Digital phase estimation method based on Karhunen-Loève series expansion for Coherent Phase Diversity Detection

A novel phase estimation method for coherent systems is presented and demonstrated. It outperforms 5.5 times the phase noise and spectral width tolerance respect to the other methods.Peer ReviewedPostprint (published version

Channel crosstalk in ultra-dense WDM PON using time-switched phase diversity optical homodyne reception

Experimental study of channel crosstalk effects in time-switched phase diversity optical homodyne reception is presented, precisely focused towards ultra-dense wavelength division multiplexed (WDM) passive optical networks (PON). This receiver achieves ultra-low channel spacing and feasible implementation.Peer ReviewedPostprint (published version

Experimental demonstration of heterodyne phase-locked loop for optical homodyne PSK receivers in PONs

Experimental demonstration of heterodyne optical Phase-Locked Loop (oPLL), using simplest optics, is carried out. For the first time, the effect of loop delay has been experimentally characterized and compared directly to the most significant oPLL configurations. It demonstrates a linewidth tolerance of 6.5 MHz if FEC codes are used.Peer ReviewedPostprint (published version

Design of a wavelength control for coherent detection of high order modulation formats

An automatic frequency control design is proposed and demonstrated. It is based on a high-speed optical VCO. An overall design has been performed, based on simulation results. Also, loop delay and phase noise impacts have been evaluated. Frequency discriminator and VCO proposed have been experimentally characterized, showing an agreement with simulation results.Peer ReviewedPostprint (published version

A comunicação com o doente oncológico em situação crítica e sua família

O presente documento apresenta-se como um relatório que pretende, de forma crítica e reflexiva, descrever as competências desenvolvidas como enfermeiro especialista em enfermagem médico-cirúrgica ao longo de um percurso metodológico formativo. Para tal, foi definido um tema-matriz: “A comunicação com o doente oncológico em situação crítica e sua família”, coadunável com a própria práxis quotidiana do enfermeiro. A sua formulação foi assumida, por conseguinte, como o mote para o desenvolvimento de competências científicas, técnicas, éticas, comportamentais e relacionais na prestação de cuidados de enfermagem especializados à pessoa em situação crítica. Para tal, o tema principal foi aprofundado através de uma abordagem tridimensional ao longo dos vários estágios vocacionados para a prática clínica - realizados no intuito de desenvolver competências especializadas em enfermagem médico-cirúrgica. Sendo assim, foram realizadas três abordagens especializadas ao tema-matriz: em Unidade de Cuidados Intensivos (módulo II – Cuidados Intensivos/ Intermédios), em situações de urgência/ emergência (módulo I – Serviços de Urgência), assim como em fase de tratamento ativo (módulo Opcional) - referente à realização de estágio num Hospital Dia de Quimioterapia. Foram desenvolvidas, por este meio, várias competências edificadas num constructo definido concomitantemente através de três eixos fundamentais: o eixo da prática clínica, o eixo da reflexão crítica e o eixo da formação em contextos clínicos. O mesmo foi apenas possível através da criação de uma terceira tríade: a pedagógica. Sendo assim, foi através desta última tríade que o próprio discente, num processo de tomada de consciência de si próprio como enfermeiro especialista, foi guiado e orientado por um docente orientador e por vários enfermeiros que rumaram continuamente (e em parceria) com o intuito de desenvolver uma nova construção pessoal e profissional: a de enfermeiro especialista em enfermagem médico-cirúrgica.The following report aims to describe, in a critical and reflexive manner, the skills developed by the specialist nurse in medical-surgical nursing throughout the academic methodological formation. In order to achieve that it was defined a main theme: “The communication with the oncological patient in critical condition and his family”, which relates to nursing daily practice. It was formulated as a starting point to the development of scientific, technical, ethical, behavioural and relational skills during the specialized practice of nursing care to the person in critical condition. To do so, the main theme was established due to a three-dimensional approach that took the length of several clinical practices, undergone in the pursuit of developing specialized skills in medical-surgical nursing. To accomplish this, there were three specialized approaches to the main theme: in an Intensive Care Unit (module II – Intensive/Intermediate Care), in urgency/emergency situations (module I – Urgency Service), and in an active treatment stage (optional module) – clinical practice in a Chemotherapy Day Care Unit. Several skills were developed in a learning construct grounded in three intertwined fundamental axis: clinical practice axis, critical reflection axis, and formation in clinical settings axis. This was only possible thanks to the creation of a third triad: the pedagogical. It was through this triad that the student, in a process of increasing self-awareness of himself as specialist nurse, was guided and coached by a tutoring teacher and by several nurses that constantly aimed to create, in partnership with the student, with the aim of developing a new personal and professional construction: a Specialized Nurse in Medical-Surgical Nursing

