Hermetic carbon coatings for electro-thermal all-fiber phase modulators

Joule effect and thermal response of several carbon-coated fibers are modelled and analysed. An electro-thermally driven all-fiber phase modulator based on these principles is proposed and a proof of concept of it is characterized. This kind of fibers could be the basis for developing all-fiber components aimed to operate in environments where the strength increase and impermeability to hydrogen diffusion guaranteed by the carbon coating is crucial.European CommissionMinisterio de Economía y CompetitividadComunidad de Madri

Hermetic All-Fiber Phase Modulators Using Joule Heating in Carbon-Coated Fibers

26ª edición del congreso internacional Optical Fiber Sensors (OFS26), 24/09/2018-28/09/2018, Lausanne, Suiza.Certain applications of fiber sensors (e.g. avionics, oil industry) imply extreme operating conditions spurring the development of hermetic all-fiber devices. We present a hermetic all-fiber phase modulator based on Joule heating in a carbon-coated fiber.European CommissionMinisterio de Economía y CompetitividadComunidad de Madri

Photonic Seismology

International Photonics and OptoElectronics Meetings 2019, OFDA, 11/11/2019-14/11/2019, Wuhan, ChinaOne of the greatest outstanding challenges in seismology is the sparsity of instrumentation across the Earth, particularly in the oceans. In this work we show that optical fiberbased distributed acoustic sensors (DAS) can represent a low-cost solution (basically inexistent so far) for monitoring seismicity in remote areas of the ocean. This solution can retrofit existing telecommunication optical fiber cables lying in the ocean and transform them (with no basic change in the cable itself) into powerful seismic sensing arrays. With a single optoelectronic unit in the end of the cable (onshore), a full span of 50-100 km can be monitored, with thousands of measuring points interrogated.Commission of the European Communities JointMinisterio de Economía y CompetitividadMinisterio de Ciencia, Innovación y UniversidadesComunidad de Madri

Monitorización de actividad sísmica usando sensores distribuidos en fibra basados en φOTDR y pulsos con chirp

XI Reunión Española de Optoelectrónica (OPTOEL 2019), 03/07/2019-05/07/2019, Zaragoza, España.Actualmente, los sistemas de comunicaciones ópticas de larga distancia se basan en una extensa red de fibra óptica que se encuentra instalada alrededor del globo. En este trabajo, presentamos cómo esta red de fibra puede ser empleada para un uso alternativo: el análisis de movimientos sísmicos del planeta. Para ello, se ha utilizado la fibra como elemento sensor en un sistema de sensado distribuido basado en OTDR sensible a fase (φOTDR) usando pulsos con chirp con el que se ha detectado un terremoto de grado 8,2 ocurrido el pasado agosto en las Islas Fiji. Este terremoto se ha detectado en dos localizaciones diferentes, un entorno metropolitano en la ciudad de Pasadena (California, EEUU) y un entorno submarino en la costa de Bélgica. Usando técnicas de procesado lineales se ha podido ex-traer información del terremoto del ruido ambiente. Los resultados aquí mostrados muestran el gran potencial de la red de fibra ya instalada para su uso como sismógrafo distribuido.Ministerio de Economía y CompetitividadComunidad de MadridEuropean Commissio

COVID-19 Severity and Survival over Time in Patients with Hematologic Malignancies: A Population-Based Registry Study

Mortality rates for COVID-19 have declined over time in the general population, but data in patients with hematologic malignancies are contradictory. We identified independent prognostic factors for COVID-19 severity and survival in unvaccinated patients with hematologic malignancies, compared mortality rates over time and versus non-cancer inpatients, and investigated post COVID-19 condition. Data were analyzed from 1166 consecutive, eligible patients with hematologic malignancies from the population-based HEMATO-MADRID registry, Spain, with COVID-19 prior to vaccination roll-out, stratified into early (February–June 2020; n = 769 (66%)) and later (July 2020–February 2021; n = 397 (34%)) cohorts. Propensity-score matched non-cancer patients were identified from the SEMI-COVID registry. A lower proportion of patients were hospitalized in the later waves (54.2%) compared to the earlier (88.6%), OR 0.15, 95%CI 0.11–0.20. The proportion of hospitalized patients admitted to the ICU was higher in the later cohort (103/215, 47.9%) compared with the early cohort (170/681, 25.0%, 2.77; 2.01–3.82). The reduced 30-day mortality between early and later cohorts of non-cancer inpatients (29.6% vs. 12.6%, OR 0.34; 0.22–0.53) was not paralleled in inpatients with hematologic malignancies (32.3% vs. 34.8%, OR 1.12; 0.81–1.5). Among evaluable patients, 27.3% had post COVID-19 condition. These findings will help inform evidence-based preventive and therapeutic strategies for patients with hematologic malignancies and COVID-19 diagnosis.Depto. de MedicinaFac. de MedicinaTRUEFundación Madrileña de Hematología y HemoterapiaFundación Leucemia y LinfomaAsociación Madrileña de Hematología y Hemoterapiapu

