1,721,006 research outputs found
Advanced Digital Signal Processing Techniques for High-Speed Optical Links
Full text linkL'abstract è presente nell'allegato / the abstract is in the attachmen
Direct-Detection Single-Sideband Systems: Performance Comparison and Practical Implementation Penalties
No full textPDL Localization and Estimation Through Linear Least Squares-Based Longitudinal Power Monitoring
Full text linkAn algorithm capable of localizing Polarization-Dependent Loss (PDL) and directly estimating its value in a multi-span optical transmission link using only Rx-side Digital Signal Processing (DSP) is presented. The algorithm employs a Linear Least Squares-based power profile estimation method and it succeeds in localizing multiple PDL sources along the link. Its performance is evaluated across diverse power levels, including SNR-maximizing ones, resulting in consistently comparable results
Longitudinal Power Monitoring Performance with Subcarrier Multiplexing Transmission
Full text linkWe investigate the performance of Longitudinal Power Monitoring (LPM) algorithms at the small symbol rates achieved with subcarrier multiplexing. We show that at those symbol rates LPM is still effective, albeit with a noisier estimation profile
PDL Localization and Estimation Through Longitudinal Power Monitoring: A Comparison between Least Squares and Correlation Methods
Full text linkIn this work, we compare two Longitudinal Power Monitoring (LPM) techniques (Least-Squares and Correlation Method) for localizing and measuring Polarization-Dependent Loss (PDL) in a multi-span optical transmission link. We consider situations with different PDL values in the link and multiple PDL sources
Observing the effect of polarization mode dispersion on nonlinear interference generation in wide-band optical links
Full text linkWith the extension of the spectral exploitation of optical fibers beyond the C-band, accurate modeling and simulation of nonlinear interference (NLI) generation is of the utmost performance. Models and numerical simulation tools rely on the widely used Manakov equation (ME): however, this approach when also considering the effect of polarization mode dispersion (PMD) is formally valid only over a narrow optical bandwidth. In order to analyze the range of validity of the ME and its applicability to future wide-band systems, we present numerical simulations, showing the interplay between NLI generation and PMD over long dispersion-uncompensated optical links, using coherent polarization division multiplexing (PDM) quadrature amplitude modulation (QAM) formats. Using a Monte-Carlo analysis of different PMD realizations based on the coupled nonlinear Schrödinger equations, we show that PMD has a negligible effect on NLI generation, independently from the total system bandwidth. Based on this, we give strong numerical evidence that the ME can be safely used to estimate NLI generation well beyond its bandwidth of validity that is limited to the PMD coherence bandwidth
A Simple Chaotic Encryption Scheme for Probabilistically Shaped Transmissions
Full text linkWe propose a simple encryption scheme that preserves the probability distribution of constellation symbols, ensuring seamless integration into communication systems employing probabilistic shaping, while enhancing security performance
Non-Linear Phase Noise Mitigation over Systems using Constellation Shaping
Full text linkThis paper presents a modified soft-decoding strategy, which improves performance in the presence of strong phase noise. This can substantially increase the reach of systems that are severely affected by phase noise, generated by fiber non-linear Kerr effect. This strategy is applied to two different experimental scenarios employing constellation shaping, which is known to generate strong non-linear phase noise. In the first experiment, we show that the strategy significantly improves the performance of probabilistically shaped (PS) 64 quadratic-amplitude modulation (QAM) over low-dispersion fibers. In the second experiment, the strategy is used to optimize the position of the points of a 32-QAM constellation (geometrical shaping). This optimized constellation is then compared to standard 32-QAM and PS 64-QAM over standard single-mode fiber. Also in this case, the modified strategy is able to give significant reach gains
Next Generation Coherent PONs: Technical Challenges and Outlook
Full text linkAfter the standardization of 50 Gbit/s PONs (ITU-T recommendation G.9804.3), the next generation of passive optical networks (PONs) is expected to achieve a data rate of 100 Gbit/s per lambda and above, with a preference towards 200 Gbit/s per lambda to maintain the usual x4 bit rate increase from one generation to the next. To support such high data rates, there is ongoing discussion about introducing coherent technologies into PONs for the first time. This decision poses several technical challenges that must be addressed. For instance, will future coherent PONs be based on single-carrier solutions (i.e., pure time division multiplexing) or multi-carrier solutions (wavelength division multiplexing, frequency division multiplexing)? And how will the burst-mode coherent DSP needed for the upstream channel be implemented
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