Sources laser fibrées hybrides de haute puissance : Amplification et conversion de fréquences

High power hybrid fiber laser sources : Amplification and frequency conversion

• Auteur / Autrice : Aurélien Benoit
• Direction : Philippe Roy, Fetah Benabid
• Type : Thèse de doctorat
• Discipline(s) : Electronique des Hautes Fréquences, Photonique et Systèmes
• Date : Soutenance le 23/04/2015
• Etablissement(s) : Limoges
• Ecole(s) doctorale(s) : École doctorale Sciences et ingénierie pour l'information, mathématiques (Limoges ; 2009-2018)
• Partenaire(s) de recherche : Laboratoire : XLIM
• Jury : Président / Présidente : Alain Barthélémy
• Jury : Examinateurs / Examinatrices : Philippe Roy, Fetah Benabid, Thibaut Sylvestre, François Salin
• Jury : Rapporteur / Rapporteuse : Marc Hanna, Géraud Bouwmans

Mots clés

Mots clés contrôlés

Lasers -- Applications industrielles

Applications scientifiques

Lasers

Mots clés libres

Laser à fibre

Fibres LMA

Gaine microstructurée apériodique

Fibres Kagome à cœur creux

Peigne Raman à large bande spectrale

Fiber lasers

LMA fibers

Apériodic clad

Kagome hollow–core fibers

Large spectral range Raman comb

Résumé

Les lasers à fibre de haute puissance constituent depuis une dizaine d’année un outil pertinent pour un nombre croissant d’applications. Dans le cadre d’un contrat CIFRE entre la société Eolite Systems et le laboratoire Xlim (UMR 7252 du CNRS et de l’Université de Limoges), mon projet de thèse a consisté à développer les briques technologiques de futures sources lasers

High-power fiber lasers adress an increasing number of applications since ten years. In the frame of a CIFRE contract between the company Eolite Systems and Xlim (joint laboratory between CNRS and the University of Limoges), the goal of this PhD project was to develop the technological blocs to achieve all-fibre high-power lasers emiting out of the conventional spectral band covered by existing lasers.Modal instabilities in large mode area (LMA) fibers are currently the main limitation of the fiber lasers power scaling. We have experimentally demonstrated the relevance of inner cladding aperiodic structures to efficiently delocalize higher order modes outside the gain region. A systematic study of passive fibers based on such structures has shown the single propagation of the fundamental mode over a wide wavelength range from 1 to 2 µm for dimension of core up to 85 µm. This effective mode delocalization even extends up to a core dimension of 140 µm at a 2 µm wavelength.The combination of high power picosecond fiber laser with an average power of 22.7 W and a hydrogen-filled inhibited coupling Kagome fiber allowed us to generate two Raman combs over five frequency octaves from 321 nm to 12.5 µm. These two combs are controlled by the laser pump polarization and generated an average power of 10.1 W displayed over 70 laser lines for circular pump polarization and 8.6 W over 30 lines for linear polarization. Some laser lines within these combs have been generated for the first time from high-power fiber source in the mid-infrared range. We have also demonstrated the generation of high-power line by optimizing the first vibrational Stokes at 1.8 µm with an average power of 9.3 W and a quantum efficiency of the frequency conversion stage close to 80%.