Skip to Main content Skip to Navigation
Theses

Mise en phase de lasers à fibre : Étude de l'influence de la turbulence atmosphérique et de l'utilisation de fibres faiblement multimodes

Abstract : There is an increasing need for powerful laser sources in order to enhance system range and sensitivity, either for civilian or military applications. Fiber technologies have already demonstrated high power lasers with very good spatial and spectral qualities. However, extracting energy from a high brightness fiber laser is limited. Beam combining is a promising way to overcome these limits and deliver increased power and brightness from fiber lasers. This thesis deals with evaluating the potential of fiber laser coherent combining with active phase control, both theoretically and experimentally. Beyond sole brightness scaling, this control offers other functionalities such as micro beam steering or wave front shaping. A theoretical analysis was performed taking into account the technological constraints. For that purpose, various criteria were implemented to assess the combining efficiency. After experimentally combining three fiber amplifiers, we used our system to compensate for atmospheric turbulence interfering with the laser beam on its path to the target. We also demonstrated the feasibility of coherent combining on a remote scattering surface using the backscattered optical signal. Then, we studied how the use of LMA few-mode fibers could impair coherent combining efficiency. In order to examine the potential of these fibers and identify the necessary trade-offs, we developed a model to assess the influence of multiple parameters on combining efficiency, including the impact of “few-mode parameter”. This study is completed by experimental investigation.
Document type :
Theses
Complete list of metadatas

Cited literature [115 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/pastel-00005847
Contributor : Ecole Télécom Paristech <>
Submitted on : Wednesday, March 3, 2010 - 8:00:00 AM
Last modification on : Friday, July 31, 2020 - 10:44:07 AM
Long-term archiving on: : Thursday, March 30, 2017 - 5:11:30 AM

Identifiers

  • HAL Id : pastel-00005847, version 1

Collections

Citation

Baya Bennaï. Mise en phase de lasers à fibre : Étude de l'influence de la turbulence atmosphérique et de l'utilisation de fibres faiblement multimodes. Physique [physics]. Télécom ParisTech, 2010. Français. ⟨pastel-00005847⟩

Share

Metrics

Record views

425

Files downloads

900