High performance TM-pass polarizer via subwavelength grating bandgap engineering

Silicon photonics systems exhibit a strong birefrin- gence which makes polarization management critical. Here we demonstrate, with full 3D-FDTD simulations, a low-loss and high- extinction ratio TM-pass polarizer based on tilted subwavelength gratings that reflects the TE0 mode into the TE1 mode, with a 150 nm bandwidth.Junta de Andalucía (P18-RT-793 and P18-RT-1453); Universidad de Málaga (UMA20-FEDERJA-158); Ministerio de Economía y Competitividad (PID2019-106747RB-I00); Ministerio de Ciencia e Innovación (TED2021- 130400B-I00); Ministerio de Universidades (FPU19/02408); Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Polarization insensitive metamaterial engineered multimode interference coupler in a 220 nm silicon-on-insulator platform

High-index contrast silicon waveguides exhibit strong birefringence that hinders the development of polarization-insensitive devices, especially for sub-micrometer silicon layer thickness. Here a polarizationindependent 2 × 2 multimode interference coupler in a 220 nm silicon-on-insulator platform is designed and experimentally demonstrated for the first time. Leveraging the advanced control of electromagnetic properties provided by a subwavelength grating metamaterial topology, our multimode interference coupler operates for both TE and TM polarization states with measured polarization dependent loss, insertion loss and imbalance all less than 1 dB, and phase errors below 5◦ in the wavelength range from 1500 nm to 1560 nm. The device has a footprint of only 3.5 μm × 47.25 μm and was fabricated using a single etch-step process with a minimum feature size of 100 nm compatible with immersion deep-UV lithography.We acknowledge funding from Ministerio de Economía y Competitividad (PID2019106747RB-I00), Junta de Andalucía (P18-RT-1453, UMA-FEDERJA-158), Ministerio de Ciencia, Innovaci ́on y Universidades (FPU16/06762, FPU19/02408), and Universidad de Málaga. Funding for open access charge: Universidad de Málaga / CBUA

Development of a Swine Model of Left Bundle Branch Block for Experimental Studies of Cardiac Resynchronization Therapy

International audienc

Quantitative analysis of lead position vs. correction of electrical dyssynchrony in an experimental model of LBBB/CRT

International audienceCardiac resynchronization therapy (CRT) is a recommended treatment in patients with electrical dyssynchrony such as left bundle branch block (LBBB). The determination of the optimal leads position, and the quantification of the changes in electrical activation are two current major challenges. In this paper, we investigate these aspects through electroanatomical data from a controlled experimental protocol, which studied pigs with no structural disease under LBBB and CRT conditions. We propose to use a quasi-conformal mapping technique to standardize electroanatomical maps of endo- and epi-cardial walls of both ventricles to a common reference geometry, in which simple quantitative indices can be computed. Then, we investigate the relation between leads and simple surrogates of the recovery of the electrical activation based either on total activation times or on the spatial distribution of the patterns. Our methodology allows a better understanding of the complex electrical activation patterns in LBBB and CRT, and confirms hypotheses about the optimal leads position from previous studies

Clinical impact of aging on outcomes of cardioneuroablation for reflex syncope or functional bradycardia. Results from the cardionEuroabLation: patiEnt selection, imaGe integrAtioN and outComEs. The ELEGANCE multicenter study

Background: Cardioneuroablation (CNA) is a novel treatment for reflex syncope. The effect of aging on CNA efficacy is not fully understood. Objective: We assessed the impact of aging on candidacy and efficacy of CNA for treating vasovagal syncope (VVS), carotid sinus syndrome (CSS) and functional bradyarrhythmia. Methods: The ELEGANCE multicenter study assessed CNA in patients with reflex syncope or severe functional bradyarrhythmia. Patients underwent pre-CNA Holter ECG, head-up tilt testing (HUT) and electrophysiologic study. CNA candidacy and efficacy was assessed in 14 young (18-40 years), 26 middle-aged (41-60 years) and 20 older (>60 years) patients. Results: Sixty patients (37 men; mean age: 51±16 years) underwent CNA. The majority (80%) had VVS, 8% CSS, and 12% functional bradycardia/AV block. Pre-CNA Holter ECG, HUT and EP findings did not differ across age groups. Acute CNA success was 93%, without differences between age groups (p=0.42). Post-CNA HUT response was negative in 53%, vasodepressor in 38%, cardioinhibitory in 7% and mixed in 2%, without differences across age groups (p=0.59). At follow-up (8 months, IQR:4-15), 53 (88%) patients were free of symptoms. Kaplan-Meier curves did not show differences in event-free survival between age groups (p=0.29). The negative predictive value of a negative HUT was 91.7%. Conclusions: CNA is a viable treatment for reflex syncope and functional bradyarrhythmia in all ages, and is highly effective in mixed VVS. HUT is a key-step of post-ablation clinical assessment

Experimental demonstration of a polarization insensitive multimode interference coupler based on a subwavelength grating metamaterial.

En este trabajo se demuestra experimentalmente un acoplador 3 dB 90o basado en un dispositivo de interferencia multimodal 2×2 independiente a la polarización. El dispositivo se ha desarrollado en una plataforma de silicio sobre aislante de 220 nm de grosor. Haciendo uso de metamateriales periódicos que ofrecen un control avanzado de las propiedades electromagnéticas de la luz, se consigue diseñar un acoplador que presenta, tanto para las polarizaciones TE y TM, unas pérdidas de inserción, pérdidas dependientes de la polarización y desbalanceo menores que 1 dB y un error de fase inferior a 5o en el rango de longitudes de onda de 1500 nm a 1560 nm. El área ocupada por el dispositivo es de solo 3.5 μm × 47.25 μm y se ha fabricado utilizando un proceso de un solo paso de grabado con un tamaño mínimo fabricado de 100 nm, compatible con litografía de ultravioleta profundo.Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad (PID2019106747RB-I00), la Junta de Andalucía (P18-RT-1453, UMA- FEDERJA-158), el Ministerio de Ciencia, Innovación y Universidades (FPU16/06762, FPU19/02408), y la Universidad de Málaga- Campus de Excelencia Internacional Andalucía Tech

Dispositivos de interferencia multimodal 2×2 de banda ultraancha basados en estructuras periódicas sub-longitud de onda para las bandas O-E-S-C

Los dispositivos de interferencia multimodal (MMI) son un bloque funcional fundamental en óptica integrada. La creciente demanda de capacidad en los enlaces de comunicaciones ópticas motiva la búsqueda de nuevas formas de incrementar el ancho de banda de compo-nentes fotónicos como los MMI. En este trabajo se diseña y evalúa las prestaciones de un MMI 2×2 para la plataforma Silicon on Insulator de 300 nm de espesor basado en una nueva estructura sub-longitud de onda: la guía Bricked-SWG (Subwavelength Grating). Este diseño se compara con uno basado en guía photonic wire y otro basado en guía SWG para la misma plataforma. Los resultados de simulación muestran que es posible conseguir anchos de banda similares (350 nm) a los ya conseguidos anteriormente con guías SWG, pero operando con un periodo mayor significativamente mayor (60 %). Por tanto, las guías Bricked-SWG permiten diseñar dispositivos de altas prestaciones y más fáciles de fabrica