1,720,966 research outputs found
Photon Ranging for Upstream ONU Activation Signaling in TWDM-PON
Full text linkThis paper focuses on upstream signaling in TWDM-PON (one of the two systems specified in the new series of ITU-T G.989.x Recommendations for NG-PON2) for what concerns the discovery phase of a new ONU. The key idea is that a new ONU, that needs to be discovered by the OLT, would send a low bit rate signal that is set to a sufficiently low power level to not affect significantly the upstream transmission performance of already active ONUs. We properly dimension the key physical layer parameters of this technique and demonstrate it experimentally. We named this proposal as "photon ranging" due to its ultra-low power transmission and we experimentally demonstrate its feasibility. As a "side effect" of our present work, we had to deeply revise the power penalty generated by the optical interferometric crosstalk, the main impairment that impacts the proposed setup, obtaining new results that may be of interest also in areas not directly related to the specific framework of TWDM-PON
Comparison of Probabilistically Shaped 64QAM with Lower-Cardinality Uniform Constellations in Long-Haul Optical Systems
Full text linkIndependence of the Impact of Inter-Channel Non-Linear Effects on Modulation Format and System Implications
No full textWe show by simulation that the impact of inter-channel non-linear effects is independent of modulation format in long-haul systems, once long-correlated non-linear phase-noise has been removed. We back-up the finding experimentally and investigate the system implications
Analytical and Experimental Results on System Maximum Reach Increase Through Symbol Rate Optimization
Full text linkWe investigated the reach increase obtained through nonlinearity mitigation by means of transmission symbol rate optimization (SRO). First, we did this theoretically and simulatively. We showed that the nonlinearity model that properly accounts for the phenomenon is the EGN model, in its version that specifically includes four-wave mixing. We then found that for PM-QPSK systems at full C-band, the reach increase may be substantial, on the order of 10-25%, with optimum symbol rates on the order of 2-6 GBd. We show that for C-band PM-QPSK systems over SMF, the potential mitigation due to SRO is greater than that ideally granted by digital backpropagation (the latter applied over a bandwidth of a 32-GBd channel). We then set up an experiment to obtain confirmation of the theoretical and simulative predictions. It consisted of 19 PM-QPSK channels, operating at 128 Gb/s per channel, over PSCF, with span length 108 km and EDFA-only amplification. We demonstrated a reach increase of about 13.5%, when going from single-carrier per channel transmission, at 32 GBd, to eight subcarrier per channel, at 4 GBd, in line with the EGN model predictions. We also extended the theoretical investigation of SRO to PM-16QAM, where we found a qualitatively similar effect to PM-QPSK, although the potential reach increase appears to be typically only about 50% to 60% that of PM-QPSK. Further investigation is, however, in order, specifically to explore the effect on PM-16QAM SRO of the removal of long-correlated phase and polarization nois
ICTON 2017: Mitigation of Transceiver Bandwidth Limitations using Multi-Subcarrier Signals
No full textPresentation given at the Flex-ON (Flexible and High-Capacity Optical Networks) workshop, co-located with the 19th International Conference on Transparent Optical Networks (ICTON)
Photon ranging techniques for upstream signalling in TWDM-PON during ONU activation
No full textA low level, low frequency technique is proposed for initial upstream communication in a TWDM NG-PON2 system when the ONU transmitter is not sufficiently calibrated in wavelength and when synchronization of discovery windows among different channels is not possible
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