Personne : Bernier, Martin
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Bernier
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Martin
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Université Laval. Département de physique, de génie physique et d'optique
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Publication Accès libre Inscription de réseaux de Bragg à fibre optique à l'aide d'impulsions brèves et applications aux lasers à fibre(2010) Bernier, Martin; Sheng, Yunlong; Vallée, RéalLes réseaux de Bragg à fibre optique photoinscrits (FBGs) constituent des composants clés dans la plupart des systèmes optiques contemporains utilisant de la fibre optique comme milieu actif ou passif. La méthode traditionnelle pour fabriquer ce type de composant consiste à utiliser l'interférence de deux faisceaux ultraviolets pour photoinscrire dans le coeur de la fibre optique, photosensible à cette lumière, un patron permanent de modulation de l'indice de réfraction. Ce dernier engendre, de par sa périodicité, une réflexion plus ou moins importante de la lumière qui se propage dans la fibre optique, suivant un spectre généralement très étroit. Or cette technique couramment utilisée n'est principalement valable que pour les fibres optiques à base de silice dopée au germanium qui présentent une importante photosensibilité à l'ultraviolet, soit à une longueur d'onde voisine de 242nm, due à la présence d'un défaut résonnant propre à la liaison germanium-oxygène. Cette technique de fabrication de FBGs est donc dépendante des matériaux constituant la fibre optique. Or depuis quelques années, une nouvelle méthode d'inscription de FBGs a été proposée, laquelle est basée sur l'utilisation d'impulsions femtosecondes à la longueur d'onde de 800nm. Cette méthode, basée sur l'absorption multiphotonique, permet l'inscription de FBGs ayant des propriétés uniques voire distinctes par rapport à ceux inscrits par la méthode traditionnelle, principalement de par son applicabilité à une vaste gamme de matériaux ainsi qu'à une stabilité thermique accrue des FBGs inscrits. Le présent ouvrage fera donc en premier lieu état de l'avancement scientifique relié au domaine de l'inscription de réseaux de Bragg à fibre optique par l'interaction d'impulsions ultrabrèves. Par la suite, une nouvelle approche basée sur la filamentation d'impulsions brèves en régime femtoseconde est proposée et démontrée expérimentalement. Cette approche a permis l'inscription de FBGs d'ordre fondamental dans des fibres optiques à base de verre de silice et de verre fluoré. Les travaux présentés sont essentiellement réunis dans 5 publications scientifiques, soumises ou publiées dans des journaux d'impact, qui font état d'avancements significatifs dans le domaine des réseaux de Bragg à fibre optique photoinscrits par laser femtoseconde ainsi que leurs applications aux lasers à fibre optique.Publication Accès libre Femtosecond laser inscription of depressed cladding single-mode mid-infrared waveguides in sapphire(Optical Society of America, 2018-12-17) Bérubé, Jean-Philippe; Vallée, Réal; Dupont, Albert (***WMS); Bernier, Martin; Lapointe, JérômeMid-infrared optical waveguides were inscribed in sapphire with femtosecond pulses at 515 nm. We show that such pulses induce a smooth negative refractive index change allowing for the inscription of a depressed cladding waveguide by closely overlapping the corresponding type I modification traces. The resulting structure consists of a highly symmetrical, uniform, and homogeneous waveguide. The size and numerical aperture of the waveguides were tailored to achieve efficient transmission in the mid-infrared. Single mode operation at a wavelength of 2850 nm and propagation loss of <0.37 dB/cm are reported for a 33 mm long depressed cladding waveguide. Thermal annealing was performed, and the refractive index contrast was still preserved to 50% (i.e., Δ𝑛=∼2.5×10−3) up to 1400°C.Publication Accès libre Infrared supercontinuum generated in concatenated InF3 and As2Se3 fibers(Optical Society of America, 2018-05-28) Théberge, Francis; Bérubé, Nancy; Robichaud, Louis-Rafaël; Poulain, Samuel; Vallée, Réal; Cozic, Solenn; Bernier, Martin; Chatigny, Stéphane; Pleau, Louis-PhilippeWe report on infrared supercontinuum (SC) generation through subsequent nonlinear propagation in concatenated step-index fluoride and As2Se3 fiber. These fibers were pumped by an all-fiber laser source based on an erbium amplifier followed by a thulium power amplifier. ZBLAN and InF3 fibers were compared for the concatenated scheme. The broadest SC produced was achieved by optimizing the length of the InF3 fiber. This arrangement allowed the generation of 200 mW infrared SC with high spectral flatness and spanning from 1.4 μm to 6.4 μm.Publication Accès libre Dysprosium-doped silica fiber as saturable absorber for mid-infrared pulsed all-fiber lasers(DC Optical Society of America, 2022-01-18) Paradis, Pascal; Fortin, Vincent; Vallée, Réal; Trzesien, Stanislaw; Bernier, Martin; Ude, Michèle; Boilard, Tommy; Dussardier, BernardWe report on a mid-infrared Q-switched erbium-doped all-fiber laser using a dysprosium-doped silica fiber as saturable absorber for the first time in this wavelength range. Moreover, we demonstrate the use of a highly reflective chirped fiber Bragg grating written in a silica fiber as the input coupler for such lasers. This Q-switched all-fiber laser generates a stable pulse train centered at 2798 nm with a maximum average power of 670 mW at a repetition rate of 140 kHz with a pulse duration of 240 ns and a pulse energy of 4.9 µJ.Publication Accès libre Mid-infrared supercontinuum generation