A process has been developed for the fabrication of preforms and fibers with Al₂O₃-P₂O₅-SiO₂ glass cores, and their optical properties have been investigated. The results demonstrate that the refractive index and optical losses of the glasses studied are nonadditive functions of Al₂O₃ and P₂O₅ contents in the range 0–20 mol %.

International audienceA silica Bragg fibre with optical losses lower than 10 dB km-1 is fabricated for the first time. The Bragg fibre manufactured by the MCVD method is intended for operation at a wavelength of 1.06 μm and has the mode-spot diameter 18.5 μm (the mode-spot area is 270 μm2). The fibre is considerably less sensitive to bending than step-index fibres and microstructure fibres with the same mode-spot size. The possibility of fabricating a Bragg fibre with the record mode-spot area (530 μm2 at the operating wavelength of 855 nm) for all-silica fibres is demonstrated

We demonstrated an all-fiber chirped-pulse amplifier with a stretcher stage based on a triple-cladding fiber and a final amplification stage based on a newly-developed highly Yb-doped large-mode area fiber with a Ge-doped pedestal. The stretcher fiber was designed to match a diffraction grating compressor in the third-order dispersion and allowed the stretching of 6 ps 1026 nm chirped pulses up to ~500 ps. These pulses were amplified in the developed Yb-doped fiber and then compressed using a transmission grating compressor down to 670 fs duration with 3.5 W average power and $61.8~\mu \text{J}$ pulse energy, corresponding to a record-high peak power of 92 MW.