Alexandre Fafin
Centre national de la recherche scientifique
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Alexandre Fafin.
Optics Express | 2014
Alexandre Fafin; Julien Cardin; Christian Dufour; Fabrice Gourbilleau
We present a comparative study of the gain achievement in a waveguide whose active layer is constituted by a silica matrix containing silicon nanograins acting as sensitizer of either neodymium ions (Nd3+) or erbium ions (Er3+). By means of an auxiliary differential equation and finite difference time domain (ADE-FDTD) approach that we developed, we investigate the steady states regime of both rare earths ions and silicon nanograins levels populations as well as the electromagnetic field for different pumping powers ranging from 1 to 104 mW/mm2. Moreover, the achievable gain has been estimated in this pumping range. The Nd3+ doped waveguide shows a higher gross gain per unit length at 1064 nm (up to 30 dB/cm) than the one with Er3+ doped active layer at 1532 nm (up to 2 dB/cm). Taking into account the experimental background losses we demonstrate that a significant positive net gain can only be achieved with the Nd3+ doped waveguide.
Optics Express | 2013
Alexandre Fafin; Julien Cardin; Christian Dufour; Fabrice Gourbilleau
A new algorithm based on auxiliary differential equation and finite difference time domain method (ADE-FDTD method) is presented to model a waveguide whose active layer is constituted of a silica matrix doped with rare-earth and silicon nanograins. The typical lifetime of rare-earth can be as large as some ms, whereas the electromagnetic field in a visible range and near-infrared is characterized by a period of the order of fs. Due to the large difference between these two characteristic times, the conventional ADE-FDTD method is not suited to treat such systems. A new algorithm is presented so that the steady state of rare earth and silicon nanograins electronic levels populations along with the electromagnetic field can be fully described. This algorithm is stable and applicable to a wide range of optical gain materials in which large differences of characteristic lifetimes are present.
Nanoscale Research Letters | 2011
Christian Dufour; Julien Cardin; Olivier Debieu; Alexandre Fafin; Fabrice Gourbilleau
By means of ADE-FDTD method, this paper investigates the electromagnetic modelling of a rib-loaded waveguide composed of a Nd3+ doped Silicon Rich Silicon Oxide active layer sandwiched between a SiO2 bottom cladding and a SiO2 rib. The Auxilliary Differential Equations are the rate equations which govern the levels populations. The Finite Difference Time Domain (FDTD) scheme is used to solve the space and time dependent Maxwell equations which describe the electromagnetic field in a copropagating scheme of both pumping (λ pump = 488 nm) and signal (λ signal = 1064 nm) waves. Such systems are characterized by extremely different specific times such as the period of electromagnetic field ~ 10-15 s and the lifetimes of the electronic levels between ~ 10-10s and ~ 10-4 s. The time scaling method is used in addition to specific initial conditions in order to decrease the computational time. We show maps of the Poynting vector along the propagation direction as a function of the silicon nanograin (Si-ng) concentrations. A threshold value of 1024 Si-ng m-3 is extracted below which the pump wave can propagate so that a signal amplication is possible.
Proceedings of SPIE | 2015
Julien Cardin; Alexandre Fafin; Christian Dufour; Fabrice Gourbilleau
A comparative study of the gain achievement is performed in a waveguide optical amplifier whose active layer is constituted by a silica matrix containing silicon nanograins acting as sensitizer of either neodymium ions (Nd3+) or erbium ions (Er3+). Due to the large difference between population levels characteristic times (ms) and finite-difference time step (10−17s), the conventional auxiliary differential equation and finite-difference time-domain (ADE-FDTD) method is not appropriate to treat such systems. Consequently, a new two loops algorithm based on ADE-FDTD method is presented in order to model this waveguide optical amplifier. We investigate the steady states regime of both rare earth ions and silicon nanograins levels populations as well as the electromagnetic field for different pumping powers ranging from 1 to 104 mW/mm2 . Furthermore, the three dimensional distribution of achievable gain per unit length has been estimated in this pumping range. The Nd3+ doped waveguide shows a higher gross gain per unit length at 1064 nm (up to 30 dB/cm-1) than the one with Er3+ doped active layer at 1532 nm (up to 2 dB/cm-1). Considering the experimental background losses found on those waveguides we demonstrate that a significant positive net gain can only be achieved with the Nd3+ doped waveguide. The developed algorithm is stable and applicable to optical gain materials with emitters having a wide range of characteristic lifetimes.
Physical review applied | 2018
Mathias Kobylko; Pierre-Eugène Coulon; Abdallah Slablab; Alexandre Fafin; Julien Cardin; Christian Dufour; Arthur Losquin; Mathieu Kociak; I. Monnet; D. Mailly; Xavier Lafosse; C. Ulysse; Enric Garcia-Caurel; Giancarlo Rizza
EMRS Spring meeting 2015 | 2015
Alexandre Fafin; Julien Cardin; Christian Dufour; Fabrice Gourbilleau
225th ECS Meeting (May 11-15, 2014) | 2014
Fabrice Gourbilleau; Alexandre Fafin; Patrick Benzo; Lucile Dumont; Julien Cardin; Christophe Labbé; Christian Dufour
7th International Conference on Materials for Advanced Technologies (ICMAT 2013), Jun 2013, Suntec, Singapore | 2013
Julien Cardin; Christian Dufour; Vladimir Khomenkov; Alexandre Fafin; I. Monnet; Giancarlo Rizza; Pierre-Eugène Coulon; Abdallah Slablab; D. Mailly; C. Ulysse; Xavier Lafosse; Sandrine Perruchas; Thierry Gacoin
7th International Conference on Materials for Advanced Technologies (ICMAT 2013) | 2013
Julien Cardin; Alexandre Fafin; Chuan-hui Liang; Christian Dufour; Olivier Debieu; Christophe Labbé; Parastesh Pirasteh; Joël Charrier; Yannick Dumeige; Yann Boucher; Fabrice Gourbilleau
223rd ECS Meeting (May 12-17, 2013) | 2013
Fabrice Gourbilleau; Chuan-hui Liang; Yong-Tao An; Alexandre Fafin; Julien Cardin; Larysa Khomenkova; Christophe Labbé; M. Morales; Christian Dufour