Robust Design by Antioptimization for Parameter Tolerant GaAs/AlOx High Contrast Grating Mirror for VCSEL Application

A GaAs/AlOx high contrast grating structure design which exhibits a 99.5% high reflectivity for a 425nm large bandwidth is reported. The high contrast grating (HCG) structure has been designed in order to enhance the properties of mid-infrared VCSEL devices by replacing the top Bragg mirror of the cavity. A robust optimization algorithm has been implemented to design the HCG structure not only as an efficient mirror but also as a robust structure against the imperfections of fabrication. The design method presented here can be easily adapted for other HCG applications at different wavelengths.Comment: (c) 2013 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists or reuse of any copyrighted components of this work in other work

Robust design of subwavelength grating mirror for mid-infrared VCSEL application

Oral Presentation - The final publication is available at http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=6041173International audienceWe present the design of a Si/Si3N4 subwavelength grating mirror optimized for an integration in mid-infrared VCSEL. The definition of a quality factor adapted to VCSEL requirements and maximized by an optimization algorithm allowed us to obtain a polarization selective and high reflectivity structure. The robustness with respect to fabrication error has been enhanced thanks to a precise study of the grating dimension tolerances

In silico design of novel probes for the atypical opioid receptor MRGPRX2

The primate-exclusive MRGPRX2 G protein-coupled receptor (GPCR) has been suggested to modulate pain and itch. Despite putative peptide and small molecule MRGPRX2 agonists, selective nanomolar potency probes have not yet been reported. To identify a MRGPRX2 probe, we first screened 5,695 small molecules and found many opioid compounds activated MRGPRX2, including (−)- and (+)-morphine, hydrocodone, sinomenine, dextromethorphan and the prodynorphin-derived peptides, dynorphin A, dynorphin B, and α- and β-neoendorphin. We used these to select for mutagenesis-validated homology models and docked almost 4 million small molecules. From this docking, we predicted ZINC-3573, which represents a potent MRGPRX2-selective agonist, showing little activity against 315 other GPCRs and 97 representative kinases, and an essentially inactive enantiomer. ZINC-3573 activates endogenous MRGPRX2 in a human mast cell line inducing degranulation and calcium release. MRGPRX2 is a unique atypical opioid-like receptor important for modulating mast cell degranulation, which can now be specifically modulated with ZINC-3573

L'habitat intelligent, la smartroom

Chapitre du livre: "Design des lieux et des services pour les personnes handicapées" ISBN : 978-2-84874-166-

Évolution des diodes lasers pour les télécommunications optiques : Lasers accordables, Lasers à émission par la surface, Lasers bas coûts

The work presented below show my work since the beginning of my thesis in 1986. They were made ​​entirely in the research center in Marcoussis Alcatel in order to design, build and test of optoelectronic semiconductor components for applications in optical telecommunications. These components are made of indium phosphide (InP ) and are intended to emit or detect light at wavelengths near 1550 nm or 1300 waves after application. I have enjoyed all the necessary infrastructure for the development and outcome of projects covering both technology ( epitaxy and structure of materials) as the means of characterization experiments to the system through the use of flat platforms available to test Alcatel. The results presented here are therefore the result of a team effort , I will focus on the end of each paragraph to clarify my personal contribution to the results.Les travaux présentés ci-après reprennent mes activités depuis le début de ma thèse en 1986. Ils ont été entièrement réalisés dans le centre de recherche d'Alcatel à Marcoussis dans le but de concevoir, réaliser et tester des composants optoélectroniques à semi-conducteurs pour des applications en télécommunications optiques. Ces composants sont à base de Phosphure d'Indium (InP) et sont destinés à émettre ou détecter de la lumière à des longueurs d'ondes proches de 1300 ou 1550 nm suivant l'application. J'ai pu bénéficier de toute l'infrastructure nécessaire au développement et à l'aboutissement des projets couvrant aussi bien les moyens technologiques (épitaxie et structuration des matériaux) que les moyens de caractérisation jusqu'aux expérimentations système grâce à l'utilisation de plate-formes de test disponibles à Alcatel. Les résultats présentés ici sont par conséquent le fruit d'un travail d'équipe ; je m'attacherai en fin de chaque paragraphe à préciser ma contribution personnelle aux résultats

Modeling of tunnel junctions for current injection in Vertical Cavity Surface Emitting Lasers (VCSELs)

International audienceTunnel junctions have been widely used in the fabrication of Vertical Cavity Surface Emitting Lasers since it allows fabrication of low electrical resistance as well as low optical absorption Bragg mirrors. The basic idea is to inject holes through a highly doped reverse biased n+/p+ tunnel junction. We present in this paper a review of the different materials that can be used for various wavelength applications ranging from UV (GaN) to IR (GaSb). We have elaborated a new modelling tool that has been validated for homo-junctions. The results show that the injection efficiency is directly linked to the energy gap of the material and to the effective mass of the electrons and light holes. The first important discussion is related to the condition on doping levels to get the material degenerate. Low band gap materials such as InAs or GaSb semiconductors are well appropriate to realise tunnel junctions with moderate doping levels. At the opposite large band-gap materials as GaN or AlN require very high doping levels to reach the tunnelling condition. GaSb based VCSELs emitting in the infrared region (2- 3 µm) can use very efficiently such electrical injection scheme. On the other side, it will be much less beneficial to use it for surface emitting laser emitting in the ultra violet wavelength range. Comparison with published papers will be discussed as well as preliminary work done in the case of hetero junctions