In the present letter the authors report on the realization of an all-fiber bismuth-doped laser with laser emission that can be chosen with corresponding fiber Bragg gratings between at least 1150 and 1225nm. In their experiments they achieved a slope efficiency of about 24% at 1200nm, which is the highest reported for this kind of laser.

In the present work, we report on the luminescence properties of bismuth-doped silicate preforms and fibers under the influence of high temperature annealing and hydrogen-loading then annealing processes. Bismuth-related luminescence is found to be very sensitive to thermal annealing processes and can even totally disappear for specific annealing processes. The observed quenching of the luminescence was attributed to the reduction of part of bismuth ions responsible for the infrared luminescence into a lower valence state of bismuth.

We propose and fabricate a novel ring-core photonic crystal fiber made of a circular ring core surrounded by a cladding constituted of air holes organized in a first circular ring surrounded by hexagonal ones. The fiber efficiently supports four different groups of orbital angular momentum (OAM) modes. The effective indices of spin-orbit aligned and spin-orbit anti-aligned modes in the same OAM modes group are separated by at least $2.13\times {10}^{\mathrm{-3}}$ at 1550 nm. The realized fiber is expected to be a good platform for applications involving OAM modes.

We report on the production of air/silica photonic crystal fiber doped with gold nanoparticles. The stack-and-draw technique was used to combine a gold nanoparticles-doped silica core rod synthesized by the sol-gel route with capillaries drawn from commercially available silica tubes. The presence of nanoparticles in the core region was confirmed at the different steps of the process down to the fiber geometry, even after multiple drawings at ∼2000°C. Optical properties of the fiber were investigated and put in evidence the impact of gold nanoparticles on both linear and nonlinear transmission.

We theoretically and experimentally analyze the benefit of hetero-structured cladding in Solid-Core Photonic BandGap fibers so as to increase the loss ratio between high order modes and fundamental mode. This property is applied to the realization of 19-cells core fibers practically single-mode around 1050 nm. When designed to operate in the 4th BandGap, a new design is proposed which permits to obtain mode field diameter of 44 μm whereas, for operation in the 3rd BandGap, a mode field diameter of 33 μm is obtained with 20 cm bending radius. The impact of the shape of hetero-structure on single-mode behavior is discussed.