Nonlinearités optiques du second ordre dans le silicium

par Mathias Berciano

Projet de thèse en Electronique et Optoélectronique, Nano- et Microtechnologies

Sous la direction de Laurent Vivien.

Thèses en préparation à Paris Saclay , dans le cadre de Electrical,Optical,Bio: PHYSICS_AND_ENGINEERING , en partenariat avec Centre de Nanosciences et de Nanotechnologies (laboratoire) , Photonique (equipe de recherche) et de Université Paris-Sud (établissement de préparation de la thèse) depuis le 01-10-2015 .


  • Résumé

    La thèse a pour objectif l'étude des non-linéarités optiques du second ordre(notamment l'effet Pockels et la génération de seconde harmonique) apparaissant dans le silicium contraint. Pour ce faire, différents matériaux seront déposés sur des guides silicium afin d'exercer une contrainte mécanique sur ces derniers. Cela permettra de briser la centrosymétrie du silicium et d'exalter des phénomènes optiques non-linéaires du second ordre qui ne sont pas présents par défaut dans ce matériau.

  • Titre traduit

    Second order optical nonlinearity in silicon for photonic applications


  • Résumé

    The performance evolution of telecommunication networks, computing systems and integrated circuits requires increasing communication bandwidth at all interconnect levels. Also, the power efficiency, i.e. the energy required to transfer data, must be considerably improved. The use of silicon photonics has been well identified as a means to overcome electrical interconnect bandwidth and power efficiency limitations. This research domain has exhibited a remarkable rate of development, with current advances which were inconceivable five years ago. This evolution is largely based on the vision that silicon as a mature integration platform can bring photonic integrated circuits closest to its electronics. Despite the demonstration of high performance silicon modulators, germanium photodetectors, and III-V lasers on silicon, their integration in a common chip is highly challenging due to the different materials and technologies involved, and is far from being cost-effective. In addition, wideband silicon modulators require bias swings of several volts to achieve good modulation behavior, which results in high power consumption and considerably degrades the global energy impact of the circuit. Furthermore, as silicon is a centrosymmetric material, it does not exhibit second order optical nonlinearities, i.e. there is no Pockels effects and no possible wavelength conversions using such processes. The objective of the PhD is to address a new route in the reduction of the energy impact of optical modulators using strained engineering in silicon. Indeed, the strain breaks the centrosymmetry of silicon, then leading to exhibit second order nonlinearities (Pockels effect and possible second harmonic generation). Recent proofs of concept have been demonstrated based on the use of silicon nitride stress layers on top of silicon. The aim will be to deposit other stress layers in order to achieve huge strain in silicon and then huge second order nonlinearities. The candidate will be fully involved in the optical and electrical simulations, in the fabrication in the host institute cleanroom and in the characterization using integrated optical benches and Raman spectrometers. The PhD student will be welcomed to the silicon photonics group at the Institute of Fundamental Electronics –CNRS/University of Paris Sud. The PhD grant will be funded by the European Research Council project (ERC). Supervisors: Laurent Vivien (Laurent.vivien@u-psud.fr) http://silicon-photonics.ief.u-psud.fr/