Towards Distributed Measurements of Electric Fields Using Optical Fibers: Proposal and Proof-Of-Concept Experiment

Nowadays there is an increasing demand for the cost-effective monitoring of potential threats to the integrity of high-voltage networks and electric power infrastructures. Optical fiber sensors are a particularly interesting solution for applications in these environments, due to their low cost and positive intrinsic features, including small size and weight, dielectric properties, and invulnerability to electromagnetic interference (EMI). However, due precisely to their intrinsic EMI-immune nature, the development of a distributed optical fiber sensing solution for the detection of partial discharges and external electrical fields is in principle very challenging. Here, we propose a method to exploit the third-order and second-order nonlinear effects in silica fibers, as a means to achieve highly sensitive distributed measurements of external electrical fields in real time. By monitoring the electric-field-induced variations in the refractive index using a highly sensitive Rayleigh-based CP-ϕOTDR scheme, we demonstrate the distributed detection of Kerr and Pockels electro-optic effects, and how those can assign a new sensing dimension to optical fibers, transducing external electric fields into visible minute disturbances in the guided light. The proposed sensing configuration, electro-optical time domain reflectometry, is validated both theoretically and experimentally, showing experimental second-order and third-order nonlinear coefficients, respectively, of χ(2) ~ 0.27 × 10−12 m/V and χ(3) ~ 2.5 × 10−22 m2 /V2 for silica fibers.QC 20220614</p

Transforming the fiber-optic network into a dense and ultrasensitive seismic sensor array

20th International Conference on Transparent Optical Networks (ICTON 2018), 01/07/2018-05/07/2018, Bucarest, Rumania.We show a technology capable of performing position-resolved measurement of nanostrain perturbations along a conventional optical fiber cable, with meter-scale resolution. This technology can be deployed in already existing networks to achieve a dense and ultrasensitive seismic sensor array. Applications ranging from seismic protection to chemical sensing are explored.European CommissionMinisterio de Economía y CompetitividadComunidad de Madri

Les jeunes et le travail

L'Institut régional du travail d'Aix-en-Provence et le LEST-CNRS (UMR 6123), avec la collaboration du Pôle régional TRavail PACA et du Réseau national des Instituts du Travail, organisent un colloque interdisciplinaire sur le thème "Les jeunes et le travail", les 4 et 5 octobre 2012 à Marseille. L'objet de ce colloque est d'éclairer la question du rapport au travail des jeunes. Il poursuit un double objectif : réunir et mettre en dialogue les éclairages diversifiés que peuvent produire les di..

Moduladores de fase en fibra basados en calentamiento Joule sobre fibras cubiertas de carbono

Este documento se considera que es una ponencia de congresos en lugar de un capítulo de libro.VII Jornadas de Jóvenes Investigadores de la Universidad de Alcalá. Alcalá de Henares, el 12 y 13 de diciembre de 2018.Ciertas aplicaciones de los sistemas de fibra óptica, como los sensores, la aviónica o el ámbito biomédico, implican condiciones extremas de humedad, presión o temperatura. Esto hace necesario el desarrollo de dispositivos de fibra dotados de un recubrimiento hermético al agua e hidrógeno. En este artículo se motiva la necesidad de estos dispositivos y se presenta un modulador de fase a modo de ejemplo y prueba de concepto.Certain applications of fiber sensors (eg. avionics, oil industry) imply extreme operating conditions spurring the development of hermetic all-fiber devices. We present a hermetic all-fiber phase modulator based on Joule heating in a carbon-coated fiber.European CommissionMinisterio de Economía y Competitivida

Fiber-based distributed bolometry

Optical fibers are inherently designed to allow no interaction between the guided light and the surrounding optical radiation. Thus, very few optical fiber-based technologies exist in the field of optical radiation sensing. Accomplishing fully-distributed optical radiation sensing appears then as even more challenging since, on top of the lack of sensitivity explained above, we should add the need of addressing thousands of measurement points in a single, continuous optical cable. Nevertheless, it is clear that there exist a number of applications which could benefit from such distributed sensing scheme, particularly if the sensitivity was sufficiently high to be able to measure correctly variations in optical radiation levels compatible with the earth surface. Distributed optical radiation sensing over large distances could be employed in applications such as Dynamic Line Rating (DLR), where it is known that solar radiation can be an important limiting factor in energy transmission through overhead power cables, and also in other applications such as thermo-solar energy. In this work, we present the proof-of-concept of the first distributed bolometer based on optical fiber technology and capable of detecting absolute changes of irradiance. The core idea of the system is the use of a special fiber coating with high emissivity (e.g. carbon coating or black paint). The high absorption of these coatings translates into a temperature change that can be read with sufficiently high sensitivity using phase-sensitive reflectometry. To demonstrate the concept, we interrogate distinct black-coated optical fibers using a chirped-pulse PhiOTDR, and we readily demonstrate the detection of light with resolutions in the order of 1% of the reference solar irradiance, offering a high potential for integration in the aforementioned applications.Commission of the European Communities JointEuropean Research CouncilHorizon 2020Ministerio de Economía y CompetitividadComunidad de Madri