enable substantial performance gains, well beyond conventionally acknowledged bounds. © 1983-2012 IEEE. Source

Leoni P.,University of Federal Defense Munich | Calabro S.,Coriant GmbH | Lankl B.,University of Federal Defense Munich
IEEE Photonics Technology Letters | Year: 2013

In this letter, we focus on coherently detected, non differentially encoded, polarisation division multiplexed 100G communication systems; through incorporating phase noise in the channel model, we assess the net coding gain achievable by various constellations that can be used in lieu of the conventional quadrature phase-shift keying (QPSK). Whereas the optical community put much effort into the optimization of the forward error correction codes for QPSK, trying to reduce the gap to the Shannon limit, we show that a potential gain of more than 2 dB is still available if different constellations are adopted. © 2013 IEEE. Source

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2011.1.1 | Award Amount: 11.63M | Year: 2012

DISCUS will analyse, design, and demonstrate a complete end-to-end architecture and technologies for an economically viable, energy efficient and environmentally sustainable future-proof optical network. It will provide a revolution in communications networks applicable across Europe and the wider world exploiting to the full the opportunity offered by LR-PONS and flat optical core networks to produce a simplified and evolvable architecture which will be the foundation for communications for the long term future. The architecture will be ultra energy efficient, simple to operate, robust to new technology introduction and providing universal availability of bandwidth and features regardless of geographic location.This ideal is obtained by a clean-slate approach to the architectural design by universal application of optical technologies throughout the fixed network eliminating traditional demarcations of metro, regional, core and access. Thus our essential concept is to use advanced optical technologies throughout giving rise to economies of scale and allowing bandwidths and flexibility hitherto unimaginable.Specifically the DISCUS architecture will: scale gracefully and economically, over a common physical infrastructure, as FTTP drives bandwidth growth by three orders of magnitude or more. It will evolve from todays architectures, adopting future technologies while co-existing with earlier generations. A unique feature will be a Principle of Equivalence whereby all network access points have equal bandwidth and service capability including core bandwidths (10Gb/s to 100\Gb/s) delivered to the access edge. It will seamlessly integrate wireless and fixed optical networks, fully exploiting both technologies. It will enable a competitive and simple regulatory environment controlled by customers and users rather than network operators and service providers.DISCUS is therefore fully aligned with the objectives of ICT-2011.1.1 and directly addresses its targets.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2009.3.7 | Award Amount: 11.62M | Year: 2010

The Mode-Gap project targets the 100 fold enhancement of the overall capacity of broadband core networks, and seeks to provide Europe with a lead in the development of the next generation internet infrastructure that will soon be desperately needed if we are to keep pace with societies ever increasing data-transmission requirements. It is now recognized that research results are within a factor of 2 of fundamental capacity limits, bounded by fibre nonlinearity and the Shannon Limit and radical approaches now need to be investigated if we are to avert grid-lock on the internet. Mode-Gap will develop multi-mode photonic band gap long haul transmission fibres, and associated enabling technologies. These fibres offer the potential of order of magnitude capacity increases through the use of multiple-input-multiple-output operation of the multi-mode fibre capacity and further order of magnitude capacity increases through the ultra low loss and ultra-low nonlinearity offered by multi-mode photonic bandgap fibre.
Specifically MODE-GAP will:\tDevelop ultra-low loss (0.1 dB/km) multi-mode (>10 modes) photonic band gap transmission fibre (MM-PBGF).\tDevelop novel rare earth doped optical amplifiers for the new transmission windows necessary for the achievement of ultra-long links.\tDevelop sources and detector arrays operating within the 1.8 to 2.1 um region\tDevelop MIMO arrangements for coupling source arrays to multi-mode fibre and multi-mode fibre to detector arrays\tDevelop MIMO and dispersion compensation signal processing algorithms applicable to both conventional solid core (glass and POF) fibres and MM-PBGF.
MODE-GAP is therefore fully aligned with the objectives of ICT-2009.3.7 and directly addresses several of its target outcomes by developing photonics technologies, components and (sub) systems driven by key applications/social needs and using them to fulfil the EU vision of future-proof networks and systems enabling unlimited bandwidth enablingmore optical processing and very high spectral-density transmission and the reductionof power consumption at the system and component level with the ultimate goal ofenabling increasing information throughput. If successful, the MODE-GAP technologywill have a significant impact in enabling future proof networks and systems ofincreasing information throughput. Without such a breakthrough the internet of thefuture will be severely compromised. The fundamental research needed to avoid this needs tobe undertaken now.

Rafique D.,Coriant GmbH | Rahman T.,Coriant GmbH | Rahman T.,TU Eindhoven | Napoli A.,Coriant GmbH | Spinnler B.,Coriant GmbH
Optics Express | Year: 2013

We report on the nonlinear transmission limits of various superchannel configurations in a flex-grid network upgrade scenario. In particular, we consider flexible data-rates ranging from 180Gb/s to 1.2Tb/s, employing either single-carrier, dual-carrier, or penta-carrier polarization multiplexed m-state quadrature amplitude modulation (PM-8QAM/PM- 16QAM) -termed as super-channels, and establish transmission performance margins for each configuration, both with and without superchannel fiber nonlinearity compensation. Our results show that the benefit of intra super-channel nonlinearity mitigation (nonlinear compensation addressing full super-channel bandwidth) reduces with increasing subcarrier count within the super-channel, and that single-carrier super-channel achieves the maximum improvement from nonlinearity mitigation (up to ~4.5dB, in Q-factor), better than dual-carrier (up to ~3.5dB) and pentacarrier (up to ~2dB) configurations. Moreover, the maximum reach improvement, compared to linear compensation only, is found to be ~170% (180Gb/s, PM-8QAM), ~150% (240Gb/s, PM-16QAM), ~100% (360Gb/s, PM-8QAM), ~100% (480Gb/s, PM-16QAM), and ~65% (1.2Tb/s, PM- 16QAM). © 2013 Optical Society of America. Source

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