First demonstration of a 12 DFB fiber laser array on a 100 GHz ITU grid, for underwater acoustic sensing application

International audienceWe report for the first time a multiplexed array of 12 distributed feedback fiber lasers (DFB FLs) on a single optical fiber, separated by only 100 GHz (0.8 nm) in the C-band. These lasers are pumped by a 200 mW laser diode at 1480 nm with no apparent impact on the sensor noise floor despite the fact that the residual reflections from adjacent gratings may be enhanced due to the smaller wavelength separation. Each DFB FL, especially developed for serial multiplexing, exhibits low lasing threshold typically between 1 and 2 mW, low intensity noise and very low frequency noise (less than 30 dB re 1 Hz²/Hz at 1 kHz from optical carrier). From these experimental results, extension to 32 DFB FLs array (on 100 GHz ITU grid) multiplexed on one fiber will be discussed

Effets d'une faible contre-réaction optique sur des lasers à fibre DFB pour applications capteurs

National audienceNous étudions l'effet d'une faible réflection externe sur des lasers à fibre à contre-réaction répartie (DFB FLs). Nous démontrons expérimentalement que la phase optique accumulée sur un aller-retour dans la cavité étendue et la réflectivité associée au miroir externe modifient la puissance de sortie et la fréquence d'émission d'un DFB FL. Comme pour un laser à semiconducteurs (SC) contre-réactionné, à réflectivité externe donnée, l'amplitude des variations est constante pour ces deux paramètres quelle que soit la longueur de la cavité externe

Phase sensitivity to axial strain of microstrustured optical silica fibers

International audienceWe compare, thanks to a Sagnac interferometer, the phase sensitivity to strain of different microstructured optical silica fibers (MSF) that we design and fabricate. Our results show that when a same elongation is applied to different MSF, the induced phase change is equal or lower than the one obtained for a standard fiber, showing no advantage on this parameter for sensing applications

Brillouin fiber laser using As38Se62 suspended-core chalcogenide fiber

International audienceIn this paper, an all-fiber Brillouin laser ring cavity using a 3-m-long suspended-core chalcogenide As38Se62 fiber is reported for the first time to our knowledge. For a nonresonant ring cavity with no servo-locking, a laser threshold power of 37 mW and an efficiency of 26 % were obtained for a fiber having a core diameter of 5 μm. The linewidth of the Brillouin fiber laser and the pump laser were respectively measured to be below 4 kHz, the resolution of our autocorrelator, and 250 kHz, thus showing the linewidth-narrowing nature of the Brillouin laser. This result paves the way to compact Brillouin lasers with low threshold power and good spectral purity. A full experimental Brillouin characterization is also reported. We measured a Brillouin gain spectrum of 14.2 MHz, a Brillouin gain coefficient of 5.6x10-9 m/W and a Brillouin frequency shift of 7.95 GHz in our fiber

Comparaison de différentes méthodes de mesure du RIN d'un laser DFB à fibre dopée

National audienceNous présentons dans cette communication la comparaison de trois méthodes de mesure du bruit d'intensité relatif (RIN) d'un laser. Notre dispositif consiste en une cavité laser à fibre dopée erbium à contre-réaction distribuée (DFB-FL) dans laquelle un réseau de Bragg de plusieurs centimètres de longueur comportant en son centre un saut de phase de π a été photoinscrit par Quantel

Late Outcomes of Transcatheter Aortic Valve Replacement in High-Risk Patients The FRANCE-2 Registry

International audienceBACKGROUND Transcatheter aortic valve replacement (TAVR) has revolutionized management of high-risk patients with severe aortic stenosis. However, survival and the incidence of severe complications have been assessed in relatively small populations and/or with limited follow-up. OBJECTIVES This report details late clinical outcome and its determinants in the FRANCE-2 (FRench Aortic National CoreValve and Edwards) registry. METHODS The FRANCE-2 registry prospectively included all TAVRs performed in France. Follow-up was scheduled at 30 days, at 6 months, and annually from 1 to 5 years. Standardized VARC (Valve Academic Research Consortium) outcome definitions were used. RESULTS A total of 4,201 patients were enrolled between January 2010 and January 2012 in 34 centers. Approaches were transarterial (transfemoral 73%, transapical 18%, subclavian 6%, and transaortic or transcarotid 3%) or, in 18% of patients, transapical. Median follow-up was 3.8 years. Vital status was available for 97.2% of patients at 3 years. The 3-year all-cause mortality was 42.0% and cardiovascular mortality was 17.5%. In a multivariate model, predictors of 3-year all-cause mortality were male sex (p = 2 of 4 (p < 0.001). Severe events according to VARC criteria occurred mainly during the first month and subsequently in < 2% of patients/year. Mean gradient, valve area, and residual aortic regurgitation were stable during follow-up. CONCLUSIONS The FRANCE-2 registry represents the largest database available on late results of TAVR. Late mortality is largely related to noncardiac causes. Incidence rates of severe events are low after the first month. Valve performance remains stable over time. (J Am Coll Cardiol 2016; 68: 1637-47) (C) 2016 by the American College of Cardiology Foundation

TAVR Patients Requiring Anticoagulation: Direct Oral Anticoagulant or Vitamin K Antagonist?

