15 research outputs found

    Measurements of non-linear noise re-distribution in an SOA

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    Field trial over 820km installed SSMF and its potential Terabit/s superchannel application with up to 57.5-Gbaud DP-QPSK transmission

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    In this paper, we report the result of a field trial of 56-Gbaud (224-Gbit/s) and 57.5-Gbaud (230-Gbit/s) dual-polarization quadrature phase shift keying (DP-QPSK) coherent optical transmission over 820 km installed standard single mode fiber (SSMF). Offline digital signal processing (DSP) was applied for signal recovery and bit-error-rate (BER) counting in our field trial experiments, and BER performance well below the 7% overhead hard-decision forward error correction (FEC) error-free threshold (4.5×10−3) at 231-1 pseudo random bit sequence (PRBS) pattern length has been achieved, with the best achievable BERs of 2×10−4 (56-Gbaud) and 3×10−4 (57.5-Gbaud), respectively. In parallel a 1.15-Tbit/s (5×230-Gbit/s) quasi-Nyquist spaced wavelength division multiplexing (WDM) superchannel transmission over the same 820 km optical field link (FL) was also investigated through numerical simulations based on the same 57.5-Gbaud DP-QPSK signal using 1% roll-off Nyquist pulse shaping with 60-GHz channel spacing, and the results indicate that the BER performance well below the 7% overhead hard-decision FEC error-free threshold (4.5×10−3) for the 1.15-Tbit/s DP-QPSK superchannel transmission can be achieved

    Quasi real-time 230-Gbit/s coherent transmission field trial over 820 km SSMF using 57.5-Gbaud dual-polarization QPSK

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    We demonstrate 230-Gbit/s (57.5-Gbaud) polarization-multiplexed QPSK coherent transmission over 820 km field-installed SSMF with quasi real-time DSP, without resorting to ETDM. BER performance well below FEC error-free threshold (2×10^-3) at 2^31-1 PRBS length was achieved

    Video quality based on a user study with video professionals for Video Assisted Refereeing (VAR) Systems

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    This document describes a user experiment with the purpose of finding a baseline quality that is suitable for system and a database for training and evaluating the objective quality measurement methods suitable for assessing the video quality of VAR systems.  A user experiment was performed involving 25 Swedish video experts. Three different video formats were incorporated 1080p, 1080i and 540i. The degradations were in most cased done using encoding with Motion JPEG (MJPEG) and H.264 in the bitrate range from 80 Mbit/s down to 10 Mbit/s.  MJPEG loses quality very fast and already at 80 Mbit/s it has significantly lower quality than the uncompressed reference and then for even lower bitrates the quality falls quickly to bad. On the other hand, H.264 was not found to be significant different from the uncompressed reference until the bitrate had dropped to 10 Mbit/s for 1080p. For 1080i 20 Mbit/s was also weakly and for 540i 20 Mbit/s was significantly lower for some of the scaling methods. For 1080i the deinterlacing requires careful consideration, since the deinterlacing scheme introduced received very low quality scores. For the scaling scheme lanczos was the best and bilinear the worst.  Requirement levels on bitrate and the encoders MJPEG and H.264 based on this experiment•    MJPEG require more than 120 Mbit/s•    H.264 require more than 50 Mbit/

    Fiber optics communications; (190.4370) Nonlinear optics, fibers

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    Abstract: The Asynchronous Phase Modulation (APM) scheme is experimentally studied for the first time. APM is shown to increase the power tolerance of NRZ-OOK over a 3x75-km link

    Objective video quality assessment methods for Video assistant refereeing (VAR) Systems

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    This report describes the work and conclusions drawn after phase 4 in the project “Assessment methods for Video assistant refereeing (VAR) System”. The performance of six different video quality models have been evaluated, that were identified during phase 1, against the subjective video quality database that was created during phase 3. The results are slightly different for 1080p compared to 1080i. For 1080p the models VQM_VFD, SSIM and VMAF performs the best with Pearson Correlation Coefficients (PCC) above 0.9. For 1080i the PCC drops a bit overall and then VMAF and VQM_VFD are close in performance and performing the best. The overall performance for both formats VMAF an VQM_VFD stands out as the best models. In this comparison VQM_VFD has the added advantage to also be able to perform its own registration i.e. to fix any misalignment between the reference video and the distorted one

    IMPROVEMENT OF NONLINEAR TOLERANCE IN 40 Gbit/s TRANSMISSION BY PHASE MODULATION AT 10 GHz

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    Abstract We propose to suppress intra-channel four-wave-mixing (IFWM
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