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 report on the optical spectroscopy of monolithic fiber preform prepared from nanoporous bismuth-doped silica glass. The experiments reveal the existence of at least two different types of active centers and clearly demonstrate that the presence in the glass matrix of other dopant is not necessary to obtain the near-IR photoluminescence connected to Bismuth.