This thesis presents a novel technique named "Core Suction" for fabricating optical fiber preforms for manufacturing highly doped fibers (HDFs) for optical amplification (Raman effect based or Erbium fiber based). The technique involves drawing the molten non-conventional core glass material into the silica cladding tube to form the preform. The developed technique is simple, inexpensive and shows great potential for fabricating preforms of highly nonlinear non-conventional multi-component glasses as the core material. Preforms were made with various core glasses such as Schott SF6, Lead-Tellurium-Germanate, Lead-Tellurium-Germanate- Neodymium -Erbium and MM2 in silica cladding tubes and then pulled into fibers. The fabricated fibers were measured for refractive index profile, loss spectrum and spontaneous Raman spectra. Elemental analysis of the fiber samples was also performed using an electron microprobe. Erbium doped fiber amplifiers (EDFAs) were setup using 30 cm, 5cm and 1 cm lengths of fabricated erbium doped fibers and their gain spectra measured. The distributed gain spectrum for an EDFA was also measured using an optical frequency domain reflectometery (OFDR) technique. Commercial dispersion compensated fiber (DCF) with very high GeO2 doping was used to setup a Raman amplifier and the gain spectrum measured. One of the needs of Raman amplification in optical fibers is to predict an accurate Raman gain, based on the fiber's refractive index profile. A method of predicting Raman gain in GeO2 doped fibers is presented and the predicted Raman gain values are compared with the measured ones in the same fibers. Raman gain issues like the dependence of the Raman gain on the GeO2 concentration, polarization dependence were taken into account for the gain calculations. An experimental setup for Raman gain measurements was made and measurement issues addressed. Polarization dependence of the Raman gain in one kilometer of polarization maintaining fiber was also measured. / Ph. D.

Cette thèse est dédiée à l’étude de la génération de supercontinuum (SCG) deforte puissance moyenne dans le domaine spectral entre 2 mm et 5,5 mm. Un laser à fibredopée thulium (Tm3+) opérant dans un régime simultanément déclenché et à verrouillage demodes (QML) a été développé. En régime continu ce laser a délivré 70 W et en régime QML,26Wmoyens ont été obtenus pour des taux de répétition en QS de 180 kHz ou plus. L’énergiela plus élevée contenue dans une enveloppe QS a été évaluée à 166 mJ avec 66 mJ contenuedans la sous-impulsion à verrouillage de mode la plus énergétique. L’émission du laser àfibre correspondait toujours à un facteur de qualité M2 excellent, entre 1,1 et 1,2. La SCGcouvrant la plage spectrale de 2 mm à 5,5 mm a été réalisée en implémentant différentes fibresen cascade. Des supercontinua jusqu’à environ 4 mm ont été générés dans des fibres en fluorurepuis pour la plage spectrale complémentaire entre 4 mm et 5,5 mm, des fibres en chalcogénureont été utilisées.La puissance moyenne maximale de 7,8 W a été démontrée pour un supercontinuum dans unefibre en ZBLAN. Le spectre s’étend jusqu’à 4,2 mm. Au total, 69%/43%/30%/16,5% de lapuissance totale ont été mesurés au-delà de 2,15 mm/2,65 mm/3,1 mm/3,5 mm respectivement.La fibre en InF3 a permis d’atteindre une puissance moyenne de 0,8 W et le supercontinuums’étend jusqu’à 2,95 mm.Pour les essais d’élargissement spectral complémentaire, trois fibres en chalcogénure ont étéutilisées. L’élargissement spectral a été démontré pour toutes les fibres en chalcogénure.Jusqu’à 20 mW de puissance ont été obtenus avec une fibre As2Se3. Le spectre a été étendujusqu’à 4,9 mm. / This thesis reports about the investigation of high power supercontinuum (SC)generation between 2 mm and 5.5 mm. A Q-switched mode-locked (QML) thulium (Tm3+)-doped fiber laser has been developped to pump different nonlinear fibers. The fiber laserprovided in continuous wave regime an output power of 70 W. In QML operation, 26 W havebeen obtained with Q-switched repetition rates of 180 kHz or higher. The highest energy of theQS envelopes has been 166 mJ with 66 mJ contained in the most-energetic ML pulses, whichhave been surrounded by Gaussian-like pedestals with temporal widths around 2.5 ns. On topof these pedestals, very short temporal peaks with pulse durations around 15 ps appeared. Thehighest achieved peak power of a pedestal has been 25 kW. The beam parameter product M2of the fiber laser has been measured in different operational regimes and resulted always in anexcellent value around 1.2.The highest SC output power level from a ZBLAN fiber has been 7.8 W. In total, 69%/43%/30%/16.5% of the transmitted SC output radiation could be converted beyond the wavelengthof 2.15 mm/2.65 mm/3.1 mm/3.5 mm, respectively, with the broadest output spectrum from theZBLAN fiber exceeding 4.2 mm. The InF3 fiber provided a total output power of 0.8 W withan output spectrum up to 2.95 mm.Successful broadening of the wavelength-limited SC output from the ZBLAN fibers has beenachieved with all three investigated chalcogenide fibers with as much as 20 mW of outputpower by using an arsenic selenide fiber. The output spectrum exceeded 4.9 mm.