International audienceOBJECTIVES: Using French transcatheter aortic valve replacement (TAVR) registries linked with the nationwide administrative databases, the study compared the rates of long-term mortality, bleeding, and ischemic events after TAVR in patients requiring oral anticoagulation with direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs). BACKGROUND: The choice of optimal drug for anticoagulation after TAVR remains debated. METHODS: Data from the France-TAVI and FRANCE-2 registries were linked to the French national health single-payer claims database, from 2010 to 2017. Propensity score matching was used to reduce treatment-selection bias. Two primary endpoints were death from any cause (efficacy) and major bleeding (safety). RESULTS: A total of 24,581 patients who underwent TAVR were included and 8,962 (36.4%) were treated with OAC. Among anticoagulated patients, 2,180 (24.3%) were on DOACs. After propensity matching, at 3 years, mortality (hazard ratio [HR]: 1.37; 95% confidence interval [CI]: 1.12-1.67; P \textless 0.005) and major bleeding including hemorrhagic stroke (HR: 1.64; 95% CI: 1.17-2.29; P \textless 0.005) were lower in patients on DOACs compared with those on VKAs. The rates of ischemic stroke (HR: 1.32; 95% CI: 0.81-2.15; P = 0.27) and acute coronary syndrome (HR: 1.17; 95% CI: 0.68-1.99; P = 0.57) did not differ among groups. CONCLUSIONS: In these large multicenter French TAVR registries with an exhaustive clinical follow-up, the long-term mortality and major bleeding were lower with DOACs than VKAs at discharge. The present study supports preferential use of DOACs rather than VKAs in patients requiring oral anticoagulation therapy after TAVR

Registry of transcatheter aortic-valve implantation in high-risk patients.

International audienceBACKGROUND: Transcatheter aortic-valve implantation (TAVI) is an emerging intervention for the treatment of high-risk patients with severe aortic stenosis and coexisting illnesses. We report the results of a prospective multicenter study of the French national transcatheter aortic-valve implantation registry, FRANCE 2. METHODS: All TAVIs performed in France, as listed in the FRANCE 2 registry, were prospectively included in the study. The primary end point was death from any cause. RESULTS: A total of 3195 patients were enrolled between January 2010 and October 2011 at 34 centers. The mean (±SD) age was 82.7±7.2 years; 49% of the patients were women. All patients were highly symptomatic and were at high surgical risk for aortic-valve replacement. Edwards SAPIEN and Medtronic CoreValve devices were implanted in 66.9% and 33.1% of patients, respectively. Approaches were either transarterial (transfemoral, 74.6%; subclavian, 5.8%; and other, 1.8%) or transapical (17.8%). The procedural success rate was 96.9%. Rates of death at 30 days and 1 year were 9.7% and 24.0%, respectively. At 1 year, the incidence of stroke was 4.1%, and the incidence of periprosthetic aortic regurgitation was 64.5%. In a multivariate model, a higher logistic risk score on the European System for Cardiac Operative Risk Evaluation (EuroSCORE), New York Heart Association functional class III or IV symptoms, the use of a transapical TAVI approach, and a higher amount of periprosthetic regurgitation were significantly associated with reduced survival. CONCLUSIONS: This prospective registry study reflected real-life TAVI experience in high-risk elderly patients with aortic stenosis, in whom TAVI appeared to be a reasonable option. (Funded by Edwards Lifesciences and Medtronic.)

Temporal Trends in Transcatheter Aortic Valve Replacement in France: FRANCE 2 to FRANCE TAVI

International audienceBackground - Transcatheter aortic valve replacement (TAVR) is standard therapy for patients with severe aortic stenosis who are at high surgical risk. However, national data regarding procedural characteristics and clinical outcomes over time are limited. Objectives - The aim of this study was to assess nationwide performance trends and clinical outcomes of TAVR during a 6-year period. Methods - TAVRs performed in 48 centers across France between January 2013 and December 2015 were prospectively included in the FRANCE TAVI (French Transcatheter Aortic Valve Implantation) registry. Findings were further compared with those reported from the FRANCE 2 (French Aortic National CoreValve and Edwards 2) registry, which captured all TAVRs performed from January 2010 to January 2012 across 34 centers. Results - A total of 12,804 patients from FRANCE TAVI and 4,165 patients from FRANCE 2 were included in this analysis. The median age of patients was 84.6 years, and 49.7% were men. FRANCE TAVI participants were older but at lower surgical risk (median logistic European System for Cardiac Operative Risk Evaluation [EuroSCORE]: 15.0% vs. 18.4%; p < 0.001). More than 80% of patients in FRANCE TAVI underwent transfemoral TAVR. Transesophageal echocardiography guidance decreased from 60.7% to 32.3% of cases, whereas more recent procedures were increasingly performed in hybrid operating rooms (15.8% vs. 35.7%). Rates of Valve Academic Research Consortium-defined device success increased from 95.3% in FRANCE 2 to 96.8% in FRANCE TAVI (p < 0.001). In-hospital and 30-day mortality rates were 4.4% and 5.4%, respectively, in FRANCE TAVI compared with 8.2% and 10.1%, respectively, in FRANCE 2 (p < 0.001 for both). Stroke and potentially life-threatening complications, such as annulus rupture or aortic dissection, remained stable over time, whereas rates of cardiac tamponade and pacemaker implantation significantly increased. Conclusions - The FRANCE TAVI registry provided reassuring data regarding trends in TAVR performance in an all-comers population on a national scale. Nonetheless, given that TAVR indications are likely to expand to patients at lower surgical risk, concerns remain regarding potentially life-threatening complications and pacemaker implantation. (Registry of Aortic Valve Bioprostheses Established by Catheter [FRANCE TAVI]; NCT01777828)