0000000000771690
AUTHOR
Sébastien Février
Taper à fibre optique microstructurée air/slice à dispersion modifiée pour une émission large bande et accordée autour de 2 µM par mélange à quatre ondes dégénérées
International audience; Ce travail rapporte la conception, la fabrication et la caractérisation d'une fibre optique mircrostructurée air/silice effilée permettant une conversion de fréquence large bande par le processus de mélange à quatre ondes vers le moyen infra-rouge. Nous démontrons expérimentalement une bande de gain paramétrique de près de 100 nm. Une utilisation envisagée de ce taper réside dans le développement de sources laser femtosecondes.
Rapid characterisation of Photonic Crystal Fibre dispersive properties by a stochastic and tunable picosecond pump source
International audience
Highly efficient few-mode spatial beam self-cleaning at 15µm
We experimentally demonstrate that spatial beam self-cleaning can be highly efficient when obtained with a few-mode excitation in graded-index multimode optical fibers. By using 160 ps long, highly chirped (6 nm bandwidth at -3dB) optical pulses at 1562 nm, we demonstrate a one-decade reduction of the power threshold for spatial beam self-cleaning, with respect to previous experiments using pulses with laser wavelengths at 1030-1064 nm. Self-cleaned beams remain spatio-temporally stable for more than a decade of their peak power variation. The impact of input pulse temporal duration is also studied.
Spatial Beam Evolution in Nonlinear Multimode Fibers
We discuss some recent results illustrating the role of input wave-front shaping, propagation dynamics and output beam diagnostics in order to observe spatial beam cleaning in nonlinear multimode fibers and amplifiers.
Spatio-Temporal Beam Mapping for Studying Nonlinear Dynamics in Graded Index Multimode Fiber
We experimentally demonstrate high-resolution mapping of the spatio-temporal dynamics of the beam cleaning process in graded index multimode fibers. This high-resolution characterization reveals the time-dependent nature of the beam self-cleaning process.
Passively mode-locked laser based on an ultra-large dispersion Yb-doped fiber
Summary form only given. We report on the first realization of a passively mode-locked oscillator featuring an ultra-large dispersion Yb-doped Bragg fiber. The gain medium is a double-clad Bragg fiber featuring a 20 μm Yb-doped core surrounded by a 120 μm inner cladding [1]. The 2 m long gain fiber is cladding-pumped with a fiber-coupled laser diode emitting at 976 nm. Passive mode locking is achieved by the combined actions of nonlinear polarization evolution and a SESAM. Mode-locking is initiated by optimizing the saturation criteria on the saturable absorber mirror using an adequate focusing lens. The emission wavelength of the oscillator is controlled using a passive spectral filter int…
Kerr beam self-cleaning in the telecom band
Multimode graded index (GRIN) fibers received a renewed interest in recent years, in particular for the development of new laser sources [1]. In many cases, the use of GRIN fibers is limited by multimodal propagation, leading to a spatially modulated intensity distribution (speckles) at the fiber output. Recent studies have found that quasi-single mode propagation can be recovered in GRIN fibers by the so-called Kerr self-cleaning effect [2]. It consists in the spontaneous recovery of the spatial beam quality, without any frequency shift [2] (as opposed to, e.g., Raman beam self-cleaning [3]). This nonlinear process was only observed so far at laser wavelengths around 1 μm, for peak power l…
Experimental evidence of the real multimode nature of geometric parametric instability
We show experimentally that geometric parametric instability in graded-index multimode fibers is composed by several multimode spectral components. The experimental observation is obtained by using a new 3D technique of high-resolution spatial and spectral analysis.
Dispersion engineered tapered photonic crystal fiber for broadband and tuned 2 µm emission using degenerate four-wave mixing
International audience; We numerically demonstrate a broadband parametric gain around 2 µm using a tapered Photonic crystal fiber.
Higher-order dispersion parameters management in highly nonlinear photonic crystal fibers for far-detuned frequency conversion
International audience; In this communication we present results dealing with the precise management of dispersion coefficients into two highly nonlinear fiber structures (a tapered PCF and an all-solid fiber) for far-detuned frequency conversion towards 2µm.