Abstract

We report a civ room-temperature upconversion fiber laser oscillation at 521 and 635 nm. The fiber was pumped simultaneously by two single spatial mode laser diodes, one at 833 nm, the other at either 985 or 1016nm. The laser medium, supplied by Le Verre Fluore, is a fluoride glass fiber doped with 2000 ppm Pr³⁺ and 4000 ppm Yb³⁺. The active ion for laser oscillation is Pr³⁺ The high lying states of the Pr³⁺ ion are excited by the sequential absorption of two photons. (See Fig. 1.) The intermediate state in the upconversion process, ¹G₄, may be populated either by ground state absorption or by energy transfer from a nearby excited Yb³⁺ ion.

© 1993 Optical Society of America