Abstract

We report the operation of a Tm³⁺/Yb³⁺ co-doped tellurite fibre laser operating in the range 1.91-1.99 μm when pumped with a 1088 nm Yb³⁺ doped silica fibre laser. This is, to the authors' knowledge, the first report of a ~2 μm laser in a tellurite based fibre. Lasers at these wavelengths have been demonstrated in Tm³⁺ doped silica [1] and fluoride [2] fibres but tellurite glass offers certain advantages over both of these glass types. Tellurite glass has a low phonon energy for an oxide glass of around 780 cm⁻¹ allowing transmission of longer wavelengths of light than silicate glass which has a phonon energy of 1100 cm⁻¹. Tellurite glass also has a higher rare-earth ion solubility than silicate glass allowing the use of short fibre lengths for compact devices. The lifetime of the Tm³⁺: ³F₄ level is three times larger in tellurite glass (2.2 ms) than in silicate glass (630 us) which, for high-power pulsed lasers where there is a requirement for energy storage, could prove tellurite glass to be a better host than silica. Tellurite glass is a more chemically and environmentally stable glass than fluoride glass, making for improved long-term reliability of devices.

© 2007 IEEE