Quenching of neodymium fluorescence by molecular hydrogen.

We show that the hydrogen-loading technique used to enhance a fiber's ultraviolet photosensitivity for writing Bragg gratings can lead to quenching of the lasing ion's fluorescence. The neodymium fluorescence and radiative lifetimes are measured for the untreated fiber, the hydrogen-loaded fiber, and the postannealed fiber. We show that postannealing can be used to remove the unreacted hydrogen molecules from the fiber laser and restore the radiative lifetime to near that of its original value.

Spectroscopy of Dy(3+) in Ge-Ga-S glass and its suitability for 1.3-microm fiber-optical amplifier applications.

Absorption and emission spectra, along with lifetime measurements, of Dy(3+) in Ge-Ga-S glasses are reported. Fluorescence is observed at 1.3, 1.8, and 2.9 microm. A Judd-Ofelt analysis is performed to determine branching ratios and quantum efficiencies. The hypersensitive transition (6)F(11/2) ? (6)H(15/2) at 1.3 microm has a quantum efficiency of 17%. Its suitability for an optical amplifier at 1.3 microm depends on the excited-state absorption from the (6)H(11/2) and (6)H(13/2) states, which has not yet been measured.

Neodymium-doped tellurite single-mode fiber laser.

A single-mode Nd(3+)-doped tellurite glass fiber laser operating at 1.061 microm is described. We believe this is the first demonstration of a single-mode fiber laser in tellurite glass. A lasing threshold of 27 mW of 818-nm absorbed pump power and a slope efficiency output power versus pump power of 23% emitted from one end were observed in the fiber cavity with 11.9% Fresnel reflection at both ends.