in fluoride fiber amplifiers : current status and future perspectives(Springer Nature, 2018-05-30) Gauthier, Jean-Christophe; Fortin, Vincent; Robichaud, Louis-Rafaël; Vallée, Réal; Bernier, MartinThe quest for a compact and efficient broadband laser source able to probe the numerous fundamental molecular absorption lines in the mid-infrared (3–8 µm) for various applications has been going on for more than a decade. While robust commercial fiber-based supercontinuum (SC) systems have started to appear on the market, they still exhibit poor energy conversion into the mid-infrared (typically under 30%) and are generally not producing wavelengths exceeding 4.7 µm. Here, we present an overview of the results obtained from a novel approach to SC generation based on spectral broadening inside of an erbium-doped fluoride fiber amplifier seeded directly at 2.8 µm, allowing mid-infrared conversion efficiencies reaching up to 95% and spectral coverage approaching the transparency limit of ZrF4 (4.2 µm) and InF3 (5.5 µm) fibers. The general concept of the approach and the physical mechanisms involved are presented alongside the various configurations of the system to adjust the output characteristics in terms of spectral coverage and output power for different applications.Publication Accès libre 10-W-level monolithic dysprosium-doped fiber laser at 3.24 μm(Optical Society, 2019-01-16) Jobin, Frédéric; Fortin, Vincent; Larose, Maxence; Vallée, Réal; Bernier, MartinWe report, to the best of our knowledge, the first entirely monolithic dysprosium (Dy)-doped fluoride fiber laser operating in the mid-IR region. The system delivers 10.1 W at 3.24 μm in continuous operation, a record for fiber oscillators in this range of wavelengths. The Dy3+ fiber is pumped in-band using an erbium-doped fiber laser at 2.83 μm made in-house and connected through a fusion splice. Two fiber Bragg gratings directly written in the Dy-doped fiber form the 3.24 μm laser cavity to provide a spectrally controlled laser output. This substantial increase of output power in the 3.0 3.3 μm spectral range–could open new possibilities for applications in spec-troscopy and advanced manufacturing.Publication Accès libre Fuseless side-pump combiner for efficient fluoride-based double-clad fiber pumping(Optical Society, 2020-10-13) Matte-Breton, Charles; Duval, Simon; Magnan-Saucier, Sébastien; Aydin, Yiğit Ozan; Fortin, Vincent; LaRochelle, Sophie; Vallée, Réal; Bernier, MartinWe report a novel technique for side-pumping fluoridebased double clad fibers allowing a record coupling efficiency of 93 % and a maximum power handling near 100 W at 981 nm. Our simple technique is based on wrapping a silica taper around a fluoride fiber and therefore does not require any complex fusion between these two dissimilar fibers. Under passive cooling, pump combiners made of undoped and erbium-doped fluoride fibers were successfully operated during several hours at respective incident powers of 91 W and 44 W. Heat management issues and active cooling strategies are also discussed. This innovative combiner is a keystone towards the development of compact and robust highpower mid infrared fiber lasers and amplifiers.Publication Accès libre 10 W-level gain-switched all-fiber laser at 2.8 μm(Optical Society of America, 2018-06-29) Paradis, Pascal; Aydin, Yiğit Ozan; Fortin, Vincent; Vallée, Réal; Bernier, MartinWe report a simply designed gain-switched all-fiber laser emitting a maximum average output power of 11.2 W at 2.826 μm. The corresponding extracted pulse energy is 80 μJ at a pulse duration of 170 ns. These performances significantly surpass previous gain-switched demonstrations and are close to the state-of-the-art Q-switched laser performances near 2.8 μm, but with a much simpler and robust all-fiber design. The spliceless laser cavity is made of a heavily erbium-doped fluoride glass fiber and is bounded by fiber Bragg gratings written directly in the gain fiber through the protective polymer coating.Publication Accès libre Flexible trans-jacket inscription of fiber Bragg gratings for directional distributed sensing(2019-08-29) Morency, Steeve; Fortier, Richard; Messaddeq, Younès; Bernier, Martin; Trépanier, François; Boilard, TommyAn array of 18 FBGs spectrally distributed over 70 nm was written in a polyimide-coated fiber, with a single uniform phase-mask, by applying strain on the fiber prior to exposition. This flexible method will be used to develop directional sensor for distributed sensing based on a hybrid glasspolymer multicore fiber.Publication Accès libre Curvature sensing using a hybrid polycarbonate-silica multicore fiber(Optical Society of America, 2020-12-21) Morency, Steeve; Bilodeau, Guillaume; Fortier, Richard; Messaddeq, Younès; Bernier, Martin; Boilard, TommyWe report on the development of a novel hybrid glass-polymer multicore fiber integrating three 80 µm polyimide-coated silica fibers inside a 750 µm polycarbonate cladding. By inscribing an array of distributed FBGs along each segment of silica fiber prior to the hybrid fiber drawing, we demonstrate a curvature sensor with an unprecedented precision of 296 pm/m−1 around 1550 nm, about 7 times more sensitive than sensors based on standard 125 µm multicore fibers. As predicted by theory, we show experimentally that the measured curvature is insensitive to temperature and strain. Also, a more precise equation to describe the curvature on a simple bending setup is presented. This new hybrid multicore fiber technology has the potential to be extended over several kilometers and can find high-end applications in 3D shape sensing and structural health monitoring.