Over-five octaves wide Raman combs in high-power picosecond-laser pumped H(2)-filled inhibited coupling Kagome fiber.

We report on the generation of over 5 octaves wide Raman combs using inhibited coupling Kagome guiding hollow-core photonic crystal fiber filled with hydrogen and pumped with 22.7 W average power and 27 picosecond pulsed fiber laser. Combs spanning from ~321 nm in the UV to ~12.

Highly efficient higher-order modes filtering into aperiodic very large mode area fibers for single-mode propagation.

We report here on the first experimental demonstration, to the best of our knowledge, of a new generation of very large mode area (VLMA) fibers intended to strengthen single-mode propagation. The originality of this work relies on an aperiodicity of the inner cladding microstructuration exacerbating the spatial rejection of higher-order-modes (HOMs) while preserving a significant confinement of the fundamental mode. The single-mode behavior was demonstrated using an optical low-coherence interferometry measurement based on the group-velocity dispersion.

Inner cladding microstructuration based on symmetry reduction for improvement of singlemode robustness in VLMA fiber.

Very large mode area, active optical fibers with a low high order mode content in the actively doped core region were designed by removing the inner cladding symmetry. The relevance of the numerical approach is demonstrated here by the investigation of a standard air-silica Large Pitch Fiber, used as a reference. A detailed study of all-solid structures is also performed.

Picosecond to femtosecond pulses from high power self mode-locked ytterbium rod-type fiber laser.

We have designed an ytterbium rod-type fiber laser oscillator with tunable pulse duration. This system that delivers more than 10 W of average power is self mode-locked. It yields femtosecond to picosecond laser pulses at a repetition rate of 74 MHz.

Hybrid master oscillator power amplifier high-power narrow-linewidth nanosecond laser source at 257 nm.

We report on a high-power narrow-linewidth pulsed laser source emitting at a wavelength of 257 nm. The system is based on a master oscillator power amplifier architecture, with Yb-doped fiber preamplifiers, a Yb:YAG single crystal fiber power amplifier used to overcome the Brillouin limitation in glass fiber and nonlinear frequency conversion stages. This particularly versatile architecture allows the generation of Fourier transform-limited 15 ns pulses at 1030 nm with 22 W of average power and a diffraction-limited beam (M(2)<1.

SCPEM-Q-switching of a fiber-rod-laser.

We demonstrate high-frequency Q-switching of a fiber rod laser with a Single-Crystal Photo-Elastic Modulator (SCPEM) made of a LiTaO₃₋ crystal. This type of photo-elastic modulator can be driven simultaneously with two different eigenmodes to achieve a shorter rise time, which is essential for high-power operation. When operated in the laser cavity, a pulse repetition frequency of 183.

Q-switching and efficient harmonic generation from a single-mode LMA photonic bandgap rod fiber laser.

We demonstrate a Single-Mode (SM) Large-Mode-Area (LMA) ytterbium-doped PCF rod fiber laser with stable and close to diffraction limited beam quality with 110W output power. Distributed-Mode-Filtering (DMF) elements integrated in the cladding of the rod fiber provide a robust spatial mode with a Mode-Field-Diameter (MFD) of 59μm. We further demonstrate high pulse energy Second-Harmonic-Generation (SHG) and Third Harmonic Generation (THG) using a simple Q-switched single-stage rod fiber laser cavity architecture reaching pulse energies up to 1mJ at 515nm and 0.

High power ytterbium-doped rod-type three-level photonic crystal fiber laser.

In this paper, we investigate power scalability of ytterbium-doped ultra large core photonic crystal fiber laser operating on the zero-line transition. We first report on an 80 microm core diameter ytterbium-doped rod-type photonic crystal fiber laser emitting up to 94 W in continuous wave regime when operating at 977 nm, which is to our knowledge the highest output power ever achieved from a single-mode solid-state laser operating at this wavelength. Key parameters of ytterbium-doped three-level laser, such as transparency pump intensity, pump absorption saturation, and gain competition between three and four-level laser operation are then discussed in the particular context of high power fiber laser operating at 977 nm.

Compensation of pulse-distortion in saturated laser amplifiers.

We derive an expression describing pre-compensation of pulse-distortion due to saturation effects in short pulse laser-amplifiers. The analytical solution determines the optimum input pulse-shape required to obtain any arbitrary target pulse-shape at the output of the saturated laser-amplifier. The relation is experimentally verified using an all-fiber amplifier chain that is seeded by a directly modulated laser-diode.

Novel diode-pumped infrared tunable laser system for multi-photon microscopy.

We report on a novel laser source, emitting high energy (20 nanoJoule) femtosecond pulses, in a broad spectrum (250 nm). This source is easily tuned from 950 to 1200 nm, without any laser adjustment, and delivers sub-300 femtosecond pulses with a 10-nm spectral width.