Abstract

Er³⁺-Tm³⁺ co-doped SiO₂-Al₂O₃-GeO₂ core optical fibers were fabricated by the MCVD technique with aerosol delivery to study laser performance of either erbium or thulium or both ions simultaneously when pumped at 980 nm. Observed luminescence spectra can be explained by the existence of a resonant non-radiative energy transfer between Er³⁺ and Tm³⁺ ions, namely from excited Er³⁺ manifolds ⁴I_13/2 and ⁴I_9/2 to the Tm³⁺ energy levels ³F₄ (luminescence with a central wavelength of 1.4 µm) and ³H₄ (1.85 µm) respectively. With the pump source wavelength between 945 and 995 nm lasing from Er³⁺ ions (around 1.55 µm), Tm³⁺ ions (around 1.85-1.96 µm) or from both ions simultaneously was possible depending on parameters of mirrors in the laser cavity, fiber length, pump rate and pump wavelength.

© 1999 Optical Society of America