22 research outputs found
DMTs and Covid-19 severity in MS: a pooled analysis from Italy and France
We evaluated the effect of DMTs on Covid-19 severity in patients with MS, with a pooled-analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid-19 severity was assessed by multivariate ordinal-logistic models and pooled by a fixed-effect meta-analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti-CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39–3.02, p < 0.001) with Covid-19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18–0.99, p = 0.047). This pooled-analysis confirms an increased risk of severe Covid-19 in patients on anti-CD20 therapies and supports the protective role of interferon
Observation of an eg-derived metallic band at the Cs/SrTiO3 interface by polarization-dependent photoemission spectroscopy
International audienc
Silicon Photonics for Low Power Consumption Communications
International audienceSilicon photonics is being considered as the future photonic platform, mainly for the reduction of photonic system costs and the increase of the number of functionalities on the same integrated chip by combining photonics and electronics. However, silicon is a centrosymmetric crystal, which inhibits Pockels effect: a second order nonlinear effect, which allows for high speed and low power consumption light modulation Over the last few years, several research groups are exploring Pockels effect in strained silicon. In this work, we present recent developments on the subject taking into account parasitic effects including plasma dispersion effect and fixed charge effect under an electric field
Advances in second order nonlinear effect in Silicon
International audienceIn this work, we present a theoretical model to determine the second order nonlinear coefficient under strain gradient in silicon. Furthermore, carrier effect due to applied electric field has also been taking into account to analyze the obtained experimental phase variation
L-shaped grating couplers engineered with subwavelength metamaterial for sub-decibel coupling loss
International audiencePractically attractive nanophotonic technologies, mostly realized on mature silicon-on-insulator (SOI) substrates, call upon availability of efficient input/output grating-coupled optical interfaces. In this work, we demonstrate, both theoretically and experimentally, ultra-directional L-shaped grating couplers for low-loss light coupling between standard optical fibres and SOI chips. Experimentally, we show grating couplers without and with subwavelength (SWG) transition, seamlessly fabricated with a 193-nm deep-ultraviolet lithography. Coupling loss of-2.7 dB is measured with a low return loss as low as-20 dB. In addition, we propose an apodized L-shaped grating coupler layouts with coupling loss below 1 dB. Apodized fiber-chip grating couplers are designed with a sub-decibel coupling performance, together with substantially relaxed requirements in terms of minimum feature dimensions
Sub-decibel off-chip fiber couplers based on L-shaped waveguides and subwavelength grating metamaterials
International audienceUniform grating couplers based on versatile L-shaped waveguides are experimentally demonstrated, with coupling loss of-2.7 dB and back-reflections of-20 dB. Apodized couplers with subwavelength-grating metamaterials predict improved fiber-chip coupling down to-0.46 dB within device layouts compatible with lithographic technologies available in nanophotonic foundries
Erbium-doped yttria-stabilised zirconia thin films grown by pulsed laser deposition for photonic applications
International audienc