Abstract

The reduced non-radiative transition rates evident in rare-earth doped fluorozirconate fibres increase the probabilities of radiative events from high-lying energy states. These states may be populated by multistep excited-state absorption of pump photons, a process which readily occurs because of increased lifetimes (relative to silicate and phosphate glasses) of intermediate levels, and spectrally-broad and sometimes overlapping ESA features. Lasing transitions from the blue region to nearly 3 microns are accessed in the preferred low-loss fibre geometry. Novel pumping schemes can be adopted using diode-laser, solid-state or fibre-laser compatible wavelengths to make visible up-conversion lasers or efficient fibre amplifiers for the largely under-used spectral region between 750nm and 1200nm.

© 1993 Optical Society of America