Abstract

Laser oscillators based on Er³⁺-doped glasses and fibers have recently become the subject of great interest, in particular for their potential use in optical communication systems operating in the 1530-1560 nm region [1-2]. In the last few years, miniaturized, practical and efficient ErbiumYtterbium glass lasers, end-pumped at 980 nm by InGaAs semiconductor lasers, have been developed by our group [3-4]. These devices are based on a suitably codoped Erbium and Ytterbium phosphate glass, where the concentrations of both dopant ions have been optimized to enhance the absorption of the pump light in very short absorption lengths (200 μm to 2.5 mm) and to achieve low threshold pump powers and high slope efficiencies. The basic resonator structure is very short (a few mm) and compact. CW single-frequency operation may be achieved either by inserting an intracavity Fabry Perot etalon as the mode selecting element [4], or using a monolithic microchip cavity with a mode separation larger than the gain bandwidth of the laser medium [5].

© 1996 IEEE