1,721,109 research outputs found
Sensing Applications in Deployed Telecommunication Fiber Infrastructures
No full textTLC-compatible coherent interferometric strategies applied to already deployed fiber networks are presented to provide not only civil structures health monitoring and traffic sensing, but also diagnostic and surveillance of the infrastructure integrity and damages localization, demonstrating fruitful synergy between telecommunication and sensing application
Dual modulation VCSEL-based sustainable transceiver for SSB DMT signals transmission
Full text linkSingle sideband DMT signal performance is analyzed in order to achieve high capacity and high spectral efficiency over 50-km uncompensated SMF. A sustainable implementation of the SSB DMT-based transceiver is proposed by means of a VCSEL source and a dual-modulator scheme, providing SSB without optical filtering and Hilbert transform implementation. Moreover, Kramers-Kronig detection, made possible by SSB, is studied at the receiver to effectively compensate the chromatic dispersion with direct detection
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Discrete Multitone Modulation for Short-Reach Mode Division Multiplexing Transmission
No full textSpatial division multiplexing (SDM) can support the capacity demand increase in short-range optical link, but the communication is affected by the intermodal crosstalk. In order to target a low-cost energy-efficient solution, we propose to exploit direct modulation and direct detection without MIMO post-processing in a mode division multiplexed (MDM) system. We theoretically analyze the frequency distribution of the crosstalk contributions taking into account that directly modulated sources at the same nominal wavelength are actually characterized by a certain frequency shift. Our model demonstrates that this shift originates a non-uniform beating noise in the frequency domain due to the intermodal crosstalk. We propose to exploit discrete multitone modulation and a guard band in the multicarrier spectrum to cope with the non-uniform crosstalk issue for typical crosstalk values due to present commercial multi-plane light conversion MUX/DEMUX devices and propagation in few few-mode fiber (FMF) kilometers. The model is validated by comparing simulations and experimental results in the case of a 2-mode MDM system. We demonstrate in a pure SDM scenario that, with respect to single mode transmission, the capacity can be increased of 2.3 times in a 10-km FMF link with 4-modes exploiting direct detection, limited-bandwidth directly modulated lasers and commercial mode MUX/DEMUXs
Enhanced Neural Network Implementation for Temperature Profile Extraction in Distributed Brillouin Scattering-based Sensors
No full textIn this work two Neural Network (NN) based solutions are proposed to recover the distributed temperature profile of a sensing fiber, measured using a commercial Brillouin Optical Time-Domain Analysis (BOTDA) interrogator. A detailed analysis in terms of temperature accuracy and processing speed is carried out for both the proposed methods, comparing the results with the ones obtained from the application of classical fitting techniques, namely cross-correlation (CORR), Lorentzian fitting (LF) and Pseudo-Voigt fitting (PV), through both simulations and real measurements carried out in laboratory environment. The results show that the first NN implementation, which aims to maximize the accuracy of the temperature profile and the processing speed, can handle different width of frequency acquisition window but needs to be optimized for a specific frequency acquisition scanning step. The second NN implementation, however, can also handle different values of the acquisition scanning step with a minor performance drop. Simulations and experimental data show a massive advantage of NN implementations in terms of processing speed with respect to classical fitting techniques, with a slightly better accuracy of the estimated temperature profiles
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