Demonstration of a full duplex PON featuring 2.5 Gbps Sub Carrier Multiplexing downstream and 1.25 Gbps upstream with colourless ONU and simple optics

We demonstrate a full-duplex DPSK SCM PON operating at 2.5Gbps/1.25Gbps bitrates, with RSOA ONU and simplified scheme. It achieves low sensitivity and is implemented with low-cost components.Peer ReviewedPostprint (published version

Spectral processing techniques for efficient monitoring in optical networks

Having ubiquitous optical monitors in dense wavelength-division multiplexing (DWDM) or flex-grid networks allows the estimation in real time of crucial parameters. Such monitoring would be even more important in disaggregated optical networks, to inspect performance issues related to inter-vendor interoperability. Several important parameters can be retrieved using optical spectrum analyzers (OSAs). However, omnipresent OSAs represent an infeasible solution. Nevertheless, the advent of new, relatively cheap, compact and medium-resolution optical channel monitors (OCMs) enable a more intensive deployment of these devices. In this paper, we identify two main scenarios for the placement of such monitors: at the ingress and at the egress of the optical nodes. In the ingress scenario, we can directly estimate the parameters related to the signals, but not those related to the filters. On the contrary, in the egress scenario, the filter-related parameters can be easily detected, but not those related to amplified spontaneous emission. Therefore, we present two methods that, leveraging a curve fitting and a machine learning regression algorithm, allow detection of the missing parameters. We verify the proposed solutions with spectral data acquired in simulation and experimental setups. We obtained good estimation accuracy for both setups and for both studied placement scenarios. It is noteworthy that in the experimental assessment of the ingress scenario, we achieved a maximum absolute error (MAE) lower than 1 GHz in filter bandwidth estimation and a MAE lower than 0.5 GHz in filter frequency shift estimation. In addition, by comparing the relative errors of the considered parameters, we identified the ingress scenario as the more beneficial. In particular, we estimated the filter central frequency shift with 84% and the filter 6 dB bandwidth with 75% higher accuracy, with respect to datasheet/reference values. This translates into a total reduction of the estimated signal-to-noise ratio (SNR) penalty, introduced by a single optical filter, of 0.24 dB.Funding: Horizon 2020 Framework Programme (765275). This work is part of the Future Optical Networks for Innovation, Research and Experimentation (ONFIRE) project (https://h2020-onfire.eu), which is supported by the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie Action.Peer ReviewedPostprint (author's final draft

Simple intradyne PSK system for UDWDM-PON

A homodyne coherent receiver for ultra-dense WDM-PON with off the shelf components is presented. It consists of a conventional DFB, phase switched clock signal, an optical coupler instead of a 90º hybrid, balanced photodetectors and digital signal processing. The phase swing for a DBPSK signal was optimized and the performance was experimentally evaluated in terms of the sensitivity for several laser linewidths. The acceptable frequency offset and clock time delay was also assessed. The results exhibit a sensitivity of -48 dBm at a BER of 10-3 and indicate a high tolerance to phase noise.Peer ReviewedPostprint (published version

Sistemes de comunicació òptics, setembre 2013

Recurs d'aprenentatge de la Universitat Oberta de Catalunya.Recurso de aprendizaje de la "Universitat Oberta de Catalunya".Learning resource of the "Universitat Oberta de Catalunya"

Sistemes de comunicació òptics, setembre 2013

Recurs d'aprenentatge de la Universitat Oberta de Catalunya.Recurso de aprendizaje de la "Universitat Oberta de Catalunya".Learning resource of the "Universitat Oberta de Catalunya"