Abstract

Fibre lasers for the 2 pm spectral range can find a number of important applications in medicine, spectroscopy, eye-safe lidar etc. Ho³⁺ -ions have the ⁵I₇→⁵I₈ transition which can be used to achieve lasing near 2 µm. Ho³⁺ -laser operates according to a three-level scheme; therefore, an effective pump absorption is required to get inversion of the active medium. The most intense absorption bands of Ho³⁺ -ions are located in the visible range. To apply commercially available semiconductor pump sources, additional co-doping by Tm³⁺ ions was suggested. Using this composition and the double-clad fibre geometry a maximum output power of 71 mW was achieved with a slope efficiency of 17.5% when a fiber laser was pumped at 800 nm with a power of up to 1.2 W [1].

© 2000 IEEE