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Norbert Hanik

Bio: Norbert Hanik is an academic researcher from Technische Universität München. The author has contributed to research in topics: Transmission (telecommunications) & Wavelength-division multiplexing. The author has an hindex of 28, co-authored 145 publications receiving 2699 citations. Previous affiliations of Norbert Hanik include Deutsche Telekom & Ludwig Maximilian University of Munich.


Papers
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Proceedings ArticleDOI
01 Jul 2017
TL;DR: A robust adaptive digital pre-distortion technique to mitigate the linear and non-linear degradation of optical communication transmitter components and indirect learning architecture is presented.
Abstract: We present a robust adaptive digital pre-distortion technique to mitigate the linear and non-linear degradation of optical communication transmitter components. The proposed method is based on the principles of memory polynomial based pre-distortion and indirect learning architecture. Effectiveness of the presented algorithm is assessed across various higher order modulation formats and higher baud rates. Significant gains are reported in back-to-back measurements and various lab and field trial experiments.

1 citations

05 Jul 2010
TL;DR: In this paper, the authors show that linear equalization is more effective in increasing the dispersion tolerance of DSM than of its single-carrier equivalent, by means of simulations.
Abstract: Digital Subcarrier Multiplexing (DSM) allows simple direct detection of multi-carrier signals. We show, by means of simulations, that linear equalization is more effective in increasing the dispersion tolerance of DSM than of its single-carrier equivalent.
Proceedings ArticleDOI
01 Jan 2019
TL;DR: Simulations over a 1800 km Raman amplified fiber link demonstrate the effectiveness of expectation maximization clustering of received nonlinear spectral data from solitonic pulses to reduce bit error rates.
Abstract: Expectation maximization clustering of received nonlinear spectral data from solitonic pulses is used to reduce bit error rates. Simulations over a 1800 km Raman amplified fiber link demonstrate the effectiveness of the method.
Journal ArticleDOI
TL;DR: In this paper, the mutual information between a complex-valued channel input and its complexvalued output is decomposed into four parts based on polar coordinates: an amplitude term, a phase term, and two mixed terms.
Abstract: The mutual information between a complex-valued channel input and its complex-valued output is decomposed into four parts based on polar coordinates: an amplitude term, a phase term, and two mixed terms. Numerical results for the additive white Gaussian noise (AWGN) channel with various inputs show that, at high signal-to-noise ratio (SNR), the amplitude and phase terms dominate the mixed terms. For the AWGN channel with a Gaussian input, analytical expressions are derived for high SNR. The decomposition method is applied to partially coherent channels and a property of such channels called "spectral loss" is developed. Spectral loss occurs in nonlinear fiber-optic channels and it may be one effect that needs to be taken into account to explain the behavior of the capacity of nonlinear fiber-optic channels presented in recent studies.
Proceedings ArticleDOI
05 Jul 2015
TL;DR: The gap of a practical FEC scheme to its asymptotic limit is studied and it is found that the gain of complex SD decoding over HD decoding can be very small.
Abstract: We study lower bounds on mutual information that are achievable rates for optimal and sub-optimal hard-decision (HD) and soft-decision (SD) decoding. These rates represent the maximum amount of information we can convey over a memoryless channel with a fixed input if ideal forward error correction (FEC) is employed. We find that the gain of complex SD decoding over HD decoding can be very small, depending on the modulation format and the system parameters. We further study the gap of a practical FEC scheme to its asymptotic limit.

Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors summarized the simultaneous transmission of several independent spatial channels of light along optical fibres to expand the data-carrying capacity of optical communications, and showed that the results achieved in both multicore and multimode optical fibers are documented.
Abstract: This Review summarizes the simultaneous transmission of several independent spatial channels of light along optical fibres to expand the data-carrying capacity of optical communications. Recent results achieved in both multicore and multimode optical fibres are documented.

2,629 citations

Journal ArticleDOI
TL;DR: In this paper, the authors give a tutorial overview of OFDM and highlight the aspects that are likely to be important in optical applications, and discuss the constraints imposed by single mode optical fiber, multimode optical fiber and optical wireless.
Abstract: Orthogonal frequency division multiplexing (OFDM) is a modulation technique which is now used in most new and emerging broadband wired and wireless communication systems because it is an effective solution to intersymbol interference caused by a dispersive channel. Very recently a number of researchers have shown that OFDM is also a promising technology for optical communications. This paper gives a tutorial overview of OFDM highlighting the aspects that are likely to be important in optical applications. To achieve good performance in optical systems OFDM must be adapted in various ways. The constraints imposed by single mode optical fiber, multimode optical fiber and optical wireless are discussed and the new forms of optical OFDM which have been developed are outlined. The main drawbacks of OFDM are its high peak to average power ratio and its sensitivity to phase noise and frequency offset. The impairments that these cause are described and their implications for optical systems discussed.

1,761 citations

Journal ArticleDOI
10 Jan 2005
TL;DR: Differential-phase-shift keying has recently been used to reach record distances in long-haul lightwave communication systems and theoretical as well as implementation aspects of DPSK are reviewed.
Abstract: Differential-phase-shift keying (DPSK) has recently been used to reach record distances in long-haul lightwave communication systems. This paper will review theoretical, as well as implementation, aspects of DPSK, and discuss experimental results.

949 citations

Journal ArticleDOI
TL;DR: ACO-OFDM requires less optical power for a given data rate than DCO- OFDM for all but the largest constellations and is better suited to adaptive systems as the same structure is optimum for all constellation.
Abstract: We present theoretical and simulation results for the performance of asymmetrically-clipped optical OFDM (ACO-OFDM) and DC-biased optical OFDM (DCO-OFDM) in AWGN for intensity-modulated direct-detection systems. Constellations from 4 QAM to 1024 QAM are considered. For DCO-OFDM, the optimum bias depends on the constellation size which limits its performance in adaptive systems. ACO-OFDM requires less optical power for a given data rate than DCO-OFDM for all but the largest constellations and is better suited to adaptive systems as the same structure is optimum for all constellations.

638 citations

Journal ArticleDOI
TL;DR: This paper focuses on SDM for fiber-optic communication using few-mode fibers or multimode fibers, in particular on the critical challenge of mode crosstalk, and presents the prospects for SDM in optical transmission and networking.
Abstract: Space-division multiplexing (SDM) uses multiplicity of space channels to increase capacity for optical communication. It is applicable for optical communication in both free space and guided waves. This paper focuses on SDM for fiber-optic communication using few-mode fibers or multimode fibers, in particular on the critical challenge of mode crosstalk. Multiple-input–multiple-output (MIMO) equalization methods developed for wireless communication can be applied as an electronic method to equalize mode crosstalk. Optical approaches, including differential modal group delay management, strong mode coupling, and multicore fibers, are necessary to bring the computational complexity for MIMO mode crosstalk equalization to practical levels. Progress in passive devices, such as (de)multiplexers, and active devices, such as amplifiers and switches, which are considered straightforward challenges in comparison with mode crosstalk, are reviewed. Finally, we present the prospects for SDM in optical transmission and networking.

621 citations