Outage probability due to intercore crosstalk from multiple cores in short-reach networks

The outage probability (OP) due to intercore crosstalk (ICXT) arising from multiple interfering cores in short-reach binary intensity modulation-direct detection optical links supported by homogeneous weakly-coupled multicore fibers is assessed through numerical simulation. The maximum acceptable ICXT level for a given OP is extracted from simulation results, for low and high skew-bit rate products (SBRPs). (i) For high SBRP, a 3 dB reduction of the maximum acceptable ICXT level per core for a given OP is observed when the number of interfering cores doubles. In this case, as a very large number ( ≫1 ) of bits of each interfering core is contributing to ICXT, the total detected ICXT tends to a Gaussian distribution that makes the maximum acceptable total ICXT level independent of the interfering core count. (ii) For low SBRP, the number of bits contributing to ICXT is similar to the interfering core count and the total detected ICXT assumes a set of discrete amplitudes, which deviates it from the Gaussian distribution. Hence, the reduction of the maximum acceptable ICXT level per core, when the number of interfering cores is doubled, is about 2 dB, and the maximum acceptable total ICXT level increases with the interfering core count, by around 3 dB, when the interfering core count increases from 1 to 8.info:eu-repo/semantics/acceptedVersio

DD-OOK multicore fiber systems impaired by intercore crosstalk and laser phase noise

Direct-detection on-off keying (DD-OOK) weakly-coupled multicore fiber (WC-MCF) systems impaired by intercore crosstalk (ICXT) and laser phase noise are investigated numerically and experimentally. This is performed for systems with a product between the bit rate and the absolute value of the skew between cores much larger than one. It is shown that the phase noise increases the instantaneous ICXT power fluctuations. The standard deviation of the short-term average ICXT (STAXT) power induced by the phase noise depends on the product between the laser linewidth and the absolute value of the skew between cores (linewidth ×| skew|). When linewidth ×| skew|\gg1, typical of distributed feedback (DFB) lasers (linewidth in the few MHz range) and MCFs with skew in the \mus range, the decrease of the standard deviation of the STAXT power induced by the phase noise is 5 dB per decade of linewidth ×| skew| increase. For linewidth ×| skew|\ll1, typical of external cavity lasers (ECLs) and DFB lasers, and MCFs with skew of a few ns, the standard deviation of the STAXT power remains almost unaffected by the phase noise. Experimental results show that, compared with low linewidth ECLs, 10 Gb/s DD-OOK WC-MCF systems using DFB lasers as optical sources in the interfering cores and skew in the range between 2.4 ns and 5.4 ns, may require an additional ICXT margin up to 8 dB for a given outage probability. The additional ICXT margin and the lower amplitude of the STAXT power fluctuations observed experimentally for DFB lasers suggest that the level of the fluctuations of the STAXT power may be an inadequate system performance indicator. The dependence of the outage probability on the interfering core count is also investigated experimentally. It is shown that, for systems with bit rate ×| skew|\gg1, the outage probability only depends on the total ICXT power and not on the interfering core count.info:eu-repo/semantics/acceptedVersio

VALIDAÇÃO DA VERSÃO EM PORTUGUÊS DA ESCALA DE AUTO-CUIDADO PARA A PESSOA COM INSUFICIÊNCIA CARDÍACA

Trata-se de uma investigação já realizada anteriormente em seres Humanos. É uma escala desenvolvida por Barbara Riegel, Professora, na Universidade da Pensilvânia Departamento de Enfermagem e aplicada nos Estados Unidos. Encontra-se traduzida em várias línguas: em Chinês e é aplicada em Hong Kong e Taiwan; em Italiano; em Espanhol e em Alemão. Por não existir nenhuma escala desta natureza em Portugal, consideramos importante a sua tradução em Português para poder ser utilizada pelos profissionais de saúde aos doentes com insuficiência cardíaca. Assim definimos como objectivo Validar a escala de auto-cuidado para a pessoa com insuficiência cardíaca, na população Portuguesa. Quanto ao método o estudo foi autorizado pela autora da versão original em inglês e começou com a tradução e adaptação cultural do questionário para a língua portuguesa. A população do estudo será de 300 participantes de dois hospitais que tem consulta de enfermagem à pessoa com insuficiência cardíaca. Os dados serão processados através do software SPSS®. Consideramos que a Escala De Auto-Cuidado Para A Pessoa Com Insuficiência Cardíaca é uma importante ferramenta de trabalho. Pois permite fazer o levantamento de informação pertinente que ajuda a centrar as intervenções e a promover intervenções mais adequadas

Cost, power consumption and performance analysis in SDM ROADM architectures for uncoupled spatial channels

