Norbert Hanik

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We experimentally investigate mutual information and generalized mutual information for coherent optical transmission systems. The impact of the assumed channel distribution on the achievable rate is investigated for distributions in up to four dimensions. Single channel and wavelength division multiplexing (WDM) transmission over transmission links with(More)
Lower bounds on mutual information (MI) of long-haul optical fiber systems for hard-decision and soft-decision decoding are studied. Ready-to-use expressions to calculate the MI are presented. Extensive numerical simulations are used to quantify how changes in the optical transmitter, receiver, and channel affect the achievable transmission rates of the(More)
This paper studies the impact of probabilistic shaping on effective signal-to-noise ratios (SNRs) and achievable information rates (AIRs) in a back-to-back configuration and in unrepeated nonlinear fiber transmissions. For back-to-back, various shaped quadrature amplitude modulation (QAM) distributions are found to have the same implementation penalty as(More)
We perform a systematic numerical optimization of preand post-compensation normalized sections using standard and dispersion compensating fibers for non-return to zero 10-Gbits/s single channel systems. By independently varying the power at the different types of fibers inputs and the compensation ratio, we find that post-compensation performs better than(More)
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(More)
We study the impact of demappers using various channel statistics, including circularly symmetric and multi-dimensional Gaussian, in fiber-optic communication systems. In nonlinear dispersion-managed fiber systems, an improvement in achievable information rate (AIR) and bit error ratio (BER) after decoding is obtained from using multi-dimensional(More)
Different aspects of probabilistic shaping for a multi-span optical communication system are studied. First, a numerical analysis of the additive white Gaussian noise (AWGN) channel investigates the effect of using a small number of input probability mass functions (PMFs) for a range of signal-to-noise ratios (SNRs), instead of optimizing the constellation(More)
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(More)
Probabilistic shaping of quadrature amplitude modulation (QAM) is used to enhance the sensitivity of an optical communication system. Sensitivity gains of 0.43 dB and 0.8 dB are demonstrated in back-to-back experiments by shaping of 16QAM and 64QAM, respectively. Further, numerical simulations are used to prove the robustness of probabilistic shaping to a(More)