Currently optical networks are reaching their maximum transport capacity. Different solutions can be used to overcome this capacity limit, but we are going to study, in particular, space division multiplexing (SDM). To use SDM, the reconfigurable optical add/drop multiplexers (ROADMs) need to be adapted to support this multiplexing. In this paper we analyze four switching strategies used in SDM ROADMs and the respective SDM ROADM architectures. These strategies are explained and analyzed, for uncoupled scenarios, in terms of cost and power consumption. The impact of the physical layer impairments (PLIs) amplified spontaneous emission noise, non-linear interference, passband narrowing due to optical filtering and in-band crosstalk is also assessed, considering a cascade of SDM ROADMs with spatial and spatial-wavelength switching granularities. The PLI inband crosstalk, has insignificant impact, in networks with a single spatial channel or in SDM networks with spatial granularity ROADM architecture, but in a SDM network with spatial wavelength granularity this PLI can lead to an OSNR penalty of around 2 dB, when the number of spatial channels is high. The other PLIs have similar impacts in all networks studied.info:eu-repo/semantics/acceptedVersio

Assessment of the combined effect of laser phase noise and intercore crosstalk on the outage probability of DD OOK Systems

We study the influence of the combined effect of laser phase noise and intercore crosstalk on the outage probability of direct-detection 10 Gbit/s on-off keying optical communication systems. We show that the laser phase noise can affect significantly the outage probability, for lasers with linewidths in the MHz range, for low and high skew-bit rate products. We also show that the laser phase noise effect on the received eye-pattern is qualitatively similar to the one found for high skew-bit rate product in the absence of laser phase noise.info:eu-repo/semantics/acceptedVersio

Weakly-coupled MCF direct-detection OOK systems impaired by laser phase noise

On-off-keying multicore fiber systems employing different lasers are experimentally investigated. Laser phase noise increases the instantaneous fluctuations of the crosstalk. DFB-based systems may require an additional crosstalk margin of 4 dB relative to ECL-based systems.info:eu-repo/semantics/acceptedVersio

Characterization of crosstalk-impaired OOK signals in WC-MCF systems with high and low skew×bit rate

The received amplitudes of crosstalk-impaired on-off keying signals in weakly-coupled multicore fibre (WC-MCF) systems are experimentally assessed for high and low skew×bit-rate. Gaussian-distributed crosstalk-induced amplitudes are shown for high skew×bit-rate. The mean of these amplitudes can also be modelled by Gaussian distributions.info:eu-repo/semantics/acceptedVersio

GABA deficiency in NF1: a multimodal [11C]-Flumazenil and spectroscopy study

Objective: To provide a comprehensive investigation of the GABA system in patients with Neurofibromatosis type 1 (NF1) that allows understanding the nature of the GABA imbalance in humans at pre- and post-synaptic levels. Methods: In this cross-sectional study, we employed multimodal imaging and spectroscopy measures to investigate GABAA receptor binding, using [11C]- Flumazenil positron emission tomography (PET), and GABA concentration, using magnetic resonance spectroscopy (MRS). 14 adult patients with NF1 and 13 matched controls were included in the study. MRS was performed in the occipital cortex and in a frontal region centered in the functionally localized frontal-eye fields. PET and MRS acquisitions were performed in the same day. Results: Patients with NF1 have reduced concentration of GABA+ in the occipital cortex (P = 0.004) and frontal-eye fields (P = 0.026). PET results showed decreased binding of GABAA receptors in patients in the parietooccipital cortex, midbrain and thalamus, which are not explained by decreased grey matter levels. Conclusions: Abnormalities in the GABA system in NF1 involve both GABA concentration and GABAA receptor density suggestive of neurodevelopmental synaptopathy with both pre- and post-synaptic involvement

5G fronthauls with multicore fibers: CPRI signals performance degradation induced by intercore crosstalk

Weakly-coupled multicore fibers (MCFs) have been proposed to support the huge data capacity demanded by future 5G fronthauls. However, in MCFs, intercore crosstalk (ICXT), i.e., power coupling between different MCF cores, can degrade significantly the performance of the 5G fronthaul, particularly, when using Common Public Radio Interface (CPRI) signals and direct-detection at the optical receiver. In this work, the performance degradation induced by ICXT in 5G fronthauls with MCFs and direct-detection is assessed by numerical simulation. We show that the study of the outage probability is essential to ensure the reliability and the good quality of service in 5G fronthauls supported by MCFs impaired by ICXT with CPRI signals transmission. The ICXT level that leads to an outage probability of 10-4 is more than 5.6 dB lower than the ICXT level necessary to reach the power penalty of 1 dB. Our results also indicate that fronthaul systems with lower extinction ratio exhibit an higher tolerance to ICXTinfo:eu-repo/semantics/acceptedVersio